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3126 lines
83 KiB
3126 lines
83 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 2011 STRATO. All rights reserved. |
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*/ |
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|
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#include <linux/mm.h> |
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#include <linux/rbtree.h> |
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#include <trace/events/btrfs.h> |
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#include "ctree.h" |
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#include "disk-io.h" |
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#include "backref.h" |
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#include "ulist.h" |
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#include "transaction.h" |
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#include "delayed-ref.h" |
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#include "locking.h" |
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#include "misc.h" |
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#include "tree-mod-log.h" |
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|
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/* Just an arbitrary number so we can be sure this happened */ |
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#define BACKREF_FOUND_SHARED 6 |
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|
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struct extent_inode_elem { |
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u64 inum; |
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u64 offset; |
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struct extent_inode_elem *next; |
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}; |
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|
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static int check_extent_in_eb(const struct btrfs_key *key, |
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const struct extent_buffer *eb, |
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const struct btrfs_file_extent_item *fi, |
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u64 extent_item_pos, |
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struct extent_inode_elem **eie, |
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bool ignore_offset) |
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{ |
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u64 offset = 0; |
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struct extent_inode_elem *e; |
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|
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if (!ignore_offset && |
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!btrfs_file_extent_compression(eb, fi) && |
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!btrfs_file_extent_encryption(eb, fi) && |
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!btrfs_file_extent_other_encoding(eb, fi)) { |
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u64 data_offset; |
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u64 data_len; |
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|
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data_offset = btrfs_file_extent_offset(eb, fi); |
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data_len = btrfs_file_extent_num_bytes(eb, fi); |
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|
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if (extent_item_pos < data_offset || |
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extent_item_pos >= data_offset + data_len) |
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return 1; |
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offset = extent_item_pos - data_offset; |
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} |
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|
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e = kmalloc(sizeof(*e), GFP_NOFS); |
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if (!e) |
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return -ENOMEM; |
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|
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e->next = *eie; |
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e->inum = key->objectid; |
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e->offset = key->offset + offset; |
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*eie = e; |
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|
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return 0; |
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} |
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|
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static void free_inode_elem_list(struct extent_inode_elem *eie) |
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{ |
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struct extent_inode_elem *eie_next; |
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|
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for (; eie; eie = eie_next) { |
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eie_next = eie->next; |
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kfree(eie); |
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} |
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} |
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|
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static int find_extent_in_eb(const struct extent_buffer *eb, |
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u64 wanted_disk_byte, u64 extent_item_pos, |
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struct extent_inode_elem **eie, |
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bool ignore_offset) |
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{ |
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u64 disk_byte; |
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struct btrfs_key key; |
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struct btrfs_file_extent_item *fi; |
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int slot; |
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int nritems; |
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int extent_type; |
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int ret; |
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|
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/* |
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* from the shared data ref, we only have the leaf but we need |
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* the key. thus, we must look into all items and see that we |
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* find one (some) with a reference to our extent item. |
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*/ |
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nritems = btrfs_header_nritems(eb); |
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for (slot = 0; slot < nritems; ++slot) { |
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btrfs_item_key_to_cpu(eb, &key, slot); |
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if (key.type != BTRFS_EXTENT_DATA_KEY) |
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continue; |
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fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); |
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extent_type = btrfs_file_extent_type(eb, fi); |
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if (extent_type == BTRFS_FILE_EXTENT_INLINE) |
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continue; |
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/* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */ |
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disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); |
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if (disk_byte != wanted_disk_byte) |
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continue; |
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|
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ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie, ignore_offset); |
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if (ret < 0) |
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return ret; |
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} |
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|
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return 0; |
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} |
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struct preftree { |
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struct rb_root_cached root; |
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unsigned int count; |
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}; |
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#define PREFTREE_INIT { .root = RB_ROOT_CACHED, .count = 0 } |
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struct preftrees { |
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struct preftree direct; /* BTRFS_SHARED_[DATA|BLOCK]_REF_KEY */ |
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struct preftree indirect; /* BTRFS_[TREE_BLOCK|EXTENT_DATA]_REF_KEY */ |
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struct preftree indirect_missing_keys; |
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}; |
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/* |
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* Checks for a shared extent during backref search. |
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* |
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* The share_count tracks prelim_refs (direct and indirect) having a |
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* ref->count >0: |
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* - incremented when a ref->count transitions to >0 |
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* - decremented when a ref->count transitions to <1 |
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*/ |
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struct share_check { |
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u64 root_objectid; |
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u64 inum; |
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int share_count; |
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}; |
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|
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static inline int extent_is_shared(struct share_check *sc) |
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{ |
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return (sc && sc->share_count > 1) ? BACKREF_FOUND_SHARED : 0; |
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} |
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|
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static struct kmem_cache *btrfs_prelim_ref_cache; |
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|
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int __init btrfs_prelim_ref_init(void) |
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{ |
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btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref", |
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sizeof(struct prelim_ref), |
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0, |
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SLAB_MEM_SPREAD, |
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NULL); |
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if (!btrfs_prelim_ref_cache) |
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return -ENOMEM; |
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return 0; |
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} |
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|
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void __cold btrfs_prelim_ref_exit(void) |
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{ |
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kmem_cache_destroy(btrfs_prelim_ref_cache); |
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} |
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|
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static void free_pref(struct prelim_ref *ref) |
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{ |
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kmem_cache_free(btrfs_prelim_ref_cache, ref); |
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} |
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|
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/* |
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* Return 0 when both refs are for the same block (and can be merged). |
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* A -1 return indicates ref1 is a 'lower' block than ref2, while 1 |
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* indicates a 'higher' block. |
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*/ |
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static int prelim_ref_compare(struct prelim_ref *ref1, |
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struct prelim_ref *ref2) |
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{ |
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if (ref1->level < ref2->level) |
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return -1; |
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if (ref1->level > ref2->level) |
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return 1; |
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if (ref1->root_id < ref2->root_id) |
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return -1; |
