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2402 lines
64 KiB
2402 lines
64 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
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* (C) 1997 Linus Torvalds |
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* (C) 1999 Andrea Arcangeli <[email protected]> (dynamic inode allocation) |
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*/ |
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#include <linux/export.h> |
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#include <linux/fs.h> |
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#include <linux/mm.h> |
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#include <linux/backing-dev.h> |
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#include <linux/hash.h> |
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#include <linux/swap.h> |
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#include <linux/security.h> |
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#include <linux/cdev.h> |
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#include <linux/memblock.h> |
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#include <linux/fscrypt.h> |
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#include <linux/fsnotify.h> |
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#include <linux/mount.h> |
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#include <linux/posix_acl.h> |
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#include <linux/prefetch.h> |
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#include <linux/buffer_head.h> /* for inode_has_buffers */ |
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#include <linux/ratelimit.h> |
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#include <linux/list_lru.h> |
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#include <linux/iversion.h> |
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#include <trace/events/writeback.h> |
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#include "internal.h" |
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|
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/* |
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* Inode locking rules: |
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* |
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* inode->i_lock protects: |
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* inode->i_state, inode->i_hash, __iget() |
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* Inode LRU list locks protect: |
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* inode->i_sb->s_inode_lru, inode->i_lru |
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* inode->i_sb->s_inode_list_lock protects: |
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* inode->i_sb->s_inodes, inode->i_sb_list |
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* bdi->wb.list_lock protects: |
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* bdi->wb.b_{dirty,io,more_io,dirty_time}, inode->i_io_list |
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* inode_hash_lock protects: |
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* inode_hashtable, inode->i_hash |
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* |
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* Lock ordering: |
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* |
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* inode->i_sb->s_inode_list_lock |
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* inode->i_lock |
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* Inode LRU list locks |
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* |
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* bdi->wb.list_lock |
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* inode->i_lock |
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* |
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* inode_hash_lock |
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* inode->i_sb->s_inode_list_lock |
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* inode->i_lock |
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* |
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* iunique_lock |
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* inode_hash_lock |
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*/ |
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|
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static unsigned int i_hash_mask __read_mostly; |
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static unsigned int i_hash_shift __read_mostly; |
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static struct hlist_head *inode_hashtable __read_mostly; |
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static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock); |
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|
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/* |
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* Empty aops. Can be used for the cases where the user does not |
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* define any of the address_space operations. |
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*/ |
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const struct address_space_operations empty_aops = { |
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}; |
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EXPORT_SYMBOL(empty_aops); |
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|
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/* |
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* Statistics gathering.. |
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*/ |
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struct inodes_stat_t inodes_stat; |
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|
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static DEFINE_PER_CPU(unsigned long, nr_inodes); |
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static DEFINE_PER_CPU(unsigned long, nr_unused); |
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|
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static struct kmem_cache *inode_cachep __read_mostly; |
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|
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static long get_nr_inodes(void) |
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{ |
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int i; |
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long sum = 0; |
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for_each_possible_cpu(i) |
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sum += per_cpu(nr_inodes, i); |
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return sum < 0 ? 0 : sum; |
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} |
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|
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static inline long get_nr_inodes_unused(void) |
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{ |
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int i; |
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long sum = 0; |
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for_each_possible_cpu(i) |
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sum += per_cpu(nr_unused, i); |
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return sum < 0 ? 0 : sum; |
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} |
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|
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long get_nr_dirty_inodes(void) |
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{ |
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/* not actually dirty inodes, but a wild approximation */ |
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long nr_dirty = get_nr_inodes() - get_nr_inodes_unused(); |
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return nr_dirty > 0 ? nr_dirty : 0; |
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} |
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|
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/* |
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* Handle nr_inode sysctl |
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*/ |
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#ifdef CONFIG_SYSCTL |
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int proc_nr_inodes(struct ctl_table *table, int write, |
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void *buffer, size_t *lenp, loff_t *ppos) |
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{ |
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inodes_stat.nr_inodes = get_nr_inodes(); |
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inodes_stat.nr_unused = get_nr_inodes_unused(); |
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return proc_doulongvec_minmax(table, write, buffer, lenp, ppos); |
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} |
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#endif |
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|
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static int no_open(struct inode *inode, struct file *file) |
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{ |
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return -ENXIO; |
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} |
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|
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/** |
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* inode_init_always - perform inode structure initialisation |
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* @sb: superblock inode belongs to |
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* @inode: inode to initialise |
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* |
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* These are initializations that need to be done on every inode |
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* allocation as the fields are not initialised by slab allocation. |
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*/ |
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int inode_init_always(struct super_block *sb, struct inode *inode) |
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{ |
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static const struct inode_operations empty_iops; |
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static const struct file_operations no_open_fops = {.open = no_open}; |
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struct address_space *const mapping = &inode->i_data; |
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|
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inode->i_sb = sb; |
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inode->i_blkbits = sb->s_blocksize_bits; |
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inode->i_flags = 0; |
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atomic64_set(&inode->i_sequence, 0); |
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atomic_set(&inode->i_count, 1); |
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inode->i_op = &empty_iops; |
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inode->i_fop = &no_open_fops; |
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inode->i_ino = 0; |
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inode->__i_nlink = 1; |
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inode->i_opflags = 0; |
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if (sb->s_xattr) |
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inode->i_opflags |= IOP_XATTR; |
