[patch 03/14] fs: icache lock inodes icache state

From: npiggin
Date: Thu Oct 21 2010 - 09:22:49 EST


Where inode_lock is currently used, add protection of the icache state of a
single inode with i_lock. This includes inode fields and membership on
icache data structures.

This means that once i_lock is held, inode_lock can be lifted without
introducing any new concurrency.

Before i_lock is held, ie. when searching icache data structures for an
inode, inode_lock can now be split into several independent locks.

spin_lock(&inode_lock)
for_each_inode_in_hash() {
/*
* hash membership is invariant
* as are all other properties of the inode and membership (or
* lack of) in other data structures at a point in time when it
* is on the hash.
*/
}

If we don't have i_lock, then we can't retain the same concurrency
invariants:

spin_lock(&inode_hash_lock)
for_each_inode_in_hash() {
/*
* hash membership is invariant
* nothing else is, except what depends on hash membership.
*/
}

Wheras if we take i_lock in the hash search (with inode_hash_lock held),
then we have our hash membership invariant, and the i_lock gives all the
other invariants of inode_lock.

Signed-off-by: Nick Piggin <npiggin@xxxxxxxxx>

---
fs/drop_caches.c | 12 +++-
fs/fs-writeback.c | 35 +++++++++++--
fs/inode.c | 127 +++++++++++++++++++++++++++++++++++++------------
fs/notify/inode_mark.c | 25 ++++++---
fs/quota/dquot.c | 30 +++++++++--
5 files changed, 176 insertions(+), 53 deletions(-)

Index: linux-2.6/fs/drop_caches.c
===================================================================
--- linux-2.6.orig/fs/drop_caches.c 2010-10-21 23:50:27.000000000 +1100
+++ linux-2.6/fs/drop_caches.c 2010-10-21 23:50:45.000000000 +1100
@@ -18,11 +18,17 @@ static void drop_pagecache_sb(struct sup

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)) {
+ spin_unlock(&inode->i_lock);
continue;
- if (inode->i_mapping->nrpages == 0)
+ }
+ if (inode->i_mapping->nrpages == 0) {
+ spin_unlock(&inode->i_lock);
continue;
- inode_get(inode);
+ }
+ inode_get_ilock(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode);
Index: linux-2.6/fs/fs-writeback.c
===================================================================
--- linux-2.6.orig/fs/fs-writeback.c 2010-10-21 23:50:27.000000000 +1100
+++ linux-2.6/fs/fs-writeback.c 2010-10-21 23:50:45.000000000 +1100
@@ -288,10 +288,12 @@ static void inode_wait_for_writeback(str
wait_queue_head_t *wqh;

wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
- while (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);
}
}

@@ -345,6 +347,7 @@ writeback_single_inode(struct inode *ino
/* 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);
@@ -366,8 +369,10 @@ writeback_single_inode(struct inode *ino
* 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)) {
@@ -377,6 +382,7 @@ writeback_single_inode(struct inode *ino
}

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)) {
@@ -487,7 +493,9 @@ static int writeback_sb_inodes(struct su
return 0;
}

+ spin_lock(&inode->i_lock);
if (inode->i_state & (I_NEW | I_WILL_FREE)) {
+ spin_unlock(&inode->i_lock);
requeue_io(inode);
continue;
}
@@ -495,11 +503,13 @@ static int writeback_sb_inodes(struct su
* 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;
+ }

BUG_ON(inode->i_state & I_FREEING);
- inode_get(inode);
+ inode_get_ilock(inode);
pages_skipped = wbc->pages_skipped;
writeback_single_inode(inode, wbc);
if (wbc->pages_skipped != pages_skipped) {
@@ -509,6 +519,7 @@ static int writeback_sb_inodes(struct su
*/
redirty_tail(inode);
}
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
iput(inode);
cond_resched();
@@ -944,6 +955,7 @@ void __mark_inode_dirty(struct inode *in
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;

@@ -994,6 +1006,7 @@ void __mark_inode_dirty(struct inode *in
}
}
out:
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);

if (wakeup_bdi)
@@ -1040,12 +1053,18 @@ static void wait_sb_inodes(struct super_
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
struct address_space *mapping;