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if (ref1->root_id > ref2->root_id) |
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return 1; |
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if (ref1->key_for_search.type < ref2->key_for_search.type) |
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return -1; |
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if (ref1->key_for_search.type > ref2->key_for_search.type) |
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return 1; |
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if (ref1->key_for_search.objectid < ref2->key_for_search.objectid) |
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return -1; |
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if (ref1->key_for_search.objectid > ref2->key_for_search.objectid) |
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return 1; |
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if (ref1->key_for_search.offset < ref2->key_for_search.offset) |
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return -1; |
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if (ref1->key_for_search.offset > ref2->key_for_search.offset) |
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return 1; |
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if (ref1->parent < ref2->parent) |
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return -1; |
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if (ref1->parent > ref2->parent) |
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return 1; |
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|
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return 0; |
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} |
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static void update_share_count(struct share_check *sc, int oldcount, |
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int newcount) |
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{ |
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if ((!sc) || (oldcount == 0 && newcount < 1)) |
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return; |
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|
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if (oldcount > 0 && newcount < 1) |
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sc->share_count--; |
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else if (oldcount < 1 && newcount > 0) |
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sc->share_count++; |
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} |
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|
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/* |
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* Add @newref to the @root rbtree, merging identical refs. |
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* |
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* Callers should assume that newref has been freed after calling. |
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*/ |
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static void prelim_ref_insert(const struct btrfs_fs_info *fs_info, |
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struct preftree *preftree, |
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struct prelim_ref *newref, |
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struct share_check *sc) |
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{ |
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struct rb_root_cached *root; |
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struct rb_node **p; |
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struct rb_node *parent = NULL; |
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struct prelim_ref *ref; |
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int result; |
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bool leftmost = true; |
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|
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root = &preftree->root; |
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p = &root->rb_root.rb_node; |
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|
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while (*p) { |
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parent = *p; |
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ref = rb_entry(parent, struct prelim_ref, rbnode); |
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result = prelim_ref_compare(ref, newref); |
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if (result < 0) { |
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p = &(*p)->rb_left; |
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} else if (result > 0) { |
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p = &(*p)->rb_right; |
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leftmost = false; |
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} else { |
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/* Identical refs, merge them and free @newref */ |
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struct extent_inode_elem *eie = ref->inode_list; |
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|
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while (eie && eie->next) |
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eie = eie->next; |
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|
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if (!eie) |
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ref->inode_list = newref->inode_list; |
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else |
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eie->next = newref->inode_list; |
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trace_btrfs_prelim_ref_merge(fs_info, ref, newref, |
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preftree->count); |
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/* |
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* A delayed ref can have newref->count < 0. |
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* The ref->count is updated to follow any |
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* BTRFS_[ADD|DROP]_DELAYED_REF actions. |
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*/ |
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update_share_count(sc, ref->count, |
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ref->count + newref->count); |
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ref->count += newref->count; |
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free_pref(newref); |
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return; |
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} |
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} |
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update_share_count(sc, 0, newref->count); |
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preftree->count++; |
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trace_btrfs_prelim_ref_insert(fs_info, newref, NULL, preftree->count); |
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rb_link_node(&newref->rbnode, parent, p); |
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rb_insert_color_cached(&newref->rbnode, root, leftmost); |
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} |
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|
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/* |
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* Release the entire tree. We don't care about internal consistency so |
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* just free everything and then reset the tree root. |
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*/ |
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static void prelim_release(struct preftree *preftree) |
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{ |
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struct prelim_ref *ref, *next_ref; |
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|
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rbtree_postorder_for_each_entry_safe(ref, next_ref, |
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&preftree->root.rb_root, rbnode) |
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free_pref(ref); |
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|
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preftree->root = RB_ROOT_CACHED; |
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preftree->count = 0; |
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} |
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|
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/* |
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* the rules for all callers of this function are: |
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* - obtaining the parent is the goal |
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* - if you add a key, you must know that it is a correct key |
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* - if you cannot add the parent or a correct key, then we will look into the |
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* block later to set a correct key |
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* |
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* delayed refs |
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* ============ |
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* backref type | shared | indirect | shared | indirect |
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* information | tree | tree | data | data |
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* --------------------+--------+----------+--------+---------- |
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* parent logical | y | - | - | - |
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* key to resolve | - | y | y | y |
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* tree block logical | - | - | - | - |
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* root for resolving | y | y | y | y |
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* |
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* - column 1: we've the parent -> done |
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* - column 2, 3, 4: we use the key to find the parent |
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* |
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* on disk refs (inline or keyed) |
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* ============================== |
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* backref type | shared | indirect | shared | indirect |
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* information | tree | tree | data | data |
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* --------------------+--------+----------+--------+---------- |
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* parent logical | y | - | y | - |
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* key to resolve | - | - | - | y |
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* tree block logical | y | y | y | y |
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* root for resolving | - | y | y | y |
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* |
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* - column 1, 3: we've the parent -> done |
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* - column 2: we take the first key from the block to find the parent |
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* (see add_missing_keys) |
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* - column 4: we use the key to find the parent |
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* |
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* additional information that's available but not required to find the parent |
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* block might help in merging entries to gain some speed. |
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*/ |
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static int add_prelim_ref(const struct btrfs_fs_info *fs_info, |
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struct preftree *preftree, u64 root_id, |
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const struct btrfs_key *key, int level, u64 parent, |
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u64 wanted_disk_byte, int count, |
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struct share_check *sc, gfp_t gfp_mask) |
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{ |
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struct prelim_ref *ref; |
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|
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if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID) |
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return 0; |
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|
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ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask); |
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if (!ref) |
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return -ENOMEM; |
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|
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ref->root_id = root_id; |
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if (key) |
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ref->key_for_search = *key; |
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else |
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memset(&ref->key_for_search, 0, sizeof(ref->key_for_search)); |
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|
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ref->inode_list = NULL; |
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ref->level = level; |
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ref->count = count; |