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i_uid_write(inode, 0); |
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i_gid_write(inode, 0); |
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atomic_set(&inode->i_writecount, 0); |
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inode->i_size = 0; |
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inode->i_write_hint = WRITE_LIFE_NOT_SET; |
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inode->i_blocks = 0; |
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inode->i_bytes = 0; |
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inode->i_generation = 0; |
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inode->i_pipe = NULL; |
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inode->i_cdev = NULL; |
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inode->i_link = NULL; |
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inode->i_dir_seq = 0; |
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inode->i_rdev = 0; |
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inode->dirtied_when = 0; |
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|
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#ifdef CONFIG_CGROUP_WRITEBACK |
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inode->i_wb_frn_winner = 0; |
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inode->i_wb_frn_avg_time = 0; |
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inode->i_wb_frn_history = 0; |
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#endif |
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|
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if (security_inode_alloc(inode)) |
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goto out; |
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spin_lock_init(&inode->i_lock); |
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lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); |
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|
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init_rwsem(&inode->i_rwsem); |
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lockdep_set_class(&inode->i_rwsem, &sb->s_type->i_mutex_key); |
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|
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atomic_set(&inode->i_dio_count, 0); |
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|
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mapping->a_ops = &empty_aops; |
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mapping->host = inode; |
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mapping->flags = 0; |
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if (sb->s_type->fs_flags & FS_THP_SUPPORT) |
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__set_bit(AS_THP_SUPPORT, &mapping->flags); |
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mapping->wb_err = 0; |
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atomic_set(&mapping->i_mmap_writable, 0); |
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#ifdef CONFIG_READ_ONLY_THP_FOR_FS |
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atomic_set(&mapping->nr_thps, 0); |
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#endif |
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mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); |
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mapping->private_data = NULL; |
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mapping->writeback_index = 0; |
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inode->i_private = NULL; |
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inode->i_mapping = mapping; |
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INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */ |
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#ifdef CONFIG_FS_POSIX_ACL |
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inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
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#endif |
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|
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#ifdef CONFIG_FSNOTIFY |
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inode->i_fsnotify_mask = 0; |
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#endif |
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inode->i_flctx = NULL; |
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this_cpu_inc(nr_inodes); |
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|
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return 0; |
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out: |
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return -ENOMEM; |
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} |
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EXPORT_SYMBOL(inode_init_always); |
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|
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void free_inode_nonrcu(struct inode *inode) |
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{ |
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kmem_cache_free(inode_cachep, inode); |
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} |
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EXPORT_SYMBOL(free_inode_nonrcu); |
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|
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static void i_callback(struct rcu_head *head) |
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{ |
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struct inode *inode = container_of(head, struct inode, i_rcu); |
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if (inode->free_inode) |
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inode->free_inode(inode); |
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else |
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free_inode_nonrcu(inode); |
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} |
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|
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static struct inode *alloc_inode(struct super_block *sb) |
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{ |
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const struct super_operations *ops = sb->s_op; |
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struct inode *inode; |
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|
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if (ops->alloc_inode) |
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inode = ops->alloc_inode(sb); |
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else |
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inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL); |
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|
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if (!inode) |
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return NULL; |
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|
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if (unlikely(inode_init_always(sb, inode))) { |
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if (ops->destroy_inode) { |
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ops->destroy_inode(inode); |
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if (!ops->free_inode) |
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return NULL; |
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} |
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inode->free_inode = ops->free_inode; |
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i_callback(&inode->i_rcu); |
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return NULL; |
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} |
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|
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return inode; |
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} |
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|
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void __destroy_inode(struct inode *inode) |
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{ |
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BUG_ON(inode_has_buffers(inode)); |
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inode_detach_wb(inode); |
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security_inode_free(inode); |
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fsnotify_inode_delete(inode); |
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locks_free_lock_context(inode); |
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if (!inode->i_nlink) { |
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WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0); |
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atomic_long_dec(&inode->i_sb->s_remove_count); |
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} |
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|
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#ifdef CONFIG_FS_POSIX_ACL |
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if (inode->i_acl && !is_uncached_acl(inode->i_acl)) |
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posix_acl_release(inode->i_acl); |
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if (inode->i_default_acl && !is_uncached_acl(inode->i_default_acl)) |
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posix_acl_release(inode->i_default_acl); |
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#endif |
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this_cpu_dec(nr_inodes); |
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} |
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EXPORT_SYMBOL(__destroy_inode); |
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|
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static void destroy_inode(struct inode *inode) |
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{ |
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const struct super_operations *ops = inode->i_sb->s_op; |
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|
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BUG_ON(!list_empty(&inode->i_lru)); |
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__destroy_inode(inode); |
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if (ops->destroy_inode) { |
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ops->destroy_inode(inode); |
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if (!ops->free_inode) |
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return; |
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} |
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inode->free_inode = ops->free_inode; |
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call_rcu(&inode->i_rcu, i_callback); |
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} |
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|
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/** |
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* drop_nlink - directly drop an inode's link count |
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* @inode: inode |
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* |
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* This is a low-level filesystem helper to replace any |
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* direct filesystem manipulation of i_nlink. In cases |
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* where we are attempting to track writes to the |
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* filesystem, a decrement to zero means an imminent |
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* write when the file is truncated and actually unlinked |