- 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;
+ }
mapping = inode->i_mapping;
- if (mapping->nrpages == 0)
+ if (mapping->nrpages == 0) {
+ spin_unlock(&inode->i_lock);
continue;
- inode_get(inode);
+ }
+ inode_get_ilock(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
/*
* We hold a reference to 'inode' so it couldn't have
@@ -1169,7 +1188,9 @@ int write_inode_now(struct inode *inode,

might_sleep();
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
ret = writeback_single_inode(inode, &wbc);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
if (sync)
inode_sync_wait(inode);
@@ -1193,7 +1214,9 @@ int sync_inode(struct inode *inode, stru
int ret;

spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
ret = writeback_single_inode(inode, wbc);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
return ret;
}
Index: linux-2.6/fs/inode.c
===================================================================
--- linux-2.6.orig/fs/inode.c 2010-10-21 23:50:27.000000000 +1100
+++ linux-2.6/fs/inode.c 2010-10-21 23:50:46.000000000 +1100
@@ -33,6 +33,10 @@
* everything
* inode->i_lock protects:
* i_count
+ * i_state
+ * i_hash
+ * i_list
+ * i_sb_list
*
* Ordering:
* inode_lock
@@ -381,8 +385,10 @@ static void dispose_list(struct list_hea
evict(inode);

spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
hlist_del_init(&inode->i_hash);
list_del_init(&inode->i_sb_list);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);

wake_up_inode(inode);
@@ -419,16 +425,21 @@ static int invalidate_list(struct list_h
if (tmp == head)
break;
inode = list_entry(tmp, struct inode, i_sb_list);
- if (inode->i_state & I_NEW)
+ spin_lock(&inode->i_lock);
+ if (inode->i_state & I_NEW) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
invalidate_inode_buffers(inode);
if (!inode->i_count) {
list_move(&inode->i_list, dispose);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
count++;
+ spin_unlock(&inode->i_lock);
continue;
}
+ spin_unlock(&inode->i_lock);
busy = 1;
}
/* only unused inodes may be cached with i_count zero */
@@ -505,28 +516,37 @@ static void prune_icache(int nr_to_scan)

inode = list_entry(inode_unused.prev, struct inode, i_list);

+ spin_lock(&inode->i_lock);
if (inode->i_state || inode->i_count) {
list_move(&inode->i_list, &inode_unused);
+ spin_unlock(&inode->i_lock);
continue;
}
if (inode_has_buffers(inode) || inode->i_data.nrpages) {
- inode_get(inode);
+ inode_get_ilock(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
if (remove_inode_buffers(inode))
reap += invalidate_mapping_pages(&inode->i_data,
0, -1);
iput(inode);
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);

if (inode != list_entry(inode_unused.next,
- struct inode, i_list))
+ struct inode, i_list)) {
+ spin_unlock(&inode->i_lock);
continue; /* wrong inode or list_empty */
- if (!can_unuse(inode))
+ }
+ if (!can_unuse(inode)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
}
list_move(&inode->i_list, &freeable);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
+ spin_unlock(&inode->i_lock);
nr_pruned++;
}
inodes_stat.nr_unused -= nr_pruned;
@@ -590,6 +610,7 @@ static struct inode *find_inode(struct s
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;
@@ -615,6 +636,7 @@ static struct inode *find_inode_fast(str
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;
@@ -662,7 +684,9 @@ void inode_add_to_lists(struct super_blo
struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino);

spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
__inode_add_to_lists(sb, head, inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
}
EXPORT_SYMBOL_GPL(inode_add_to_lists);
@@ -694,9 +718,11 @@ struct inode *new_inode(struct super_blo
inode = alloc_inode(sb);
if (inode) {
spin_lock(&inode_lock);
- __inode_add_to_lists(sb, NULL, inode);
+ spin_lock(&inode->i_lock);
inode->i_ino = ++last_ino;
inode->i_state = 0;
+ __inode_add_to_lists(sb, NULL, inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
}
return inode;
@@ -763,8 +789,10 @@ static struct inode *get_new_inode(struc
if (set(inode, data))
goto set_failed;

- __inode_add_to_lists(sb, head, inode);
+ spin_lock(&inode->i_lock);
inode->i_state = I_NEW;
+ __inode_add_to_lists(sb, head, inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);

