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1228 lines
27 KiB
1228 lines
27 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* |
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* Copyright (C) 2011 Novell Inc. |
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*/ |
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|
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#include <linux/fs.h> |
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#include <linux/slab.h> |
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#include <linux/namei.h> |
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#include <linux/file.h> |
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#include <linux/xattr.h> |
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#include <linux/rbtree.h> |
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#include <linux/security.h> |
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#include <linux/cred.h> |
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#include <linux/ratelimit.h> |
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#include "overlayfs.h" |
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|
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struct ovl_cache_entry { |
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unsigned int len; |
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unsigned int type; |
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u64 real_ino; |
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u64 ino; |
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struct list_head l_node; |
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struct rb_node node; |
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struct ovl_cache_entry *next_maybe_whiteout; |
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bool is_upper; |
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bool is_whiteout; |
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char name[]; |
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}; |
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struct ovl_dir_cache { |
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long refcount; |
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u64 version; |
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struct list_head entries; |
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struct rb_root root; |
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}; |
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struct ovl_readdir_data { |
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struct dir_context ctx; |
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struct dentry *dentry; |
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bool is_lowest; |
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struct rb_root *root; |
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struct list_head *list; |
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struct list_head middle; |
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struct ovl_cache_entry *first_maybe_whiteout; |
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int count; |
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int err; |
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bool is_upper; |
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bool d_type_supported; |
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}; |
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struct ovl_dir_file { |
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bool is_real; |
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bool is_upper; |
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struct ovl_dir_cache *cache; |
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struct list_head *cursor; |
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struct file *realfile; |
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struct file *upperfile; |
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}; |
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static struct ovl_cache_entry *ovl_cache_entry_from_node(struct rb_node *n) |
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{ |
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return rb_entry(n, struct ovl_cache_entry, node); |
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} |
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|
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static bool ovl_cache_entry_find_link(const char *name, int len, |
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struct rb_node ***link, |
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struct rb_node **parent) |
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{ |
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bool found = false; |
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struct rb_node **newp = *link; |
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|
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while (!found && *newp) { |
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int cmp; |
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struct ovl_cache_entry *tmp; |
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*parent = *newp; |
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tmp = ovl_cache_entry_from_node(*newp); |
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cmp = strncmp(name, tmp->name, len); |
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if (cmp > 0) |
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newp = &tmp->node.rb_right; |
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else if (cmp < 0 || len < tmp->len) |
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newp = &tmp->node.rb_left; |
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else |
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found = true; |
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} |
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*link = newp; |
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|
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return found; |
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} |
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static struct ovl_cache_entry *ovl_cache_entry_find(struct rb_root *root, |
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const char *name, int len) |
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{ |
