/*
- * linux/fs/inode.c
- *
* (C) 1997 Linus Torvalds
+ * (C) 1999 Andrea Arcangeli <andrea@suse.de> (dynamic inode allocation)
*/
-
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/dcache.h>
#include <linux/mount.h>
#include <linux/async.h>
#include <linux/posix_acl.h>
+#include <linux/prefetch.h>
#include <linux/ima.h>
+#include <linux/cred.h>
+#include <linux/buffer_head.h> /* for inode_has_buffers */
+#include "internal.h"
/*
- * This is needed for the following functions:
- * - inode_has_buffers
- * - invalidate_bdev
+ * Inode locking rules:
*
- * FIXME: remove all knowledge of the buffer layer from this file
- */
-#include <linux/buffer_head.h>
-
-/*
- * New inode.c implementation.
+ * inode->i_lock protects:
+ * inode->i_state, inode->i_hash, __iget()
+ * inode->i_sb->s_inode_lru_lock protects:
+ * inode->i_sb->s_inode_lru, inode->i_lru
+ * inode_sb_list_lock protects:
+ * sb->s_inodes, inode->i_sb_list
+ * bdi->wb.list_lock protects:
+ * bdi->wb.b_{dirty,io,more_io}, inode->i_wb_list
+ * inode_hash_lock protects:
+ * inode_hashtable, inode->i_hash
*
- * This implementation has the basic premise of trying
- * to be extremely low-overhead and SMP-safe, yet be
- * simple enough to be "obviously correct".
+ * Lock ordering:
*
- * Famous last words.
- */
-
-/* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
-
-/* #define INODE_PARANOIA 1 */
-/* #define INODE_DEBUG 1 */
-
-/*
- * Inode lookup is no longer as critical as it used to be:
- * most of the lookups are going to be through the dcache.
+ * inode_sb_list_lock
+ * inode->i_lock
+ * inode->i_sb->s_inode_lru_lock
+ *
+ * bdi->wb.list_lock
+ * inode->i_lock
+ *
+ * inode_hash_lock
+ * inode_sb_list_lock
+ * inode->i_lock
+ *
+ * iunique_lock
+ * inode_hash_lock
*/
-#define I_HASHBITS i_hash_shift
-#define I_HASHMASK i_hash_mask
static unsigned int i_hash_mask __read_mostly;
static unsigned int i_hash_shift __read_mostly;
-
-/*
- * Each inode can be on two separate lists. One is
- * the hash list of the inode, used for lookups. The
- * other linked list is the "type" list:
- * "in_use" - valid inode, i_count > 0, i_nlink > 0
- * "dirty" - as "in_use" but also dirty
- * "unused" - valid inode, i_count = 0
- *
- * A "dirty" list is maintained for each super block,
- * allowing for low-overhead inode sync() operations.
- */
-
-static LIST_HEAD(inode_lru);
static struct hlist_head *inode_hashtable __read_mostly;
+static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);
-/*
- * A simple spinlock to protect the list manipulations.
- *
- * NOTE! You also have to own the lock if you change
- * the i_state of an inode while it is in use..
- */
-DEFINE_SPINLOCK(inode_lock);
+__cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock);
/*
- * iprune_sem provides exclusion between the icache shrinking and the
- * umount path.
- *
- * We don't actually need it to protect anything in the umount path,
- * but only need to cycle through it to make sure any inode that
- * prune_icache took off the LRU list has been fully torn down by the
- * time we are past evict_inodes.
+ * Empty aops. Can be used for the cases where the user does not
+ * define any of the address_space operations.
*/
-static DECLARE_RWSEM(iprune_sem);
+const struct address_space_operations empty_aops = {
+};
+EXPORT_SYMBOL(empty_aops);
/*
* Statistics gathering..