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* on the filesystem. |
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*/ |
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void drop_nlink(struct inode *inode) |
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{ |
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WARN_ON(inode->i_nlink == 0); |
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inode->__i_nlink--; |
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if (!inode->i_nlink) |
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atomic_long_inc(&inode->i_sb->s_remove_count); |
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} |
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EXPORT_SYMBOL(drop_nlink); |
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|
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/** |
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* clear_nlink - directly zero an inode's link count |
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* @inode: inode |
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* |
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* This is a low-level filesystem helper to replace any |
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* direct filesystem manipulation of i_nlink. See |
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* drop_nlink() for why we care about i_nlink hitting zero. |
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*/ |
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void clear_nlink(struct inode *inode) |
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{ |
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if (inode->i_nlink) { |
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inode->__i_nlink = 0; |
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atomic_long_inc(&inode->i_sb->s_remove_count); |
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} |
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} |
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EXPORT_SYMBOL(clear_nlink); |
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|
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/** |
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* set_nlink - directly set an inode's link count |
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* @inode: inode |
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* @nlink: new nlink (should be non-zero) |
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* |
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* This is a low-level filesystem helper to replace any |
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* direct filesystem manipulation of i_nlink. |
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*/ |
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void set_nlink(struct inode *inode, unsigned int nlink) |
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{ |
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if (!nlink) { |
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clear_nlink(inode); |
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} else { |
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/* Yes, some filesystems do change nlink from zero to one */ |
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if (inode->i_nlink == 0) |
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atomic_long_dec(&inode->i_sb->s_remove_count); |
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|
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inode->__i_nlink = nlink; |
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} |
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} |
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EXPORT_SYMBOL(set_nlink); |
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|
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/** |
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* inc_nlink - directly increment an inode's link count |
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* @inode: inode |
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* |
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* This is a low-level filesystem helper to replace any |
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* direct filesystem manipulation of i_nlink. Currently, |
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* it is only here for parity with dec_nlink(). |
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*/ |
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void inc_nlink(struct inode *inode) |
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{ |
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if (unlikely(inode->i_nlink == 0)) { |
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WARN_ON(!(inode->i_state & I_LINKABLE)); |
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atomic_long_dec(&inode->i_sb->s_remove_count); |
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} |
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|
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inode->__i_nlink++; |
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} |
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EXPORT_SYMBOL(inc_nlink); |
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|
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static void __address_space_init_once(struct address_space *mapping) |
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{ |
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xa_init_flags(&mapping->i_pages, XA_FLAGS_LOCK_IRQ | XA_FLAGS_ACCOUNT); |
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init_rwsem(&mapping->i_mmap_rwsem); |
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INIT_LIST_HEAD(&mapping->private_list); |
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spin_lock_init(&mapping->private_lock); |
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mapping->i_mmap = RB_ROOT_CACHED; |
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} |
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|
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void address_space_init_once(struct address_space *mapping) |
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{ |
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memset(mapping, 0, sizeof(*mapping)); |
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__address_space_init_once(mapping); |
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} |
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EXPORT_SYMBOL(address_space_init_once); |
|
|
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/* |
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* These are initializations that only need to be done |
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* once, because the fields are idempotent across use |
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* of the inode, so let the slab aware of that. |
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*/ |
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void inode_init_once(struct inode *inode) |
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{ |
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memset(inode, 0, sizeof(*inode)); |
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INIT_HLIST_NODE(&inode->i_hash); |
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INIT_LIST_HEAD(&inode->i_devices); |
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INIT_LIST_HEAD(&inode->i_io_list); |
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INIT_LIST_HEAD(&inode->i_wb_list); |
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INIT_LIST_HEAD(&inode->i_lru); |
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__address_space_init_once(&inode->i_data); |
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i_size_ordered_init(inode); |
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} |
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EXPORT_SYMBOL(inode_init_once); |
|
|
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static void init_once(void *foo) |
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{ |
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struct inode *inode = (struct inode *) foo; |
|
|
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inode_init_once(inode); |
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} |
|
|
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/* |
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* inode->i_lock must be held |
|
*/ |
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void __iget(struct inode *inode) |
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{ |
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atomic_inc(&inode->i_count); |
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} |
|
|
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/* |
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* get additional reference to inode; caller must already hold one. |
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*/ |
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void ihold(struct inode *inode) |
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{ |
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WARN_ON(atomic_inc_return(&inode->i_count) < 2); |
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} |
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EXPORT_SYMBOL(ihold); |
|
|
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static void inode_lru_list_add(struct inode *inode) |
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{ |
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if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru)) |
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this_cpu_inc(nr_unused); |
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else |
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inode->i_state |= I_REFERENCED; |
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} |
|
|
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/* |
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* Add inode to LRU if needed (inode is unused and clean). |
|
* |
|
* Needs inode->i_lock held. |
|
*/ |
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void inode_add_lru(struct inode *inode) |
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{ |
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if (!(inode->i_state & (I_DIRTY_ALL | I_SYNC | |
|
I_FREEING | I_WILL_FREE)) && |
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!atomic_read(&inode->i_count) && inode->i_sb->s_flags & SB_ACTIVE) |
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inode_lru_list_add(inode); |
|
} |
|
|
|
|
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static void inode_lru_list_del(struct inode *inode) |
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{ |
|
|
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if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru)) |
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this_cpu_dec(nr_unused); |
|
} |
|
|
|
/** |
|
* inode_sb_list_add - add inode to the superblock list of inodes |
|
* @inode: inode to add |
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*/ |
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void inode_sb_list_add(struct inode *inode) |
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{ |
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spin_lock(&inode->i_sb->s_inode_list_lock); |
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list_add(&inode->i_sb_list, &inode->i_sb->s_inodes); |
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spin_unlock(&inode->i_sb->s_inode_list_lock); |
|
} |
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EXPORT_SYMBOL_GPL(inode_sb_list_add); |