/* Return the locked inode with I_NEW set, the
@@ -778,7 +806,8 @@ static struct inode *get_new_inode(struc
* us. Use the old inode instead of the one we just
* allocated.
*/
- inode_get(old);
+ inode_get_ilock(old);
+ spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
destroy_inode(inode);
inode = old;
@@ -809,9 +838,11 @@ static struct inode *get_new_inode_fast(
/* We released the lock, so.. */
old = find_inode_fast(sb, head, ino);
if (!old) {
+ spin_lock(&inode->i_lock);
inode->i_ino = ino;
- __inode_add_to_lists(sb, head, inode);
inode->i_state = I_NEW;
+ __inode_add_to_lists(sb, head, inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);

/* Return the locked inode with I_NEW set, the
@@ -825,7 +856,8 @@ static struct inode *get_new_inode_fast(
* us. Use the old inode instead of the one we just
* allocated.
*/
- inode_get(old);
+ inode_get_ilock(old);
+ spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
destroy_inode(inode);
inode = old;
@@ -867,6 +899,8 @@ ino_t iunique(struct super_block *sb, in
res = counter++;
head = inode_hashtable + hash(sb, res);
inode = find_inode_fast(sb, head, res);
+ if (inode)
+ spin_unlock(&inode->i_lock);
} while (inode != NULL);
spin_unlock(&inode_lock);

@@ -876,18 +910,23 @@ EXPORT_SYMBOL(iunique);

struct inode *igrab(struct inode *inode)
{
+ struct inode *ret = inode;
+
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
if (!(inode->i_state & (I_FREEING|I_WILL_FREE)))
- inode_get(inode);
+ inode_get_ilock(inode);
else
/*
* 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;
+ ret = NULL;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
- return inode;
+
+ return ret;
}
EXPORT_SYMBOL(igrab);

@@ -919,7 +958,8 @@ static struct inode *ifind(struct super_
spin_lock(&inode_lock);
inode = find_inode(sb, head, test, data);
if (inode) {
- inode_get(inode);
+ inode_get_ilock(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
if (likely(wait))
wait_on_inode(inode);
@@ -952,7 +992,8 @@ static struct inode *ifind_fast(struct s
spin_lock(&inode_lock);
inode = find_inode_fast(sb, head, ino);
if (inode) {
- inode_get(inode);
+ inode_get_ilock(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
wait_on_inode(inode);
return inode;
@@ -1126,16 +1167,22 @@ int insert_inode_locked(struct inode *in
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;
+ }
+ goto found_old;
}
- if (likely(!node)) {
- hlist_add_head(&inode->i_hash, head);
- spin_unlock(&inode_lock);
- return 0;
- }
- inode_get(old);
+ spin_lock(&inode->i_lock);
+ hlist_add_head(&inode->i_hash, head);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_lock);
+ return 0;
+
+found_old:
+ inode_get_ilock(old);
+ spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
wait_on_inode(old);
if (unlikely(!hlist_unhashed(&old->i_hash))) {
@@ -1165,16 +1212,22 @@ int insert_inode_locked4(struct inode *i
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)) {
- hlist_add_head(&inode->i_hash, head);
- spin_unlock(&inode_lock);
- return 0;
+ }
+ goto found_old;
}
- inode_get(old);
+ spin_lock(&inode->i_lock);
+ hlist_add_head(&inode->i_hash, head);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_lock);
+ return 0;
+
+found_old:
+ inode_get_ilock(old);
+ spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
wait_on_inode(old);
if (unlikely(!hlist_unhashed(&old->i_hash))) {
@@ -1198,7 +1251,9 @@ void __insert_inode_hash(struct inode *i
{
struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
hlist_add_head(&inode->i_hash, head);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
}
EXPORT_SYMBOL(__insert_inode_hash);
@@ -1212,7 +1267,9 @@ EXPORT_SYMBOL(__insert_inode_hash);
void remove_inode_hash(struct inode *inode)
{
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
hlist_del_init(&inode->i_hash);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
}
EXPORT_SYMBOL(remove_inode_hash);
@@ -1260,14 +1317,17 @@ static void iput_final(struct inode *ino
list_move(&inode->i_list, &inode_unused);
inodes_stat.nr_unused++;
if (sb->s_flags & MS_ACTIVE) {
+ 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;
inodes_stat.nr_unused--;
@@ -1278,10 +1338,13 @@ static void iput_final(struct inode *ino
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
inodes_stat.nr_inodes--;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
evict(inode);
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
hlist_del_init(&inode->i_hash);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
wake_up_inode(inode);
BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
@@ -1307,7 +1370,6 @@ void iput(struct inode *inode)
spin_lock(&inode->i_lock);
inode->i_count--;
if (inode->i_count == 0) {
- spin_unlock(&inode->i_lock);
iput_final(inode);
} else {
spin_unlock(&inode->i_lock);
@@ -1493,6 +1555,8 @@ EXPORT_SYMBOL(inode_wait);
* wake_up_inode() after removing from the hash list will DTRT.
*
* This is called with inode_lock held.
+ *
+ * Called with i_lock held and returns with it dropped.
*/
static void __wait_on_freeing_inode(struct inode *inode)
{
@@ -1500,6 +1564,7 @@ static void __wait_on_freeing_inode(stru
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);
Index: linux-2.6/fs/quota/dquot.c
===================================================================
--- linux-2.6.orig/fs/quota/dquot.c 2010-10-21 23:50:27.000000000 +1100
+++ linux-2.6/fs/quota/dquot.c 2010-10-21 23:50:45.000000000 +1100
@@ -246,6 +246,7 @@ struct dqstats dqstats;
EXPORT_SYMBOL(dqstats);

