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10e1407310
Commitb35250c081
("writeback: Protect inode->i_io_list with inode->i_lock") made inode->i_io_list not only protected by wb->list_lock but also inode->i_lock, but inode_io_list_move_locked() was missed. Add lock there and also update comment describing things protected by inode->i_lock. This also fixes a race where __mark_inode_dirty() could move inode under flush worker's hands and thus sync(2) could miss writing some inodes. Fixes:b35250c081
("writeback: Protect inode->i_io_list with inode->i_lock") Link: https://lore.kernel.org/r/20220524150540.12552-1-sunjunchao2870@gmail.com CC: stable@vger.kernel.org Signed-off-by: Jchao Sun <sunjunchao2870@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
2408 lines
64 KiB
C
2408 lines
64 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* (C) 1997 Linus Torvalds
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* (C) 1999 Andrea Arcangeli <andrea@suse.de> (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/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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* 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(), inode->i_io_list
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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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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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* 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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static DEFINE_PER_CPU(unsigned long, nr_inodes);
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static DEFINE_PER_CPU(unsigned long, nr_unused);
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static struct kmem_cache *inode_cachep __read_mostly;
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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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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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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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* Handle nr_inode sysctl
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*/
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#ifdef CONFIG_SYSCTL
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/*
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* Statistics gathering..
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*/
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static struct inodes_stat_t inodes_stat;
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static int proc_nr_inodes(struct ctl_table *table, int write, void *buffer,
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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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static struct ctl_table inodes_sysctls[] = {
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{
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.procname = "inode-nr",
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.data = &inodes_stat,
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.maxlen = 2*sizeof(long),
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.mode = 0444,
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.proc_handler = proc_nr_inodes,
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},
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{
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.procname = "inode-state",
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.data = &inodes_stat,
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.maxlen = 7*sizeof(long),
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.mode = 0444,
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.proc_handler = proc_nr_inodes,
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},
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{ }
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};
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static int __init init_fs_inode_sysctls(void)
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{
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register_sysctl_init("fs", inodes_sysctls);
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return 0;
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}
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early_initcall(init_fs_inode_sysctls);
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#endif
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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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* 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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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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#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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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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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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atomic_set(&inode->i_dio_count, 0);
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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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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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init_rwsem(&mapping->invalidate_lock);
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lockdep_set_class_and_name(&mapping->invalidate_lock,
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&sb->s_type->invalidate_lock_key,
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"mapping.invalidate_lock");
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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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#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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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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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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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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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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if (ops->alloc_inode)
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inode = ops->alloc_inode(sb);
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else
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inode = alloc_inode_sb(sb, inode_cachep, GFP_KERNEL);
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if (!inode)
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return NULL;
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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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return inode;
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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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#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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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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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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* 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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* 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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* 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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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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* 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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inode->__i_nlink++;
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}
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EXPORT_SYMBOL(inc_nlink);
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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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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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*/
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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_add_lru(struct inode *inode, bool rotate)
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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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return;
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if (atomic_read(&inode->i_count))
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return;
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if (!(inode->i_sb->s_flags & SB_ACTIVE))
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return;
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if (!mapping_shrinkable(&inode->i_data))
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return;
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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 if (rotate)
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inode->i_state |= I_REFERENCED;
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}
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|
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/*
|
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* Add inode to LRU if needed (inode is unused and clean).
|
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*
|
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* Needs inode->i_lock held.
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*/
|
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void inode_add_lru(struct inode *inode)
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{
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__inode_add_lru(inode, false);
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}
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|
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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);
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}
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|
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/**
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* inode_sb_list_add - add inode to the superblock list of inodes
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* @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);
|
|
|
|
static inline void inode_sb_list_del(struct inode *inode)
|
|
{
|
|
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);
|
|
}
|
|
}
|
|
|
|
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 dump_mapping(const struct address_space *mapping)
|
|
{
|
|
struct inode *host;
|
|
const struct address_space_operations *a_ops;
|
|
struct hlist_node *dentry_first;
|
|
struct dentry *dentry_ptr;
|
|
struct dentry dentry;
|
|
unsigned long ino;
|
|
|
|
/*
|
|
* If mapping is an invalid pointer, we don't want to crash
|
|
* accessing it, so probe everything depending on it carefully.
|
|
*/
|
|
if (get_kernel_nofault(host, &mapping->host) ||
|
|
get_kernel_nofault(a_ops, &mapping->a_ops)) {
|
|
pr_warn("invalid mapping:%px\n", mapping);
|
|
return;
|
|
}
|
|
|
|
if (!host) {
|
|
pr_warn("aops:%ps\n", a_ops);
|
|
return;
|
|
}
|
|
|
|
if (get_kernel_nofault(dentry_first, &host->i_dentry.first) ||
|
|
get_kernel_nofault(ino, &host->i_ino)) {
|
|
pr_warn("aops:%ps invalid inode:%px\n", a_ops, host);
|
|
return;
|
|
}
|
|
|
|
if (!dentry_first) {
|
|
pr_warn("aops:%ps ino:%lx\n", a_ops, ino);
|
|
return;
|
|
}
|
|
|
|
dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias);
|
|
if (get_kernel_nofault(dentry, dentry_ptr)) {
|
|
pr_warn("aops:%ps ino:%lx invalid dentry:%px\n",
|
|
a_ops, ino, dentry_ptr);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* if dentry is corrupted, the %pd handler may still crash,
|
|
* but it's unlikely that we reach here with a corrupt mapping
|
|
*/
|
|
pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n", a_ops, ino, &dentry);
|
|
}
|
|
|
|
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);
|
|
/*
|
|
* Almost always, mapping_empty(&inode->i_data) here; but there are
|
|
* two known and long-standing ways in which nodes may get left behind
|
|
* (when deep radix-tree node allocation failed partway; or when THP
|
|
* collapse_file() failed). Until those two known cases are cleaned up,
|
|
* or a cleanup function is called here, do not BUG_ON(!mapping_empty),
|
|
* nor even WARN_ON(!mapping_empty).
|
|
*/
|
|
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.
|
|
*
|
|
* 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;
|
|
|
|
/*
|
|
* Inodes can get referenced, redirtied, or repopulated while
|
|
* they're already on the LRU, and this can make them
|
|
* unreclaimable for a while. Remove them lazily here; iput,
|
|
* sync, or the last page cache deletion will requeue them.
|
|
*/
|
|
if (atomic_read(&inode->i_count) ||
|
|
(inode->i_state & ~I_REFERENCED) ||
|
|
!mapping_shrinkable(&inode->i_data)) {
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* On highmem systems, mapping_shrinkable() permits dropping
|
|
* page cache in order to free up struct inodes: lowmem might
|
|
* be under pressure before the cache inside the highmem zone.
|
|
*/
|
|
if (inode_has_buffers(inode) || !mapping_empty(&inode->i_data)) {
|
|
__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, true);
|
|
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.
|
|
*/
|
|
int inode_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);
|
|
}
|
|
EXPORT_SYMBOL(inode_update_time);
|
|
|
|
/**
|
|
* 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);
|
|
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 = inode_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_fsuid_set(inode, 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_fsgid_set(inode, 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);
|