|
|
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static inline void inode_sb_list_del(struct inode *inode) |
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{ |
|
if (!list_empty(&inode->i_sb_list)) { |
|
spin_lock(&inode->i_sb->s_inode_list_lock); |
|
list_del_init(&inode->i_sb_list); |
|
spin_unlock(&inode->i_sb->s_inode_list_lock); |
|
} |
|
} |
|
|
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static unsigned long hash(struct super_block *sb, unsigned long hashval) |
|
{ |
|
unsigned long tmp; |
|
|
|
tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / |
|
L1_CACHE_BYTES; |
|
tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift); |
|
return tmp & i_hash_mask; |
|
} |
|
|
|
/** |
|
* __insert_inode_hash - hash an inode |
|
* @inode: unhashed inode |
|
* @hashval: unsigned long value used to locate this object in the |
|
* inode_hashtable. |
|
* |
|
* Add an inode to the inode hash for this superblock. |
|
*/ |
|
void __insert_inode_hash(struct inode *inode, unsigned long hashval) |
|
{ |
|
struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval); |
|
|
|
spin_lock(&inode_hash_lock); |
|
spin_lock(&inode->i_lock); |
|
hlist_add_head_rcu(&inode->i_hash, b); |
|
spin_unlock(&inode->i_lock); |
|
spin_unlock(&inode_hash_lock); |
|
} |
|
EXPORT_SYMBOL(__insert_inode_hash); |
|
|
|
/** |
|
* __remove_inode_hash - remove an inode from the hash |
|
* @inode: inode to unhash |
|
* |
|
* Remove an inode from the superblock. |
|
*/ |
|
void __remove_inode_hash(struct inode *inode) |
|
{ |
|
spin_lock(&inode_hash_lock); |
|
spin_lock(&inode->i_lock); |
|
hlist_del_init_rcu(&inode->i_hash); |
|
spin_unlock(&inode->i_lock); |
|
spin_unlock(&inode_hash_lock); |
|
} |
|
EXPORT_SYMBOL(__remove_inode_hash); |
|
|
|
void clear_inode(struct inode *inode) |
|
{ |
|
/* |
|
* We have to cycle the i_pages lock here because reclaim can be in the |
|
* process of removing the last page (in __delete_from_page_cache()) |
|
* and we must not free the mapping under it. |
|
*/ |
|
xa_lock_irq(&inode->i_data.i_pages); |
|
BUG_ON(inode->i_data.nrpages); |
|
BUG_ON(inode->i_data.nrexceptional); |
|
xa_unlock_irq(&inode->i_data.i_pages); |
|
BUG_ON(!list_empty(&inode->i_data.private_list)); |
|
BUG_ON(!(inode->i_state & I_FREEING)); |
|
BUG_ON(inode->i_state & I_CLEAR); |
|
BUG_ON(!list_empty(&inode->i_wb_list)); |
|
/* don't need i_lock here, no concurrent mods to i_state */ |
|
inode->i_state = I_FREEING | I_CLEAR; |
|
} |
|
EXPORT_SYMBOL(clear_inode); |
|
|
|
/* |
|
* Free the inode passed in, removing it from the lists it is still connected |
|
* to. We remove any pages still attached to the inode and wait for any IO that |
|
* is still in progress before finally destroying the inode. |
|
* |
|
* An inode must already be marked I_FREEING so that we avoid the inode being |
|
* moved back onto lists if we race with other code that manipulates the lists |
|
* (e.g. writeback_single_inode). The caller is responsible for setting this. |
|
* |
|
* An inode must already be removed from the LRU list before being evicted from |
|
* the cache. This should occur atomically with setting the I_FREEING state |
|
* flag, so no inodes here should ever be on the LRU when being evicted. |
|
*/ |
|
static void evict(struct inode *inode) |
|
{ |
|
const struct super_operations *op = inode->i_sb->s_op; |
|
|
|
BUG_ON(!(inode->i_state & I_FREEING)); |
|
BUG_ON(!list_empty(&inode->i_lru)); |
|
|
|
if (!list_empty(&inode->i_io_list)) |
|
inode_io_list_del(inode); |
|
|
|
inode_sb_list_del(inode); |
|
|
|
/* |
|
* Wait for flusher thread to be done with the inode so that filesystem |
|
* does not start destroying it while writeback is still running. Since |
|
* the inode has I_FREEING set, flusher thread won't start new work on |
|
* the inode. We just have to wait for running writeback to finish. |
|
*/ |
|
inode_wait_for_writeback(inode); |
|
|
|
if (op->evict_inode) { |
|
op->evict_inode(inode); |
|
} else { |
|
truncate_inode_pages_final(&inode->i_data); |
|
clear_inode(inode); |
|
} |
|
if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
|
cd_forget(inode); |
|
|
|
remove_inode_hash(inode); |
|
|
|
spin_lock(&inode->i_lock); |
|
wake_up_bit(&inode->i_state, __I_NEW); |
|
BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); |
|
spin_unlock(&inode->i_lock); |
|
|
|
destroy_inode(inode); |
|
} |
|
|
|
/* |
|
* dispose_list - dispose of the contents of a local list |
|
* @head: the head of the list to free |
|
* |
|
* Dispose-list gets a local list with local inodes in it, so it doesn't |
|
* need to worry about list corruption and SMP locks. |
|
*/ |
|
static void dispose_list(struct list_head *head) |
|
{ |
|
while (!list_empty(head)) { |
|
struct inode *inode; |
|
|
|
inode = list_first_entry(head, struct inode, i_lru); |
|
list_del_init(&inode->i_lru); |
|
|
|
evict(inode); |
|
cond_resched(); |
|
} |
|
} |
|
|
|
/** |
|
* evict_inodes - evict all evictable inodes for a superblock |
|
* @sb: superblock to operate on |
|
* |
|
* Make sure that no inodes with zero refcount are retained. This is |
|
* called by superblock shutdown after having SB_ACTIVE flag removed, |
|
* so any inode reaching zero refcount during or after that call will |
|
* be immediately evicted. |
|
*/ |
|
void evict_inodes(struct super_block *sb) |
|
{ |
|
struct inode *inode, *next; |
|
LIST_HEAD(dispose); |
|
|
|
again: |
|
spin_lock(&sb->s_inode_list_lock); |
|
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
|
if (atomic_read(&inode->i_count)) |
|
continue; |
|
|
|
spin_lock(&inode->i_lock); |
|
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
|
spin_unlock(&inode->i_lock); |
|
continue; |
|
} |
|
|
|
inode->i_state |= I_FREEING; |
|
inode_lru_list_del(inode); |
|
spin_unlock(&inode->i_lock); |
|
list_add(&inode->i_lru, &dispose); |
|
|
|
/* |
|
* We can have a ton of inodes to evict at unmount time given |
|
* enough memory, check to see if we need to go to sleep for a |
|
* bit so we don't livelock. |
|
*/ |
|
if (need_resched()) { |
|
spin_unlock(&sb->s_inode_list_lock); |
|
cond_resched(); |
|
dispose_list(&dispose); |
|
goto again; |
|
} |
|
} |
|
spin_unlock(&sb->s_inode_list_lock); |
|
|
|
dispose_list(&dispose); |
|
} |
|
EXPORT_SYMBOL_GPL(evict_inodes); |
|
|
|
/** |
|
* invalidate_inodes - attempt to free all inodes on a superblock |
|
* @sb: superblock to operate on |
|
* @kill_dirty: flag to guide handling of dirty inodes |
|
* |
|
* Attempts to free all inodes for a given superblock. If there were any |
|
* busy inodes return a non-zero value, else zero. |
|
* If @kill_dirty is set, discard dirty inodes too, otherwise treat |
|
* them as busy. |
|
*/ |
|
int invalidate_inodes(struct super_block *sb, bool kill_dirty) |
|
{ |
|
int busy = 0; |
|
struct inode *inode, *next; |
|
LIST_HEAD(dispose); |
|
|
|
again: |
|
spin_lock(&sb->s_inode_list_lock); |
|
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
|
spin_lock(&inode->i_lock); |
|
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
|
spin_unlock(&inode->i_lock); |
|
continue; |
|
} |
|
if (inode->i_state & I_DIRTY_ALL && !kill_dirty) { |
|
spin_unlock(&inode->i_lock); |
|
busy = 1; |
|
continue; |
|
} |
|
if (atomic_read(&inode->i_count)) { |
|
spin_unlock(&inode->i_lock); |
|
busy = 1; |
|
continue; |
|
} |
|
|
|
inode->i_state |= I_FREEING; |
|
inode_lru_list_del(inode); |
|
spin_unlock(&inode->i_lock); |
|
list_add(&inode->i_lru, &dispose); |
|
if (need_resched()) { |
|
spin_unlock(&sb->s_inode_list_lock); |
|
cond_resched(); |
|
dispose_list(&dispose); |
|
goto again; |
|
} |
|
} |
|
spin_unlock(&sb->s_inode_list_lock); |
|
|
|
dispose_list(&dispose); |
|
|
|
return busy; |
|
} |
|
|
|
/* |
|
* Isolate the inode from the LRU in preparation for freeing it. |
|
* |
|
* Any inodes which are pinned purely because of attached pagecache have their |
|
* pagecache removed. If the inode has metadata buffers attached to |
|
* mapping->private_list then try to remove them. |
|
* |
|
* If the inode has the I_REFERENCED flag set, then it means that it has been |
|
* used recently - the flag is set in iput_final(). When we encounter such an |
|
* inode, clear the flag and move it to the back of the LRU so it gets another |
|
* pass through the LRU before it gets reclaimed. This is necessary because of |
|
* the fact we are doing lazy LRU updates to minimise lock contention so the |
|
* LRU does not have strict ordering. Hence we don't want to reclaim inodes |
|
* with this flag set because they are the inodes that are out of order. |
|
*/ |
|
static enum lru_status inode_lru_isolate(struct list_head *item, |
|
struct list_lru_one *lru, spinlock_t *lru_lock, void *arg) |
|
{ |
|
struct list_head *freeable = arg; |
|
struct inode *inode = container_of(item, struct inode, i_lru); |
|
|
|
/* |
|
* we are inverting the lru lock/inode->i_lock here, so use a trylock. |
|
* If we fail to get the lock, just skip it. |
|
*/ |
|
if (!spin_trylock(&inode->i_lock)) |
|
return LRU_SKIP; |
|
|
|
/* |
|
* Referenced or dirty inodes are still in use. Give them another pass |
|
* through the LRU as we canot reclaim them now. |
|
*/ |
|
if (atomic_read(&inode->i_count) || |
|
(inode->i_state & ~I_REFERENCED)) { |
|
list_lru_isolate(lru, &inode->i_lru); |
|
spin_unlock(&inode->i_lock); |
|
this_cpu_dec(nr_unused); |
|
return LRU_REMOVED; |
|
} |
|
|
|
/* recently referenced inodes get one more pass */ |
|
if (inode->i_state & I_REFERENCED) { |
|
inode->i_state &= ~I_REFERENCED; |
|
spin_unlock(&inode->i_lock); |
|
return LRU_ROTATE; |
|
} |
|
|
|
if (inode_has_buffers(inode) || inode->i_data.nrpages) { |
|
__iget(inode); |
|
spin_unlock(&inode->i_lock); |
|
spin_unlock(lru_lock); |
|
if (remove_inode_buffers(inode)) { |
|
unsigned long reap; |
|
reap = invalidate_mapping_pages(&inode->i_data, 0, -1); |
|
if (current_is_kswapd()) |
|
__count_vm_events(KSWAPD_INODESTEAL, reap); |
|
else |
|
__count_vm_events(PGINODESTEAL, reap); |
|
if (current->reclaim_state) |
|
current->reclaim_state->reclaimed_slab += reap; |
|
} |
|
iput(inode); |
|
spin_lock(lru_lock); |
|
return LRU_RETRY; |
|
} |
|
|
|
WARN_ON(inode->i_state & I_NEW); |
|
inode->i_state |= I_FREEING; |
|
list_lru_isolate_move(lru, &inode->i_lru, freeable); |
|
spin_unlock(&inode->i_lock); |
|
|
|
this_cpu_dec(nr_unused); |
|
return LRU_REMOVED; |
|
} |
|
|
|
/* |
|
* Walk the superblock inode LRU for freeable inodes and attempt to free them. |
|
* This is called from the superblock shrinker function with a number of inodes |
|
* to trim from the LRU. Inodes to be freed are moved to a temporary list and |
|
* then are freed outside inode_lock by dispose_list(). |
|
*/ |
|
long prune_icache_sb(struct super_block *sb, struct shrink_control *sc) |
|
{ |
|
LIST_HEAD(freeable); |
|
long freed; |
|
|
|
freed = list_lru_shrink_walk(&sb->s_inode_lru, sc, |
|
inode_lru_isolate, &freeable); |
|
dispose_list(&freeable); |
|
return freed; |
|
} |
|
|
|
static void __wait_on_freeing_inode(struct inode *inode); |
|
/* |
|
* Called with the inode lock held. |
|
*/ |
|
static struct inode *find_inode(struct super_block *sb, |
|
struct hlist_head *head, |
|
int (*test)(struct inode *, void *), |
|
void *data) |
|
{ |
|
struct inode *inode = NULL; |
|
|
|
repeat: |
|
hlist_for_each_entry(inode, head, i_hash) { |
|
if (inode->i_sb != sb) |
|
continue; |
|
if (!test(inode, data)) |
|
continue; |
|
spin_lock(&inode->i_lock); |
|
if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
|
__wait_on_freeing_inode(inode); |
|
goto repeat; |
|
} |
|
if (unlikely(inode->i_state & I_CREATING)) { |
|
spin_unlock(&inode->i_lock); |
|
return ERR_PTR(-ESTALE); |
|
} |
|
__iget(inode); |
|
spin_unlock(&inode->i_lock); |
|
return inode; |
|
} |
|
return NULL; |
|
} |
|
|
|
/* |
|
* find_inode_fast is the fast path version of find_inode, see the comment at |
|
* iget_locked for details. |
|
*/ |
|