struct inodes_stat_t inodes_stat;
static DEFINE_PER_CPU(unsigned int, nr_inodes);
+static DEFINE_PER_CPU(unsigned int, nr_unused);
static struct kmem_cache *inode_cachep __read_mostly;
static inline int get_nr_inodes_unused(void)
{
- return inodes_stat.nr_unused;
+ int i;
+ int sum = 0;
+ for_each_possible_cpu(i)
+ sum += per_cpu(nr_unused, i);
+ return sum < 0 ? 0 : sum;
}
int get_nr_dirty_inodes(void)
void __user *buffer, size_t *lenp, loff_t *ppos)
{
inodes_stat.nr_inodes = get_nr_inodes();
+ inodes_stat.nr_unused = get_nr_inodes_unused();
return proc_dointvec(table, write, buffer, lenp, ppos);
}
#endif
-static void wake_up_inode(struct inode *inode)
-{
- /*
- * Prevent speculative execution through spin_unlock(&inode_lock);
- */
- smp_mb();
- wake_up_bit(&inode->i_state, __I_NEW);
-}
-
/**
* inode_init_always - perform inode structure intialisation
* @sb: superblock inode belongs to
*/
int inode_init_always(struct super_block *sb, struct inode *inode)
{
- static const struct address_space_operations empty_aops;
static const struct inode_operations empty_iops;
static const struct file_operations empty_fops;
struct address_space *const mapping = &inode->i_data;
mutex_init(&inode->i_mutex);
lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
- init_rwsem(&inode->i_alloc_sem);
- lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key);
+ atomic_set(&inode->i_dio_count, 0);
mapping->a_ops = &empty_aops;
mapping->host = inode;
memset(mapping, 0, sizeof(*mapping));
INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
spin_lock_init(&mapping->tree_lock);
- spin_lock_init(&mapping->i_mmap_lock);
+ mutex_init(&mapping->i_mmap_mutex);
INIT_LIST_HEAD(&mapping->private_list);
spin_lock_init(&mapping->private_lock);
INIT_RAW_PRIO_TREE_ROOT(&mapping->i_mmap);
INIT_LIST_HEAD(&mapping->i_mmap_nonlinear);
- mutex_init(&mapping->unmap_mutex);
}
EXPORT_SYMBOL(address_space_init_once);
}
/*
- * inode_lock must be held
+ * inode->i_lock must be held
*/
void __iget(struct inode *inode)
{
static void inode_lru_list_add(struct inode *inode)
{
+ spin_lock(&inode->i_sb->s_inode_lru_lock);
if (list_empty(&inode->i_lru)) {
- list_add(&inode->i_lru, &inode_lru);
- inodes_stat.nr_unused++;
+ list_add(&inode->i_lru, &inode->i_sb->s_inode_lru);
+ inode->i_sb->s_nr_inodes_unused++;
+ this_cpu_inc(nr_unused);
}
+ spin_unlock(&inode->i_sb->s_inode_lru_lock);
}
static void inode_lru_list_del(struct inode *inode)
{
+ spin_lock(&inode->i_sb->s_inode_lru_lock);
if (!list_empty(&inode->i_lru)) {
list_del_init(&inode->i_lru);
- inodes_stat.nr_unused--;
+ inode->i_sb->s_nr_inodes_unused--;
+ this_cpu_dec(nr_unused);
}
-}
-
-static inline void __inode_sb_list_add(struct inode *inode)
-{
- list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
+ spin_unlock(&inode->i_sb->s_inode_lru_lock);
}
/**
*/
void inode_sb_list_add(struct inode *inode)
{
- spin_lock(&inode_lock);
- __inode_sb_list_add(inode);
- spin_unlock(&inode_lock);
+ spin_lock(&inode_sb_list_lock);
+ list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
+ spin_unlock(&inode_sb_list_lock);
}
EXPORT_SYMBOL_GPL(inode_sb_list_add);
-static inline void __inode_sb_list_del(struct inode *inode)
+static inline void inode_sb_list_del(struct inode *inode)
{
- list_del_init(&inode->i_sb_list);
+ if (!list_empty(&inode->i_sb_list)) {
+ spin_lock(&inode_sb_list_lock);
+ list_del_init(&inode->i_sb_list);
+ spin_unlock(&inode_sb_list_lock);
+ }
}
static unsigned long hash(struct super_block *sb, unsigned long hashval)
tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
L1_CACHE_BYTES;
- tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
- return tmp & I_HASHMASK;
+ tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
+ return tmp & i_hash_mask;
}
/**
{
struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
+ spin_lock(&inode->i_lock);
hlist_add_head(&inode->i_hash, b);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_hash_lock);
}
EXPORT_SYMBOL(__insert_inode_hash);
*
* Remove an inode from the superblock.