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struct rb_node *node = root->rb_node; |
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int cmp; |
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|
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while (node) { |
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struct ovl_cache_entry *p = ovl_cache_entry_from_node(node); |
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cmp = strncmp(name, p->name, len); |
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if (cmp > 0) |
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node = p->node.rb_right; |
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else if (cmp < 0 || len < p->len) |
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node = p->node.rb_left; |
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else |
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return p; |
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} |
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|
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return NULL; |
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} |
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static bool ovl_calc_d_ino(struct ovl_readdir_data *rdd, |
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struct ovl_cache_entry *p) |
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{ |
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/* Don't care if not doing ovl_iter() */ |
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if (!rdd->dentry) |
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return false; |
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|
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/* Always recalc d_ino when remapping lower inode numbers */ |
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if (ovl_xino_bits(rdd->dentry->d_sb)) |
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return true; |
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|
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/* Always recalc d_ino for parent */ |
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if (strcmp(p->name, "..") == 0) |
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return true; |
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|
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/* If this is lower, then native d_ino will do */ |
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if (!rdd->is_upper) |
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return false; |
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|
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/* |
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* Recalc d_ino for '.' and for all entries if dir is impure (contains |
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* copied up entries) |
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*/ |
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if ((p->name[0] == '.' && p->len == 1) || |
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ovl_test_flag(OVL_IMPURE, d_inode(rdd->dentry))) |
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return true; |
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return false; |
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} |
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static struct ovl_cache_entry *ovl_cache_entry_new(struct ovl_readdir_data *rdd, |
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const char *name, int len, |
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u64 ino, unsigned int d_type) |
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{ |
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struct ovl_cache_entry *p; |
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size_t size = offsetof(struct ovl_cache_entry, name[len + 1]); |
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|
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p = kmalloc(size, GFP_KERNEL); |
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if (!p) |
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return NULL; |
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memcpy(p->name, name, len); |
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p->name[len] = '\0'; |
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p->len = len; |
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p->type = d_type; |
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p->real_ino = ino; |
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p->ino = ino; |
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/* Defer setting d_ino for upper entry to ovl_iterate() */ |
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if (ovl_calc_d_ino(rdd, p)) |
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p->ino = 0; |
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p->is_upper = rdd->is_upper; |
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p->is_whiteout = false; |
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|
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if (d_type == DT_CHR) { |
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p->next_maybe_whiteout = rdd->first_maybe_whiteout; |
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rdd->first_maybe_whiteout = p; |
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} |
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return p; |
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} |
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static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd, |
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const char *name, int len, u64 ino, |
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unsigned int d_type) |
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{ |
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struct rb_node **newp = &rdd->root->rb_node; |
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struct rb_node *parent = NULL; |
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struct ovl_cache_entry *p; |
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|
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if (ovl_cache_entry_find_link(name, len, &newp, &parent)) |
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return 0; |
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p = ovl_cache_entry_new(rdd, name, len, ino, d_type); |
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if (p == NULL) { |