static struct inode *find_inode_fast(struct super_block *sb, |
|
struct hlist_head *head, unsigned long ino) |
|
{ |
|
struct inode *inode = NULL; |
|
|
|
repeat: |
|
hlist_for_each_entry(inode, head, i_hash) { |
|
if (inode->i_ino != ino) |
|
continue; |
|
if (inode->i_sb != sb) |
|
continue; |
|
spin_lock(&inode->i_lock); |
|
if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
|
__wait_on_freeing_inode(inode); |
|
goto repeat; |
|
} |
|
if (unlikely(inode->i_state & I_CREATING)) { |
|
spin_unlock(&inode->i_lock); |
|
return ERR_PTR(-ESTALE); |
|
} |
|
__iget(inode); |
|
spin_unlock(&inode->i_lock); |
|
return inode; |
|
} |
|
return NULL; |
|
} |
|
|
|
/* |
|
* Each cpu owns a range of LAST_INO_BATCH numbers. |
|
* 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations, |
|
* to renew the exhausted range. |
|
* |
|
* This does not significantly increase overflow rate because every CPU can |
|
* consume at most LAST_INO_BATCH-1 unused inode numbers. So there is |
|
* NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the |
|
* 2^32 range, and is a worst-case. Even a 50% wastage would only increase |
|
* overflow rate by 2x, which does not seem too significant. |
|
* |
|
* On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
|
* error if st_ino won't fit in target struct field. Use 32bit counter |
|
* here to attempt to avoid that. |
|
*/ |
|
#define LAST_INO_BATCH 1024 |
|
static DEFINE_PER_CPU(unsigned int, last_ino); |
|
|
|
unsigned int get_next_ino(void) |
|
{ |
|
unsigned int *p = &get_cpu_var(last_ino); |
|
unsigned int res = *p; |
|
|
|
#ifdef CONFIG_SMP |
|
if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) { |
|
static atomic_t shared_last_ino; |
|
int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino); |
|
|
|
res = next - LAST_INO_BATCH; |
|
} |
|
#endif |
|
|
|
res++; |
|
/* get_next_ino should not provide a 0 inode number */ |
|
if (unlikely(!res)) |
|
res++; |
|
*p = res; |
|
put_cpu_var(last_ino); |
|
return res; |
|
} |
|
EXPORT_SYMBOL(get_next_ino); |
|
|
|
/** |
|
* new_inode_pseudo - obtain an inode |
|
* @sb: superblock |
|
* |
|
* Allocates a new inode for given superblock. |
|
* Inode wont be chained in superblock s_inodes list |
|
* This means : |
|
* - fs can't be unmount |
|
* - quotas, fsnotify, writeback can't work |
|
*/ |
|
struct inode *new_inode_pseudo(struct super_block *sb) |
|
{ |
|
struct inode *inode = alloc_inode(sb); |
|
|
|
if (inode) { |
|
spin_lock(&inode->i_lock); |
|
inode->i_state = 0; |
|
spin_unlock(&inode->i_lock); |
|
INIT_LIST_HEAD(&inode->i_sb_list); |
|
} |
|
return inode; |
|
} |
|
|
|
/** |
|
* new_inode - obtain an inode |
|
* @sb: superblock |
|
* |
|
* Allocates a new inode for given superblock. The default gfp_mask |
|
* for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. |
|
* If HIGHMEM pages are unsuitable or it is known that pages allocated |
|
* for the page cache are not reclaimable or migratable, |
|
* mapping_set_gfp_mask() must be called with suitable flags on the |
|
* newly created inode's mapping |
|
* |
|
*/ |
|
struct inode *new_inode(struct super_block *sb) |
|
{ |
|
struct inode *inode; |
|
|
|
spin_lock_prefetch(&sb->s_inode_list_lock); |
|
|
|
inode = new_inode_pseudo(sb); |
|
if (inode) |
|
inode_sb_list_add(inode); |
|
return inode; |
|
} |
|
EXPORT_SYMBOL(new_inode); |
|
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC |
|
void lockdep_annotate_inode_mutex_key(struct inode *inode) |
|
{ |
|
if (S_ISDIR(inode->i_mode)) { |
|
struct file_system_type *type = inode->i_sb->s_type; |
|
|
|
/* Set new key only if filesystem hasn't already changed it */ |
|
if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) { |
|
/* |
|
* ensure nobody is actually holding i_mutex |
|
*/ |
|
// mutex_destroy(&inode->i_mutex); |
|
init_rwsem(&inode->i_rwsem); |
|
lockdep_set_class(&inode->i_rwsem, |
|
&type->i_mutex_dir_key); |
|
} |
|
} |
|
} |
|
EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key); |
|
#endif |
|
|
|
/** |
|
* unlock_new_inode - clear the I_NEW state and wake up any waiters |
|
* @inode: new inode to unlock |
|
* |
|
* Called when the inode is fully initialised to clear the new state of the |
|
* inode and wake up anyone waiting for the inode to finish initialisation. |
|
*/ |
|
void unlock_new_inode(struct inode *inode) |
|
{ |
|
lockdep_annotate_inode_mutex_key(inode); |
|
spin_lock(&inode->i_lock); |
|
WARN_ON(!(inode->i_state & I_NEW)); |
|
inode->i_state &= ~I_NEW & ~I_CREATING; |
|
smp_mb(); |
|
wake_up_bit(&inode->i_state, __I_NEW); |
|
spin_unlock(&inode->i_lock); |
|
} |
|
EXPORT_SYMBOL(unlock_new_inode); |
|
|
|
void discard_new_inode(struct inode *inode) |
|
{ |
|
lockdep_annotate_inode_mutex_key(inode); |
|
spin_lock(&inode->i_lock); |
|
WARN_ON(!(inode->i_state & I_NEW)); |
|
inode->i_state &= ~I_NEW; |
|
smp_mb(); |
|
wake_up_bit(&inode->i_state, __I_NEW); |
|
spin_unlock(&inode->i_lock); |
|
iput(inode); |
|
} |
|
EXPORT_SYMBOL(discard_new_inode); |
|
|
|
/** |
|
* lock_two_nondirectories - take two i_mutexes on non-directory objects |
|
* |
|
* Lock any non-NULL argument that is not a directory. |
|
* Zero, one or two objects may be locked by this function. |
|
* |
|
* @inode1: first inode to lock |
|
* @inode2: second inode to lock |
|
*/ |
|
void lock_two_nondirectories(struct inode *inode1, struct inode *inode2) |
|
{ |
|
if (inode1 > inode2) |
|
swap(inode1, inode2); |
|
|
|
if (inode1 && !S_ISDIR(inode1->i_mode)) |
|
inode_lock(inode1); |
|
if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1) |
|
inode_lock_nested(inode2, I_MUTEX_NONDIR2); |
|
} |
|
EXPORT_SYMBOL(lock_two_nondirectories); |
|
|
|
/** |
|
* unlock_two_nondirectories - release locks from lock_two_nondirectories() |
|
* @inode1: first inode to unlock |
|
* @inode2: second inode to unlock |
|
*/ |
|
void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2) |
|
{ |
|
if (inode1 && !S_ISDIR(inode1->i_mode)) |
|
inode_unlock(inode1); |
|
if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1) |
|
inode_unlock(inode2); |
|
} |
|
EXPORT_SYMBOL(unlock_two_nondirectories); |
|
|
|
/** |
|
* inode_insert5 - obtain an inode from a mounted file system |
|
* @inode: pre-allocated inode to use for insert to cache |
|
* @hashval: hash value (usually inode number) to get |
|
* @test: callback used for comparisons between inodes |
|
* @set: callback used to initialize a new struct inode |
|
* @data: opaque data pointer to pass to @test and @set |
|
* |
|
* Search for the inode specified by @hashval and @data in the inode cache, |
|
* and if present it is return it with an increased reference count. This is |
|
* a variant of iget5_locked() for callers that don't want to fail on memory |
|
* allocation of inode. |
|
* |
|
* If the inode is not in cache, insert the pre-allocated inode to cache and |
|
* return it locked, hashed, and with the I_NEW flag set. The file system gets |
|
* to fill it in before unlocking it via unlock_new_inode(). |
|
* |
|
* Note both @test and @set are called with the inode_hash_lock held, so can't |
|
* sleep. |
|
*/ |
|
struct inode *inode_insert5(struct inode *inode, unsigned long hashval, |
|
int (*test)(struct inode *, void *), |
|
int (*set)(struct inode *, void *), void *data) |
|
{ |
|
struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval); |
|
struct inode *old; |
|
bool creating = inode->i_state & I_CREATING; |
|
|
|
again: |
|
spin_lock(&inode_hash_lock); |
|
old = find_inode(inode->i_sb, head, test, data); |
|
if (unlikely(old)) { |
|
/* |
|
* Uhhuh, somebody else created the same inode under us. |
|
* Use the old inode instead of the preallocated one. |
|
*/ |
|
spin_unlock(&inode_hash_lock); |
|
if (IS_ERR(old)) |
|
return NULL; |
|
wait_on_inode(old); |
|
if (unlikely(inode_unhashed(old))) { |
|
iput(old); |
|
goto again; |
|
} |
|
return old; |
|
} |
|
|
|
if (set && unlikely(set(inode, data))) { |
|
inode = NULL; |
|
goto unlock; |
|
} |
|
|
|
/* |
|
* Return the locked inode with I_NEW set, the |
|
* caller is responsible for filling in the contents |
|
*/ |
|
spin_lock(&inode->i_lock); |
|
inode->i_state |= I_NEW; |
|
hlist_add_head_rcu(&inode->i_hash, head); |
|
spin_unlock(&inode->i_lock); |
|
if (!creating) |
|
inode_sb_list_add(inode); |
|
unlock: |
|
spin_unlock(&inode_hash_lock); |
|
|
|
return inode; |
|
} |
|
EXPORT_SYMBOL(inode_insert5); |
|
|
|
/** |
|
* iget5_locked - obtain an inode from a mounted file system |
|
* @sb: super block of file system |
|
* @hashval: hash value (usually inode number) to get |
|
* @test: callback used for comparisons between inodes |
|
* @set: callback used to initialize a new struct inode |
|
* @data: opaque data pointer to pass to @test and @set |
|
* |
|
* Search for the inode specified by @hashval and @data in the inode cache, |
|
* and if present it is return it with an increased reference count. This is |
|
* a generalized version of iget_locked() for file systems where the inode |
|
* number is not sufficient for unique identification of an inode. |
|
* |
|
* If the inode is not in cache, allocate a new inode and return it locked, |
|
* hashed, and with the I_NEW flag set. The file system gets to fill it in |
|
* before unlocking it via unlock_new_inode(). |
|
* |
|
* Note both @test and @set are called with the inode_hash_lock held, so can't |
|
* sleep. |
|
*/ |
|
struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, |
|
int (*test)(struct inode *, void *), |
|
int (*set)(struct inode *, void *), void *data) |
|
{ |
|
struct inode *inode = ilookup5(sb, hashval, test, data); |
|
|
|
if (!inode) { |
|
struct inode *new = alloc_inode(sb); |
|
|
|
if (new) { |
|
new->i_state = 0; |
|
inode = inode_insert5(new, hashval, test, set, data); |
|
if (unlikely(inode != new)) |
|
destroy_inode(new); |
|
} |
|
} |
|
return inode; |
|
} |
|
EXPORT_SYMBOL(iget5_locked); |
|
|
|
/** |
|
* iget_locked - obtain an inode from a mounted file system |
|
* @sb: super block of file system |
|
* @ino: inode number to get |
|
* |
|
* Search for the inode specified by @ino in the inode cache and if present |
|
* return it with an increased reference count. This is for file systems |
|
* where the inode number is sufficient for unique identification of an inode. |
|
* |
|
* If the inode is not in cache, allocate a new inode and return it locked, |
|
* hashed, and with the I_NEW flag set. The file system gets to fill it in |
|
* before unlocking it via unlock_new_inode(). |
|
*/ |
|
struct inode *iget_locked(struct super_block *sb, unsigned long ino) |
|
{ |
|
struct hlist_head *head = inode_hashtable + hash(sb, ino); |
|
struct inode *inode; |
|
again: |
|
spin_lock(&inode_hash_lock); |
|
inode = find_inode_fast(sb, head, ino); |
|
spin_unlock(&inode_hash_lock); |
|
if (inode) { |
|
if (IS_ERR(inode)) |
|
return NULL; |
|
wait_on_inode(inode); |
|
if (unlikely(inode_unhashed(inode))) { |
|
iput(inode); |
|
goto again; |
|
} |
|
return inode; |
|
} |
|
|
|
inode = alloc_inode(sb); |
|
if (inode) { |
|
struct inode *old; |
|
|
|
spin_lock(&inode_hash_lock); |
|
/* We released the lock, so.. */ |
|
old = find_inode_fast(sb, head, ino); |
|
if (!old) { |
|
inode->i_ino = ino; |
|
spin_lock(&inode->i_lock); |
|
inode->i_state = I_NEW; |
|
hlist_add_head_rcu(&inode->i_hash, head); |
|
spin_unlock(&inode->i_lock); |
|
inode_sb_list_add(inode); |
|
spin_unlock(&inode_hash_lock); |
|
|
|
/* Return the locked inode with I_NEW set, the |
|
* caller is responsible for filling in the contents |
|
*/ |
|
return inode; |
|
} |
|
|
|
/* |
|
* Uhhuh, somebody else created the same inode under |
|
* us. Use the old inode instead of the one we just |
|
* allocated. |
|
*/ |
|
spin_unlock(&inode_hash_lock); |
|
destroy_inode(inode); |
|
if (IS_ERR(old)) |
|
return NULL; |
|
inode = old; |
|
wait_on_inode(inode); |
|
if (unlikely(inode_unhashed(inode))) { |
|
iput(inode); |
|
goto again; |
|
} |
|
} |
|
return inode; |
|
} |
|