*/
-static void __remove_inode_hash(struct inode *inode)
+void __remove_inode_hash(struct inode *inode)
{
+ spin_lock(&inode_hash_lock);
+ spin_lock(&inode->i_lock);
hlist_del_init(&inode->i_hash);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_hash_lock);
}
-
-/**
- * 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_lock);
- hlist_del_init(&inode->i_hash);
- spin_unlock(&inode_lock);
-}
-EXPORT_SYMBOL(remove_inode_hash);
+EXPORT_SYMBOL(__remove_inode_hash);
void end_writeback(struct inode *inode)
{
might_sleep();
+ /*
+ * We have to cycle tree_lock here because reclaim can be still in the
+ * process of removing the last page (in __delete_from_page_cache())
+ * and we must not free mapping under it.
+ */
+ spin_lock_irq(&inode->i_data.tree_lock);
BUG_ON(inode->i_data.nrpages);
+ spin_unlock_irq(&inode->i_data.tree_lock);
BUG_ON(!list_empty(&inode->i_data.private_list));
BUG_ON(!(inode->i_state & I_FREEING));
BUG_ON(inode->i_state & I_CLEAR);
}
EXPORT_SYMBOL(end_writeback);
+/*
+ * 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_wb_list))
+ inode_wb_list_del(inode);
+
+ inode_sb_list_del(inode);
+
if (op->evict_inode) {
op->evict_inode(inode);
} else {
bd_forget(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);
}
/*
list_del_init(&inode->i_lru);
evict(inode);
-
- spin_lock(&inode_lock);
- __remove_inode_hash(inode);
- __inode_sb_list_del(inode);
- spin_unlock(&inode_lock);
-
- wake_up_inode(inode);
- destroy_inode(inode);
}
}
struct inode *inode, *next;
LIST_HEAD(dispose);
- spin_lock(&inode_lock);
+ spin_lock(&inode_sb_list_lock);
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
if (atomic_read(&inode->i_count))
continue;
- if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE))
+
+ 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;
-
- /*
- * Move the inode off the IO lists and LRU once I_FREEING is
- * set so that it won't get moved back on there if it is dirty.
- */
- list_move(&inode->i_lru, &dispose);
- list_del_init(&inode->i_wb_list);
- if (!(inode->i_state & (I_DIRTY | I_SYNC)))
- inodes_stat.nr_unused--;
+ inode_lru_list_del(inode);
+ spin_unlock(&inode->i_lock);
+ list_add(&inode->i_lru, &dispose);
}
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_sb_list_lock);
dispose_list(&dispose);
-
- /*
- * Cycle through iprune_sem to make sure any inode that prune_icache
- * moved off the list before we took the lock has been fully torn
- * down.
- */
- down_write(&iprune_sem);
- up_write(&iprune_sem);
}
/**
struct inode *inode, *next;
LIST_HEAD(dispose);
- spin_lock(&inode_lock);
+ spin_lock(&inode_sb_list_lock);
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
- if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE))
+ 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 && !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;
-
- /*
- * Move the inode off the IO lists and LRU once I_FREEING is
- * set so that it won't get moved back on there if it is dirty.
- */
- list_move(&inode->i_lru, &dispose);
- list_del_init(&inode->i_wb_list);
- if (!(inode->i_state & (I_DIRTY | I_SYNC)))
- inodes_stat.nr_unused--;
+ inode_lru_list_del(inode);
+ spin_unlock(&inode->i_lock);
+ list_add(&inode->i_lru, &dispose);
}
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_sb_list_lock);
dispose_list(&dispose);
}
/*
- * Scan `goal' inodes on the unused list for freeable ones. They are moved to a
- * temporary list and then are freed outside inode_lock by dispose_list().
+ * 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().