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rdd->err = -ENOMEM; |
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return -ENOMEM; |
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} |
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list_add_tail(&p->l_node, rdd->list); |
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rb_link_node(&p->node, parent, newp); |
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rb_insert_color(&p->node, rdd->root); |
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return 0; |
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} |
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static int ovl_fill_lowest(struct ovl_readdir_data *rdd, |
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const char *name, int namelen, |
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loff_t offset, u64 ino, unsigned int d_type) |
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{ |
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struct ovl_cache_entry *p; |
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p = ovl_cache_entry_find(rdd->root, name, namelen); |
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if (p) { |
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list_move_tail(&p->l_node, &rdd->middle); |
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} else { |
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p = ovl_cache_entry_new(rdd, name, namelen, ino, d_type); |
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if (p == NULL) |
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rdd->err = -ENOMEM; |
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else |
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list_add_tail(&p->l_node, &rdd->middle); |
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} |
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|
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return rdd->err; |
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} |
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void ovl_cache_free(struct list_head *list) |
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{ |
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struct ovl_cache_entry *p; |
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struct ovl_cache_entry *n; |
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list_for_each_entry_safe(p, n, list, l_node) |
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kfree(p); |
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|
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INIT_LIST_HEAD(list); |
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} |
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void ovl_dir_cache_free(struct inode *inode) |
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{ |
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struct ovl_dir_cache *cache = ovl_dir_cache(inode); |
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if (cache) { |
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ovl_cache_free(&cache->entries); |
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kfree(cache); |
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} |
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} |
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static void ovl_cache_put(struct ovl_dir_file *od, struct dentry *dentry) |
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{ |
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struct ovl_dir_cache *cache = od->cache; |
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|
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WARN_ON(cache->refcount <= 0); |
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cache->refcount--; |
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if (!cache->refcount) { |
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if (ovl_dir_cache(d_inode(dentry)) == cache) |
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ovl_set_dir_cache(d_inode(dentry), NULL); |
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ovl_cache_free(&cache->entries); |
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kfree(cache); |
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} |
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} |
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static int ovl_fill_merge(struct dir_context *ctx, const char *name, |
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int namelen, loff_t offset, u64 ino, |
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unsigned int d_type) |
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{ |
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struct ovl_readdir_data *rdd = |
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container_of(ctx, struct ovl_readdir_data, ctx); |
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|
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rdd->count++; |
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if (!rdd->is_lowest) |
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return ovl_cache_entry_add_rb(rdd, name, namelen, ino, d_type); |
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else |
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return ovl_fill_lowest(rdd, name, namelen, offset, ino, d_type); |
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} |
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static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd) |
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{ |
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int err; |
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struct ovl_cache_entry *p; |
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struct dentry *dentry; |
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const struct cred *old_cred; |
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old_cred = ovl_override_creds(rdd->dentry->d_sb); |
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err = down_write_killable(&dir->d_inode->i_rwsem); |
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if (!err) { |
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while (rdd->first_maybe_whiteout) { |
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p = rdd->first_maybe_whiteout; |
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rdd->first_maybe_whiteout = p->next_maybe_whiteout; |
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dentry = lookup_one_len(p->name, dir, p->len); |