EXPORT_SYMBOL(iget_locked); |
|
|
|
/* |
|
* search the inode cache for a matching inode number. |
|
* If we find one, then the inode number we are trying to |
|
* allocate is not unique and so we should not use it. |
|
* |
|
* Returns 1 if the inode number is unique, 0 if it is not. |
|
*/ |
|
static int test_inode_iunique(struct super_block *sb, unsigned long ino) |
|
{ |
|
struct hlist_head *b = inode_hashtable + hash(sb, ino); |
|
struct inode *inode; |
|
|
|
hlist_for_each_entry_rcu(inode, b, i_hash) { |
|
if (inode->i_ino == ino && inode->i_sb == sb) |
|
return 0; |
|
} |
|
return 1; |
|
} |
|
|
|
/** |
|
* iunique - get a unique inode number |
|
* @sb: superblock |
|
* @max_reserved: highest reserved inode number |
|
* |
|
* Obtain an inode number that is unique on the system for a given |
|
* superblock. This is used by file systems that have no natural |
|
* permanent inode numbering system. An inode number is returned that |
|
* is higher than the reserved limit but unique. |
|
* |
|
* BUGS: |
|
* With a large number of inodes live on the file system this function |
|
* currently becomes quite slow. |
|
*/ |
|
ino_t iunique(struct super_block *sb, ino_t max_reserved) |
|
{ |
|
/* |
|
* On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
|
* error if st_ino won't fit in target struct field. Use 32bit counter |
|
* here to attempt to avoid that. |
|
*/ |
|
static DEFINE_SPINLOCK(iunique_lock); |
|
static unsigned int counter; |
|
ino_t res; |
|
|
|
rcu_read_lock(); |
|
spin_lock(&iunique_lock); |
|
do { |
|
if (counter <= max_reserved) |
|
counter = max_reserved + 1; |
|
res = counter++; |
|
} while (!test_inode_iunique(sb, res)); |
|
spin_unlock(&iunique_lock); |
|
rcu_read_unlock(); |
|
|
|
return res; |
|
} |
|
EXPORT_SYMBOL(iunique); |
|
|
|
struct inode *igrab(struct inode *inode) |
|
{ |
|
spin_lock(&inode->i_lock); |
|
if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) { |
|
__iget(inode); |
|
spin_unlock(&inode->i_lock); |
|
} else { |
|
spin_unlock(&inode->i_lock); |
|
/* |
|
* Handle the case where s_op->clear_inode is not been |
|
* called yet, and somebody is calling igrab |
|
* while the inode is getting freed. |
|
*/ |
|
inode = NULL; |
|
} |
|
return inode; |
|
} |
|
EXPORT_SYMBOL(igrab); |
|
|
|
/** |
|
* ilookup5_nowait - search for an inode in the inode cache |
|
* @sb: super block of file system to search |
|
* @hashval: hash value (usually inode number) to search for |
|
* @test: callback used for comparisons between inodes |
|
* @data: opaque data pointer to pass to @test |
|
* |
|
* Search for the inode specified by @hashval and @data in the inode cache. |
|
* If the inode is in the cache, the inode is returned with an incremented |
|
* reference count. |
|
* |
|
* Note: I_NEW is not waited upon so you have to be very careful what you do |
|
* with the returned inode. You probably should be using ilookup5() instead. |
|
* |
|
* Note2: @test is called with the inode_hash_lock held, so can't sleep. |
|
*/ |
|
struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, |
|
int (*test)(struct inode *, void *), void *data) |
|
{ |
|
struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
|
struct inode *inode; |
|
|
|
spin_lock(&inode_hash_lock); |
|
inode = find_inode(sb, head, test, data); |
|
spin_unlock(&inode_hash_lock); |
|
|
|
return IS_ERR(inode) ? NULL : inode; |
|
} |
|
EXPORT_SYMBOL(ilookup5_nowait); |
|
|
|
/** |
|
* ilookup5 - search for an inode in the inode cache |
|
* @sb: super block of file system to search |
|
* @hashval: hash value (usually inode number) to search for |
|
* @test: callback used for comparisons between inodes |
|
* @data: opaque data pointer to pass to @test |
|
* |
|
* Search for the inode specified by @hashval and @data in the inode cache, |
|
* and if the inode is in the cache, return the inode with an incremented |
|
* reference count. Waits on I_NEW before returning the inode. |
|
* returned with an incremented reference count. |
|
* |
|
* This is a generalized version of ilookup() for file systems where the |
|
* inode number is not sufficient for unique identification of an inode. |
|
* |
|
* Note: @test is called with the inode_hash_lock held, so can't sleep. |
|
*/ |
|
struct inode *ilookup5(struct super_block *sb, unsigned long hashval, |
|
int (*test)(struct inode *, void *), void *data) |
|
{ |
|
struct inode *inode; |
|
again: |
|
inode = ilookup5_nowait(sb, hashval, test, data); |
|
if (inode) { |
|
wait_on_inode(inode); |
|
if (unlikely(inode_unhashed(inode))) { |
|
iput(inode); |
|
goto again; |
|
} |
|
} |
|
return inode; |
|
} |
|
EXPORT_SYMBOL(ilookup5); |
|
|
|
/** |
|
* ilookup - search for an inode in the inode cache |
|
* @sb: super block of file system to search |
|
* @ino: inode number to search for |
|
* |
|
* Search for the inode @ino in the inode cache, and if the inode is in the |
|
* cache, the inode is returned with an incremented reference count. |
|
*/ |
|
struct inode *ilookup(struct super_block *sb, unsigned long ino) |
|
{ |
|
struct hlist_head *head = inode_hashtable + hash(sb, ino); |
|
struct inode *inode; |
|
again: |
|
spin_lock(&inode_hash_lock); |
|
inode = find_inode_fast(sb, head, ino); |
|
spin_unlock(&inode_hash_lock); |
|
|
|
if (inode) { |
|
if (IS_ERR(inode)) |
|
return NULL; |
|
wait_on_inode(inode); |
|
if (unlikely(inode_unhashed(inode))) { |
|
iput(inode); |
|
goto again; |
|
} |
|
} |
|
return inode; |
|
} |
|
EXPORT_SYMBOL(ilookup); |
|
|
|
/** |
|
* find_inode_nowait - find an inode in the inode cache |
|
* @sb: super block of file system to search |
|
* @hashval: hash value (usually inode number) to search for |
|
* @match: callback used for comparisons between inodes |
|
* @data: opaque data pointer to pass to @match |
|
* |
|
* Search for the inode specified by @hashval and @data in the inode |
|
* cache, where the helper function @match will return 0 if the inode |
|
* does not match, 1 if the inode does match, and -1 if the search |
|
* should be stopped. The @match function must be responsible for |
|
* taking the i_lock spin_lock and checking i_state for an inode being |
|
* freed or being initialized, and incrementing the reference count |
|
* before returning 1. It also must not sleep, since it is called with |
|
* the inode_hash_lock spinlock held. |
|
* |
|
* This is a even more generalized version of ilookup5() when the |
|
* function must never block --- find_inode() can block in |
|
* __wait_on_freeing_inode() --- or when the caller can not increment |
|
* the reference count because the resulting iput() might cause an |
|
* inode eviction. The tradeoff is that the @match funtion must be |
|
* very carefully implemented. |
|
*/ |
|
struct inode *find_inode_nowait(struct super_block *sb, |
|
unsigned long hashval, |
|
int (*match)(struct inode *, unsigned long, |
|
void *), |
|
void *data) |
|
{ |
|
struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
|
struct inode *inode, *ret_inode = NULL; |
|
int mval; |
|
|
|
spin_lock(&inode_hash_lock); |
|
hlist_for_each_entry(inode, head, i_hash) { |
|
if (inode->i_sb != sb) |
|
continue; |
|
mval = match(inode, hashval, data); |
|
if (mval == 0) |
|
continue; |
|
if (mval == 1) |
|
ret_inode = inode; |
|
goto out; |
|
} |
|
out: |
|
spin_unlock(&inode_hash_lock); |
|
return ret_inode; |
|
} |
|
EXPORT_SYMBOL(find_inode_nowait); |
|
|
|
/** |
|
* find_inode_rcu - find an inode in the inode cache |
|
* @sb: Super block of file system to search |
|
* @hashval: Key to hash |
|
* @test: Function to test match on an inode |
|
* @data: Data for test function |
|
* |
|
* Search for the inode specified by @hashval and @data in the inode cache, |
|
* where the helper function @test will return 0 if the inode does not match |
|
* and 1 if it does. The @test function must be responsible for taking the |
|
* i_lock spin_lock and checking i_state for an inode being freed or being |
|
* initialized. |
|
* |
|
* If successful, this will return the inode for which the @test function |
|
* returned 1 and NULL otherwise. |
|
* |
|
* The @test function is not permitted to take a ref on any inode presented. |
|
* It is also not permitted to sleep. |
|
* |
|
* The caller must hold the RCU read lock. |
|
*/ |
|
struct inode *find_inode_rcu(struct super_block *sb, unsigned long hashval, |
|
int (*test)(struct inode *, void *), void *data) |
|
{ |
|
struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
|
struct inode *inode; |
|
|
|
RCU_LOCKDEP_WARN(!rcu_read_lock_held(), |
|
"suspicious find_inode_rcu() usage"); |
|
|
|
hlist_for_each_entry_rcu(inode, head, i_hash) { |
|
if (inode->i_sb == sb && |
|
!(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE)) && |
|
test(inode, data)) |
|
return inode; |
|
} |
|
return NULL; |
|
} |
|
EXPORT_SYMBOL(find_inode_rcu); |
|
|
|
/** |
|
* find_inode_by_ino_rcu - Find an inode in the inode cache |
|
* @sb: Super block of file system to search |
|
* @ino: The inode number to match |
|
* |
|
* Search for the inode specified by @hashval and @data in the inode cache, |
|
* where the helper function @test will return 0 if the inode does not match |
|
* and 1 if it does. The @test function must be responsible for taking the |
|
* i_lock spin_lock and checking i_state for an inode being freed or being |
|
* initialized. |
|
* |
|
* If successful, this will return the inode for which the @test function |
|
* returned 1 and NULL otherwise. |
|
* |
|
* The @test function is not permitted to take a ref on any inode presented. |
|
* It is also not permitted to sleep. |
|
* |
|
* The caller must hold the RCU read lock. |
|
*/ |
|
struct inode *find_inode_by_ino_rcu(struct super_block *sb, |
|
unsigned long ino) |
|
{ |
|
struct hlist_head *head = inode_hashtable + hash(sb, ino); |
|
struct inode *inode; |
|
|
|
RCU_LOCKDEP_WARN(!rcu_read_lock_held(), |
|
"suspicious find_inode_by_ino_rcu() usage"); |
|
|
|
hlist_for_each_entry_rcu(inode, head, i_hash) { |
|
if (inode->i_ino == ino && |
|
inode->i_sb == sb && |
|
!(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE))) |
|
return inode; |
|
} |
|
return NULL; |
|
} |
|
EXPORT_SYMBOL(find_inode_by_ino_rcu); |
|
|
|
int insert_inode_locked(struct inode *inode) |
|
{ |
|
struct super_block *sb = inode->i_sb; |
|
ino_t ino = inode->i_ino; |
|
struct hlist_head *head = inode_hashtable + hash(sb, ino); |
|
|
|
while (1) { |
|
struct inode *old = NULL; |
|
spin_lock(&inode_hash_lock); |
|
hlist_for_each_entry(old, head, i_hash) { |
|
if (old->i_ino != ino) |
|
continue; |
|
if (old->i_sb != sb) |
|
continue; |
|
spin_lock(&old->i_lock); |
|
if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
|
spin_unlock(&old->i_lock); |
|
continue; |
|
} |
|
break; |
|
} |
|
if (likely(!old)) { |
|
spin_lock(&inode->i_lock); |
|
inode->i_state |= I_NEW | I_CREATING; |
|
hlist_add_head_rcu(&inode->i_hash, head); |
|
spin_unlock(&inode->i_lock); |
|
spin_unlock(&inode_hash_lock); |
|
return 0; |
|
} |
|
if (unlikely(old->i_state & I_CREATING)) { |
|
spin_unlock(&old->i_lock); |
|
spin_unlock(&inode_hash_lock); |
|
return -EBUSY; |
|
} |
|
__iget(old); |
|
spin_unlock(&old->i_lock); |
|
spin_unlock(&inode_hash_lock); |
|
wait_on_inode(old); |
|
if (unlikely(!inode_unhashed(old))) { |
|
iput(old); |
|
return -EBUSY; |
|
} |
|
iput(old); |
|
} |
|
} |
|
EXPORT_SYMBOL(insert_inode_locked); |
|
|
|
int insert_inode_locked4(struct inode *inode, unsigned long hashval, |
|
int (*test)(struct inode *, void *), void *data) |
|
{ |
|
struct inode *old; |
|
|
|
inode->i_state |= I_CREATING; |
|
old = inode_insert5(inode, hashval, test, NULL, data); |
|
|
|
if (old != inode) { |
|
iput(old); |
|
return -EBUSY; |
|
} |
|
return 0; |
|
} |
|
EXPORT_SYMBOL(insert_inode_locked4); |
|
|
|
|
|
int generic_delete_inode(struct inode *inode) |
|
{ |
|
return 1; |
|
} |
|
EXPORT_SYMBOL(generic_delete_inode); |
|
|
|
/* |
|
* Called when we're dropping the last reference |
|
