[PATCH 1/8] fs: protect inode->i_state with inode->i_lock

From: Dave Chinner
Date: Thu Oct 28 2010 - 23:24:48 EST

From: Dave Chinner <dchinner@xxxxxxxxxx>

Protect inode state transitions and validity checks with the
inode->i_lock. This enables us to make inode state transitions
independently of the inode_lock and is the first step to peeling
away the inode_lock from the code.

This requires that __iget() is done atomically with i_state checks
during list traversals so that we don't race with another thread
marking the inode I_FREEING between the state check and grabbing the
reference.

Also remove the unlock_new_inode() memory barrier optimisation
required to avoid taking the inode_lock when clearing I_NEW.
Simplify the code by simply taking the inode->i_lock around the
state change and wakeup. Because the wakeup is no longer tricky,
remove the wake_up_inode() function and open code the wakeup where
necessary.

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
fs/drop_caches.c | 9 ++-
fs/fs-writeback.c | 42 +++++++++++---
fs/inode.c | 138 +++++++++++++++++++++++++++++++++---------------
fs/notify/inode_mark.c | 21 +++++--
fs/quota/dquot.c | 13 +++--
5 files changed, 157 insertions(+), 66 deletions(-)

diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 2195c21..62dd8ee 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -18,11 +18,14 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)

spin_lock(&inode_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
- continue;
- if (inode->i_mapping->nrpages == 0)
+ spin_lock(&inode->i_lock);
+ if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+ (inode->i_mapping->nrpages == 0)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
__iget(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode);
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index f6af81a..50de4f1 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -293,9 +293,11 @@ static void inode_wait_for_writeback(struct inode *inode)

wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
while (inode->i_state & I_SYNC) {
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
__wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
}
}

@@ -319,6 +321,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
unsigned dirty;
int ret;

+ spin_lock(&inode->i_lock);
if (!atomic_read(&inode->i_count))
WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING)));
else
@@ -334,6 +337,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* completed a full scan of b_io.
*/
if (wbc->sync_mode != WB_SYNC_ALL) {
+ spin_unlock(&inode->i_lock);
requeue_io(inode);
return 0;
}
@@ -349,6 +353,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
/* Set I_SYNC, reset I_DIRTY_PAGES */
inode->i_state |= I_SYNC;
inode->i_state &= ~I_DIRTY_PAGES;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);

ret = do_writepages(mapping, wbc);
@@ -370,8 +375,10 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* write_inode()
*/
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
dirty = inode->i_state & I_DIRTY;
inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
/* Don't write the inode if only I_DIRTY_PAGES was set */
if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
@@ -381,6 +388,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
}

spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
inode->i_state &= ~I_SYNC;
if (!(inode->i_state & I_FREEING)) {
if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
@@ -422,6 +430,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
}
}
inode_sync_complete(inode);
+ spin_unlock(&inode->i_lock);
return ret;
}

@@ -492,7 +501,9 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
* kind does not need peridic writeout yet, and for the latter
* kind writeout is handled by the freer.
*/
+ spin_lock(&inode->i_lock);
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
+ spin_unlock(&inode->i_lock);
requeue_io(inode);
continue;
}
@@ -501,10 +512,14 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
* Was this inode dirtied after sync_sb_inodes was called?
* This keeps sync from extra jobs and livelock.
*/
- if (inode_dirtied_after(inode, wbc->wb_start))
+ if (inode_dirtied_after(inode, wbc->wb_start)) {
+ spin_unlock(&inode->i_lock);
return 1;
+ }

__iget(inode);
+ spin_unlock(&inode->i_lock);
+
pages_skipped = wbc->pages_skipped;
writeback_single_inode(inode, wbc);
if (wbc->pages_skipped != pages_skipped) {
@@ -681,7 +696,9 @@ static long wb_writeback(struct bdi_writeback *wb,
if (!list_empty(&wb->b_more_io)) {
inode = wb_inode(wb->b_more_io.prev);
trace_wbc_writeback_wait(&wbc, wb->bdi);
+ spin_lock(&inode->i_lock);
inode_wait_for_writeback(inode);
+ spin_unlock(&inode->i_lock);
}
spin_unlock(&inode_lock);
}
@@ -947,6 +964,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
block_dump___mark_inode_dirty(inode);

spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
if ((inode->i_state & flags) != flags) {
const int was_dirty = inode->i_state & I_DIRTY;