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if (!IS_ERR(dentry)) { |
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p->is_whiteout = ovl_is_whiteout(dentry); |
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dput(dentry); |
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} |
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} |
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inode_unlock(dir->d_inode); |
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} |
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revert_creds(old_cred); |
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return err; |
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} |
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static inline int ovl_dir_read(struct path *realpath, |
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struct ovl_readdir_data *rdd) |
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{ |
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struct file *realfile; |
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int err; |
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realfile = ovl_path_open(realpath, O_RDONLY | O_LARGEFILE); |
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if (IS_ERR(realfile)) |
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return PTR_ERR(realfile); |
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rdd->first_maybe_whiteout = NULL; |
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rdd->ctx.pos = 0; |
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do { |
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rdd->count = 0; |
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rdd->err = 0; |
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err = iterate_dir(realfile, &rdd->ctx); |
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if (err >= 0) |
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err = rdd->err; |
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} while (!err && rdd->count); |
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if (!err && rdd->first_maybe_whiteout && rdd->dentry) |
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err = ovl_check_whiteouts(realpath->dentry, rdd); |
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fput(realfile); |
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return err; |
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} |
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static void ovl_dir_reset(struct file *file) |
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{ |
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struct ovl_dir_file *od = file->private_data; |
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struct ovl_dir_cache *cache = od->cache; |
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struct dentry *dentry = file->f_path.dentry; |
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bool is_real; |
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if (cache && ovl_dentry_version_get(dentry) != cache->version) { |
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ovl_cache_put(od, dentry); |
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od->cache = NULL; |
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od->cursor = NULL; |
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} |
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is_real = ovl_dir_is_real(dentry); |
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if (od->is_real != is_real) { |
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/* is_real can only become false when dir is copied up */ |
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if (WARN_ON(is_real)) |
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return; |
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od->is_real = false; |
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} |
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} |
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static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list, |
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struct rb_root *root) |
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{ |
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int err; |
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struct path realpath; |
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struct ovl_readdir_data rdd = { |
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.ctx.actor = ovl_fill_merge, |
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.dentry = dentry, |
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.list = list, |
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.root = root, |
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.is_lowest = false, |
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}; |
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int idx, next; |
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|
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for (idx = 0; idx != -1; idx = next) { |
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next = ovl_path_next(idx, dentry, &realpath); |
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rdd.is_upper = ovl_dentry_upper(dentry) == realpath.dentry; |
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|
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if (next != -1) { |
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err = ovl_dir_read(&realpath, &rdd); |
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if (err) |
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break; |
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} else { |
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/* |
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* Insert lowest layer entries before upper ones, this |
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* allows offsets to be reasonably constant |
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*/ |
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list_add(&rdd.middle, rdd.list); |
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rdd.is_lowest = true; |
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err = ovl_dir_read(&realpath, &rdd); |
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list_del(&rdd.middle); |
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} |
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} |
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return err; |