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ref->parent = parent; |
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ref->wanted_disk_byte = wanted_disk_byte; |
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prelim_ref_insert(fs_info, preftree, ref, sc); |
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return extent_is_shared(sc); |
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} |
|
|
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/* direct refs use root == 0, key == NULL */ |
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static int add_direct_ref(const struct btrfs_fs_info *fs_info, |
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struct preftrees *preftrees, int level, u64 parent, |
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u64 wanted_disk_byte, int count, |
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struct share_check *sc, gfp_t gfp_mask) |
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{ |
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return add_prelim_ref(fs_info, &preftrees->direct, 0, NULL, level, |
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parent, wanted_disk_byte, count, sc, gfp_mask); |
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} |
|
|
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/* indirect refs use parent == 0 */ |
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static int add_indirect_ref(const struct btrfs_fs_info *fs_info, |
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struct preftrees *preftrees, u64 root_id, |
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const struct btrfs_key *key, int level, |
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u64 wanted_disk_byte, int count, |
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struct share_check *sc, gfp_t gfp_mask) |
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{ |
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struct preftree *tree = &preftrees->indirect; |
|
|
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if (!key) |
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tree = &preftrees->indirect_missing_keys; |
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return add_prelim_ref(fs_info, tree, root_id, key, level, 0, |
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wanted_disk_byte, count, sc, gfp_mask); |
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} |
|
|
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static int is_shared_data_backref(struct preftrees *preftrees, u64 bytenr) |
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{ |
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struct rb_node **p = &preftrees->direct.root.rb_root.rb_node; |
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struct rb_node *parent = NULL; |
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struct prelim_ref *ref = NULL; |
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struct prelim_ref target = {}; |
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int result; |
|
|
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target.parent = bytenr; |
|
|
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while (*p) { |
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parent = *p; |
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ref = rb_entry(parent, struct prelim_ref, rbnode); |
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result = prelim_ref_compare(ref, &target); |
|
|
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if (result < 0) |
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p = &(*p)->rb_left; |
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else if (result > 0) |
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p = &(*p)->rb_right; |
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else |
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return 1; |
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} |
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return 0; |
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} |
|
|
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static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, |
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struct ulist *parents, |
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struct preftrees *preftrees, struct prelim_ref *ref, |
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int level, u64 time_seq, const u64 *extent_item_pos, |
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bool ignore_offset) |
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{ |
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int ret = 0; |
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int slot; |
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struct extent_buffer *eb; |
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struct btrfs_key key; |
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struct btrfs_key *key_for_search = &ref->key_for_search; |
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struct btrfs_file_extent_item *fi; |
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struct extent_inode_elem *eie = NULL, *old = NULL; |
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u64 disk_byte; |
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u64 wanted_disk_byte = ref->wanted_disk_byte; |
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u64 count = 0; |
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u64 data_offset; |
|
|
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if (level != 0) { |
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eb = path->nodes[level]; |
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ret = ulist_add(parents, eb->start, 0, GFP_NOFS); |
|
if (ret < 0) |
|
return ret; |
|
return 0; |
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} |
|
|
|
/* |
|
* 1. We normally enter this function with the path already pointing to |
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* the first item to check. But sometimes, we may enter it with |
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* slot == nritems. |
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* 2. We are searching for normal backref but bytenr of this leaf |
|
* matches shared data backref |
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* 3. The leaf owner is not equal to the root we are searching |
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* |
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* For these cases, go to the next leaf before we continue. |
|
*/ |
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eb = path->nodes[0]; |
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if (path->slots[0] >= btrfs_header_nritems(eb) || |
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is_shared_data_backref(preftrees, eb->start) || |
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ref->root_id != btrfs_header_owner(eb)) { |
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if (time_seq == BTRFS_SEQ_LAST) |
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ret = btrfs_next_leaf(root, path); |
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else |
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ret = btrfs_next_old_leaf(root, path, time_seq); |
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} |
|
|
|
while (!ret && count < ref->count) { |
|
eb = path->nodes[0]; |
|
slot = path->slots[0]; |
|
|
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btrfs_item_key_to_cpu(eb, &key, slot); |
|
|
|
if (key.objectid != key_for_search->objectid || |
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key.type != BTRFS_EXTENT_DATA_KEY) |
|
break; |
|
|
|
/* |
|
* We are searching for normal backref but bytenr of this leaf |
|
* matches shared data backref, OR |
|
* the leaf owner is not equal to the root we are searching for |
|
*/ |
|
if (slot == 0 && |
|
(is_shared_data_backref(preftrees, eb->start) || |
|
ref->root_id != btrfs_header_owner(eb))) { |
|
if (time_seq == BTRFS_SEQ_LAST) |
|
ret = btrfs_next_leaf(root, path); |
|
else |
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ret = btrfs_next_old_leaf(root, path, time_seq); |
|
continue; |
|
} |
|
fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); |
|
disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); |
|
data_offset = btrfs_file_extent_offset(eb, fi); |
|
|
|
if (disk_byte == wanted_disk_byte) { |
|
eie = NULL; |
|
old = NULL; |
|
if (ref->key_for_search.offset == key.offset - data_offset) |
|
count++; |
|
else |
|
goto next; |
|
if (extent_item_pos) { |
|
ret = check_extent_in_eb(&key, eb, fi, |
|
*extent_item_pos, |
|
&eie, ignore_offset); |
|
if (ret < 0) |
|
break; |
|
} |
|
if (ret > 0) |
|
goto next; |
|
ret = ulist_add_merge_ptr(parents, eb->start, |
|
eie, (void **)&old, GFP_NOFS); |
|
if (ret < 0) |
|
break; |
|
if (!ret && extent_item_pos) { |
|
while (old->next) |
|
old = old->next; |
|
old->next = eie; |
|
} |
|
eie = NULL; |
|
} |
|
next: |
|
if (time_seq == BTRFS_SEQ_LAST) |
|
ret = btrfs_next_item(root, path); |
|
else |
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ret = btrfs_next_old_item(root, path, time_seq); |
|
} |
|
|
|
if (ret > 0) |
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ret = 0; |
|
else if (ret < 0) |
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free_inode_elem_list(eie); |
|
return ret; |
|
} |
|
|
|
/* |
|
* resolve an indirect backref in the form (root_id, key, level) |
|
* to a logical address |
|
*/ |
|
static int resolve_indirect_ref(struct btrfs_fs_info *fs_info, |
|
struct btrfs_path *path, u64 time_seq, |
|
struct preftrees *preftrees, |
|
struct prelim_ref *ref, struct ulist *parents, |
|
const u64 *extent_item_pos, bool ignore_offset) |
|
{ |
|
struct btrfs_root *root; |
|
struct extent_buffer *eb; |
|
int ret = 0; |
|
int root_level; |
|
int level = ref->level; |
|
struct btrfs_key search_key = ref->key_for_search; |
|
|
|
/* |
|
* If we're search_commit_root we could possibly be holding locks on |
|
* other tree nodes. This happens when qgroups does backref walks when |
|
* adding new delayed refs. To deal with this we need to look in cache |
|
* for the root, and if we don't find it then we need to search the |
|
* tree_root's commit root, thus the btrfs_get_fs_root_commit_root usage |
|
* here. |
|
*/ |
|
if (path->search_commit_root) |
|
root = btrfs_get_fs_root_commit_root(fs_info, path, ref->root_id); |
|
else |
|
root = btrfs_get_fs_root(fs_info, ref->root_id, false); |
|
if (IS_ERR(root)) { |
|
ret = PTR_ERR(root); |
|
goto out_free; |
|
} |
|
|
|
if (!path->search_commit_root && |
|
test_bit(BTRFS_ROOT_DELETING, &root->state)) { |
|
ret = -ENOENT; |
|
goto out; |
|
} |
|
|
|
if (btrfs_is_testing(fs_info)) { |
|
ret = -ENOENT; |
|
goto out; |
|
} |
|
|
|
if (path->search_commit_root) |
|
root_level = btrfs_header_level(root->commit_root); |
|
else if (time_seq == BTRFS_SEQ_LAST) |
|
root_level = btrfs_header_level(root->node); |
|
else |
|
root_level = btrfs_old_root_level(root, time_seq); |
|
|
|
if (root_level + 1 == level) |
|
goto out; |
|
|
|
/* |
|
* We can often find data backrefs with an offset that is too large |
|
* (>= LLONG_MAX, maximum allowed file offset) due to underflows when |
|
* subtracting a file's offset with the data offset of its |
|
* corresponding extent data item. This can happen for example in the |
|
* clone ioctl. |
|
* |
|
* So if we detect such case we set the search key's offset to zero to |
|
* make sure we will find the matching file extent item at |
|
* add_all_parents(), otherwise we will miss it because the offset |
|
* taken form the backref is much larger then the offset of the file |
|
* extent item. This can make us scan a very large number of file |
|
* extent items, but at least it will not make us miss any. |
|
* |
|
* This is an ugly workaround for a behaviour that should have never |
|
* existed, but it does and a fix for the clone ioctl would touch a lot |
|
* of places, cause backwards incompatibility and would not fix the |
|
* problem for extents cloned with older kernels. |
|
*/ |
|
if (search_key.type == BTRFS_EXTENT_DATA_KEY && |
|
search_key.offset >= LLONG_MAX) |
|
search_key.offset = 0; |
|
path->lowest_level = level; |
|
if (time_seq == BTRFS_SEQ_LAST) |
|
ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); |
|
else |
|
ret = btrfs_search_old_slot(root, &search_key, path, time_seq); |
|
|
|
btrfs_debug(fs_info, |
|
"search slot in root %llu (level %d, ref count %d) returned %d for key (%llu %u %llu)", |
|
ref->root_id, level, ref->count, ret, |
|
ref->key_for_search.objectid, ref->key_for_search.type, |
|
ref->key_for_search.offset); |
|
if (ret < 0) |
|
goto out; |
|
|
|
eb = path->nodes[level]; |
|
while (!eb) { |
|
if (WARN_ON(!level)) { |
|
ret = 1; |
|
goto out; |
|
} |
|
level--; |
|
eb = path->nodes[level]; |
|
} |
|
|
|
ret = add_all_parents(root, path, parents, preftrees, ref, level, |
|
time_seq, extent_item_pos, ignore_offset); |
|
out: |
|
btrfs_put_root(root); |
|
out_free: |
|
path->lowest_level = 0; |
|
btrfs_release_path(path); |
|
return ret; |
|
} |
|
|
|
static struct extent_inode_elem * |
|
unode_aux_to_inode_list(struct ulist_node *node) |
|
{ |
|
if (!node) |
|
return NULL; |
|
return (struct extent_inode_elem *)(uintptr_t)node->aux; |
|
} |
|
|
|
/* |
|
* We maintain three separate rbtrees: one for direct refs, one for |
|
* indirect refs which have a key, and one for indirect refs which do not |
|
* have a key. Each tree does merge on insertion. |
|
* |
|
* Once all of the references are located, we iterate over the tree of |
|
* indirect refs with missing keys. An appropriate key is located and |
|
* the ref is moved onto the tree for indirect refs. After all missing |
|
* keys are thus located, we iterate over the indirect ref tree, resolve |
|
* each reference, and then insert the resolved reference onto the |
|
* direct tree (merging there too). |
|
* |
|
* New backrefs (i.e., for parent nodes) are added to the appropriate |