*
* Any inodes which are pinned purely because of attached pagecache have their
* pagecache removed. If the inode has metadata buffers attached to
* 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 void prune_icache(int nr_to_scan)
+void prune_icache_sb(struct super_block *sb, int nr_to_scan)
{
LIST_HEAD(freeable);
int nr_scanned;
unsigned long reap = 0;
- down_read(&iprune_sem);
- spin_lock(&inode_lock);
- for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
+ spin_lock(&sb->s_inode_lru_lock);
+ for (nr_scanned = nr_to_scan; nr_scanned >= 0; nr_scanned--) {
struct inode *inode;
- if (list_empty(&inode_lru))
+ if (list_empty(&sb->s_inode_lru))
break;
- inode = list_entry(inode_lru.prev, struct inode, i_lru);
+ inode = list_entry(sb->s_inode_lru.prev, struct inode, i_lru);
+
+ /*
+ * we are inverting the sb->s_inode_lru_lock/inode->i_lock here,
+ * so use a trylock. If we fail to get the lock, just move the
+ * inode to the back of the list so we don't spin on it.
+ */
+ if (!spin_trylock(&inode->i_lock)) {
+ list_move(&inode->i_lru, &sb->s_inode_lru);
+ continue;
+ }
/*
* Referenced or dirty inodes are still in use. Give them
if (atomic_read(&inode->i_count) ||
(inode->i_state & ~I_REFERENCED)) {
list_del_init(&inode->i_lru);
- inodes_stat.nr_unused--;
+ spin_unlock(&inode->i_lock);
+ sb->s_nr_inodes_unused--;
+ this_cpu_dec(nr_unused);
continue;
}
/* recently referenced inodes get one more pass */
if (inode->i_state & I_REFERENCED) {
- list_move(&inode->i_lru, &inode_lru);
inode->i_state &= ~I_REFERENCED;
+ list_move(&inode->i_lru, &sb->s_inode_lru);
+ spin_unlock(&inode->i_lock);
continue;
}
if (inode_has_buffers(inode) || inode->i_data.nrpages) {
__iget(inode);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&sb->s_inode_lru_lock);
if (remove_inode_buffers(inode))
reap += invalidate_mapping_pages(&inode->i_data,
0, -1);
iput(inode);
- spin_lock(&inode_lock);
+ spin_lock(&sb->s_inode_lru_lock);
- if (inode != list_entry(inode_lru.next,
+ if (inode != list_entry(sb->s_inode_lru.next,
struct inode, i_lru))
continue; /* wrong inode or list_empty */
- if (!can_unuse(inode))
+ /* avoid lock inversions with trylock */
+ if (!spin_trylock(&inode->i_lock))
+ continue;
+ if (!can_unuse(inode)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
}
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
+ spin_unlock(&inode->i_lock);
- /*
- * Move the inode off the IO lists and LRU once I_FREEING is
- * set so that it won't get moved back on there if it is dirty.
- */
list_move(&inode->i_lru, &freeable);
- list_del_init(&inode->i_wb_list);
- inodes_stat.nr_unused--;
+ sb->s_nr_inodes_unused--;
+ this_cpu_dec(nr_unused);
}
if (current_is_kswapd())
__count_vm_events(KSWAPD_INODESTEAL, reap);
else
__count_vm_events(PGINODESTEAL, reap);
- spin_unlock(&inode_lock);
+ spin_unlock(&sb->s_inode_lru_lock);
dispose_list(&freeable);
- up_read(&iprune_sem);
-}
-
-/*
- * shrink_icache_memory() will attempt to reclaim some unused inodes. Here,
- * "unused" means that no dentries are referring to the inodes: the files are
- * not open and the dcache references to those inodes have already been
- * reclaimed.
- *
- * This function is passed the number of inodes to scan, and it returns the
- * total number of remaining possibly-reclaimable inodes.
- */
-static int shrink_icache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask)
-{
- if (nr) {
- /*
- * Nasty deadlock avoidance. We may hold various FS locks,
- * and we don't want to recurse into the FS that called us
- * in clear_inode() and friends..