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} |
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|
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static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos) |
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{ |
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struct list_head *p; |
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loff_t off = 0; |
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|
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list_for_each(p, &od->cache->entries) { |
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if (off >= pos) |
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break; |
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off++; |
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} |
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/* Cursor is safe since the cache is stable */ |
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od->cursor = p; |
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} |
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|
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static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry) |
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{ |
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int res; |
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struct ovl_dir_cache *cache; |
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|
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cache = ovl_dir_cache(d_inode(dentry)); |
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if (cache && ovl_dentry_version_get(dentry) == cache->version) { |
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WARN_ON(!cache->refcount); |
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cache->refcount++; |
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return cache; |
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} |
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ovl_set_dir_cache(d_inode(dentry), NULL); |
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|
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cache = kzalloc(sizeof(struct ovl_dir_cache), GFP_KERNEL); |
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if (!cache) |
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return ERR_PTR(-ENOMEM); |
|
|
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cache->refcount = 1; |
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INIT_LIST_HEAD(&cache->entries); |
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cache->root = RB_ROOT; |
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|
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res = ovl_dir_read_merged(dentry, &cache->entries, &cache->root); |
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if (res) { |
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ovl_cache_free(&cache->entries); |
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kfree(cache); |
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return ERR_PTR(res); |
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} |
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cache->version = ovl_dentry_version_get(dentry); |
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ovl_set_dir_cache(d_inode(dentry), cache); |
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|
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return cache; |
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} |
|
|
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/* Map inode number to lower fs unique range */ |
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static u64 ovl_remap_lower_ino(u64 ino, int xinobits, int fsid, |
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const char *name, int namelen, bool warn) |
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{ |
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unsigned int xinoshift = 64 - xinobits; |
|
|
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if (unlikely(ino >> xinoshift)) { |
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if (warn) { |
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pr_warn_ratelimited("d_ino too big (%.*s, ino=%llu, xinobits=%d)\n", |
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namelen, name, ino, xinobits); |
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} |
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return ino; |
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} |
|
|
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/* |
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* The lowest xinobit is reserved for mapping the non-peresistent inode |
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* numbers range, but this range is only exposed via st_ino, not here. |
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*/ |
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return ino | ((u64)fsid) << (xinoshift + 1); |
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} |
|
|
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/* |
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* Set d_ino for upper entries. Non-upper entries should always report |
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* the uppermost real inode ino and should not call this function. |
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* |
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* When not all layer are on same fs, report real ino also for upper. |
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* |
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* When all layers are on the same fs, and upper has a reference to |
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* copy up origin, call vfs_getattr() on the overlay entry to make |
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* sure that d_ino will be consistent with st_ino from stat(2). |
|
*/ |
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static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p) |
|
|
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{ |
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struct dentry *dir = path->dentry; |
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struct dentry *this = NULL; |
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enum ovl_path_type type; |
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u64 ino = p->real_ino; |
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int xinobits = ovl_xino_bits(dir->d_sb); |