|
* rbtree as they are encountered. The new backrefs are subsequently |
|
* resolved as above. |
|
*/ |
|
static int resolve_indirect_refs(struct btrfs_fs_info *fs_info, |
|
struct btrfs_path *path, u64 time_seq, |
|
struct preftrees *preftrees, |
|
const u64 *extent_item_pos, |
|
struct share_check *sc, bool ignore_offset) |
|
{ |
|
int err; |
|
int ret = 0; |
|
struct ulist *parents; |
|
struct ulist_node *node; |
|
struct ulist_iterator uiter; |
|
struct rb_node *rnode; |
|
|
|
parents = ulist_alloc(GFP_NOFS); |
|
if (!parents) |
|
return -ENOMEM; |
|
|
|
/* |
|
* We could trade memory usage for performance here by iterating |
|
* the tree, allocating new refs for each insertion, and then |
|
* freeing the entire indirect tree when we're done. In some test |
|
* cases, the tree can grow quite large (~200k objects). |
|
*/ |
|
while ((rnode = rb_first_cached(&preftrees->indirect.root))) { |
|
struct prelim_ref *ref; |
|
|
|
ref = rb_entry(rnode, struct prelim_ref, rbnode); |
|
if (WARN(ref->parent, |
|
"BUG: direct ref found in indirect tree")) { |
|
ret = -EINVAL; |
|
goto out; |
|
} |
|
|
|
rb_erase_cached(&ref->rbnode, &preftrees->indirect.root); |
|
preftrees->indirect.count--; |
|
|
|
if (ref->count == 0) { |
|
free_pref(ref); |
|
continue; |
|
} |
|
|
|
if (sc && sc->root_objectid && |
|
ref->root_id != sc->root_objectid) { |
|
free_pref(ref); |
|
ret = BACKREF_FOUND_SHARED; |
|
goto out; |
|
} |
|
err = resolve_indirect_ref(fs_info, path, time_seq, preftrees, |
|
ref, parents, extent_item_pos, |
|
ignore_offset); |
|
/* |
|
* we can only tolerate ENOENT,otherwise,we should catch error |
|
* and return directly. |
|
*/ |
|
if (err == -ENOENT) { |
|
prelim_ref_insert(fs_info, &preftrees->direct, ref, |
|
NULL); |
|
continue; |
|
} else if (err) { |
|
free_pref(ref); |
|
ret = err; |
|
goto out; |
|
} |
|
|
|
/* we put the first parent into the ref at hand */ |
|
ULIST_ITER_INIT(&uiter); |
|
node = ulist_next(parents, &uiter); |
|
ref->parent = node ? node->val : 0; |
|
ref->inode_list = unode_aux_to_inode_list(node); |
|
|
|
/* Add a prelim_ref(s) for any other parent(s). */ |
|
while ((node = ulist_next(parents, &uiter))) { |
|
struct prelim_ref *new_ref; |
|
|
|
new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache, |
|
GFP_NOFS); |
|
if (!new_ref) { |
|
free_pref(ref); |
|
ret = -ENOMEM; |
|
goto out; |
|
} |
|
memcpy(new_ref, ref, sizeof(*ref)); |
|
new_ref->parent = node->val; |
|
new_ref->inode_list = unode_aux_to_inode_list(node); |
|
prelim_ref_insert(fs_info, &preftrees->direct, |
|
new_ref, NULL); |
|
} |
|
|
|
/* |
|
* Now it's a direct ref, put it in the direct tree. We must |
|
* do this last because the ref could be merged/freed here. |
|
*/ |
|
prelim_ref_insert(fs_info, &preftrees->direct, ref, NULL); |
|
|
|
ulist_reinit(parents); |
|
cond_resched(); |
|
} |
|
out: |
|
ulist_free(parents); |
|
return ret; |
|
} |
|
|
|
/* |
|
* read tree blocks and add keys where required. |
|
*/ |
|
static int add_missing_keys(struct btrfs_fs_info *fs_info, |
|
struct preftrees *preftrees, bool lock) |
|
{ |
|
struct prelim_ref *ref; |
|
struct extent_buffer *eb; |
|
struct preftree *tree = &preftrees->indirect_missing_keys; |
|
struct rb_node *node; |
|
|
|
while ((node = rb_first_cached(&tree->root))) { |
|
ref = rb_entry(node, struct prelim_ref, rbnode); |
|
rb_erase_cached(node, &tree->root); |
|
|
|
BUG_ON(ref->parent); /* should not be a direct ref */ |
|
BUG_ON(ref->key_for_search.type); |
|
BUG_ON(!ref->wanted_disk_byte); |
|
|
|
eb = read_tree_block(fs_info, ref->wanted_disk_byte, |
|
ref->root_id, 0, ref->level - 1, NULL); |
|
if (IS_ERR(eb)) { |
|
free_pref(ref); |
|
return PTR_ERR(eb); |
|
} else if (!extent_buffer_uptodate(eb)) { |
|
free_pref(ref); |
|
free_extent_buffer(eb); |
|
return -EIO; |
|
} |
|
if (lock) |
|
btrfs_tree_read_lock(eb); |
|
if (btrfs_header_level(eb) == 0) |
|
btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0); |
|
else |
|
btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0); |
|
if (lock) |
|
btrfs_tree_read_unlock(eb); |
|
free_extent_buffer(eb); |
|
prelim_ref_insert(fs_info, &preftrees->indirect, ref, NULL); |
|
cond_resched(); |
|
} |
|
return 0; |
|
} |
|
|
|
/* |
|
* add all currently queued delayed refs from this head whose seq nr is |
|
* smaller or equal that seq to the list |
|
*/ |
|
static int add_delayed_refs(const struct btrfs_fs_info *fs_info, |
|
struct btrfs_delayed_ref_head *head, u64 seq, |
|
struct preftrees *preftrees, struct share_check *sc) |
|
{ |
|
struct btrfs_delayed_ref_node *node; |
|
struct btrfs_delayed_extent_op *extent_op = head->extent_op; |
|
struct btrfs_key key; |
|
struct btrfs_key tmp_op_key; |
|
struct rb_node *n; |
|
int count; |
|
int ret = 0; |
|
|
|
if (extent_op && extent_op->update_key) |
|
btrfs_disk_key_to_cpu(&tmp_op_key, &extent_op->key); |
|
|
|
spin_lock(&head->lock); |
|
for (n = rb_first_cached(&head->ref_tree); n; n = rb_next(n)) { |
|
node = rb_entry(n, struct btrfs_delayed_ref_node, |
|
ref_node); |
|
if (node->seq > seq) |
|
continue; |
|
|
|
switch (node->action) { |
|
case BTRFS_ADD_DELAYED_EXTENT: |
|
case BTRFS_UPDATE_DELAYED_HEAD: |
|
WARN_ON(1); |
|
continue; |
|
case BTRFS_ADD_DELAYED_REF: |
|
count = node->ref_mod; |
|
break; |
|
case BTRFS_DROP_DELAYED_REF: |
|
count = node->ref_mod * -1; |
|
break; |
|
default: |
|
BUG(); |
|
} |
|
switch (node->type) { |
|
case BTRFS_TREE_BLOCK_REF_KEY: { |
|
/* NORMAL INDIRECT METADATA backref */ |
|
struct btrfs_delayed_tree_ref *ref; |
|
|
|
ref = btrfs_delayed_node_to_tree_ref(node); |
|
ret = add_indirect_ref(fs_info, preftrees, ref->root, |
|
&tmp_op_key, ref->level + 1, |
|
node->bytenr, count, sc, |
|
GFP_ATOMIC); |
|
break; |
|
} |
|
case BTRFS_SHARED_BLOCK_REF_KEY: { |
|
/* SHARED DIRECT METADATA backref */ |
|
struct btrfs_delayed_tree_ref *ref; |
|
|
|
ref = btrfs_delayed_node_to_tree_ref(node); |
|
|
|
ret = add_direct_ref(fs_info, preftrees, ref->level + 1, |
|
ref->parent, node->bytenr, count, |
|
sc, GFP_ATOMIC); |
|
break; |
|
} |
|
case BTRFS_EXTENT_DATA_REF_KEY: { |
|
/* NORMAL INDIRECT DATA backref */ |
|
struct btrfs_delayed_data_ref *ref; |
|
ref = btrfs_delayed_node_to_data_ref(node); |
|
|
|
key.objectid = ref->objectid; |
|
key.type = BTRFS_EXTENT_DATA_KEY; |
|
key.offset = ref->offset; |
|
|
|
/* |
|
* Found a inum that doesn't match our known inum, we |
|
* know it's shared. |
|
*/ |
|
if (sc && sc->inum && ref->objectid != sc->inum) { |
|
ret = BACKREF_FOUND_SHARED; |
|
goto out; |
|
} |
|
|
|
ret = add_indirect_ref(fs_info, preftrees, ref->root, |
|
&key, 0, node->bytenr, count, sc, |
|
GFP_ATOMIC); |
|
break; |
|
} |
|
case BTRFS_SHARED_DATA_REF_KEY: { |
|
/* SHARED DIRECT FULL backref */ |
|
struct btrfs_delayed_data_ref *ref; |
|
|
|
ref = btrfs_delayed_node_to_data_ref(node); |
|
|
|
ret = add_direct_ref(fs_info, preftrees, 0, ref->parent, |
|
node->bytenr, count, sc, |
|
GFP_ATOMIC); |
|
break; |
|
} |
|
default: |
|
WARN_ON(1); |
|
} |
|
/* |
|
* We must ignore BACKREF_FOUND_SHARED until all delayed |
|
* refs have been checked. |
|
*/ |
|
if (ret && (ret != BACKREF_FOUND_SHARED)) |
|
break; |
|
} |
|
if (!ret) |
|
ret = extent_is_shared(sc); |
|
out: |
|
spin_unlock(&head->lock); |
|
return ret; |
|
} |
|
|
|
/* |
|
* add all inline backrefs for bytenr to the list |
|
* |
|
* Returns 0 on success, <0 on error, or BACKREF_FOUND_SHARED. |
|
*/ |
|
static int add_inline_refs(const struct btrfs_fs_info *fs_info, |
|
struct btrfs_path *path, u64 bytenr, |
|
int *info_level, struct preftrees *preftrees, |
|
struct share_check *sc) |
|
{ |
|
int ret = 0; |
|
int slot; |
|
struct extent_buffer *leaf; |
|
struct btrfs_key key; |
|
struct btrfs_key found_key; |
|
unsigned long ptr; |
|
unsigned long end; |
|
struct btrfs_extent_item *ei; |
|
u64 flags; |
|
u64 item_size; |
|
|
|
/* |
|
* enumerate all inline refs |
|
*/ |
|
leaf = path->nodes[0]; |
|
slot = path->slots[0]; |
|
|
|
item_size = btrfs_item_size_nr(leaf, slot); |
|
BUG_ON(item_size < sizeof(*ei)); |
|
|
|
ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); |
|
flags = btrfs_extent_flags(leaf, ei); |
|
btrfs_item_key_to_cpu(leaf, &found_key, slot); |
|
|
|
ptr = (unsigned long)(ei + 1); |
|
end = (unsigned long)ei + item_size; |
|
|
|
if (found_key.type == BTRFS_EXTENT_ITEM_KEY && |
|
flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { |
|
struct btrfs_tree_block_info *info; |
|
|
|
info = (struct btrfs_tree_block_info *)ptr; |
|
*info_level = btrfs_tree_block_level(leaf, info); |
|
ptr += sizeof(struct btrfs_tree_block_info); |
|
BUG_ON(ptr > end); |
|
} else if (found_key.type == BTRFS_METADATA_ITEM_KEY) { |
|
*info_level = found_key.offset; |
|
} else { |
|
BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA)); |
|
} |
|
|
|
while (ptr < end) { |
|
struct btrfs_extent_inline_ref *iref; |
|
u64 offset; |
|
int type; |
|
|
|
iref = (struct btrfs_extent_inline_ref *)ptr; |
|
type = btrfs_get_extent_inline_ref_type(leaf, iref, |
|
BTRFS_REF_TYPE_ANY); |
|
if (type == BTRFS_REF_TYPE_INVALID) |
|
return -EUCLEAN; |
|
|
|
offset = btrfs_extent_inline_ref_offset(leaf, iref); |
|
|
|
switch (type) { |
|
case BTRFS_SHARED_BLOCK_REF_KEY: |
|
ret = add_direct_ref(fs_info, preftrees, |
|
*info_level + 1, offset, |
|
bytenr, 1, NULL, GFP_NOFS); |
|
break; |
|
case BTRFS_SHARED_DATA_REF_KEY: { |
|
struct btrfs_shared_data_ref *sdref; |
|
int count; |
|
|
|
sdref = (struct btrfs_shared_data_ref *)(iref + 1); |
|
count = btrfs_shared_data_ref_count(leaf, sdref); |
|
|
|
ret = add_direct_ref(fs_info, preftrees, 0, offset, |
|
bytenr, count, sc, GFP_NOFS); |
|
break; |
|
} |
|
case BTRFS_TREE_BLOCK_REF_KEY: |
|
ret = add_indirect_ref(fs_info, preftrees, offset, |
|
NULL, *info_level + 1, |
|
bytenr, 1, NULL, GFP_NOFS); |
|
break; |
|
case BTRFS_EXTENT_DATA_REF_KEY: { |
|
struct btrfs_extent_data_ref *dref; |
|
int count; |
|
u64 root; |
|
|
|
dref = (struct btrfs_extent_data_ref *)(&iref->offset); |
|
count = btrfs_extent_data_ref_count(leaf, dref); |
|
key.objectid = btrfs_extent_data_ref_objectid(leaf, |
|
dref); |
|
key.type = BTRFS_EXTENT_DATA_KEY; |
|
key.offset = btrfs_extent_data_ref_offset(leaf, dref); |
|
|
|
if (sc && sc->inum && key.objectid != sc->inum) { |
|
ret = BACKREF_FOUND_SHARED; |
|
break; |
|
} |
|
|
|
root = btrfs_extent_data_ref_root(leaf, dref); |
|
|
|
ret = add_indirect_ref(fs_info, preftrees, root, |
|
&key, 0, bytenr, count, |
|
sc, GFP_NOFS); |
|
break; |
|
} |
|
default: |
|
WARN_ON(1); |
|
} |
|
if (ret) |
|
return ret; |
|
ptr += btrfs_extent_inline_ref_size(type); |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* add all non-inline backrefs for bytenr to the list |
|
* |
|
* Returns 0 on success, <0 on error, or BACKREF_FOUND_SHARED. |
|
*/ |
|
static int add_keyed_refs(struct btrfs_fs_info *fs_info, |
|
struct btrfs_path *path, u64 bytenr, |
|
int info_level, struct preftrees *preftrees, |
|
struct share_check *sc) |
|
{ |
|
struct btrfs_root *extent_root = fs_info->extent_root; |
|
int ret; |
|
int slot; |
|
struct extent_buffer *leaf; |
|
struct btrfs_key key; |
|
|
|
while (1) { |
|
ret = btrfs_next_item(extent_root, path); |
|
if (ret < 0) |
|
break; |
|
if (ret) { |
|
ret = 0; |
|
break; |
|
} |
|
|
|
slot = path->slots[0]; |
|
leaf = path->nodes[0]; |
|
btrfs_item_key_to_cpu(leaf, &key, slot); |
|
|
|
if (key.objectid != bytenr) |
|
break; |
|
if (key.type < BTRFS_TREE_BLOCK_REF_KEY) |
|
continue; |
|
if (key.type > BTRFS_SHARED_DATA_REF_KEY) |
|
break; |
|
|
|
switch (key.type) { |
|
case BTRFS_SHARED_BLOCK_REF_KEY: |
|
/* SHARED DIRECT METADATA backref */ |
|
ret = add_direct_ref(fs_info, preftrees, |
|
info_level + 1, key.offset, |
|
bytenr, 1, NULL, GFP_NOFS); |
|
break; |
|
case BTRFS_SHARED_DATA_REF_KEY: { |
|
/* SHARED DIRECT FULL backref */ |
|
struct btrfs_shared_data_ref *sdref; |
|
int count; |
|
|
|
sdref = btrfs_item_ptr(leaf, slot, |
|
struct btrfs_shared_data_ref); |
|
count = btrfs_shared_data_ref_count(leaf, sdref); |
|
ret = add_direct_ref(fs_info, preftrees, 0, |
|
key.offset, bytenr, count, |
|
sc, GFP_NOFS); |
|
break; |
|
} |
|
case BTRFS_TREE_BLOCK_REF_KEY: |
|
/* NORMAL INDIRECT METADATA backref */ |
|
ret = add_indirect_ref(fs_info, preftrees, key.offset, |
|
NULL, info_level + 1, bytenr, |
|
1, NULL, GFP_NOFS); |
|
break; |
|
case BTRFS_EXTENT_DATA_REF_KEY: { |
|
/* NORMAL INDIRECT DATA backref */ |
|
struct btrfs_extent_data_ref *dref; |
|
int count; |
|
u64 root; |
|
|
|
dref = btrfs_item_ptr(leaf, slot, |
|
struct btrfs_extent_data_ref); |
|
count = btrfs_extent_data_ref_count(leaf, dref); |
|
key.objectid = btrfs_extent_data_ref_objectid(leaf, |
|
dref); |
|
key.type = BTRFS_EXTENT_DATA_KEY; |
|
key.offset = btrfs_extent_data_ref_offset(leaf, dref); |
|
|
|
if (sc && sc->inum && key.objectid != sc->inum) { |
|
ret = BACKREF_FOUND_SHARED; |
|
break; |
|
} |
|
|
|
root = btrfs_extent_data_ref_root(leaf, dref); |
|
ret = add_indirect_ref(fs_info, preftrees, root, |
|
&key, 0, bytenr, count, |
|
sc, GFP_NOFS); |
|
break; |
|
} |
|
default: |
|
WARN_ON(1); |
|
} |
|
if (ret) |
|
return ret; |
|
|
|
} |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* this adds all existing backrefs (inline backrefs, backrefs and delayed |
|
* refs) for the given bytenr to the refs list, merges duplicates and resolves |
|
* indirect refs to their parent bytenr. |
|
* When roots are found, they're added to the roots list |
|
* |
|
* If time_seq is set to BTRFS_SEQ_LAST, it will not search delayed_refs, and |
|
* behave much like trans == NULL case, the difference only lies in it will not |
|
* commit root. |
|
* The special case is for qgroup to search roots in commit_transaction(). |
|
* |
|
* @sc - if !NULL, then immediately return BACKREF_FOUND_SHARED when a |
|
* shared extent is detected. |
|
* |
|
* Otherwise this returns 0 for success and <0 for an error. |
|
* |
|
* If ignore_offset is set to false, only extent refs whose offsets match |
|
* extent_item_pos are returned. If true, every extent ref is returned |
|
* and extent_item_pos is ignored. |
|
* |
|
* FIXME some caching might speed things up |