@@ -958,7 +976,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
* superblock list, based upon its state.
*/
if (inode->i_state & I_SYNC)
- goto out;
+ goto out_unlock_inode;

/*
* Only add valid (hashed) inodes to the superblock's
@@ -966,11 +984,12 @@ void __mark_inode_dirty(struct inode *inode, int flags)
*/
if (!S_ISBLK(inode->i_mode)) {
if (inode_unhashed(inode))
- goto out;
+ goto out_unlock_inode;
}
if (inode->i_state & I_FREEING)
- goto out;
+ goto out_unlock_inode;

+ spin_unlock(&inode->i_lock);
/*
* If the inode was already on b_dirty/b_io/b_more_io, don't
* reposition it (that would break b_dirty time-ordering).
@@ -995,7 +1014,10 @@ void __mark_inode_dirty(struct inode *inode, int flags)
inode->dirtied_when = jiffies;
list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
}
+ goto out;
}
+out_unlock_inode:
+ spin_unlock(&inode->i_lock);
out:
spin_unlock(&inode_lock);

@@ -1041,14 +1063,16 @@ static void wait_sb_inodes(struct super_block *sb)
* we still have to wait for that writeout.
*/
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
- struct address_space *mapping;
+ struct address_space *mapping = inode->i_mapping;

- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
- continue;
- mapping = inode->i_mapping;
- if (mapping->nrpages == 0)
+ spin_lock(&inode->i_lock);
+ if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+ (mapping->nrpages == 0)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
__iget(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
/*
* We hold a reference to 'inode' so it couldn't have
diff --git a/fs/inode.c b/fs/inode.c
index a6d6068..4c84acb 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -26,6 +26,17 @@
#include <linux/posix_acl.h>

/*
+ * inode locking rules.
+ *
+ * inode->i_lock protects:
+ * inode->i_state, __iget()
+ *
+ * Lock ordering:
+ * inode_lock
+ * inode->i_lock
+ */
+
+/*
* This is needed for the following functions:
* - inode_has_buffers
* - invalidate_bdev
@@ -136,15 +147,6 @@ int proc_nr_inodes(ctl_table *table, int write,
}
#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
@@ -314,7 +316,7 @@ static void init_once(void *foo)
}

/*
- * inode_lock must be held
+ * inode->i_lock must be held
*/
void __iget(struct inode *inode)
{
@@ -429,7 +431,9 @@ void end_writeback(struct inode *inode)
BUG_ON(!(inode->i_state & I_FREEING));
BUG_ON(inode->i_state & I_CLEAR);
inode_sync_wait(inode);
+ spin_lock(&inode->i_lock);
inode->i_state = I_FREEING | I_CLEAR;
+ spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(end_writeback);

@@ -472,7 +476,9 @@ static void dispose_list(struct list_head *head)
__inode_sb_list_del(inode);
spin_unlock(&inode_lock);

- wake_up_inode(inode);
+ spin_lock(&inode->i_lock);
+ wake_up_bit(&inode->i_state, __I_NEW);
+ spin_unlock(&inode->i_lock);
destroy_inode(inode);
}
}
@@ -498,12 +504,17 @@ void evict_inodes(struct super_block *sb)
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);
WARN_ON(1);
continue;
}

inode->i_state |= I_FREEING;
+ if (!(inode->i_state & (I_DIRTY | I_SYNC)))
+ percpu_counter_dec(&nr_inodes_unused);
+ spin_unlock(&inode->i_lock);

/*
* Move the inode off the IO lists and LRU once I_FREEING is
@@ -511,8 +522,6 @@ void evict_inodes(struct super_block *sb)
*/
list_move(&inode->i_lru, &dispose);
list_del_init(&inode->i_wb_list);
- if (!(inode->i_state & (I_DIRTY | I_SYNC)))
- percpu_counter_dec(&nr_inodes_unused);
}
spin_unlock(&inode_lock);