|
int err = 0; |
|
|
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if (!ovl_same_dev(dir->d_sb)) |
|
goto out; |
|
|
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if (p->name[0] == '.') { |
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if (p->len == 1) { |
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this = dget(dir); |
|
goto get; |
|
} |
|
if (p->len == 2 && p->name[1] == '.') { |
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/* we shall not be moved */ |
|
this = dget(dir->d_parent); |
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goto get; |
|
} |
|
} |
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this = lookup_one_len(p->name, dir, p->len); |
|
if (IS_ERR_OR_NULL(this) || !this->d_inode) { |
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if (IS_ERR(this)) { |
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err = PTR_ERR(this); |
|
this = NULL; |
|
goto fail; |
|
} |
|
goto out; |
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} |
|
|
|
get: |
|
type = ovl_path_type(this); |
|
if (OVL_TYPE_ORIGIN(type)) { |
|
struct kstat stat; |
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struct path statpath = *path; |
|
|
|
statpath.dentry = this; |
|
err = vfs_getattr(&statpath, &stat, STATX_INO, 0); |
|
if (err) |
|
goto fail; |
|
|
|
/* |
|
* Directory inode is always on overlay st_dev. |
|
* Non-dir with ovl_same_dev() could be on pseudo st_dev in case |
|
* of xino bits overflow. |
|
*/ |
|
WARN_ON_ONCE(S_ISDIR(stat.mode) && |
|
dir->d_sb->s_dev != stat.dev); |
|
ino = stat.ino; |
|
} else if (xinobits && !OVL_TYPE_UPPER(type)) { |
|
ino = ovl_remap_lower_ino(ino, xinobits, |
|
ovl_layer_lower(this)->fsid, |
|
p->name, p->len, |
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ovl_xino_warn(dir->d_sb)); |
|
} |
|
|
|
out: |
|
p->ino = ino; |
|
dput(this); |
|
return err; |
|
|
|
fail: |
|
pr_warn_ratelimited("failed to look up (%s) for ino (%i)\n", |
|
p->name, err); |
|
goto out; |
|
} |
|
|
|
static int ovl_fill_plain(struct dir_context *ctx, const char *name, |
|
int namelen, loff_t offset, u64 ino, |
|
unsigned int d_type) |
|
{ |
|
struct ovl_cache_entry *p; |
|
struct ovl_readdir_data *rdd = |
|
container_of(ctx, struct ovl_readdir_data, ctx); |
|
|
|
rdd->count++; |
|
p = ovl_cache_entry_new(rdd, name, namelen, ino, d_type); |
|
if (p == NULL) { |
|
rdd->err = -ENOMEM; |
|
return -ENOMEM; |
|
} |
|
list_add_tail(&p->l_node, rdd->list); |
|
|
|
return 0; |
|
} |
|
|
|
static int ovl_dir_read_impure(struct path *path, struct list_head *list, |
|
struct rb_root *root) |
|
{ |
|
int err; |
|
struct path realpath; |
|
struct ovl_cache_entry *p, *n; |
|
struct ovl_readdir_data rdd = { |
|
.ctx.actor = ovl_fill_plain, |
|
.list = list, |
|
.root = root, |
|
}; |
|
|
|
INIT_LIST_HEAD(list); |
|
*root = RB_ROOT; |
|
ovl_path_upper(path->dentry, &realpath); |
|
|
|
err = ovl_dir_read(&realpath, &rdd); |
|
if (err) |
|
return err; |
|
|
|
list_for_each_entry_safe(p, n, list, l_node) { |
|
if (strcmp(p->name, ".") != 0 && |
|
strcmp(p->name, "..") != 0) { |
|
err = ovl_cache_update_ino(path, p); |
|
if (err) |
|
return err; |
|
} |
|
if (p->ino == p->real_ino) { |
|
list_del(&p->l_node); |
|
kfree(p); |
|
} else { |
|
struct rb_node **newp = &root->rb_node; |
|
struct rb_node *parent = NULL; |
|
|
|
if (WARN_ON(ovl_cache_entry_find_link(p->name, p->len, |
|
&newp, &parent))) |
|
return -EIO; |
|
|
|
rb_link_node(&p->node, parent, newp); |
|
rb_insert_color(&p->node, root); |
|
} |
|
} |
|
return 0; |
|
} |
|
|
|
static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path) |
|
{ |
|
int res; |
|
struct dentry *dentry = path->dentry; |
|
struct ovl_fs *ofs = OVL_FS(dentry->d_sb); |
|
struct ovl_dir_cache *cache; |
|
|
|
cache = ovl_dir_cache(d_inode(dentry)); |
|
if (cache && ovl_dentry_version_get(dentry) == cache->version) |
|
return cache; |
|
|
|
/* Impure cache is not refcounted, free it here */ |
|
ovl_dir_cache_free(d_inode(dentry)); |
|
ovl_set_dir_cache(d_inode(dentry), NULL); |
|
|
|
cache = kzalloc(sizeof(struct ovl_dir_cache), GFP_KERNEL); |
|
if (!cache) |
|
return ERR_PTR(-ENOMEM); |
|
|
|
res = ovl_dir_read_impure(path, &cache->entries, &cache->root); |
|
if (res) { |
|
ovl_cache_free(&cache->entries); |
|
kfree(cache); |
|
return ERR_PTR(res); |
|
} |
|
if (list_empty(&cache->entries)) { |
|
/* |
|
* A good opportunity to get rid of an unneeded "impure" flag. |
|
* Removing the "impure" xattr is best effort. |
|
*/ |
|
if (!ovl_want_write(dentry)) { |
|
ovl_do_removexattr(ofs, ovl_dentry_upper(dentry), |
|
OVL_XATTR_IMPURE); |
|
ovl_drop_write(dentry); |
|
} |
|
ovl_clear_flag(OVL_IMPURE, d_inode(dentry)); |
|
kfree(cache); |
|
return NULL; |
|
} |
|
|
|
cache->version = ovl_dentry_version_get(dentry); |
|
ovl_set_dir_cache(d_inode(dentry), cache); |
|
|
|
return cache; |
|
} |
|
|
|
struct ovl_readdir_translate { |
|
struct dir_context *orig_ctx; |
|
struct ovl_dir_cache *cache; |
|
struct dir_context ctx; |
|
u64 parent_ino; |
|
int fsid; |
|
int xinobits; |
|
bool xinowarn; |
|
}; |
|
|
|
static int ovl_fill_real(struct dir_context *ctx, const char *name, |
|
int namelen, loff_t offset, u64 ino, |
|
unsigned int d_type) |
|
{ |
|
struct ovl_readdir_translate *rdt = |
|
container_of(ctx, struct ovl_readdir_translate, ctx); |
|
struct dir_context *orig_ctx = rdt->orig_ctx; |
|
|
|
if (rdt->parent_ino && strcmp(name, "..") == 0) { |
|
ino = rdt->parent_ino; |
|
} else if (rdt->cache) { |
|
struct ovl_cache_entry *p; |
|
|
|
p = ovl_cache_entry_find(&rdt->cache->root, name, namelen); |
|
if (p) |
|
ino = p->ino; |
|
} else if (rdt->xinobits) { |
|
ino = ovl_remap_lower_ino(ino, rdt->xinobits, rdt->fsid, |
|
name, namelen, rdt->xinowarn); |
|
} |
|
|
|
return orig_ctx->actor(orig_ctx, name, namelen, offset, ino, d_type); |
|
} |
|
|
|
static bool ovl_is_impure_dir(struct file *file) |
|
{ |
|
struct ovl_dir_file *od = file->private_data; |
|
struct inode *dir = d_inode(file->f_path.dentry); |
|
|
|
/* |
|
* Only upper dir can be impure, but if we are in the middle of |
|
* iterating a lower real dir, dir could be copied up and marked |
|
* impure. We only want the impure cache if we started iterating |
|
* a real upper dir to begin with. |
|
*/ |
|
return od->is_upper && ovl_test_flag(OVL_IMPURE, dir); |
|
|
|
} |
|
|
|
static int ovl_iterate_real(struct file *file, struct dir_context *ctx) |
|
{ |
|
int err; |
|
struct ovl_dir_file *od = file->private_data; |
|
struct dentry *dir = file->f_path.dentry; |
|
const struct ovl_layer *lower_layer = ovl_layer_lower(dir); |