- */
- if (!(gfp_mask & __GFP_FS))
- return -1;
- prune_icache(nr);
- }
- return (get_nr_inodes_unused() / 100) * sysctl_vfs_cache_pressure;
}
-static struct shrinker icache_shrinker = {
- .shrink = shrink_icache_memory,
- .seeks = DEFAULT_SEEKS,
-};
-
static void __wait_on_freeing_inode(struct inode *inode);
/*
* Called with the inode lock held.
repeat:
hlist_for_each_entry(inode, node, head, i_hash) {
- if (inode->i_sb != sb)
+ spin_lock(&inode->i_lock);
+ if (inode->i_sb != sb) {
+ spin_unlock(&inode->i_lock);
continue;
- if (!test(inode, data))
+ }
+ if (!test(inode, data)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
__wait_on_freeing_inode(inode);
goto repeat;
}
__iget(inode);
+ spin_unlock(&inode->i_lock);
return inode;
}
return NULL;
repeat:
hlist_for_each_entry(inode, node, head, i_hash) {
- if (inode->i_ino != ino)
+ spin_lock(&inode->i_lock);
+ if (inode->i_ino != ino) {
+ spin_unlock(&inode->i_lock);
continue;
- if (inode->i_sb != sb)
+ }
+ if (inode->i_sb != sb) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
__wait_on_freeing_inode(inode);
goto repeat;
}
__iget(inode);
+ spin_unlock(&inode->i_lock);
return inode;
}
return NULL;
}
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
{
struct inode *inode;
- spin_lock_prefetch(&inode_lock);
+ spin_lock_prefetch(&inode_sb_list_lock);
- inode = alloc_inode(sb);
- if (inode) {
- spin_lock(&inode_lock);
- __inode_sb_list_add(inode);
- inode->i_state = 0;
- spin_unlock(&inode_lock);
- }
+ inode = new_inode_pseudo(sb);
+ if (inode)
+ inode_sb_list_add(inode);
return inode;
}
EXPORT_SYMBOL(new_inode);
+/**
+ * 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)
{
#ifdef CONFIG_DEBUG_LOCK_ALLOC
}
}
#endif
- /*
- * This is special! We do not need the spinlock when clearing I_NEW,
- * because we're guaranteed that nobody else tries to do anything about
- * the state of the inode when it is locked, as we just created it (so
- * there can be no old holders that haven't tested I_NEW).
- * However we must emit the memory barrier so that other CPUs reliably
- * see the clearing of I_NEW after the other inode initialisation has
- * completed.
- */
- smp_mb();
+ spin_lock(&inode->i_lock);
WARN_ON(!(inode->i_state & I_NEW));
inode->i_state &= ~I_NEW;
- wake_up_inode(inode);
+ wake_up_bit(&inode->i_state, __I_NEW);
+ spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(unlock_new_inode);
-/*
- * This is called without the inode lock held.. Be careful.
+/**
+ * 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.
*
- * We no longer cache the sb_flags in i_flags - see fs.h
- * -- rmk@arm.uk.linux.org
+ * 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.
*/
-static struct inode *get_new_inode(struct super_block *sb,
- struct hlist_head *head,
- int (*test)(struct inode *, void *),
- int (*set)(struct inode *, void *),
- void *data)
+struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
+ int (*test)(struct inode *, void *),
+ int (*set)(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);
+
+ if (inode) {
+ wait_on_inode(inode);
+ return inode;
+ }
+
inode = alloc_inode(sb);
if (inode) {
struct inode *old;
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
/* We released the lock, so.. */
old = find_inode(sb, head, test, data);
if (!old) {
if (set(inode, data))
goto set_failed;
- hlist_add_head(&inode->i_hash, head);
- __inode_sb_list_add(inode);
+ spin_lock(&inode->i_lock);
inode->i_state = I_NEW;
- spin_unlock(&inode_lock);
+ hlist_add_head(&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
* us. Use the old inode instead of the one we just
* allocated.
*/
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
destroy_inode(inode);
inode = old;
wait_on_inode(inode);
return inode;
set_failed:
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
destroy_inode(inode);
return NULL;
}
+EXPORT_SYMBOL(iget5_locked);
-/*
- * get_new_inode_fast is the fast path version of get_new_inode, see the
- * comment at iget_locked for details.
+/**
+ * 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().