@@ -537,14 +546,21 @@ int invalidate_inodes(struct super_block *sb)

spin_lock(&inode_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 (atomic_read(&inode->i_count)) {
+ spin_unlock(&inode->i_lock);
busy = 1;
continue;
}

inode->i_state |= I_FREEING;
+ if (!(inode->i_state & (I_DIRTY | I_SYNC)))
+ percpu_counter_dec(&nr_inodes_unused);
+ spin_unlock(&inode->i_lock);

/*
* Move the inode off the IO lists and LRU once I_FREEING is
@@ -552,8 +568,6 @@ int invalidate_inodes(struct super_block *sb)
*/
list_move(&inode->i_lru, &dispose);
list_del_init(&inode->i_wb_list);
- if (!(inode->i_state & (I_DIRTY | I_SYNC)))
- percpu_counter_dec(&nr_inodes_unused);
}
spin_unlock(&inode_lock);

@@ -612,8 +626,10 @@ static void prune_icache(int nr_to_scan)
* Referenced or dirty inodes are still in use. Give them
* another pass through the LRU as we canot reclaim them now.
*/
+ spin_lock(&inode->i_lock);
if (atomic_read(&inode->i_count) ||
(inode->i_state & ~I_REFERENCED)) {
+ spin_unlock(&inode->i_lock);
list_del_init(&inode->i_lru);
percpu_counter_dec(&nr_inodes_unused);
continue;
@@ -621,12 +637,14 @@ static void prune_icache(int nr_to_scan)

/* 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;
+ spin_unlock(&inode->i_lock);
+ list_move(&inode->i_lru, &inode_lru);
continue;
}
if (inode_has_buffers(inode) || inode->i_data.nrpages) {
__iget(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
if (remove_inode_buffers(inode))
reap += invalidate_mapping_pages(&inode->i_data,
@@ -637,11 +655,15 @@ static void prune_icache(int nr_to_scan)
if (inode != list_entry(inode_lru.next,
struct inode, i_lru))
continue; /* wrong inode or list_empty */
- if (!can_unuse(inode))
+ spin_lock(&inode->i_lock);
+ 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
@@ -708,11 +730,13 @@ repeat:
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;
}
__iget(inode);
+ spin_unlock(&inode->i_lock);
return inode;
}
return NULL;
@@ -734,11 +758,13 @@ repeat:
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;
}
__iget(inode);
+ spin_unlock(&inode->i_lock);
return inode;
}
return NULL;
@@ -803,14 +829,23 @@ struct inode *new_inode(struct super_block *sb)
inode = alloc_inode(sb);
if (inode) {
spin_lock(&inode_lock);
- __inode_sb_list_add(inode);
+ spin_lock(&inode->i_lock);
inode->i_state = 0;
+ spin_unlock(&inode->i_lock);
+ __inode_sb_list_add(inode);
spin_unlock(&inode_lock);
}
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
@@ -830,19 +865,11 @@ void unlock_new_inode(struct inode *inode)
}
}
#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);

@@ -871,9 +898,11 @@ static struct inode *get_new_inode(struct super_block *sb,
if (set(inode, data))
goto set_failed;

+ spin_lock(&inode->i_lock);
+ inode->i_state = I_NEW;
+ spin_unlock(&inode->i_lock);
hlist_add_head(&inode->i_hash, head);
__inode_sb_list_add(inode);
- inode->i_state = I_NEW;
spin_unlock(&inode_lock);

/* Return the locked inode with I_NEW set, the
@@ -917,10 +946,12 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
/* We released the lock, so.. */
old = find_inode_fast(sb, head, ino);
if (!old) {
+ spin_lock(&inode->i_lock);
inode->i_ino = ino;
+ inode->i_state = I_NEW;
+ spin_unlock(&inode->i_lock);
hlist_add_head(&inode->i_hash, head);
__inode_sb_list_add(inode);
- inode->i_state = I_NEW;
spin_unlock(&inode_lock);

/* Return the locked inode with I_NEW set, the
@@ -1005,15 +1036,19 @@ EXPORT_SYMBOL(iunique);
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;
}
@@ -1242,7 +1277,9 @@ int insert_inode_locked(struct inode *inode)
ino_t ino = inode->i_ino;
struct hlist_head *head = inode_hashtable + hash(sb, ino);