|
struct ovl_readdir_translate rdt = { |
|
.ctx.actor = ovl_fill_real, |
|
.orig_ctx = ctx, |
|
.xinobits = ovl_xino_bits(dir->d_sb), |
|
.xinowarn = ovl_xino_warn(dir->d_sb), |
|
}; |
|
|
|
if (rdt.xinobits && lower_layer) |
|
rdt.fsid = lower_layer->fsid; |
|
|
|
if (OVL_TYPE_MERGE(ovl_path_type(dir->d_parent))) { |
|
struct kstat stat; |
|
struct path statpath = file->f_path; |
|
|
|
statpath.dentry = dir->d_parent; |
|
err = vfs_getattr(&statpath, &stat, STATX_INO, 0); |
|
if (err) |
|
return err; |
|
|
|
WARN_ON_ONCE(dir->d_sb->s_dev != stat.dev); |
|
rdt.parent_ino = stat.ino; |
|
} |
|
|
|
if (ovl_is_impure_dir(file)) { |
|
rdt.cache = ovl_cache_get_impure(&file->f_path); |
|
if (IS_ERR(rdt.cache)) |
|
return PTR_ERR(rdt.cache); |
|
} |
|
|
|
err = iterate_dir(od->realfile, &rdt.ctx); |
|
ctx->pos = rdt.ctx.pos; |
|
|
|
return err; |
|
} |
|
|
|
|
|
static int ovl_iterate(struct file *file, struct dir_context *ctx) |
|
{ |
|
struct ovl_dir_file *od = file->private_data; |
|
struct dentry *dentry = file->f_path.dentry; |
|
struct ovl_cache_entry *p; |
|
const struct cred *old_cred; |
|
int err; |
|
|
|
old_cred = ovl_override_creds(dentry->d_sb); |
|
if (!ctx->pos) |
|
ovl_dir_reset(file); |
|
|
|
if (od->is_real) { |
|
/* |
|
* If parent is merge, then need to adjust d_ino for '..', if |
|
* dir is impure then need to adjust d_ino for copied up |
|
* entries. |
|
*/ |
|
if (ovl_xino_bits(dentry->d_sb) || |
|
(ovl_same_fs(dentry->d_sb) && |
|
(ovl_is_impure_dir(file) || |
|
OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent))))) { |
|
err = ovl_iterate_real(file, ctx); |
|
} else { |
|
err = iterate_dir(od->realfile, ctx); |
|
} |
|
goto out; |
|
} |
|
|
|
if (!od->cache) { |
|
struct ovl_dir_cache *cache; |
|
|
|
cache = ovl_cache_get(dentry); |
|
err = PTR_ERR(cache); |
|
if (IS_ERR(cache)) |
|
goto out; |
|
|
|
od->cache = cache; |
|
ovl_seek_cursor(od, ctx->pos); |
|
} |
|
|
|
while (od->cursor != &od->cache->entries) { |
|
p = list_entry(od->cursor, struct ovl_cache_entry, l_node); |
|
if (!p->is_whiteout) { |
|
if (!p->ino) { |
|
err = ovl_cache_update_ino(&file->f_path, p); |
|
if (err) |
|
goto out; |
|
} |
|
if (!dir_emit(ctx, p->name, p->len, p->ino, p->type)) |
|
break; |
|
} |
|
od->cursor = p->l_node.next; |
|
ctx->pos++; |
|
} |
|
err = 0; |
|
out: |
|
revert_creds(old_cred); |
|
return err; |
|
} |
|
|
|
static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin) |
|
{ |
|
loff_t res; |
|
struct ovl_dir_file *od = file->private_data; |
|
|
|
inode_lock(file_inode(file)); |
|
if (!file->f_pos) |
|
ovl_dir_reset(file); |
|
|
|
if (od->is_real) { |
|
res = vfs_llseek(od->realfile, offset, origin); |
|
file->f_pos = od->realfile->f_pos; |
|
} else { |
|
res = -EINVAL; |
|
|
|
switch (origin) { |
|
case SEEK_CUR: |
|
offset += file->f_pos; |
|
break; |
|
case SEEK_SET: |
|
break; |
|
default: |
|
goto out_unlock; |
|
} |
|
if (offset < 0) |
|
goto out_unlock; |
|
|
|
if (offset != file->f_pos) { |
|
file->f_pos = offset; |
|
if (od->cache) |
|
ovl_seek_cursor(od, offset); |
|
} |
|
res = offset; |
|
} |
|
out_unlock: |
|
inode_unlock(file_inode(file)); |
|
|
|
return res; |
|
} |
|
|
|
static struct file *ovl_dir_open_realfile(const struct file *file, |
|
struct path *realpath) |
|
{ |
|
struct file *res; |
|
const struct cred *old_cred; |
|
|
|
old_cred = ovl_override_creds(file_inode(file)->i_sb); |
|
res = ovl_path_open(realpath, O_RDONLY | (file->f_flags & O_LARGEFILE)); |
|
revert_creds(old_cred); |
|
|
|
return res; |
|
} |
|
|
|
/* |
|
* Like ovl_real_fdget(), returns upperfile if dir was copied up since open. |
|
* Unlike ovl_real_fdget(), this caches upperfile in file->private_data. |
|
* |
|
* TODO: use same abstract type for file->private_data of dir and file so |
|
* upperfile could also be cached for files as well. |
|
*/ |
|
struct file *ovl_dir_real_file(const struct file *file, bool want_upper) |
|
{ |
|
|
|
struct ovl_dir_file *od = file->private_data; |
|
struct dentry *dentry = file->f_path.dentry; |
|
struct file *old, *realfile = od->realfile; |
|
|
|
if (!OVL_TYPE_UPPER(ovl_path_type(dentry))) |
|
return want_upper ? NULL : realfile; |
|
|
|
/* |
|
* Need to check if we started out being a lower dir, but got copied up |
|
*/ |
|
if (!od->is_upper) { |
|
realfile = READ_ONCE(od->upperfile); |
|
if (!realfile) { |
|
struct path upperpath; |
|
|
|
ovl_path_upper(dentry, &upperpath); |
|
realfile = ovl_dir_open_realfile(file, &upperpath); |
|
if (IS_ERR(realfile)) |
|
return realfile; |
|
|
|
old = cmpxchg_release(&od->upperfile, NULL, realfile); |
|
if (old) { |
|
fput(realfile); |
|
realfile = old; |
|
} |
|
} |
|
} |
|
|
|
return realfile; |
|
} |
|
|
|
static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end, |
|
int datasync) |
|
{ |
|
struct file *realfile; |
|
int err; |
|
|
|
err = ovl_sync_status(OVL_FS(file->f_path.dentry->d_sb)); |
|
if (err <= 0) |
|
return err; |
|
|
|
realfile = ovl_dir_real_file(file, true); |
|
err = PTR_ERR_OR_ZERO(realfile); |
|
|
|
/* Nothing to sync for lower */ |
|
if (!realfile || err) |
|
return err; |
|
|
|
return vfs_fsync_range(realfile, start, end, datasync); |
|
} |
|
|
|
static int ovl_dir_release(struct inode *inode, struct file *file) |
|
{ |
|
struct ovl_dir_file *od = file->private_data; |
|
|
|
if (od->cache) { |
|
inode_lock(inode); |
|
ovl_cache_put(od, file->f_path.dentry); |
|
inode_unlock(inode); |
|
} |
|
fput(od->realfile); |
|
if (od->upperfile) |
|
fput(od->upperfile); |
|
kfree(od); |
|
|
|
return 0; |
|
} |
|
|
|
static int ovl_dir_open(struct inode *inode, struct file *file) |
|
{ |
|
struct path realpath; |
|
struct file *realfile; |
|
struct ovl_dir_file *od; |
|
enum ovl_path_type type; |
|
|
|
od = kzalloc(sizeof(struct ovl_dir_file), GFP_KERNEL); |
|
if (!od) |
|
return -ENOMEM; |
|
|
|
type = ovl_path_real(file->f_path.dentry, &realpath); |
|
realfile = ovl_dir_open_realfile(file, &realpath); |
|
if (IS_ERR(realfile)) { |
|
kfree(od); |
|
return PTR_ERR(realfile); |
|
} |
|
od->realfile = realfile; |
|
od->is_real = ovl_dir_is_real(file->f_path.dentry); |
|
od->is_upper = OVL_TYPE_UPPER(type); |
|
file->private_data = od; |
|
|
|
return 0; |
|
} |
|
|
|
const struct file_operations ovl_dir_operations = { |
|
.read = generic_read_dir, |
|
.open = ovl_dir_open, |
|
.iterate = ovl_iterate, |
|
.llseek = ovl_dir_llseek, |
|
.fsync = ovl_dir_fsync, |
|
.release = ovl_dir_release, |
|
}; |
|
|
|
int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list) |
|
{ |
|
int err; |
|
struct ovl_cache_entry *p, *n; |
|
struct rb_root root = RB_ROOT; |