*/
-static struct inode *get_new_inode_fast(struct super_block *sb,
- struct hlist_head *head, unsigned long ino)
+struct inode *iget_locked(struct super_block *sb, unsigned long ino)
{
+ struct hlist_head *head = inode_hashtable + hash(sb, ino);
struct inode *inode;
+ spin_lock(&inode_hash_lock);
+ inode = find_inode_fast(sb, head, ino);
+ spin_unlock(&inode_hash_lock);
+ if (inode) {
+ wait_on_inode(inode);
+ return inode;
+ }
+
inode = alloc_inode(sb);
if (inode) {
struct inode *old;
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
/* We released the lock, so.. */
old = find_inode_fast(sb, head, ino);
if (!old) {
inode->i_ino = ino;
- hlist_add_head(&inode->i_hash, head);
- __inode_sb_list_add(inode);
+ spin_lock(&inode->i_lock);
inode->i_state = I_NEW;
- spin_unlock(&inode_lock);
+ hlist_add_head(&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
* us. Use the old inode instead of the one we just
* allocated.
*/
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
destroy_inode(inode);
inode = old;
wait_on_inode(inode);
}
return inode;
}
+EXPORT_SYMBOL(iget_locked);
/*
* search the inode cache for a matching inode number.
struct hlist_node *node;
struct inode *inode;
+ spin_lock(&inode_hash_lock);
hlist_for_each_entry(inode, node, b, i_hash) {
- if (inode->i_ino == ino && inode->i_sb == sb)
+ if (inode->i_ino == ino && inode->i_sb == sb) {
+ spin_unlock(&inode_hash_lock);
return 0;
+ }
}
+ spin_unlock(&inode_hash_lock);
return 1;
}
static unsigned int counter;
ino_t res;
- spin_lock(&inode_lock);
spin_lock(&iunique_lock);
do {
if (counter <= max_reserved)
res = counter++;
} while (!test_inode_iunique(sb, res));
spin_unlock(&iunique_lock);
- spin_unlock(&inode_lock);
return res;
}
struct inode *igrab(struct inode *inode)
{
- spin_lock(&inode_lock);
- if (!(inode->i_state & (I_FREEING|I_WILL_FREE)))
+ spin_lock(&inode->i_lock);
+ if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
__iget(inode);
- else
+ 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;
- spin_unlock(&inode_lock);
+ }
return inode;
}
EXPORT_SYMBOL(igrab);
-/**
- * ifind - internal function, you want ilookup5() or iget5().
- * @sb: super block of file system to search
- * @head: the head of the list to search
- * @test: callback used for comparisons between inodes
- * @data: opaque data pointer to pass to @test
- * @wait: if true wait for the inode to be unlocked, if false do not
- *
- * ifind() searches for the inode specified by @data in the inode
- * cache. This is a generalized version of ifind_fast() for file systems where
- * the inode number is not sufficient for unique identification of an inode.
- *
- * If the inode is in the cache, the inode is returned with an incremented
- * reference count.
- *
- * Otherwise NULL is returned.
- *
- * Note, @test is called with the inode_lock held, so can't sleep.
- */
-static struct inode *ifind(struct super_block *sb,
- struct hlist_head *head, int (*test)(struct inode *, void *),
- void *data, const int wait)
-{
- struct inode *inode;
-
- spin_lock(&inode_lock);
- inode = find_inode(sb, head, test, data);
- if (inode) {
- spin_unlock(&inode_lock);
- if (likely(wait))
- wait_on_inode(inode);
- return inode;
- }
- spin_unlock(&inode_lock);
- return NULL;
-}
-
-/**
- * ifind_fast - internal function, you want ilookup() or iget().
- * @sb: super block of file system to search
- * @head: head of the list to search
- * @ino: inode number to search for
- *
- * ifind_fast() searches for the inode @ino in the inode cache. This is for
- * file systems where the inode number is sufficient for unique identification
- * of an inode.
- *
- * If the inode is in the cache, the inode is returned with an incremented
- * reference count.
- *
- * Otherwise NULL is returned.
- */
-static struct inode *ifind_fast(struct super_block *sb,
- struct hlist_head *head, unsigned long ino)
-{
- struct inode *inode;
-
- spin_lock(&inode_lock);
- inode = find_inode_fast(sb, head, ino);
- if (inode) {
- spin_unlock(&inode_lock);
- wait_on_inode(inode);
- return inode;
- }
- spin_unlock(&inode_lock);
- return NULL;
-}
-
/**
* ilookup5_nowait - search for an inode in the inode cache
* @sb: super block of file system to search
* @test: callback used for comparisons between inodes
* @data: opaque data pointer to pass to @test
*
- * ilookup5() uses ifind() to search for the inode specified by @hashval and
- * @data in the inode cache. This is a generalized version of ilookup() for
- * file systems where the inode number is not sufficient for unique
- * identification of an inode.