* to an inode. |
|
* |
|
* Call the FS "drop_inode()" function, defaulting to |
|
* the legacy UNIX filesystem behaviour. If it tells |
|
* us to evict inode, do so. Otherwise, retain inode |
|
* in cache if fs is alive, sync and evict if fs is |
|
* shutting down. |
|
*/ |
|
static void iput_final(struct inode *inode) |
|
{ |
|
struct super_block *sb = inode->i_sb; |
|
const struct super_operations *op = inode->i_sb->s_op; |
|
unsigned long state; |
|
int drop; |
|
|
|
WARN_ON(inode->i_state & I_NEW); |
|
|
|
if (op->drop_inode) |
|
drop = op->drop_inode(inode); |
|
else |
|
drop = generic_drop_inode(inode); |
|
|
|
if (!drop && |
|
!(inode->i_state & I_DONTCACHE) && |
|
(sb->s_flags & SB_ACTIVE)) { |
|
inode_add_lru(inode); |
|
spin_unlock(&inode->i_lock); |
|
return; |
|
} |
|
|
|
state = inode->i_state; |
|
if (!drop) { |
|
WRITE_ONCE(inode->i_state, state | I_WILL_FREE); |
|
spin_unlock(&inode->i_lock); |
|
|
|
write_inode_now(inode, 1); |
|
|
|
spin_lock(&inode->i_lock); |
|
state = inode->i_state; |
|
WARN_ON(state & I_NEW); |
|
state &= ~I_WILL_FREE; |
|
} |
|
|
|
WRITE_ONCE(inode->i_state, state | I_FREEING); |
|
if (!list_empty(&inode->i_lru)) |
|
inode_lru_list_del(inode); |
|
spin_unlock(&inode->i_lock); |
|
|
|
evict(inode); |
|
} |
|
|
|
/** |
|
* iput - put an inode |
|
* @inode: inode to put |
|
* |
|
* Puts an inode, dropping its usage count. If the inode use count hits |
|
* zero, the inode is then freed and may also be destroyed. |
|
* |
|
* Consequently, iput() can sleep. |
|
*/ |
|
void iput(struct inode *inode) |
|
{ |
|
if (!inode) |
|
return; |
|
BUG_ON(inode->i_state & I_CLEAR); |
|
retry: |
|
if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) { |
|
if (inode->i_nlink && (inode->i_state & I_DIRTY_TIME)) { |
|
atomic_inc(&inode->i_count); |
|
spin_unlock(&inode->i_lock); |
|
trace_writeback_lazytime_iput(inode); |
|
mark_inode_dirty_sync(inode); |
|
goto retry; |
|
} |
|
iput_final(inode); |
|
} |
|
} |
|
EXPORT_SYMBOL(iput); |
|
|
|
#ifdef CONFIG_BLOCK |
|
/** |
|
* bmap - find a block number in a file |
|
* @inode: inode owning the block number being requested |
|
* @block: pointer containing the block to find |
|
* |
|
* Replaces the value in ``*block`` with the block number on the device holding |
|
* corresponding to the requested block number in the file. |
|
* That is, asked for block 4 of inode 1 the function will replace the |
|
* 4 in ``*block``, with disk block relative to the disk start that holds that |
|
* block of the file. |
|
* |
|
* Returns -EINVAL in case of error, 0 otherwise. If mapping falls into a |
|
* hole, returns 0 and ``*block`` is also set to 0. |
|
*/ |
|
int bmap(struct inode *inode, sector_t *block) |
|
{ |
|
if (!inode->i_mapping->a_ops->bmap) |
|
return -EINVAL; |
|
|
|
*block = inode->i_mapping->a_ops->bmap(inode->i_mapping, *block); |
|
return 0; |
|
} |
|
EXPORT_SYMBOL(bmap); |
|
#endif |
|
|
|
/* |
|
* With relative atime, only update atime if the previous atime is |
|
* earlier than either the ctime or mtime or if at least a day has |
|
* passed since the last atime update. |
|
*/ |
|
static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, |
|
struct timespec64 now) |
|
{ |
|
|
|
if (!(mnt->mnt_flags & MNT_RELATIME)) |
|
return 1; |
|
/* |
|
* Is mtime younger than atime? If yes, update atime: |
|
*/ |
|
if (timespec64_compare(&inode->i_mtime, &inode->i_atime) >= 0) |
|
return 1; |
|
/* |
|
* Is ctime younger than atime? If yes, update atime: |
|
*/ |
|
if (timespec64_compare(&inode->i_ctime, &inode->i_atime) >= 0) |
|
return 1; |
|
|
|
/* |
|
* Is the previous atime value older than a day? If yes, |
|
* update atime: |
|
*/ |
|
if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60) |
|
return 1; |
|
/* |
|
* Good, we can skip the atime update: |
|
*/ |
|
return 0; |
|
} |
|
|
|
int generic_update_time(struct inode *inode, struct timespec64 *time, int flags) |
|
{ |
|
int dirty_flags = 0; |
|
|
|
if (flags & (S_ATIME | S_CTIME | S_MTIME)) { |
|
if (flags & S_ATIME) |
|
inode->i_atime = *time; |
|
if (flags & S_CTIME) |
|
inode->i_ctime = *time; |
|
if (flags & S_MTIME) |
|
inode->i_mtime = *time; |
|
|
|
if (inode->i_sb->s_flags & SB_LAZYTIME) |
|
dirty_flags |= I_DIRTY_TIME; |
|
else |
|
dirty_flags |= I_DIRTY_SYNC; |
|
} |
|
|
|
if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false)) |
|
dirty_flags |= I_DIRTY_SYNC; |
|
|
|
__mark_inode_dirty(inode, dirty_flags); |
|
return 0; |
|
} |
|
EXPORT_SYMBOL(generic_update_time); |
|
|
|
/* |
|
* This does the actual work of updating an inodes time or version. Must have |
|
* had called mnt_want_write() before calling this. |
|
*/ |
|
static int update_time(struct inode *inode, struct timespec64 *time, int flags) |
|
{ |
|
if (inode->i_op->update_time) |
|
return inode->i_op->update_time(inode, time, flags); |
|
return generic_update_time(inode, time, flags); |
|
} |
|
|
|
/** |
|
* atime_needs_update - update the access time |
|
* @path: the &struct path to update |
|
* @inode: inode to update |
|
* |
|
* Update the accessed time on an inode and mark it for writeback. |
|
* This function automatically handles read only file systems and media, |
|
* as well as the "noatime" flag and inode specific "noatime" markers. |
|
*/ |
|
bool atime_needs_update(const struct path *path, struct inode *inode) |
|
{ |
|
struct vfsmount *mnt = path->mnt; |
|
struct timespec64 now; |
|
|
|
if (inode->i_flags & S_NOATIME) |
|
return false; |
|
|
|
/* Atime updates will likely cause i_uid and i_gid to be written |
|
* back improprely if their true value is unknown to the vfs. |
|
*/ |
|
if (HAS_UNMAPPED_ID(mnt_user_ns(mnt), inode)) |
|
return false; |
|
|
|
if (IS_NOATIME(inode)) |
|
return false; |
|
if ((inode->i_sb->s_flags & SB_NODIRATIME) && S_ISDIR(inode->i_mode)) |
|
return false; |
|
|
|
if (mnt->mnt_flags & MNT_NOATIME) |
|
return false; |
|
if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) |
|
return false; |
|
|
|
now = current_time(inode); |
|
|
|
if (!relatime_need_update(mnt, inode, now)) |
|
return false; |
|
|
|
if (timespec64_equal(&inode->i_atime, &now)) |
|
return false; |
|
|
|
return true; |
|
} |
|
|
|
void touch_atime(const struct path *path) |
|
{ |
|
struct vfsmount *mnt = path->mnt; |
|
struct inode *inode = d_inode(path->dentry); |
|
struct timespec64 now; |
|
|
|
if (!atime_needs_update(path, inode)) |
|
return; |
|
|
|
if (!sb_start_write_trylock(inode->i_sb)) |
|
return; |
|
|
|
if (__mnt_want_write(mnt) != 0) |
|
goto skip_update; |
|
/* |
|
* File systems can error out when updating inodes if they need to |
|
* allocate new space to modify an inode (such is the case for |
|
* Btrfs), but since we touch atime while walking down the path we |
|
* really don't care if we failed to update the atime of the file, |
|
* so just ignore the return value. |
|
* We may also fail on filesystems that have the ability to make parts |
|
* of the fs read only, e.g. subvolumes in Btrfs. |
|
*/ |
|
now = current_time(inode); |
|
update_time(inode, &now, S_ATIME); |
|
__mnt_drop_write(mnt); |
|
skip_update: |
|
sb_end_write(inode->i_sb); |
|
} |
|
EXPORT_SYMBOL(touch_atime); |
|
|
|
/* |
|
* The logic we want is |
|
* |
|
* if suid or (sgid and xgrp) |
|
* remove privs |
|
*/ |
|
int should_remove_suid(struct dentry *dentry) |
|
{ |
|
umode_t mode = d_inode(dentry)->i_mode; |
|
int kill = 0; |
|
|
|
/* suid always must be killed */ |
|
if (unlikely(mode & S_ISUID)) |
|
kill = ATTR_KILL_SUID; |
|
|
|
/* |
|
* sgid without any exec bits is just a mandatory locking mark; leave |
|
* it alone. If some exec bits are set, it's a real sgid; kill it. |
|
*/ |
|
if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) |
|
kill |= ATTR_KILL_SGID; |
|
|
|
if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) |
|
return kill; |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL(should_remove_suid); |
|
|
|
/* |
|
* Return mask of changes for notify_change() that need to be done as a |
|
* response to write or truncate. Return 0 if nothing has to be changed. |
|
* Negative value on error (change should be denied). |
|
*/ |
|
int dentry_needs_remove_privs(struct dentry *dentry) |
|
{ |
|
struct inode *inode = d_inode(dentry); |
|
int mask = 0; |
|
int ret; |
|
|
|
if (IS_NOSEC(inode)) |
|
return 0; |
|
|
|
mask = should_remove_suid(dentry); |
|
ret = security_inode_need_killpriv(dentry); |
|
if (ret < 0) |
|
return ret; |
|
if (ret) |
|
mask |= ATTR_KILL_PRIV; |
|
return mask; |
|
} |
|
|
|
static int __remove_privs(struct user_namespace *mnt_userns, |
|
struct dentry *dentry, int kill) |
|
{ |
|
struct iattr newattrs; |
|
|
|
newattrs.ia_valid = ATTR_FORCE | kill; |
|
/* |
|
* Note we call this on write, so notify_change will not |
|
* encounter any conflicting delegations: |
|
*/ |
|
return notify_change(mnt_userns, dentry, &newattrs, NULL); |
|
} |
|
|
|
/* |
|
* Remove special file priviledges (suid, capabilities) when file is written |
|
* to or truncated. |
|
*/ |
|
int file_remove_privs(struct file *file) |
|
{ |
|
struct dentry *dentry = file_dentry(file); |
|
struct inode *inode = file_inode(file); |
|
int kill; |
|
int error = 0; |
|
|
|
/* |
|
* Fast path for nothing security related. |
|
* As well for non-regular files, e.g. blkdev inodes. |
|
* For example, blkdev_write_iter() might get here |
|
* trying to remove privs which it is not allowed to. |
|
*/ |
|
if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode)) |
|
return 0; |
|
|
|
kill = dentry_needs_remove_privs(dentry); |
|
if (kill < 0) |
|
return kill; |
|
if (kill) |
|
error = __remove_privs(file_mnt_user_ns(file), dentry, kill); |
|
if (!error) |
|
inode_has_no_xattr(inode); |
|
|
|
return error; |
|
} |
|
EXPORT_SYMBOL(file_remove_privs); |
|
|
|
/** |
|
* file_update_time - update mtime and ctime time |
|
* @file: file accessed |
|
* |
|
* Update the mtime and ctime members of an inode and mark the inode |
|
* for writeback. Note that this function is meant exclusively for |
|
* usage in the file write path of filesystems, and filesystems may |
|
* choose to explicitly ignore update via this function with the |
|
* S_NOCMTIME inode flag, e.g. for network filesystem where these |
|
* timestamps are handled by the server. This can return an error for |
|
* file systems who need to allocate space in order to update an inode. |
|
*/ |
|
|
|
int file_update_time(struct file *file) |
|
{ |
|
struct inode *inode = file_inode(file); |
|
struct timespec64 now; |
|
int sync_it = 0; |
|
int ret; |
|
|
|
/* First try to exhaust all avenues to not sync */ |
|
if (IS_NOCMTIME(inode)) |
|
return 0; |
|
|
|
now = current_time(inode); |
|
if (!timespec64_equal(&inode->i_mtime, &now)) |
|
sync_it = S_MTIME; |
|
|
|
if (!timespec64_equal(&inode->i_ctime, &now)) |
|
sync_it |= S_CTIME; |
|
|
|
if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode)) |
|
sync_it |= S_VERSION; |
|
|
|
if (!sync_it) |
|
return 0; |
|
|
|
/* Finally allowed to write? Takes lock. */ |
|
if (__mnt_want_write_file(file)) |
|
return 0; |
|
|
|
ret = update_time(inode, &now, sync_it); |
|
__mnt_drop_write_file(file); |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL(file_update_time); |
|
|
|
/* Caller must hold the file's inode lock */ |
|
int file_modified(struct file *file) |
|
{ |
|
int err; |
|
|
|
/* |
|
* Clear the security bits if the process is not being run by root. |
|
* This keeps people from modifying setuid and setgid binaries. |
|
*/ |
|
err = file_remove_privs(file); |
|
if (err) |
|
return err; |
|
|
|
if (unlikely(file->f_mode & FMODE_NOCMTIME)) |
|
return 0; |
|
|
|
return file_update_time(file); |
|
} |
|
EXPORT_SYMBOL(file_modified); |
|
|
|
int inode_needs_sync(struct inode *inode) |
|
{ |
|
if (IS_SYNC(inode)) |
|
return 1; |
|
if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) |
|
return 1; |
|
return 0; |
|
} |
|
EXPORT_SYMBOL(inode_needs_sync); |
|
|
|
/* |
|