|
const struct cred *old_cred; |
|
|
|
old_cred = ovl_override_creds(dentry->d_sb); |
|
err = ovl_dir_read_merged(dentry, list, &root); |
|
revert_creds(old_cred); |
|
if (err) |
|
return err; |
|
|
|
err = 0; |
|
|
|
list_for_each_entry_safe(p, n, list, l_node) { |
|
/* |
|
* Select whiteouts in upperdir, they should |
|
* be cleared when deleting this directory. |
|
*/ |
|
if (p->is_whiteout) { |
|
if (p->is_upper) |
|
continue; |
|
goto del_entry; |
|
} |
|
|
|
if (p->name[0] == '.') { |
|
if (p->len == 1) |
|
goto del_entry; |
|
if (p->len == 2 && p->name[1] == '.') |
|
goto del_entry; |
|
} |
|
err = -ENOTEMPTY; |
|
break; |
|
|
|
del_entry: |
|
list_del(&p->l_node); |
|
kfree(p); |
|
} |
|
|
|
return err; |
|
} |
|
|
|
void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list) |
|
{ |
|
struct ovl_cache_entry *p; |
|
|
|
inode_lock_nested(upper->d_inode, I_MUTEX_CHILD); |
|
list_for_each_entry(p, list, l_node) { |
|
struct dentry *dentry; |
|
|
|
if (WARN_ON(!p->is_whiteout || !p->is_upper)) |
|
continue; |
|
|
|
dentry = lookup_one_len(p->name, upper, p->len); |
|
if (IS_ERR(dentry)) { |
|
pr_err("lookup '%s/%.*s' failed (%i)\n", |
|
upper->d_name.name, p->len, p->name, |
|
(int) PTR_ERR(dentry)); |
|
continue; |
|
} |
|
if (dentry->d_inode) |
|
ovl_cleanup(upper->d_inode, dentry); |
|
dput(dentry); |
|
} |
|
inode_unlock(upper->d_inode); |
|
} |
|
|
|
static int ovl_check_d_type(struct dir_context *ctx, const char *name, |
|
int namelen, loff_t offset, u64 ino, |
|
unsigned int d_type) |
|
{ |
|
struct ovl_readdir_data *rdd = |
|
container_of(ctx, struct ovl_readdir_data, ctx); |
|
|
|
/* Even if d_type is not supported, DT_DIR is returned for . and .. */ |
|
if (!strncmp(name, ".", namelen) || !strncmp(name, "..", namelen)) |
|
return 0; |
|
|
|
if (d_type != DT_UNKNOWN) |
|
rdd->d_type_supported = true; |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* Returns 1 if d_type is supported, 0 not supported/unknown. Negative values |
|
* if error is encountered. |
|
*/ |
|
int ovl_check_d_type_supported(struct path *realpath) |
|
{ |
|
int err; |
|
struct ovl_readdir_data rdd = { |
|
.ctx.actor = ovl_check_d_type, |
|
.d_type_supported = false, |
|
}; |
|
|
|
err = ovl_dir_read(realpath, &rdd); |
|
if (err) |
|
return err; |
|
|
|
return rdd.d_type_supported; |
|
} |
|
|
|
#define OVL_INCOMPATDIR_NAME "incompat" |
|
|
|
static int ovl_workdir_cleanup_recurse(struct path *path, int level) |
|
{ |
|
int err; |
|
struct inode *dir = path->dentry->d_inode; |
|
LIST_HEAD(list); |
|
struct rb_root root = RB_ROOT; |
|
struct ovl_cache_entry *p; |
|
struct ovl_readdir_data rdd = { |
|
.ctx.actor = ovl_fill_merge, |
|
.dentry = NULL, |
|
.list = &list, |
|
.root = &root, |
|
.is_lowest = false, |
|
}; |
|
bool incompat = false; |
|
|
|
/* |
|
* The "work/incompat" directory is treated specially - if it is not |
|
* empty, instead of printing a generic error and mounting read-only, |
|
* we will error about incompat features and fail the mount. |
|
* |
|
* When called from ovl_indexdir_cleanup(), path->dentry->d_name.name |
|
* starts with '#'. |
|
*/ |
|
if (level == 2 && |
|
!strcmp(path->dentry->d_name.name, OVL_INCOMPATDIR_NAME)) |
|
incompat = true; |
|
|
|
err = ovl_dir_read(path, &rdd); |
|
if (err) |
|
goto out; |
|
|
|
inode_lock_nested(dir, I_MUTEX_PARENT); |
|
list_for_each_entry(p, &list, l_node) { |
|
struct dentry *dentry; |
|
|
|
if (p->name[0] == '.') { |
|
if (p->len == 1) |
|
continue; |
|
if (p->len == 2 && p->name[1] == '.') |
|
continue; |
|
} else if (incompat) { |
|
pr_err("overlay with incompat feature '%s' cannot be mounted\n", |
|
p->name); |
|
err = -EINVAL; |
|
break; |
|
} |
|
dentry = lookup_one_len(p->name, path->dentry, p->len); |
|
if (IS_ERR(dentry)) |
|
continue; |
|
if (dentry->d_inode) |
|
err = ovl_workdir_cleanup(dir, path->mnt, dentry, level); |
|
dput(dentry); |
|
if (err) |
|
break; |
|
} |
|
inode_unlock(dir); |
|
out: |
|
ovl_cache_free(&list); |
|
return err; |
|
} |
|
|
|
int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, |
|
struct dentry *dentry, int level) |
|
{ |
|
int err; |
|
|
|
if (!d_is_dir(dentry) || level > 1) { |
|
return ovl_cleanup(dir, dentry); |
|
} |
|
|
|
err = ovl_do_rmdir(dir, dentry); |
|
if (err) { |
|
struct path path = { .mnt = mnt, .dentry = dentry }; |
|
|
|
inode_unlock(dir); |
|
err = ovl_workdir_cleanup_recurse(&path, level + 1); |
|
inode_lock_nested(dir, I_MUTEX_PARENT); |
|
if (!err) |
|
err = ovl_cleanup(dir, dentry); |
|
} |
|
|
|
return err; |
|
} |
|
|
|
int ovl_indexdir_cleanup(struct ovl_fs *ofs) |
|
{ |
|
int err; |
|
struct dentry *indexdir = ofs->indexdir; |
|
struct dentry *index = NULL; |
|
struct inode *dir = indexdir->d_inode; |
|
struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = indexdir }; |
|
LIST_HEAD(list); |
|
struct rb_root root = RB_ROOT; |
|
struct ovl_cache_entry *p; |
|
struct ovl_readdir_data rdd = { |
|
.ctx.actor = ovl_fill_merge, |
|
.dentry = NULL, |
|
.list = &list, |
|
.root = &root, |
|
.is_lowest = false, |
|
}; |
|
|
|
err = ovl_dir_read(&path, &rdd); |
|
if (err) |
|
goto out; |
|
|
|
inode_lock_nested(dir, I_MUTEX_PARENT); |
|
list_for_each_entry(p, &list, l_node) { |
|
if (p->name[0] == '.') { |
|
if (p->len == 1) |
|
continue; |
|
if (p->len == 2 && p->name[1] == '.') |
|
continue; |
|
} |
|
index = lookup_one_len(p->name, indexdir, p->len); |
|
if (IS_ERR(index)) { |
|
err = PTR_ERR(index); |
|
index = NULL; |
|
break; |
|
} |
|
/* Cleanup leftover from index create/cleanup attempt */ |
|
if (index->d_name.name[0] == '#') { |
|
err = ovl_workdir_cleanup(dir, path.mnt, index, 1); |
|
if (err) |
|
break; |
|
goto next; |
|
} |
|
err = ovl_verify_index(ofs, index); |
|
if (!err) { |
|
goto next; |
|
} else if (err == -ESTALE) { |
|
/* Cleanup stale index entries */ |
|
err = ovl_cleanup(dir, index); |
|
} else if (err != -ENOENT) { |
|
/* |
|
* Abort mount to avoid corrupting the index if |
|
* an incompatible index entry was found or on out |
|
* of memory. |
|
*/ |
|
break; |
|
} else if (ofs->config.nfs_export) { |
|
/* |
|
* Whiteout orphan index to block future open by |
|
* handle after overlay nlink dropped to zero. |
|
*/ |
|
err = ovl_cleanup_and_whiteout(ofs, dir, index); |
|
} else { |
|
/* Cleanup orphan index entries */ |
|
err = ovl_cleanup(dir, index); |
|
} |
|
|
|
if (err) |
|
break; |
|
|
|
next: |
|
dput(index); |
|
index = NULL; |
|
} |
|
dput(index); |
|
inode_unlock(dir); |
|
out: |
|
ovl_cache_free(&list); |
|
if (err) |
|
pr_err("failed index dir cleanup (%i)\n", err); |
|
return err; |
|
}
|
|
|