+ spin_lock(&inode->i_lock);
inode->i_state |= I_NEW;
+ spin_unlock(&inode->i_lock);
while (1) {
struct hlist_node *node;
struct inode *old = NULL;
@@ -1252,8 +1289,11 @@ int insert_inode_locked(struct inode *inode)
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)) {
@@ -1262,6 +1302,7 @@ int insert_inode_locked(struct inode *inode)
return 0;
}
__iget(old);
+ spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
@@ -1279,7 +1320,9 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
struct super_block *sb = inode->i_sb;
struct hlist_head *head = inode_hashtable + hash(sb, hashval);

+ spin_lock(&inode->i_lock);
inode->i_state |= I_NEW;
+ spin_unlock(&inode->i_lock);

while (1) {
struct hlist_node *node;
@@ -1291,8 +1334,11 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
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)) {
@@ -1301,6 +1347,7 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
return 0;
}
__iget(old);
+ spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
@@ -1346,6 +1393,9 @@ static void iput_final(struct inode *inode)
const struct super_operations *op = inode->i_sb->s_op;
int drop;

+ spin_lock(&inode->i_lock);
+ WARN_ON(inode->i_state & I_NEW);
+
if (op && op->drop_inode)
drop = op->drop_inode(inode);
else
@@ -1357,21 +1407,23 @@ static void iput_final(struct inode *inode)
if (!(inode->i_state & (I_DIRTY|I_SYNC))) {
inode_lru_list_add(inode);
}
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
return;
}
- WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_WILL_FREE;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_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;
+ spin_unlock(&inode->i_lock);

/*
* Move the inode off the IO lists and LRU once I_FREEING is
@@ -1384,8 +1436,10 @@ static void iput_final(struct inode *inode)
spin_unlock(&inode_lock);
evict(inode);
remove_inode_hash(inode);
- wake_up_inode(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);
}

@@ -1582,9 +1636,8 @@ EXPORT_SYMBOL(inode_wait);
* 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)
{
@@ -1592,6 +1645,7 @@ 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->i_lock);
spin_unlock(&inode_lock);
schedule();
finish_wait(wq, &wait.wait);
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 21ed106..9c0fb09 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -249,8 +249,11 @@ void fsnotify_unmount_inodes(struct list_head *list)
* I_WILL_FREE, or I_NEW which is fine because by that point
* the inode cannot have any associated watches.
*/
- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+ spin_lock(&inode->i_lock);
+ if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }

/*
* If i_count is zero, the inode cannot have any watches and
@@ -258,8 +261,10 @@ void fsnotify_unmount_inodes(struct list_head *list)
* evict all inodes with zero i_count from icache which is
* unnecessarily violent and may in fact be illegal to do.
*/
- if (!atomic_read(&inode->i_count))
+ if (!atomic_read(&inode->i_count)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }

need_iput_tmp = need_iput;
need_iput = NULL;
@@ -269,13 +274,17 @@ void fsnotify_unmount_inodes(struct list_head *list)
__iget(inode);
else
need_iput_tmp = NULL;
+ spin_unlock(&inode->i_lock);

/* In case the dropping of a reference would nuke next_i. */
if ((&next_i->i_sb_list != list) &&
- atomic_read(&next_i->i_count) &&
- !(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
- __iget(next_i);
- need_iput = next_i;
+ atomic_read(&next_i->i_count)) {
+ spin_lock(&next_i->i_lock);
+ if (!(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
+ __iget(next_i);
+ need_iput = next_i;
+ }
+ spin_unlock(&next_i->i_lock);
}

/*
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index aad1316..a2d89f8 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -898,18 +898,19 @@ static void add_dquot_ref(struct super_block *sb, int type)

spin_lock(&inode_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+ spin_lock(&inode->i_lock);
+ if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+ !atomic_read(&inode->i_writecount) ||
+ !dqinit_needed(inode, type)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
#ifdef CONFIG_QUOTA_DEBUG
if (unlikely(inode_get_rsv_space(inode) > 0))
reserved = 1;
#endif
- if (!atomic_read(&inode->i_writecount))
- continue;
- if (!dqinit_needed(inode, type))
- continue;
-
__iget(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);

iput(old_inode);
--
1.7.1

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