* If we try to find an inode in the inode hash while it is being |
|
* deleted, we have to wait until the filesystem completes its |
|
* deletion before reporting that it isn't found. This function waits |
|
* until the deletion _might_ have completed. Callers are responsible |
|
* to recheck inode state. |
|
* |
|
* It doesn't matter if I_NEW is not set initially, a call to |
|
* wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list |
|
* will DTRT. |
|
*/ |
|
static void __wait_on_freeing_inode(struct inode *inode) |
|
{ |
|
wait_queue_head_t *wq; |
|
DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); |
|
wq = bit_waitqueue(&inode->i_state, __I_NEW); |
|
prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE); |
|
spin_unlock(&inode->i_lock); |
|
spin_unlock(&inode_hash_lock); |
|
schedule(); |
|
finish_wait(wq, &wait.wq_entry); |
|
spin_lock(&inode_hash_lock); |
|
} |
|
|
|
static __initdata unsigned long ihash_entries; |
|
static int __init set_ihash_entries(char *str) |
|
{ |
|
if (!str) |
|
return 0; |
|
ihash_entries = simple_strtoul(str, &str, 0); |
|
return 1; |
|
} |
|
__setup("ihash_entries=", set_ihash_entries); |
|
|
|
/* |
|
* Initialize the waitqueues and inode hash table. |
|
*/ |
|
void __init inode_init_early(void) |
|
{ |
|
/* If hashes are distributed across NUMA nodes, defer |
|
* hash allocation until vmalloc space is available. |
|
*/ |
|
if (hashdist) |
|
return; |
|
|
|
inode_hashtable = |
|
alloc_large_system_hash("Inode-cache", |
|
sizeof(struct hlist_head), |
|
ihash_entries, |
|
14, |
|
HASH_EARLY | HASH_ZERO, |
|
&i_hash_shift, |
|
&i_hash_mask, |
|
0, |
|
0); |
|
} |
|
|
|
void __init inode_init(void) |
|
{ |
|
/* inode slab cache */ |
|
inode_cachep = kmem_cache_create("inode_cache", |
|
sizeof(struct inode), |
|
0, |
|
(SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
|
SLAB_MEM_SPREAD|SLAB_ACCOUNT), |
|
init_once); |
|
|
|
/* Hash may have been set up in inode_init_early */ |
|
if (!hashdist) |
|
return; |
|
|
|
inode_hashtable = |
|
alloc_large_system_hash("Inode-cache", |
|
sizeof(struct hlist_head), |
|
ihash_entries, |
|
14, |
|
HASH_ZERO, |
|
&i_hash_shift, |
|
&i_hash_mask, |
|
0, |
|
0); |
|
} |
|
|
|
void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) |
|
{ |
|
inode->i_mode = mode; |
|
if (S_ISCHR(mode)) { |
|
inode->i_fop = &def_chr_fops; |
|
inode->i_rdev = rdev; |
|
} else if (S_ISBLK(mode)) { |
|
inode->i_fop = &def_blk_fops; |
|
inode->i_rdev = rdev; |
|
} else if (S_ISFIFO(mode)) |
|
inode->i_fop = &pipefifo_fops; |
|
else if (S_ISSOCK(mode)) |
|
; /* leave it no_open_fops */ |
|
else |
|
printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for" |
|
" inode %s:%lu\n", mode, inode->i_sb->s_id, |
|
inode->i_ino); |
|
} |
|
EXPORT_SYMBOL(init_special_inode); |
|
|
|
/** |
|
* inode_init_owner - Init uid,gid,mode for new inode according to posix standards |
|
* @mnt_userns: User namespace of the mount the inode was created from |
|
* @inode: New inode |
|
* @dir: Directory inode |
|
* @mode: mode of the new inode |
|
* |
|
* If the inode has been created through an idmapped mount the user namespace of |
|
* the vfsmount must be passed through @mnt_userns. This function will then take |
|
* care to map the inode according to @mnt_userns before checking permissions |
|
* and initializing i_uid and i_gid. On non-idmapped mounts or if permission |
|
* checking is to be performed on the raw inode simply passs init_user_ns. |
|
*/ |
|
void inode_init_owner(struct user_namespace *mnt_userns, struct inode *inode, |
|
const struct inode *dir, umode_t mode) |
|
{ |
|
inode->i_uid = fsuid_into_mnt(mnt_userns); |
|
if (dir && dir->i_mode & S_ISGID) { |
|
inode->i_gid = dir->i_gid; |
|
|
|
/* Directories are special, and always inherit S_ISGID */ |
|
if (S_ISDIR(mode)) |
|
mode |= S_ISGID; |
|
else if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP) && |
|
!in_group_p(i_gid_into_mnt(mnt_userns, dir)) && |
|
!capable_wrt_inode_uidgid(mnt_userns, dir, CAP_FSETID)) |
|
mode &= ~S_ISGID; |
|
} else |
|
inode->i_gid = fsgid_into_mnt(mnt_userns); |
|
inode->i_mode = mode; |
|
} |
|
EXPORT_SYMBOL(inode_init_owner); |
|
|
|
/** |
|
* inode_owner_or_capable - check current task permissions to inode |
|
* @mnt_userns: user namespace of the mount the inode was found from |
|
* @inode: inode being checked |
|
* |
|
* Return true if current either has CAP_FOWNER in a namespace with the |
|
* inode owner uid mapped, or owns the file. |
|
* |
|
* If the inode has been found through an idmapped mount the user namespace of |
|
* the vfsmount must be passed through @mnt_userns. This function will then take |
|
* care to map the inode according to @mnt_userns before checking permissions. |
|
* On non-idmapped mounts or if permission checking is to be performed on the |
|
* raw inode simply passs init_user_ns. |
|
*/ |
|
bool inode_owner_or_capable(struct user_namespace *mnt_userns, |
|
const struct inode *inode) |
|
{ |
|
kuid_t i_uid; |
|
struct user_namespace *ns; |
|
|
|
i_uid = i_uid_into_mnt(mnt_userns, inode); |
|
if (uid_eq(current_fsuid(), i_uid)) |
|
return true; |
|
|
|
ns = current_user_ns(); |
|
if (kuid_has_mapping(ns, i_uid) && ns_capable(ns, CAP_FOWNER)) |
|
return true; |
|
return false; |
|
} |
|
EXPORT_SYMBOL(inode_owner_or_capable); |
|
|
|
/* |
|
* Direct i/o helper functions |
|
*/ |
|
static void __inode_dio_wait(struct inode *inode) |
|
{ |
|
wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP); |
|
DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP); |
|
|
|
do { |
|
prepare_to_wait(wq, &q.wq_entry, TASK_UNINTERRUPTIBLE); |
|
if (atomic_read(&inode->i_dio_count)) |
|
schedule(); |
|
} while (atomic_read(&inode->i_dio_count)); |
|
finish_wait(wq, &q.wq_entry); |
|
} |
|
|
|
/** |
|
* inode_dio_wait - wait for outstanding DIO requests to finish |
|
* @inode: inode to wait for |
|
* |
|
* Waits for all pending direct I/O requests to finish so that we can |
|
* proceed with a truncate or equivalent operation. |
|
* |
|
* Must be called under a lock that serializes taking new references |
|
* to i_dio_count, usually by inode->i_mutex. |
|
*/ |
|
void inode_dio_wait(struct inode *inode) |
|
{ |
|
if (atomic_read(&inode->i_dio_count)) |
|
__inode_dio_wait(inode); |
|
} |
|
EXPORT_SYMBOL(inode_dio_wait); |
|
|
|
/* |
|
* inode_set_flags - atomically set some inode flags |
|
* |
|
* Note: the caller should be holding i_mutex, or else be sure that |
|
* they have exclusive access to the inode structure (i.e., while the |
|
* inode is being instantiated). The reason for the cmpxchg() loop |
|
* --- which wouldn't be necessary if all code paths which modify |
|
* i_flags actually followed this rule, is that there is at least one |
|
* code path which doesn't today so we use cmpxchg() out of an abundance |
|
* of caution. |
|
* |
|
* In the long run, i_mutex is overkill, and we should probably look |
|
* at using the i_lock spinlock to protect i_flags, and then make sure |
|
* it is so documented in include/linux/fs.h and that all code follows |
|
* the locking convention!! |
|
*/ |
|
void inode_set_flags(struct inode *inode, unsigned int flags, |
|
unsigned int mask) |
|
{ |
|
WARN_ON_ONCE(flags & ~mask); |
|
set_mask_bits(&inode->i_flags, mask, flags); |
|
} |
|
EXPORT_SYMBOL(inode_set_flags); |
|
|
|
void inode_nohighmem(struct inode *inode) |
|
{ |
|
mapping_set_gfp_mask(inode->i_mapping, GFP_USER); |
|
} |
|
EXPORT_SYMBOL(inode_nohighmem); |
|
|
|
/** |
|
* timestamp_truncate - Truncate timespec to a granularity |
|
* @t: Timespec |
|
* @inode: inode being updated |
|
* |
|
* Truncate a timespec to the granularity supported by the fs |
|
* containing the inode. Always rounds down. gran must |
|
* not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns). |
|
*/ |
|
struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode) |
|
{ |
|
struct super_block *sb = inode->i_sb; |
|
unsigned int gran = sb->s_time_gran; |
|
|
|
t.tv_sec = clamp(t.tv_sec, sb->s_time_min, sb->s_time_max); |
|
if (unlikely(t.tv_sec == sb->s_time_max || t.tv_sec == sb->s_time_min)) |
|
t.tv_nsec = 0; |
|
|
|
/* Avoid division in the common cases 1 ns and 1 s. */ |
|
if (gran == 1) |
|
; /* nothing */ |
|
else if (gran == NSEC_PER_SEC) |
|
t.tv_nsec = 0; |
|
else if (gran > 1 && gran < NSEC_PER_SEC) |
|
t.tv_nsec -= t.tv_nsec % gran; |
|
else |
|
WARN(1, "invalid file time granularity: %u", gran); |
|
return t; |
|
} |
|
EXPORT_SYMBOL(timestamp_truncate); |
|
|
|
/** |
|
* current_time - Return FS time |
|
* @inode: inode. |
|
* |
|
* Return the current time truncated to the time granularity supported by |
|
* the fs. |
|
* |
|
* Note that inode and inode->sb cannot be NULL. |
|
* Otherwise, the function warns and returns time without truncation. |
|
*/ |
|
struct timespec64 current_time(struct inode *inode) |
|
{ |
|
struct timespec64 now; |
|
|
|
ktime_get_coarse_real_ts64(&now); |
|
|
|
if (unlikely(!inode->i_sb)) { |
|
WARN(1, "current_time() called with uninitialized super_block in the inode"); |
|
return now; |
|
} |
|
|
|
return timestamp_truncate(now, inode); |
|
} |
|
EXPORT_SYMBOL(current_time); |
|
|
|
/* |
|
* Generic function to check FS_IOC_SETFLAGS values and reject any invalid |
|
* configurations. |
|
* |
|
* Note: the caller should be holding i_mutex, or else be sure that they have |
|
* exclusive access to the inode structure. |
|
*/ |
|
int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags, |
|
unsigned int flags) |
|
{ |
|
/* |
|
* The IMMUTABLE and APPEND_ONLY flags can only be changed by |
|
* the relevant capability. |
|
* |
|
* This test looks nicer. Thanks to Pauline Middelink |
|
*/ |
|
if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) && |
|
!capable(CAP_LINUX_IMMUTABLE)) |
|
return -EPERM; |
|
|
|
return fscrypt_prepare_setflags(inode, oldflags, flags); |
|
} |
|
EXPORT_SYMBOL(vfs_ioc_setflags_prepare); |
|
|
|
/* |
|
* Generic function to check FS_IOC_FSSETXATTR values and reject any invalid |
|
* configurations. |
|
* |
|
* Note: the caller should be holding i_mutex, or else be sure that they have |
|
* exclusive access to the inode structure. |
|
*/ |
|
int vfs_ioc_fssetxattr_check(struct inode *inode, const struct fsxattr *old_fa, |
|
struct fsxattr *fa) |
|
{ |
|
/* |
|
* Can't modify an immutable/append-only file unless we have |
|
* appropriate permission. |
|
*/ |
|
if ((old_fa->fsx_xflags ^ fa->fsx_xflags) & |
|
(FS_XFLAG_IMMUTABLE | FS_XFLAG_APPEND) && |
|
!capable(CAP_LINUX_IMMUTABLE)) |
|
return -EPERM; |
|
|
|
/* |
|
* Project Quota ID state is only allowed to change from within the init |
|
* namespace. Enforce that restriction only if we are trying to change |
|
* the quota ID state. Everything else is allowed in user namespaces. |
|
*/ |
|
if (current_user_ns() != &init_user_ns) { |
|
if (old_fa->fsx_projid != fa->fsx_projid) |
|
return -EINVAL; |
|
if ((old_fa->fsx_xflags ^ fa->fsx_xflags) & |
|
FS_XFLAG_PROJINHERIT) |
|
return -EINVAL; |
|
} |
|
|
|
/* Check extent size hints. */ |
|
if ((fa->fsx_xflags & FS_XFLAG_EXTSIZE) && !S_ISREG(inode->i_mode)) |
|
return -EINVAL; |
|
|
|
if ((fa->fsx_xflags & FS_XFLAG_EXTSZINHERIT) && |
|
!S_ISDIR(inode->i_mode)) |
|
return -EINVAL; |
|
|
|
if ((fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) && |
|
!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
|
return -EINVAL; |
|
|
|
/* |
|
* It is only valid to set the DAX flag on regular files and |
|
* directories on filesystems. |
|
*/ |
|
if ((fa->fsx_xflags & FS_XFLAG_DAX) && |
|
!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))) |
|
return -EINVAL; |
|
|
|
/* Extent size hints of zero turn off the flags. */ |
|
if (fa->fsx_extsize == 0) |
|
fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT); |
|
if (fa->fsx_cowextsize == 0) |
|
fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE; |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL(vfs_ioc_fssetxattr_check);
|
|
|