- *
+ * 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, the inode lock 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.
+ * reference count.
*
- * Otherwise NULL is returned.
+ * 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.
*
- * Note, @test is called with the inode_lock held, so can't sleep.
+ * 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 ifind(sb, head, test, data, 0);
+ return inode;
}
EXPORT_SYMBOL(ilookup5_nowait);
* @test: callback used for comparisons between inodes
* @data: opaque data pointer to pass to @test
*
- * ilookup5() uses ifind() to search for the inode specified by @hashval and
- * @data in the inode cache. This is a generalized version of ilookup() for
- * file systems where the inode number is not sufficient for unique
- * identification of an inode.
- *
- * If the inode is in the cache, the inode lock is waited upon and the inode is
+ * 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.
*
- * Otherwise NULL is returned.
+ * 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_lock held, so can't sleep.
+ * 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 hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct inode *inode = ilookup5_nowait(sb, hashval, test, data);
- return ifind(sb, head, test, data, 1);
+ if (inode)
+ wait_on_inode(inode);
+ return inode;
}
EXPORT_SYMBOL(ilookup5);
* @sb: super block of file system to search
* @ino: inode number to search for
*
- * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
- * This is for file systems where the inode number is sufficient for unique
- * identification of an inode.
- *
- * If the inode is in the cache, the inode is returned with an incremented
- * reference count.
- *
- * Otherwise NULL is returned.
+ * 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);
-
- return ifind_fast(sb, head, ino);
-}
-EXPORT_SYMBOL(ilookup);
-
-/**
- * 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
- *
- * iget5_locked() uses ifind() to search for the inode specified by @hashval
- * and @data in the inode cache and if present it is returned 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, get_new_inode() is called to allocate a new
- * inode and this is returned 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_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 hlist_head *head = inode_hashtable + hash(sb, hashval);
struct inode *inode;
- inode = ifind(sb, head, test, data, 1);
- if (inode)
- return inode;
- /*
- * get_new_inode() will do the right thing, re-trying the search
- * in case it had to block at any point.
- */
- return get_new_inode(sb, head, test, set, data);
-}
-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
- *
- * iget_locked() uses ifind_fast() to search for the inode specified by @ino in
- * the inode cache and if present it is returned 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, get_new_inode_fast() is called to allocate a
- * new inode and this is returned 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;
+ spin_lock(&inode_hash_lock);
+ inode = find_inode_fast(sb, head, ino);
+ spin_unlock(&inode_hash_lock);
- inode = ifind_fast(sb, head, ino);
if (inode)
- return inode;
- /*
- * get_new_inode_fast() will do the right thing, re-trying the search
- * in case it had to block at any point.