|
*/ |
|
static int find_parent_nodes(struct btrfs_trans_handle *trans, |
|
struct btrfs_fs_info *fs_info, u64 bytenr, |
|
u64 time_seq, struct ulist *refs, |
|
struct ulist *roots, const u64 *extent_item_pos, |
|
struct share_check *sc, bool ignore_offset) |
|
{ |
|
struct btrfs_key key; |
|
struct btrfs_path *path; |
|
struct btrfs_delayed_ref_root *delayed_refs = NULL; |
|
struct btrfs_delayed_ref_head *head; |
|
int info_level = 0; |
|
int ret; |
|
struct prelim_ref *ref; |
|
struct rb_node *node; |
|
struct extent_inode_elem *eie = NULL; |
|
struct preftrees preftrees = { |
|
.direct = PREFTREE_INIT, |
|
.indirect = PREFTREE_INIT, |
|
.indirect_missing_keys = PREFTREE_INIT |
|
}; |
|
|
|
key.objectid = bytenr; |
|
key.offset = (u64)-1; |
|
if (btrfs_fs_incompat(fs_info, SKINNY_METADATA)) |
|
key.type = BTRFS_METADATA_ITEM_KEY; |
|
else |
|
key.type = BTRFS_EXTENT_ITEM_KEY; |
|
|
|
path = btrfs_alloc_path(); |
|
if (!path) |
|
return -ENOMEM; |
|
if (!trans) { |
|
path->search_commit_root = 1; |
|
path->skip_locking = 1; |
|
} |
|
|
|
if (time_seq == BTRFS_SEQ_LAST) |
|
path->skip_locking = 1; |
|
|
|
/* |
|
* grab both a lock on the path and a lock on the delayed ref head. |
|
* We need both to get a consistent picture of how the refs look |
|
* at a specified point in time |
|
*/ |
|
again: |
|
head = NULL; |
|
|
|
ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0); |
|
if (ret < 0) |
|
goto out; |
|
BUG_ON(ret == 0); |
|
|
|
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS |
|
if (trans && likely(trans->type != __TRANS_DUMMY) && |
|
time_seq != BTRFS_SEQ_LAST) { |
|
#else |
|
if (trans && time_seq != BTRFS_SEQ_LAST) { |
|
#endif |
|
/* |
|
* look if there are updates for this ref queued and lock the |
|
* head |
|
*/ |
|
delayed_refs = &trans->transaction->delayed_refs; |
|
spin_lock(&delayed_refs->lock); |
|
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr); |
|
if (head) { |
|
if (!mutex_trylock(&head->mutex)) { |
|
refcount_inc(&head->refs); |
|
spin_unlock(&delayed_refs->lock); |
|
|
|
btrfs_release_path(path); |
|
|
|
/* |
|
* Mutex was contended, block until it's |
|
* released and try again |
|
*/ |
|
mutex_lock(&head->mutex); |
|
mutex_unlock(&head->mutex); |
|
btrfs_put_delayed_ref_head(head); |
|
goto again; |
|
} |
|
spin_unlock(&delayed_refs->lock); |
|
ret = add_delayed_refs(fs_info, head, time_seq, |
|
&preftrees, sc); |
|
mutex_unlock(&head->mutex); |
|
if (ret) |
|
goto out; |
|
} else { |
|
spin_unlock(&delayed_refs->lock); |
|
} |
|
} |
|
|
|
if (path->slots[0]) { |
|
struct extent_buffer *leaf; |
|
int slot; |
|
|
|
path->slots[0]--; |
|
leaf = path->nodes[0]; |
|
slot = path->slots[0]; |
|
btrfs_item_key_to_cpu(leaf, &key, slot); |
|
if (key.objectid == bytenr && |
|
(key.type == BTRFS_EXTENT_ITEM_KEY || |
|
key.type == BTRFS_METADATA_ITEM_KEY)) { |
|
ret = add_inline_refs(fs_info, path, bytenr, |
|
&info_level, &preftrees, sc); |
|
if (ret) |
|
goto out; |
|
ret = add_keyed_refs(fs_info, path, bytenr, info_level, |
|
&preftrees, sc); |
|
if (ret) |
|
goto out; |
|
} |
|
} |
|
|
|
btrfs_release_path(path); |
|
|
|
ret = add_missing_keys(fs_info, &preftrees, path->skip_locking == 0); |
|
if (ret) |
|
goto out; |
|
|
|
WARN_ON(!RB_EMPTY_ROOT(&preftrees.indirect_missing_keys.root.rb_root)); |
|
|
|
ret = resolve_indirect_refs(fs_info, path, time_seq, &preftrees, |
|
extent_item_pos, sc, ignore_offset); |
|
if (ret) |
|
goto out; |
|
|
|
WARN_ON(!RB_EMPTY_ROOT(&preftrees.indirect.root.rb_root)); |
|
|
|
/* |
|
* This walks the tree of merged and resolved refs. Tree blocks are |
|
* read in as needed. Unique entries are added to the ulist, and |
|
* the list of found roots is updated. |
|
* |
|
* We release the entire tree in one go before returning. |
|
*/ |
|
node = rb_first_cached(&preftrees.direct.root); |
|
while (node) { |
|
ref = rb_entry(node, struct prelim_ref, rbnode); |
|
node = rb_next(&ref->rbnode); |
|
/* |
|
* ref->count < 0 can happen here if there are delayed |
|
* refs with a node->action of BTRFS_DROP_DELAYED_REF. |
|
* prelim_ref_insert() relies on this when merging |
|
* identical refs to keep the overall count correct. |
|
* prelim_ref_insert() will merge only those refs |
|
* which compare identically. Any refs having |
|
* e.g. different offsets would not be merged, |
|
* and would retain their original ref->count < 0. |
|
*/ |
|
if (roots && ref->count && ref->root_id && ref->parent == 0) { |
|
if (sc && sc->root_objectid && |
|
ref->root_id != sc->root_objectid) { |
|
ret = BACKREF_FOUND_SHARED; |
|
goto out; |
|
} |
|
|
|
/* no parent == root of tree */ |
|
ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS); |
|
if (ret < 0) |
|
goto out; |
|
} |
|
if (ref->count && ref->parent) { |
|
if (extent_item_pos && !ref->inode_list && |
|
ref->level == 0) { |
|
struct extent_buffer *eb; |
|
|
|
eb = read_tree_block(fs_info, ref->parent, 0, |
|
0, ref->level, NULL); |
|
if (IS_ERR(eb)) { |
|
ret = PTR_ERR(eb); |
|
goto out; |
|
} else if (!extent_buffer_uptodate(eb)) { |
|
free_extent_buffer(eb); |
|
ret = -EIO; |
|
goto out; |
|
} |
|
|
|
if (!path->skip_locking) |
|
btrfs_tree_read_lock(eb); |
|
ret = find_extent_in_eb(eb, bytenr, |
|
*extent_item_pos, &eie, ignore_offset); |
|
if (!path->skip_locking) |
|
btrfs_tree_read_unlock(eb); |
|
free_extent_buffer(eb); |
|
if (ret < 0) |
|
goto out; |
|
ref->inode_list = eie; |
|
} |
|
ret = ulist_add_merge_ptr(refs, ref->parent, |
|
ref->inode_list, |
|
(void **)&eie, GFP_NOFS); |
|
if (ret < 0) |
|
goto out; |
|
if (!ret && extent_item_pos) { |
|
/* |
|
* we've recorded that parent, so we must extend |
|
* its inode list here |
|
*/ |
|
BUG_ON(!eie); |
|
while (eie->next) |
|
eie = eie->next; |
|
eie->next = ref->inode_list; |
|
} |
|
eie = NULL; |
|
} |
|
cond_resched(); |
|
} |
|
|
|
out: |
|
btrfs_free_path(path); |
|
|
|
prelim_release(&preftrees.direct); |
|
prelim_release(&preftrees.indirect); |
|
prelim_release(&preftrees.indirect_missing_keys); |
|
|
|
if (ret < 0) |
|
free_inode_elem_list(eie); |
|
return ret; |
|
} |
|
|
|
static void free_leaf_list(struct ulist *blocks) |
|
{ |
|
struct ulist_node *node = NULL; |
|
struct extent_inode_elem *eie; |
|
struct ulist_iterator uiter; |
|
|
|
ULIST_ITER_INIT(&uiter); |
|
while ((node = ulist_next(blocks, &uiter))) { |
|
if (!node->aux) |
|
continue; |
|
eie = unode_aux_to_inode_list(node); |
|
free_inode_elem_list(eie); |
|
node->aux = 0; |
|
} |
|
|
|
ulist_free(blocks); |
|
} |
|
|
|
/* |
|
* Finds all leafs with a reference to the specified combination of bytenr and |
|
* offset. key_list_head will point to a list of corresponding keys (caller must |
|
* free each list element). The leafs will be stored in the leafs ulist, which |
|
* must be freed with ulist_free. |
|
* |
|
* returns 0 on success, <0 on error |
|
*/ |
|
int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, |
|
struct btrfs_fs_info *fs_info, u64 bytenr, |
|
u64 time_seq, struct ulist **leafs, |
|
const u64 *extent_item_pos, bool ignore_offset) |
|
{ |
|
int ret; |
|
|
|
*leafs = ulist_alloc(GFP_NOFS); |
|
if (!*leafs) |
|
return -ENOMEM; |
|
|
|
ret = find_parent_nodes(trans, fs_info, bytenr, time_seq, |
|
*leafs, NULL, extent_item_pos, NULL, ignore_offset); |
|
if (ret < 0 && ret != -ENOENT) { |
|
free_leaf_list(*leafs); |
|
return ret; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* walk all backrefs for a given extent to find all roots that reference this |
|
* extent. Walking a backref means finding all extents that reference this |
|
* extent and in turn walk the backrefs of those, too. Naturally this is a |
|
* recursive process, but here it is implemented in an iterative fashion: We |
|
* find all referencing extents for the extent in question and put them on a |
|
* list. In turn, we find all referencing extents for those, further appending |
|
* to the list. The way we iterate the list allows adding more elements after |
|
* the current while iterating. The process stops when we reach the end of the |
|
* list. Found roots are added to the roots list. |
|
* |
|
* returns 0 on success, < 0 on error. |
|
*/ |
|
static int btrfs_find_all_roots_safe(struct btrfs_trans_handle *trans, |
|
struct btrfs_fs_info *fs_info, u64 bytenr, |
|
u64 time_seq, struct ulist **roots, |
|
bool ignore_offset) |
|
{ |
|
struct ulist *tmp; |
|
struct ulist_node *node = NULL; |
|
struct ulist_iterator uiter; |
|
int ret; |
|
|
|
tmp = ulist_alloc(GFP_NOFS); |
|
if (!tmp) |
|
return -ENOMEM; |
|
*roots = ulist_alloc(GFP_NOFS); |
|
if (!*roots) { |
|
ulist_free(tmp); |
|
return -ENOMEM; |
|
} |
|
|
|
ULIST_ITER_INIT(&uiter); |
|
while (1) { |
|
ret = find_parent_nodes(trans, fs_info, bytenr, time_seq, |
|
tmp, *roots, NULL, NULL, ignore_offset); |
|
if (ret < 0 && ret != -ENOENT) { |
|
ulist_free(tmp); |
|
ulist_free(*roots); |
|
*roots = NULL; |
|
return ret; |
|
} |
|
node = ulist_next(tmp, &uiter); |
|
if (!node) |
|
break; |
|
bytenr = node->val; |
|
cond_resched(); |
|
} |
|
|
|
ulist_free(tmp); |
|
return 0; |
|
} |
|
|
|
int btrfs_find_all_roots(struct btrfs_trans_handle *trans, |
|
struct btrfs_fs_info *fs_info, u64 bytenr, |
|
u64 time_seq, struct ulist **roots, |
|
bool ignore_offset, bool skip_commit_root_sem) |
|
{ |
|
int ret; |
|
|
|
if (!trans && !skip_commit_root_sem) |
|
down_read(&fs_info->commit_root_sem); |
|
ret = btrfs_find_all_roots_safe(trans, fs_info, bytenr, |
|
time_seq, roots, ignore_offset); |
|
if (!trans && !skip_commit_root_sem) |
|
up_read(&fs_info->commit_root_sem); |
|
return ret; |
|
} |
|
|
|
/** |
|
* Check if an extent is shared or not |
|
* |
|
* @root: root inode belongs to |
|
* @inum: inode number of the inode whose extent we are checking |
|
* @bytenr: logical bytenr of the extent we are checking |
|
* @roots: list of roots this extent is shared among |
|
* @tmp: temporary list used for iteration |
|
* |
|
* btrfs_check_shared uses the backref walking code but will short |
|
* circuit as soon as it finds a root or inode that doesn't match the |
|
* one passed in. This provides a significant performance benefit for |
|
* callers (such as fiemap) which want to know whether the extent is |
|
* shared but do not need a ref count. |
|
* |
|
* This attempts to attach to the running transaction in order to account for |
|
* delayed refs, but continues on even when no running transaction exists. |
|
* |
|
* Return: 0 if extent is not shared, 1 if it is shared, < 0 on error. |
|
*/ |
|
int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr, |
|
struct ulist *roots, struct ulist *tmp) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
struct btrfs_trans_handle *trans; |
|
struct ulist_iterator uiter; |
|
struct ulist_node *node; |
|
struct btrfs_seq_list elem = BTRFS_SEQ_LIST_INIT(elem); |
|
int ret = 0; |
|
struct share_check shared = { |
|
.root_objectid = root->root_key.objectid, |
|
.inum = inum, |
|
.share_count = 0, |
|
}; |
|
|
|
ulist_init(roots); |
|
ulist_init(tmp); |
|
|
|
trans = btrfs_join_transaction_nostart(root); |
|
if (IS_ERR(trans)) { |
|
if (PTR_ERR(trans) != -ENOENT && PTR_ERR(trans) != -EROFS) { |
|
ret = PTR_ERR(trans); |
|
goto out; |
|
} |
|
trans = NULL; |
|
down_read(&fs_info->commit_root_sem); |
|
} else { |
|
btrfs_get_tree_mod_seq(fs_info, &elem); |
|
} |
|
|
|
ULIST_ITER_INIT(&uiter); |
|
while (1) { |
|
ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp, |
|
roots, NULL, &shared, false); |
|
if (ret == BACKREF_FOUND_SHARED) { |
|
/* this is the only condition under which we return 1 */ |
|
ret = 1; |
|
break; |
|
} |
|
if (ret < 0 && ret != -ENOENT) |
|
break; |
|
ret = 0; |
|
node = ulist_next(tmp, &uiter); |
|
if (!node) |
|
break; |
|
bytenr = node->val; |
|
shared.share_count = 0; |
|
cond_resched(); |
|
} |
|
|
|
if (trans) { |
|
btrfs_put_tree_mod_seq(fs_info, &elem); |
|
btrfs_end_transaction(trans); |
|
} else { |
|
up_read(&fs_info->commit_root_sem); |
|
} |
|
out: |
|
ulist_release(roots); |
|
ulist_release(tmp); |
|
return ret; |
|
} |
|
|
|
int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid, |
|
u64 start_off, struct btrfs_path *path, |
|
struct btrfs_inode_extref **ret_extref, |
|
u64 *found_off) |
|
{ |
|
int ret, slot; |
|
struct btrfs_key key; |
|
struct btrfs_key found_key; |
|
struct btrfs_inode_extref *extref; |
|
const struct extent_buffer *leaf; |
|
unsigned long ptr; |
|
|
|
key.objectid = inode_objectid; |
|
key.type = BTRFS_INODE_EXTREF_KEY; |
|
key.offset = start_off; |
|
|
|
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
|
if (ret < 0) |
|
return ret; |
|
|
|
while (1) { |
|
leaf = path->nodes[0]; |
|
slot = path->slots[0]; |
|
if (slot >= btrfs_header_nritems(leaf)) { |
|
/* |
|
* If the item at offset is not found, |
|
* btrfs_search_slot will point us to the slot |
|
* where it should be inserted. In our case |
|
* that will be the slot directly before the |
|
* next INODE_REF_KEY_V2 item. In the case |
|
* that we're pointing to the last slot in a |
|
* leaf, we must move one leaf over. |
|
*/ |
|
ret = btrfs_next_leaf(root, path); |
|
if (ret) { |
|
if (ret >= 1) |
|
ret = -ENOENT; |
|
break; |
|
} |
|
continue; |
|
} |
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, slot); |
|
|
|
/* |
|
* Check that we're still looking at an extended ref key for |
|
* this particular objectid. If we have different |
|
* objectid or type then there are no more to be found |
|
* in the tree and we can exit. |
|
*/ |
|
ret = -ENOENT; |
|
if (found_key.objectid != inode_objectid) |
|
break; |
|
if (found_key.type != BTRFS_INODE_EXTREF_KEY) |
|
break; |
|
|
|
ret = 0; |
|
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); |
|
extref = (struct btrfs_inode_extref *)ptr; |
|
*ret_extref = extref; |
|
if (found_off) |
|
*found_off = found_key.offset; |
|
break; |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* this iterates to turn a name (from iref/extref) into a full filesystem path. |
|
* Elements of the path are separated by '/' and the path is guaranteed to be |
|
* 0-terminated. the path is only given within the current file system. |
|
* Therefore, it never starts with a '/'. the caller is responsible to provide |
|
* "size" bytes in "dest". the dest buffer will be filled backwards. finally, |
|
* the start point of the resulting string is returned. this pointer is within |
|
* dest, normally. |
|
* in case the path buffer would overflow, the pointer is decremented further |
|
* as if output was written to the buffer, though no more output is actually |
|
* generated. that way, the caller can determine how much space would be |
|
* required for the path to fit into the buffer. in that case, the returned |
|
* value will be smaller than dest. callers must check this! |
|
*/ |
|
char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path, |
|
u32 name_len, unsigned long name_off, |
|
struct extent_buffer *eb_in, u64 parent, |
|
char *dest, u32 size) |
|
{ |
|
int slot; |
|
u64 next_inum; |
|
int ret; |
|
s64 bytes_left = ((s64)size) - 1; |
|
struct extent_buffer *eb = eb_in; |
|
struct btrfs_key found_key; |
|
struct btrfs_inode_ref *iref; |
|
|
|
if (bytes_left >= 0) |
|
dest[bytes_left] = '\0'; |
|
|
|
while (1) { |
|
bytes_left -= name_len; |
|
if (bytes_left >= 0) |
|
read_extent_buffer(eb, dest + bytes_left, |
|
name_off, name_len); |
|
if (eb != eb_in) { |
|
if (!path->skip_locking) |
|
btrfs_tree_read_unlock(eb); |
|
free_extent_buffer(eb); |
|
} |
|
ret = btrfs_find_item(fs_root, path, parent, 0, |
|
BTRFS_INODE_REF_KEY, &found_key); |
|
if (ret > 0) |
|
ret = -ENOENT; |
|
if (ret) |
|
break; |
|
|
|
next_inum = found_key.offset; |
|
|
|
/* regular exit ahead */ |
|
if (parent == next_inum) |
|
break; |
|
|
|
slot = path->slots[0]; |
|
eb = path->nodes[0]; |
|
/* make sure we can use eb after releasing the path */ |
|
if (eb != eb_in) { |
|
path->nodes[0] = NULL; |
|
path->locks[0] = 0; |
|
} |
|
btrfs_release_path(path); |
|
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); |
|
|
|
name_len = btrfs_inode_ref_name_len(eb, iref); |
|
name_off = (unsigned long)(iref + 1); |
|
|
|
parent = next_inum; |
|
--bytes_left; |
|
if (bytes_left >= 0) |
|
dest[bytes_left] = '/'; |
|
} |
|
|
|
btrfs_release_path(path); |
|
|
|
if (ret) |
|
return ERR_PTR(ret); |
|
|
|
return dest + bytes_left; |
|
} |
|
|
|
/* |
|
* this makes the path point to (logical EXTENT_ITEM *) |
|
* returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for |
|
* tree blocks and <0 on error. |
|
*/ |
|
int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical, |
|
struct btrfs_path *path, struct btrfs_key *found_key, |
|
u64 *flags_ret) |
|
{ |
|
int ret; |
|
u64 flags; |
|
u64 size = 0; |
|
u32 item_size; |
|
const struct extent_buffer *eb; |
|
struct btrfs_extent_item *ei; |
|
struct btrfs_key key; |
|
|
|
if (btrfs_fs_incompat(fs_info, SKINNY_METADATA)) |
|
key.type = BTRFS_METADATA_ITEM_KEY; |
|
else |
|
key.type = BTRFS_EXTENT_ITEM_KEY; |
|
key.objectid = logical; |
|
key.offset = (u64)-1; |
|
|
|
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0); |
|
if (ret < 0) |
|
return ret; |
|
|
|
ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0); |
|
if (ret) { |
|
if (ret > 0) |
|
ret = -ENOENT; |
|
return ret; |
|
} |
|
btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]); |
|
if (found_key->type == BTRFS_METADATA_ITEM_KEY) |
|
size = fs_info->nodesize; |
|
else if (found_key->type == BTRFS_EXTENT_ITEM_KEY) |
|
size = found_key->offset; |
|
|
|
if (found_key->objectid > logical || |
|
found_key->objectid + size <= logical) { |
|
btrfs_debug(fs_info, |
|
"logical %llu is not within any extent", logical); |
|
return -ENOENT; |
|
} |
|
|
|
eb = path->nodes[0]; |
|
item_size = btrfs_item_size_nr(eb, path->slots[0]); |
|
BUG_ON(item_size < sizeof(*ei)); |
|
|
|
ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); |
|
flags = btrfs_extent_flags(eb, ei); |
|
|
|
btrfs_debug(fs_info, |
|
"logical %llu is at position %llu within the extent (%llu EXTENT_ITEM %llu) flags %#llx size %u", |
|
logical, logical - found_key->objectid, found_key->objectid, |
|
found_key->offset, flags, item_size); |
|
|
|
WARN_ON(!flags_ret); |
|
if (flags_ret) { |
|
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) |
|
*flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK; |
|
else if (flags & BTRFS_EXTENT_FLAG_DATA) |
|
*flags_ret = BTRFS_EXTENT_FLAG_DATA; |
|
else |
|
BUG(); |
|
return 0; |
|
} |
|
|
|
return -EIO; |
|
} |
|
|
|
/* |
|
* helper function to iterate extent inline refs. ptr must point to a 0 value |
|
* for the first call and may be modified. it is used to track state. |
|
* if more refs exist, 0 is returned and the next call to |
|
* get_extent_inline_ref must pass the modified ptr parameter to get the |
|
* next ref. after the last ref was processed, 1 is returned. |
|
* returns <0 on error |
|
*/ |
|
static int get_extent_inline_ref(unsigned long *ptr, |
|
const struct extent_buffer *eb, |
|
const struct btrfs_key *key, |
|
const struct btrfs_extent_item *ei, |
|
u32 item_size, |
|
struct btrfs_extent_inline_ref **out_eiref, |
|
int *out_type) |
|
{ |
|
unsigned long end; |
|
u64 flags; |
|
struct btrfs_tree_block_info *info; |
|
|
|
if (!*ptr) { |
|
/* first call */ |
|
flags = btrfs_extent_flags(eb, ei); |
|
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { |
|
if (key->type == BTRFS_METADATA_ITEM_KEY) { |
|
/* a skinny metadata extent */ |
|
*out_eiref = |
|
(struct btrfs_extent_inline_ref *)(ei + 1); |
|
} else { |
|
WARN_ON(key->type != BTRFS_EXTENT_ITEM_KEY); |
|
info = (struct btrfs_tree_block_info *)(ei + 1); |
|
*out_eiref = |
|
(struct btrfs_extent_inline_ref *)(info + 1); |
|
} |
|
} else { |
|
*out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1); |
|
} |
|
*ptr = (unsigned long)*out_eiref; |
|
if ((unsigned long)(*ptr) >= (unsigned long)ei + item_size) |
|
return -ENOENT; |
|
} |
|
|
|
end = (unsigned long)ei + item_size; |
|
*out_eiref = (struct btrfs_extent_inline_ref *)(*ptr); |
|
*out_type = btrfs_get_extent_inline_ref_type(eb, *out_eiref, |
|
BTRFS_REF_TYPE_ANY); |
|
if (*out_type == BTRFS_REF_TYPE_INVALID) |
|
return -EUCLEAN; |
|
|
|
*ptr += btrfs_extent_inline_ref_size(*out_type); |
|
WARN_ON(*ptr > end); |
|
if (*ptr == end) |
|
return 1; /* last */ |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* reads the tree block backref for an extent. tree level and root are returned |
|
* through out_level and out_root. ptr must point to a 0 value for the first |
|
* call and may be modified (see get_extent_inline_ref comment). |
|
* returns 0 if data was provided, 1 if there was no more data to provide or |
|
* <0 on error. |
|
*/ |
|
int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb, |
|
struct btrfs_key *key, struct btrfs_extent_item *ei, |
|
u32 item_size, u64 *out_root, u8 *out_level) |
|
{ |
|
int ret; |
|
int type; |
|
struct btrfs_extent_inline_ref *eiref; |
|
|
|
if (*ptr == (unsigned long)-1) |
|
return 1; |
|
|
|
while (1) { |
|
ret = get_extent_inline_ref(ptr, eb, key, ei, item_size, |
|
&eiref, &type); |
|
if (ret < 0) |
|
return ret; |
|
|
|
if (type == BTRFS_TREE_BLOCK_REF_KEY || |
|
type == BTRFS_SHARED_BLOCK_REF_KEY) |
|
break; |
|
|
|
if (ret == 1) |
|
return 1; |
|
} |
|
|
|
/* we can treat both ref types equally here */ |
|
*out_root = btrfs_extent_inline_ref_offset(eb, eiref); |
|
|
|
if (key->type == BTRFS_EXTENT_ITEM_KEY) { |
|
struct btrfs_tree_block_info *info; |
|
|
|
info = (struct btrfs_tree_block_info *)(ei + 1); |
|
*out_level = btrfs_tree_block_level(eb, info); |
|
} else { |
|
ASSERT(key->type == BTRFS_METADATA_ITEM_KEY); |
|
*out_level = (u8)key->offset; |
|
} |
|
|
|
if (ret == 1) |
|
*ptr = (unsigned long)-1; |
|
|
|
return 0; |
|
} |
|
|
|
static int iterate_leaf_refs(struct btrfs_fs_info *fs_info, |
|
struct extent_inode_elem *inode_list, |
|
u64 root, u64 extent_item_objectid, |
|
iterate_extent_inodes_t *iterate, void *ctx) |
|
{ |
|
struct extent_inode_elem *eie; |
|
int ret = 0; |
|
|
|
for (eie = inode_list; eie; eie = eie->next) { |
|
btrfs_debug(fs_info, |
|
"ref for %llu resolved, key (%llu EXTEND_DATA %llu), root %llu", |
|
extent_item_objectid, eie->inum, |
|
eie->offset, root); |
|
ret = iterate(eie->inum, eie->offset, root, ctx); |
|
if (ret) { |
|
btrfs_debug(fs_info, |
|
"stopping iteration for %llu due to ret=%d", |
|
extent_item_objectid, ret); |
|
break; |
|
} |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* calls iterate() for every inode that references the extent identified by |
|
* the given parameters. |
|
* when the iterator function returns a non-zero value, iteration stops. |
|
*/ |
|
int iterate_extent_inodes(struct btrfs_fs_info *fs_info, |
|
u64 extent_item_objectid, u64 extent_item_pos, |
|
int search_commit_root, |
|
iterate_extent_inodes_t *iterate, void *ctx, |
|
bool ignore_offset) |
|
{ |
|
int ret; |
|
struct btrfs_trans_handle *trans = NULL; |
|
struct ulist *refs = NULL; |
|
struct ulist *roots = NULL; |
|
struct ulist_node *ref_node = NULL; |
|
struct ulist_node *root_node = NULL; |
|
struct btrfs_seq_list seq_elem = BTRFS_SEQ_LIST_INIT(seq_elem); |
|
struct ulist_iterator ref_uiter; |
|
struct ulist_iterator root_uiter; |
|
|
|
btrfs_debug(fs_info, "resolving all inodes for extent %llu", |
|
extent_item_objectid); |
|
|
|
if (!search_commit_root) { |
|
trans = btrfs_attach_transaction(fs_info->extent_root); |
|
if (IS_ERR(trans)) { |
|
if (PTR_ERR(trans) != -ENOENT && |
|
PTR_ERR(trans) != -EROFS) |
|
return PTR_ERR(trans); |
|
trans = NULL; |
|
} |
|
} |
|
|
|
if (trans) |
|
btrfs_get_tree_mod_seq(fs_info, &seq_elem); |
|
else |
|
down_read(&fs_info->commit_root_sem); |
|
|
|
ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid, |
|
seq_elem.seq, &refs, |
|
&extent_item_pos, ignore_offset); |
|
if (ret) |
|
goto out; |
|
|
|
ULIST_ITER_INIT(&ref_uiter); |
|
while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) { |
|
ret = btrfs_find_all_roots_safe(trans, fs_info, ref_node->val, |
|
seq_elem.seq, &roots, |
|
ignore_offset); |
|
if (ret) |
|
break; |
|
ULIST_ITER_INIT(&root_uiter); |
|
while (!ret && (root_node = ulist_next(roots, &root_uiter))) { |
|
btrfs_debug(fs_info, |
|
"root %llu references leaf %llu, data list %#llx", |
|
root_node->val, ref_node->val, |
|
ref_node->aux); |
|
ret = iterate_leaf_refs(fs_info, |
|
(struct extent_inode_elem *) |
|
(uintptr_t)ref_node->aux, |
|
root_node->val, |
|
extent_item_objectid, |
|
iterate, ctx); |
|
} |
|
ulist_free(roots); |
|
} |
|
|
|
free_leaf_list(refs); |
|
out: |
|
if (trans) { |
|
btrfs_put_tree_mod_seq(fs_info, &seq_elem); |
|
btrfs_end_transaction(trans); |
|
} else { |
|
up_read(&fs_info->commit_root_sem); |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info, |
|
struct btrfs_path *path, |
|
iterate_extent_inodes_t *iterate, void *ctx, |
|
bool ignore_offset) |
|
{ |
|
int ret; |
|
u64 extent_item_pos; |
|
u64 flags = 0; |
|
struct btrfs_key found_key; |
|
int search_commit_root = path->search_commit_root; |
|
|
|
ret = extent_from_logical(fs_info, logical, path, &found_key, &flags); |
|
btrfs_release_path(path); |
|
if (ret < 0) |
|
return ret; |
|
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) |
|
return -EINVAL; |
|
|
|
extent_item_pos = logical - found_key.objectid; |
|
ret = iterate_extent_inodes(fs_info, found_key.objectid, |
|
extent_item_pos, search_commit_root, |
|
iterate, ctx, ignore_offset); |
|
|
|
return ret; |
|
} |
|
|
|
typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off, |
|
struct extent_buffer *eb, void *ctx); |
|
|
|
static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root, |
|
struct btrfs_path *path, |
|
iterate_irefs_t *iterate, void *ctx) |
|
{ |
|
int ret = 0; |
|
int slot; |
|
u32 cur; |
|
u32 len; |
|
u32 name_len; |
|
u64 parent = 0; |
|
int found = 0; |
|
struct extent_buffer *eb; |
|
struct btrfs_item *item; |
|
struct btrfs_inode_ref *iref; |
|
struct btrfs_key found_key; |
|
|
|
while (!ret) { |
|
ret = btrfs_find_item(fs_root, path, inum, |
|
parent ? parent + 1 : 0, BTRFS_INODE_REF_KEY, |
|
&found_key); |
|
|
|
if (ret < 0) |
|
break; |
|
if (ret) { |
|
ret = found ? 0 : -ENOENT; |
|
break; |
|
} |
|
++found; |
|
|
|
parent = found_key.offset; |
|
slot = path->slots[0]; |
|
eb = btrfs_clone_extent_buffer(path->nodes[0]); |
|
if (!eb) { |
|
ret = -ENOMEM; |
|
break; |
|
} |
|
btrfs_release_path(path); |
|
|
|
item = btrfs_item_nr(slot); |
|
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); |
|
|
|
for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) { |
|
name_len = btrfs_inode_ref_name_len(eb, iref); |
|
/* path must be released before calling iterate()! */ |
|
btrfs_debug(fs_root->fs_info, |
|
"following ref at offset %u for inode %llu in tree %llu", |
|
cur, found_key.objectid, |
|
fs_root->root_key.objectid); |
|
ret = iterate(parent, name_len, |
|
(unsigned long)(iref + 1), eb, ctx); |
|
if (ret) |
|
break; |
|
len = sizeof(*iref) + name_len; |
|
iref = (struct btrfs_inode_ref *)((char *)iref + len); |
|
} |
|
free_extent_buffer(eb); |
|
} |
|
|
|
btrfs_release_path(path); |
|
|
|
return ret; |
|
} |
|
|
|
static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, |
|
struct btrfs_path *path, |
|
iterate_irefs_t *iterate, void *ctx) |
|
{ |
|
int ret; |
|
int slot; |
|
u64 offset = 0; |
|
u64 parent; |
|
int found = 0; |
|
struct extent_buffer *eb; |
|
struct btrfs_inode_extref *extref; |
|
u32 item_size; |
|
u32 cur_offset; |
|
unsigned long ptr; |
|
|
|
while (1) { |
|
ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref, |
|
&offset); |
|
if (ret < 0) |
|
break; |
|
if (ret) { |
|
ret = found ? 0 : -ENOENT; |
|
break; |
|
} |
|
++found; |
|
|
|
slot = path->slots[0]; |
|
eb = btrfs_clone_extent_buffer(path->nodes[0]); |
|
if (!eb) { |
|
ret = -ENOMEM; |
|
break; |
|
} |
|
btrfs_release_path(path); |
|
|
|
item_size = btrfs_item_size_nr(eb, slot); |
|
ptr = btrfs_item_ptr_offset(eb, slot); |
|
cur_offset = 0; |
|
|
|
while (cur_offset < item_size) { |
|
u32 name_len; |
|
|
|
extref = (struct btrfs_inode_extref *)(ptr + cur_offset); |
|
parent = btrfs_inode_extref_parent(eb, extref); |
|
name_len = btrfs_inode_extref_name_len(eb, extref); |
|
ret = iterate(parent, name_len, |
|
(unsigned long)&extref->name, eb, ctx); |
|
if (ret) |
|
break; |
|
|
|