- */
- return get_new_inode_fast(sb, head, ino);
+ wait_on_inode(inode);
+ return inode;
}
-EXPORT_SYMBOL(iget_locked);
+EXPORT_SYMBOL(ilookup);
int insert_inode_locked(struct inode *inode)
{
ino_t ino = inode->i_ino;
struct hlist_head *head = inode_hashtable + hash(sb, ino);
- inode->i_state |= I_NEW;
while (1) {
struct hlist_node *node;
struct inode *old = NULL;
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
hlist_for_each_entry(old, node, head, i_hash) {
if (old->i_ino != ino)
continue;
if (old->i_sb != sb)
continue;
- if (old->i_state & (I_FREEING|I_WILL_FREE))
+ spin_lock(&old->i_lock);
+ if (old->i_state & (I_FREEING|I_WILL_FREE)) {
+ spin_unlock(&old->i_lock);
continue;
+ }
break;
}
if (likely(!node)) {
+ spin_lock(&inode->i_lock);
+ inode->i_state |= I_NEW;
hlist_add_head(&inode->i_hash, head);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_hash_lock);
return 0;
}
__iget(old);
- spin_unlock(&inode_lock);
+ spin_unlock(&old->i_lock);
+ spin_unlock(&inode_hash_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
iput(old);
struct super_block *sb = inode->i_sb;
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
- inode->i_state |= I_NEW;
-
while (1) {
struct hlist_node *node;
struct inode *old = NULL;
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
hlist_for_each_entry(old, node, head, i_hash) {
if (old->i_sb != sb)
continue;
if (!test(old, data))
continue;
- if (old->i_state & (I_FREEING|I_WILL_FREE))
+ spin_lock(&old->i_lock);
+ if (old->i_state & (I_FREEING|I_WILL_FREE)) {
+ spin_unlock(&old->i_lock);
continue;
+ }
break;
}
if (likely(!node)) {
+ spin_lock(&inode->i_lock);
+ inode->i_state |= I_NEW;
hlist_add_head(&inode->i_hash, head);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_hash_lock);
return 0;
}
__iget(old);
- spin_unlock(&inode_lock);
+ spin_unlock(&old->i_lock);
+ spin_unlock(&inode_hash_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
iput(old);
const struct super_operations *op = inode->i_sb->s_op;
int drop;
- if (op && op->drop_inode)
+ WARN_ON(inode->i_state & I_NEW);
+
+ if (op->drop_inode)
drop = op->drop_inode(inode);
else
drop = generic_drop_inode(inode);
+ if (!drop && (sb->s_flags & MS_ACTIVE)) {
+ inode->i_state |= I_REFERENCED;
+ if (!(inode->i_state & (I_DIRTY|I_SYNC)))
+ inode_lru_list_add(inode);
+ spin_unlock(&inode->i_lock);
+ return;
+ }
+
if (!drop) {
- if (sb->s_flags & MS_ACTIVE) {
- inode->i_state |= I_REFERENCED;
- if (!(inode->i_state & (I_DIRTY|I_SYNC))) {
- inode_lru_list_add(inode);
- }
- spin_unlock(&inode_lock);
- return;
- }
- WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_WILL_FREE;
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
write_inode_now(inode, 1);
- spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state &= ~I_WILL_FREE;
- __remove_inode_hash(inode);
}
- WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
-
- /*
- * Move the inode off the IO lists and LRU once I_FREEING is
- * set so that it won't get moved back on there if it is dirty.
- */
inode_lru_list_del(inode);
- list_del_init(&inode->i_wb_list);
+ spin_unlock(&inode->i_lock);
- __inode_sb_list_del(inode);
- spin_unlock(&inode_lock);
evict(inode);
- remove_inode_hash(inode);
- wake_up_inode(inode);
- BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
- destroy_inode(inode);
}
/**
if (inode) {
BUG_ON(inode->i_state & I_CLEAR);
- if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
+ if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock))
iput_final(inode);
}
}
* to recheck inode state.
*
* It doesn't matter if I_NEW is not set initially, a call to
- * wake_up_inode() after removing from the hash list will DTRT.
- *
- * This is called with inode_lock held.
+ * 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)
{
DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
wq = bit_waitqueue(&inode->i_state, __I_NEW);
prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_hash_lock);
schedule();
finish_wait(wq, &wait.wait);
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
}
static __initdata unsigned long ihash_entries;
(SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
SLAB_MEM_SPREAD),
init_once);
- register_shrinker(&icache_shrinker);
/* Hash may have been set up in inode_init_early */
if (!hashdist)
inode->i_mode = mode;
}
EXPORT_SYMBOL(inode_init_owner);
+
+/**
+ * inode_owner_or_capable - check current task permissions to inode
+ * @inode: inode being checked
+ *
+ * Return true if current either has CAP_FOWNER to the inode, or
+ * owns the file.
+ */
+bool inode_owner_or_capable(const struct inode *inode)
+{
+ struct user_namespace *ns = inode_userns(inode);
+
+ if (current_user_ns() == ns && current_fsuid() == inode->i_uid)
+ return true;
+ if (ns_capable(ns, CAP_FOWNER))
+ return true;
+ return false;
+}
+EXPORT_SYMBOL(inode_owner_or_capable);
Code Review / linux-2.6.git / blobdiff