cur_offset += btrfs_inode_extref_name_len(eb, extref); |
|
cur_offset += sizeof(*extref); |
|
} |
|
free_extent_buffer(eb); |
|
|
|
offset++; |
|
} |
|
|
|
btrfs_release_path(path); |
|
|
|
return ret; |
|
} |
|
|
|
static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, |
|
struct btrfs_path *path, iterate_irefs_t *iterate, |
|
void *ctx) |
|
{ |
|
int ret; |
|
int found_refs = 0; |
|
|
|
ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx); |
|
if (!ret) |
|
++found_refs; |
|
else if (ret != -ENOENT) |
|
return ret; |
|
|
|
ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx); |
|
if (ret == -ENOENT && found_refs) |
|
return 0; |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* returns 0 if the path could be dumped (probably truncated) |
|
* returns <0 in case of an error |
|
*/ |
|
static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off, |
|
struct extent_buffer *eb, void *ctx) |
|
{ |
|
struct inode_fs_paths *ipath = ctx; |
|
char *fspath; |
|
char *fspath_min; |
|
int i = ipath->fspath->elem_cnt; |
|
const int s_ptr = sizeof(char *); |
|
u32 bytes_left; |
|
|
|
bytes_left = ipath->fspath->bytes_left > s_ptr ? |
|
ipath->fspath->bytes_left - s_ptr : 0; |
|
|
|
fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr; |
|
fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len, |
|
name_off, eb, inum, fspath_min, bytes_left); |
|
if (IS_ERR(fspath)) |
|
return PTR_ERR(fspath); |
|
|
|
if (fspath > fspath_min) { |
|
ipath->fspath->val[i] = (u64)(unsigned long)fspath; |
|
++ipath->fspath->elem_cnt; |
|
ipath->fspath->bytes_left = fspath - fspath_min; |
|
} else { |
|
++ipath->fspath->elem_missed; |
|
ipath->fspath->bytes_missing += fspath_min - fspath; |
|
ipath->fspath->bytes_left = 0; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* this dumps all file system paths to the inode into the ipath struct, provided |
|
* is has been created large enough. each path is zero-terminated and accessed |
|
* from ipath->fspath->val[i]. |
|
* when it returns, there are ipath->fspath->elem_cnt number of paths available |
|
* in ipath->fspath->val[]. when the allocated space wasn't sufficient, the |
|
* number of missed paths is recorded in ipath->fspath->elem_missed, otherwise, |
|
* it's zero. ipath->fspath->bytes_missing holds the number of bytes that would |
|
* have been needed to return all paths. |
|
*/ |
|
int paths_from_inode(u64 inum, struct inode_fs_paths *ipath) |
|
{ |
|
return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path, |
|
inode_to_path, ipath); |
|
} |
|
|
|
struct btrfs_data_container *init_data_container(u32 total_bytes) |
|
{ |
|
struct btrfs_data_container *data; |
|
size_t alloc_bytes; |
|
|
|
alloc_bytes = max_t(size_t, total_bytes, sizeof(*data)); |
|
data = kvmalloc(alloc_bytes, GFP_KERNEL); |
|
if (!data) |
|
return ERR_PTR(-ENOMEM); |
|
|
|
if (total_bytes >= sizeof(*data)) { |
|
data->bytes_left = total_bytes - sizeof(*data); |
|
data->bytes_missing = 0; |
|
} else { |
|
data->bytes_missing = sizeof(*data) - total_bytes; |
|
data->bytes_left = 0; |
|
} |
|
|
|
data->elem_cnt = 0; |
|
data->elem_missed = 0; |
|
|
|
return data; |
|
} |
|
|
|
/* |
|
* allocates space to return multiple file system paths for an inode. |
|
* total_bytes to allocate are passed, note that space usable for actual path |
|
* information will be total_bytes - sizeof(struct inode_fs_paths). |
|
* the returned pointer must be freed with free_ipath() in the end. |
|
*/ |
|
struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root, |
|
struct btrfs_path *path) |
|
{ |
|
struct inode_fs_paths *ifp; |
|
struct btrfs_data_container *fspath; |
|
|
|
fspath = init_data_container(total_bytes); |
|
if (IS_ERR(fspath)) |
|
return ERR_CAST(fspath); |
|
|
|
ifp = kmalloc(sizeof(*ifp), GFP_KERNEL); |
|
if (!ifp) { |
|
kvfree(fspath); |
|
return ERR_PTR(-ENOMEM); |
|
} |
|
|
|
ifp->btrfs_path = path; |
|
ifp->fspath = fspath; |
|
ifp->fs_root = fs_root; |
|
|
|
return ifp; |
|
} |
|
|
|
void free_ipath(struct inode_fs_paths *ipath) |
|
{ |
|
if (!ipath) |
|
return; |
|
kvfree(ipath->fspath); |
|
kfree(ipath); |
|
} |
|
|
|
struct btrfs_backref_iter *btrfs_backref_iter_alloc( |
|
struct btrfs_fs_info *fs_info, gfp_t gfp_flag) |
|
{ |
|
struct btrfs_backref_iter *ret; |
|
|
|
ret = kzalloc(sizeof(*ret), gfp_flag); |
|
if (!ret) |
|
return NULL; |
|
|
|
ret->path = btrfs_alloc_path(); |
|
if (!ret->path) { |
|
kfree(ret); |
|
return NULL; |
|
} |
|
|
|
/* Current backref iterator only supports iteration in commit root */ |
|
ret->path->search_commit_root = 1; |
|
ret->path->skip_locking = 1; |
|
ret->fs_info = fs_info; |
|
|
|
return ret; |
|
} |
|
|
|
int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr) |
|
{ |
|
struct btrfs_fs_info *fs_info = iter->fs_info; |
|
struct btrfs_path *path = iter->path; |
|
struct btrfs_extent_item *ei; |
|
struct btrfs_key key; |
|
int ret; |
|
|
|
key.objectid = bytenr; |
|
key.type = BTRFS_METADATA_ITEM_KEY; |
|
key.offset = (u64)-1; |
|
iter->bytenr = bytenr; |
|
|
|
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0); |
|
if (ret < 0) |
|
return ret; |
|
if (ret == 0) { |
|
ret = -EUCLEAN; |
|
goto release; |
|
} |
|
if (path->slots[0] == 0) { |
|
WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG)); |
|
ret = -EUCLEAN; |
|
goto release; |
|
} |
|
path->slots[0]--; |
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); |
|
if ((key.type != BTRFS_EXTENT_ITEM_KEY && |
|
key.type != BTRFS_METADATA_ITEM_KEY) || key.objectid != bytenr) { |
|
ret = -ENOENT; |
|
goto release; |
|
} |
|
memcpy(&iter->cur_key, &key, sizeof(key)); |
|
iter->item_ptr = (u32)btrfs_item_ptr_offset(path->nodes[0], |
|
path->slots[0]); |
|
iter->end_ptr = (u32)(iter->item_ptr + |
|
btrfs_item_size_nr(path->nodes[0], path->slots[0])); |
|
ei = btrfs_item_ptr(path->nodes[0], path->slots[0], |
|
struct btrfs_extent_item); |
|
|
|
/* |
|
* Only support iteration on tree backref yet. |
|
* |
|
* This is an extra precaution for non skinny-metadata, where |
|
* EXTENT_ITEM is also used for tree blocks, that we can only use |
|
* extent flags to determine if it's a tree block. |
|
*/ |
|
if (btrfs_extent_flags(path->nodes[0], ei) & BTRFS_EXTENT_FLAG_DATA) { |
|
ret = -ENOTSUPP; |
|
goto release; |
|
} |
|
iter->cur_ptr = (u32)(iter->item_ptr + sizeof(*ei)); |
|
|
|
/* If there is no inline backref, go search for keyed backref */ |
|
if (iter->cur_ptr >= iter->end_ptr) { |
|
ret = btrfs_next_item(fs_info->extent_root, path); |
|
|
|
/* No inline nor keyed ref */ |
|
if (ret > 0) { |
|
ret = -ENOENT; |
|
goto release; |
|
} |
|
if (ret < 0) |
|
goto release; |
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &iter->cur_key, |
|
path->slots[0]); |
|
if (iter->cur_key.objectid != bytenr || |
|
(iter->cur_key.type != BTRFS_SHARED_BLOCK_REF_KEY && |
|
iter->cur_key.type != BTRFS_TREE_BLOCK_REF_KEY)) { |
|
ret = -ENOENT; |
|
goto release; |
|
} |
|
iter->cur_ptr = (u32)btrfs_item_ptr_offset(path->nodes[0], |
|
path->slots[0]); |
|
iter->item_ptr = iter->cur_ptr; |
|
iter->end_ptr = (u32)(iter->item_ptr + btrfs_item_size_nr( |
|
path->nodes[0], path->slots[0])); |
|
} |
|
|
|
return 0; |
|
release: |
|
btrfs_backref_iter_release(iter); |
|
return ret; |
|
} |
|
|
|
/* |
|
* Go to the next backref item of current bytenr, can be either inlined or |
|
* keyed. |
|
* |
|
* Caller needs to check whether it's inline ref or not by iter->cur_key. |
|
* |
|
* Return 0 if we get next backref without problem. |
|
* Return >0 if there is no extra backref for this bytenr. |
|
* Return <0 if there is something wrong happened. |
|
*/ |
|
int btrfs_backref_iter_next(struct btrfs_backref_iter *iter) |
|
{ |
|
struct extent_buffer *eb = btrfs_backref_get_eb(iter); |
|
struct btrfs_path *path = iter->path; |
|
struct btrfs_extent_inline_ref *iref; |
|
int ret; |
|
u32 size; |
|
|
|
if (btrfs_backref_iter_is_inline_ref(iter)) { |
|
/* We're still inside the inline refs */ |
|
ASSERT(iter->cur_ptr < iter->end_ptr); |
|
|
|
if (btrfs_backref_has_tree_block_info(iter)) { |
|
/* First tree block info */ |
|
size = sizeof(struct btrfs_tree_block_info); |
|
} else { |
|
/* Use inline ref type to determine the size */ |
|
int type; |
|
|
|
iref = (struct btrfs_extent_inline_ref *) |
|
((unsigned long)iter->cur_ptr); |
|
type = btrfs_extent_inline_ref_type(eb, iref); |
|
|
|
size = btrfs_extent_inline_ref_size(type); |
|
} |
|
iter->cur_ptr += size; |
|
if (iter->cur_ptr < iter->end_ptr) |
|
return 0; |
|
|
|
/* All inline items iterated, fall through */ |
|
} |
|
|
|
/* We're at keyed items, there is no inline item, go to the next one */ |
|
ret = btrfs_next_item(iter->fs_info->extent_root, iter->path); |
|
if (ret) |
|
return ret; |
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &iter->cur_key, path->slots[0]); |
|
if (iter->cur_key.objectid != iter->bytenr || |
|
(iter->cur_key.type != BTRFS_TREE_BLOCK_REF_KEY && |
|
iter->cur_key.type != BTRFS_SHARED_BLOCK_REF_KEY)) |
|
return 1; |
|
iter->item_ptr = (u32)btrfs_item_ptr_offset(path->nodes[0], |
|
path->slots[0]); |
|
iter->cur_ptr = iter->item_ptr; |
|
iter->end_ptr = iter->item_ptr + (u32)btrfs_item_size_nr(path->nodes[0], |
|
path->slots[0]); |
|
return 0; |
|
} |
|
|
|
void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info, |
|
struct btrfs_backref_cache *cache, int is_reloc) |
|
{ |
|
int i; |
|
|
|
cache->rb_root = RB_ROOT; |
|
for (i = 0; i < BTRFS_MAX_LEVEL; i++) |
|
INIT_LIST_HEAD(&cache->pending[i]); |
|
INIT_LIST_HEAD(&cache->changed); |
|
INIT_LIST_HEAD(&cache->detached); |
|
INIT_LIST_HEAD(&cache->leaves); |
|
INIT_LIST_HEAD(&cache->pending_edge); |
|
INIT_LIST_HEAD(&cache->useless_node); |
|
cache->fs_info = fs_info; |
|
cache->is_reloc = is_reloc; |
|
} |
|
|
|
struct btrfs_backref_node *btrfs_backref_alloc_node( |
|
struct btrfs_backref_cache *cache, u64 bytenr, int level) |
|
{ |
|
struct btrfs_backref_node *node; |
|
|
|
ASSERT(level >= 0 && level < BTRFS_MAX_LEVEL); |
|
node = kzalloc(sizeof(*node), GFP_NOFS); |
|
if (!node) |
|
return node; |
|
|
|
INIT_LIST_HEAD(&node->list); |
|
INIT_LIST_HEAD(&node->upper); |
|
INIT_LIST_HEAD(&node->lower); |
|
RB_CLEAR_NODE(&node->rb_node); |
|
cache->nr_nodes++; |
|
node->level = level; |
|
node->bytenr = bytenr; |
|
|
|
return node; |
|
} |
|
|
|
struct btrfs_backref_edge *btrfs_backref_alloc_edge( |
|
struct btrfs_backref_cache *cache) |
|
{ |
|
struct btrfs_backref_edge *edge; |
|
|
|
edge = kzalloc(sizeof(*edge), GFP_NOFS); |
|
if (edge) |
|
cache->nr_edges++; |
|
return edge; |
|
} |
|
|
|
/* |
|
* Drop the backref node from cache, also cleaning up all its |
|
* upper edges and any uncached nodes in the path. |
|
* |
|
* This cleanup happens bottom up, thus the node should either |
|
* be the lowest node in the cache or a detached node. |
|
*/ |
|
void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache, |
|
struct btrfs_backref_node *node) |
|
{ |
|
struct btrfs_backref_node *upper; |
|
struct btrfs_backref_edge *edge; |
|
|
|
if (!node) |
|
return; |
|
|
|
BUG_ON(!node->lowest && !node->detached); |
|
while (!list_empty(&node->upper)) { |
|
edge = list_entry(node->upper.next, struct btrfs_backref_edge, |
|
list[LOWER]); |
|
upper = edge->node[UPPER]; |
|
list_del(&edge->list[LOWER]); |
|
list_del(&edge->list[UPPER]); |
|
btrfs_backref_free_edge(cache, edge); |
|
|
|
/* |
|
* Add the node to leaf node list if no other child block |
|
* cached. |
|
*/ |
|
if (list_empty(&upper->lower)) { |
|
list_add_tail(&upper->lower, &cache->leaves); |
|
upper->lowest = 1; |
|
} |
|
} |
|
|
|
btrfs_backref_drop_node(cache, node); |
|
} |
|
|
|
/* |
|
* Release all nodes/edges from current cache |
|
*/ |
|
void btrfs_backref_release_cache(struct btrfs_backref_cache *cache) |
|
{ |
|
struct btrfs_backref_node *node; |
|
int i; |
|
|
|
while (!list_empty(&cache->detached)) { |
|
node = list_entry(cache->detached.next, |
|
struct btrfs_backref_node, list); |
|
btrfs_backref_cleanup_node(cache, node); |
|
} |
|
|
|
while (!list_empty(&cache->leaves)) { |
|
node = list_entry(cache->leaves.next, |
|
struct btrfs_backref_node, lower); |
|
btrfs_backref_cleanup_node(cache, node); |
|
} |
|
|
|
cache->last_trans = 0; |
|
|
|
for (i = 0; i < BTRFS_MAX_LEVEL; i++) |
|
ASSERT(list_empty(&cache->pending[i])); |
|
ASSERT(list_empty(&cache->pending_edge)); |
|
ASSERT(list_empty(&cache->useless_node)); |
|
ASSERT(list_empty(&cache->changed)); |
|
ASSERT(list_empty(&cache->detached)); |
|
ASSERT(RB_EMPTY_ROOT(&cache->rb_root)); |
|
ASSERT(!cache->nr_nodes); |
|
ASSERT(!cache->nr_edges); |
|
} |
|
|
|
/* |
|
* Handle direct tree backref |
|
* |
|
* Direct tree backref means, the backref item shows its parent bytenr |
|
* directly. This is for SHARED_BLOCK_REF backref (keyed or inlined). |
|
* |
|
* @ref_key: The converted backref key. |
|
* For keyed backref, it's the item key. |
|
* For inlined backref, objectid is the bytenr, |
|
* type is btrfs_inline_ref_type, offset is |
|
* btrfs_inline_ref_offset. |
|
*/ |
|
static int handle_direct_tree_backref(struct btrfs_backref_cache *cache, |
|
struct btrfs_key *ref_key, |
|
struct btrfs_backref_node *cur) |
|
{ |
|
struct btrfs_backref_edge *edge; |
|
struct btrfs_backref_node *upper; |
|
struct rb_node *rb_node; |
|
|
|
ASSERT(ref_key->type == BTRFS_SHARED_BLOCK_REF_KEY); |
|
|
|
/* Only reloc root uses backref pointing to itself */ |
|
if (ref_key->objectid == ref_key->offset) { |
|
struct btrfs_root *root; |
|
|
|
cur->is_reloc_root = 1; |
|
/* Only reloc backref cache cares about a specific root */ |
|
if (cache->is_reloc) { |
|
root = find_reloc_root(cache->fs_info, cur->bytenr); |
|
if (!root) |
|
return -ENOENT; |
|
cur->root = root; |
|
} else { |
|
/* |
|
* For generic purpose backref cache, reloc root node |
|
* is useless. |
|
*/ |
|
list_add(&cur->list, &cache->useless_node); |
|
} |
|
return 0; |
|
} |
|
|
|
edge = btrfs_backref_alloc_edge(cache); |
|
if (!edge) |
|
return -ENOMEM; |
|
|
|
rb_node = rb_simple_search(&cache->rb_root, ref_key->offset); |
|
if (!rb_node) { |
|
/* Parent node not yet cached */ |
|
upper = btrfs_backref_alloc_node(cache, ref_key->offset, |
|
cur->level + 1); |
|
if (!upper) { |
|
btrfs_backref_free_edge(cache, edge); |
|
return -ENOMEM; |
|
} |
|
|
|
/* |
|
* Backrefs for the upper level block isn't cached, add the |
|
* block to pending list |
|
*/ |
|
list_add_tail(&edge->list[UPPER], &cache->pending_edge); |
|
} else { |
|
/* Parent node already cached */ |
|
upper = rb_entry(rb_node, struct btrfs_backref_node, rb_node); |
|
ASSERT(upper->checked); |
|
INIT_LIST_HEAD(&edge->list[UPPER]); |
|
} |
|
btrfs_backref_link_edge(edge, cur, upper, LINK_LOWER); |
|
return 0; |
|
} |
|
|
|
/* |
|
* Handle indirect tree backref |
|
* |
|
* Indirect tree backref means, we only know which tree the node belongs to. |
|
* We still need to do a tree search to find out the parents. This is for |
|
* TREE_BLOCK_REF backref (keyed or inlined). |
|
* |
|
* @ref_key: The same as @ref_key in handle_direct_tree_backref() |
|
* @tree_key: The first key of this tree block. |
|
* @path: A clean (released) path, to avoid allocating path every time |
|
* the function get called. |
|
*/ |
|
static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache, |
|
struct btrfs_path *path, |
|
struct btrfs_key *ref_key, |
|
struct btrfs_key *tree_key, |
|
struct btrfs_backref_node *cur) |
|
{ |
|
struct btrfs_fs_info *fs_info = cache->fs_info; |
|
struct btrfs_backref_node *upper; |
|
struct btrfs_backref_node *lower; |
|
struct btrfs_backref_edge *edge; |
|
struct extent_buffer *eb; |
|
struct btrfs_root *root; |
|
struct rb_node *rb_node; |
|
int level; |
|
bool need_check = true; |
|
int ret; |
|
|
|
root = btrfs_get_fs_root(fs_info, ref_key->offset, false); |
|
if (IS_ERR(root)) |
|
return PTR_ERR(root); |
|
if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) |
|
cur->cowonly = 1; |
|
|
|
if (btrfs_root_level(&root->root_item) == cur->level) { |
|
/* Tree root */ |
|
ASSERT(btrfs_root_bytenr(&root->root_item) == cur->bytenr); |
|
/* |
|
* For reloc backref cache, we may ignore reloc root. But for |
|
* general purpose backref cache, we can't rely on |
|
* btrfs_should_ignore_reloc_root() as it may conflict with |
|
* current running relocation and lead to missing root. |
|
* |
|
* For general purpose backref cache, reloc root detection is |
|
* completely relying on direct backref (key->offset is parent |
|
* bytenr), thus only do such check for reloc cache. |
|
*/ |
|
if (btrfs_should_ignore_reloc_root(root) && cache->is_reloc) { |
|
btrfs_put_root(root); |
|
list_add(&cur->list, &cache->useless_node); |
|
} else { |
|
cur->root = root; |
|
} |
|
return 0; |
|
} |
|
|
|
level = cur->level + 1; |
|
|
|
/* Search the tree to find parent blocks referring to the block */ |
|
path->search_commit_root = 1; |
|
path->skip_locking = 1; |
|
path->lowest_level = level; |
|
ret = btrfs_search_slot(NULL, root, tree_key, path, 0, 0); |
|
path->lowest_level = 0; |
|
if (ret < 0) { |
|
btrfs_put_root(root); |
|
return ret; |
|
} |
|
if (ret > 0 && path->slots[level] > 0) |
|
path->slots[level]--; |
|
|
|
eb = path->nodes[level]; |
|
if (btrfs_node_blockptr(eb, path->slots[level]) != cur->bytenr) { |
|
btrfs_err(fs_info, |
|
"couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)", |
|
cur->bytenr, level - 1, root->root_key.objectid, |
|
tree_key->objectid, tree_key->type, tree_key->offset); |
|
btrfs_put_root(root); |
|
ret = -ENOENT; |
|
goto out; |
|
} |
|
lower = cur; |
|
|
|
/* Add all nodes and edges in the path */ |
|
for (; level < BTRFS_MAX_LEVEL; level++) { |
|
if (!path->nodes[level]) { |
|
ASSERT(btrfs_root_bytenr(&root->root_item) == |
|
lower->bytenr); |
|
/* Same as previous should_ignore_reloc_root() call */ |
|
if (btrfs_should_ignore_reloc_root(root) && |
|
cache->is_reloc) { |
|
btrfs_put_root(root); |
|
list_add(&lower->list, &cache->useless_node); |
|
} else { |
|
lower->root = root; |
|
} |
|
break; |
|
} |
|
|
|
edge = btrfs_backref_alloc_edge(cache); |
|
if (!edge) { |
|
btrfs_put_root(root); |
|
ret = -ENOMEM; |
|
goto out; |
|
} |
|
|
|
eb = path->nodes[level]; |
|
rb_node = rb_simple_search(&cache->rb_root, eb->start); |
|
if (!rb_node) { |
|
upper = btrfs_backref_alloc_node(cache, eb->start, |
|
lower->level + 1); |
|
if (!upper) { |
|
btrfs_put_root(root); |
|
btrfs_backref_free_edge(cache, edge); |
|
ret = -ENOMEM; |
|
goto out; |
|
} |
|
upper->owner = btrfs_header_owner(eb); |
|
if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) |
|
upper->cowonly = 1; |
|
|
|
/* |
|
* If we know the block isn't shared we can avoid |
|
* checking its backrefs. |
|
*/ |
|
if (btrfs_block_can_be_shared(root, eb)) |
|
upper->checked = 0; |
|
else |
|
upper->checked = 1; |
|
|
|
/* |
|
* Add the block to pending list if we need to check its |
|
* backrefs, we only do this once while walking up a |
|
* tree as we will catch anything else later on. |
|
*/ |
|
if (!upper->checked && need_check) { |
|
need_check = false; |
|
list_add_tail(&edge->list[UPPER], |
|
&cache->pending_edge); |
|
} else { |
|
if (upper->checked) |
|
need_check = true; |
|
INIT_LIST_HEAD(&edge->list[UPPER]); |
|
} |
|
} else { |
|
upper = rb_entry(rb_node, struct btrfs_backref_node, |
|
rb_node); |
|
ASSERT(upper->checked); |
|
INIT_LIST_HEAD(&edge->list[UPPER]); |
|
if (!upper->owner) |
|
upper->owner = btrfs_header_owner(eb); |
|
} |
|
btrfs_backref_link_edge(edge, lower, upper, LINK_LOWER); |
|
|
|
if (rb_node) { |
|
btrfs_put_root(root); |
|
break; |
|
} |
|
lower = upper; |
|
upper = NULL; |
|
} |
|
out: |
|
btrfs_release_path(path); |
|
return ret; |
|
} |
|
|
|
/* |
|
* Add backref node @cur into @cache. |
|
* |
|
* NOTE: Even if the function returned 0, @cur is not yet cached as its upper |
|
* links aren't yet bi-directional. Needs to finish such links. |
|
* Use btrfs_backref_finish_upper_links() to finish such linkage. |
|
* |
|
* @path: Released path for indirect tree backref lookup |
|
* @iter: Released backref iter for extent tree search |
|
* @node_key: The first key of the tree block |
|
*/ |
|
int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache, |
|
struct btrfs_path *path, |
|
struct btrfs_backref_iter *iter, |
|
struct btrfs_key *node_key, |
|
struct btrfs_backref_node *cur) |
|
{ |
|
struct btrfs_fs_info *fs_info = cache->fs_info; |
|
struct btrfs_backref_edge *edge; |
|
struct btrfs_backref_node *exist; |
|
int ret; |
|
|
|
ret = btrfs_backref_iter_start(iter, cur->bytenr); |
|
if (ret < 0) |
|
return ret; |
|
/* |
|
* We skip the first btrfs_tree_block_info, as we don't use the key |
|
* stored in it, but fetch it from the tree block |
|
*/ |
|
if (btrfs_backref_has_tree_block_info(iter)) { |
|
ret = btrfs_backref_iter_next(iter); |
|
if (ret < 0) |
|
goto out; |
|
/* No extra backref? This means the tree block is corrupted */ |
|
if (ret > 0) { |
|
ret = -EUCLEAN; |
|
goto out; |
|
} |
|
} |
|
WARN_ON(cur->checked); |
|
if (!list_empty(&cur->upper)) { |
|
/* |
|
* The backref was added previously when processing backref of |
|
* type BTRFS_TREE_BLOCK_REF_KEY |
|
*/ |
|
ASSERT(list_is_singular(&cur->upper)); |
|
edge = list_entry(cur->upper.next, struct btrfs_backref_edge, |
|
list[LOWER]); |
|
ASSERT(list_empty(&edge->list[UPPER])); |
|
exist = edge->node[UPPER]; |
|
/* |
|
* Add the upper level block to pending list if we need check |
|
* its backrefs |
|
*/ |
|
if (!exist->checked) |
|
list_add_tail(&edge->list[UPPER], &cache->pending_edge); |
|
} else { |
|
exist = NULL; |
|
} |
|
|
|
for (; ret == 0; ret = btrfs_backref_iter_next(iter)) { |
|
struct extent_buffer *eb; |
|
struct btrfs_key key; |
|
int type; |
|
|
|
cond_resched(); |
|
eb = btrfs_backref_get_eb(iter); |
|
|
|
key.objectid = iter->bytenr; |
|
if (btrfs_backref_iter_is_inline_ref(iter)) { |
|
struct btrfs_extent_inline_ref *iref; |
|
|
|
/* Update key for inline backref */ |
|
iref = (struct btrfs_extent_inline_ref *) |
|
((unsigned long)iter->cur_ptr); |
|
type = btrfs_get_extent_inline_ref_type(eb, iref, |
|
BTRFS_REF_TYPE_BLOCK); |
|
if (type == BTRFS_REF_TYPE_INVALID) { |
|
ret = -EUCLEAN; |
|
goto out; |
|
} |
|
key.type = type; |
|
key.offset = btrfs_extent_inline_ref_offset(eb, iref); |
|
} else { |
|
key.type = iter->cur_key.type; |
|
key.offset = iter->cur_key.offset; |
|
} |
|
|
|
/* |
|
* Parent node found and matches current inline ref, no need to |
|
* rebuild this node for this inline ref |
|
*/ |
|
if (exist && |
|
((key.type == BTRFS_TREE_BLOCK_REF_KEY && |
|
exist->owner == key.offset) || |
|
(key.type == BTRFS_SHARED_BLOCK_REF_KEY && |
|
exist->bytenr == key.offset))) { |
|
exist = NULL; |
|
continue; |
|
} |
|
|
|
/* SHARED_BLOCK_REF means key.offset is the parent bytenr */ |
|
if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) { |
|
ret = handle_direct_tree_backref(cache, &key, cur); |
|
if (ret < 0) |
|
goto out; |
|
continue; |
|
} else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) { |
|
ret = -EINVAL; |
|
btrfs_print_v0_err(fs_info); |
|
btrfs_handle_fs_error(fs_info, ret, NULL); |
|
goto out; |
|
} else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) { |
|
continue; |
|
} |
|
|
|
/* |
|
* key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset |
|
* means the root objectid. We need to search the tree to get |
|
* its parent bytenr. |
|
*/ |
|
ret = handle_indirect_tree_backref(cache, path, &key, node_key, |
|
cur); |
|
if (ret < 0) |
|
goto out; |
|
} |
|
ret = 0; |
|
cur->checked = 1; |
|
WARN_ON(exist); |
|
out: |
|
btrfs_backref_iter_release(iter); |
|
return ret; |
|
} |
|
|
|
/* |
|
* Finish the upwards linkage created by btrfs_backref_add_tree_node() |
|
*/ |
|
int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache, |
|
struct btrfs_backref_node *start) |
|
{ |
|
struct list_head *useless_node = &cache->useless_node; |
|
struct btrfs_backref_edge *edge; |
|
struct rb_node *rb_node; |
|
LIST_HEAD(pending_edge); |
|
|
|
ASSERT(start->checked); |
|
|
|
/* Insert this node to cache if it's not COW-only */ |
|
if (!start->cowonly) { |
|
rb_node = rb_simple_insert(&cache->rb_root, start->bytenr, |
|
&start->rb_node); |
|
if (rb_node) |
|
btrfs_backref_panic(cache->fs_info, start->bytenr, |
|
-EEXIST); |
|
list_add_tail(&start->lower, &cache->leaves); |
|
} |
|
|
|
/* |
|
* Use breadth first search to iterate all related edges. |
|
* |
|
* The starting points are all the edges of this node |
|
*/ |
|
list_for_each_entry(edge, &start->upper, list[LOWER]) |
|
list_add_tail(&edge->list[UPPER], &pending_edge); |
|
|
|
while (!list_empty(&pending_edge)) { |
|
struct btrfs_backref_node *upper; |
|
struct btrfs_backref_node *lower; |
|
|
|
edge = list_first_entry(&pending_edge, |
|
struct btrfs_backref_edge, list[UPPER]); |
|
list_del_init(&edge->list[UPPER]); |
|
upper = edge->node[UPPER]; |
|
lower = edge->node[LOWER]; |
|
|
|
/* Parent is detached, no need to keep any edges */ |
|
if (upper->detached) { |
|
list_del(&edge->list[LOWER]); |
|
btrfs_backref_free_edge(cache, edge); |
|
|
|
/* Lower node is orphan, queue for cleanup */ |
|
if (list_empty(&lower->upper)) |
|
list_add(&lower->list, useless_node); |
|
continue; |
|
} |
|
|
|
/* |
|
* All new nodes added in current build_backref_tree() haven't |
|
* been linked to the cache rb tree. |
|
* So if we have upper->rb_node populated, this means a cache |
|
* hit. We only need to link the edge, as @upper and all its |
|
* parents have already been linked. |
|
*/ |
|
if (!RB_EMPTY_NODE(&upper->rb_node)) { |
|
if (upper->lowest) { |
|
list_del_init(&upper->lower); |
|
upper->lowest = 0; |
|
} |
|
|
|
list_add_tail(&edge->list[UPPER], &upper->lower); |
|
continue; |
|
} |
|
|
|
/* Sanity check, we shouldn't have any unchecked nodes */ |
|
if (!upper->checked) { |
|
ASSERT(0); |
|
return -EUCLEAN; |
|
} |
|
|
|
/* Sanity check, COW-only node has non-COW-only parent */ |
|
if (start->cowonly != upper->cowonly) { |
|
ASSERT(0); |
|
return -EUCLEAN; |
|
} |
|
|
|
/* Only cache non-COW-only (subvolume trees) tree blocks */ |
|
if (!upper->cowonly) { |
|
rb_node = rb_simple_insert(&cache->rb_root, upper->bytenr, |
|
&upper->rb_node); |
|
if (rb_node) { |
|
btrfs_backref_panic(cache->fs_info, |
|
upper->bytenr, -EEXIST); |
|
return -EUCLEAN; |
|
} |
|
} |
|
|
|
list_add_tail(&edge->list[UPPER], &upper->lower); |
|
|
|
/* |
|
* Also queue all the parent edges of this uncached node |
|
* to finish the upper linkage |
|
*/ |
|
list_for_each_entry(edge, &upper->upper, list[LOWER]) |
|
list_add_tail(&edge->list[UPPER], &pending_edge); |
|
} |
|
return 0; |
|
} |
|
|
|
void btrfs_backref_error_cleanup(struct btrfs_backref_cache *cache, |
|
struct btrfs_backref_node *node) |
|
{ |
|
struct btrfs_backref_node *lower; |
|
struct btrfs_backref_node *upper; |
|
struct btrfs_backref_edge *edge; |
|
|
|
while (!list_empty(&cache->useless_node)) { |
|
lower = list_first_entry(&cache->useless_node, |
|
struct btrfs_backref_node, list); |
|
list_del_init(&lower->list); |
|
} |
|
while (!list_empty(&cache->pending_edge)) { |
|
edge = list_first_entry(&cache->pending_edge, |
|
struct btrfs_backref_edge, list[UPPER]); |
|
list_del(&edge->list[UPPER]); |
|
list_del(&edge->list[LOWER]); |
|
lower = edge->node[LOWER]; |
|
upper = edge->node[UPPER]; |
|
btrfs_backref_free_edge(cache, edge); |
|
|
|
/* |
|
* Lower is no longer linked to any upper backref nodes and |
|
* isn't in the cache, we can free it ourselves. |
|
*/ |
|
if (list_empty(&lower->upper) && |
|
RB_EMPTY_NODE(&lower->rb_node)) |
|
list_add(&lower->list, &cache->useless_node); |
|
|
|
if (!RB_EMPTY_NODE(&upper->rb_node)) |
|
continue; |
|
|
|
/* Add this guy's upper edges to the list to process */ |
|
list_for_each_entry(edge, &upper->upper, list[LOWER]) |
|
list_add_tail(&edge->list[UPPER], |
|
&cache->pending_edge); |
|
if (list_empty(&upper->upper)) |
|
list_add(&upper->list, &cache->useless_node); |
|
} |
|
|
|
while (!list_empty(&cache->useless_node)) { |
|
lower = list_first_entry(&cache->useless_node, |
|
struct btrfs_backref_node, list); |
|
list_del_init(&lower->list); |
|
if (lower == node) |
|
node = NULL; |
|
btrfs_backref_drop_node(cache, lower); |
|
} |
|
|
|
btrfs_backref_cleanup_node(cache, node); |
|
ASSERT(list_empty(&cache->useless_node) && |
|
list_empty(&cache->pending_edge)); |
|
}
|
|
|