static qsize_t inode_get_rsv_space(struct inode *inode);
+static qsize_t __inode_get_rsv_space(struct inode *inode);
static void __dquot_initialize(struct inode *inode, int type);

static inline unsigned int
@@ -898,18 +899,26 @@ static void add_dquot_ref(struct super_b

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)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
#ifdef CONFIG_QUOTA_DEBUG
- if (unlikely(inode_get_rsv_space(inode) > 0))
+ if (unlikely(__inode_get_rsv_space(inode) > 0))
reserved = 1;
#endif
- if (!atomic_read(&inode->i_writecount))
+ if (!atomic_read(&inode->i_writecount)) {
+ spin_unlock(&inode->i_lock);
continue;
- if (!dqinit_needed(inode, type))
+ }
+ if (!dqinit_needed(inode, type)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }

- inode_get(inode);
+ inode_get_ilock(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);

iput(old_inode);
@@ -1488,6 +1497,17 @@ void inode_sub_rsv_space(struct inode *i
}
EXPORT_SYMBOL(inode_sub_rsv_space);

+/* no i_lock variant of inode_get_rsv_space */
+static qsize_t __inode_get_rsv_space(struct inode *inode)
+{
+ qsize_t ret;
+
+ if (!inode->i_sb->dq_op->get_reserved_space)
+ return 0;
+ ret = *inode_reserved_space(inode);
+ return ret;
+}
+
static qsize_t inode_get_rsv_space(struct inode *inode)
{
qsize_t ret;
Index: linux-2.6/fs/notify/inode_mark.c
===================================================================
--- linux-2.6.orig/fs/notify/inode_mark.c 2010-10-21 23:50:27.000000000 +1100
+++ linux-2.6/fs/notify/inode_mark.c 2010-10-21 23:50:46.000000000 +1100
@@ -248,8 +248,11 @@ void fsnotify_unmount_inodes(struct 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
@@ -257,24 +260,30 @@ void fsnotify_unmount_inodes(struct list
* evict all inodes with zero i_count from icache which is
* unnecessarily violent and may in fact be illegal to do.
*/
- if (!inode->i_count)
+ if (!inode->i_count) {
+ spin_unlock(&inode->i_lock);
continue;
+ }

need_iput_tmp = need_iput;
need_iput = NULL;

/* In case fsnotify_inode_delete() drops a reference. */
if (inode != need_iput_tmp)
- inode_get(inode);
+ inode_get_ilock(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) &&
- next_i->i_count &&
- !(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
- inode_get(next_i);
- need_iput = next_i;
+ if ((&next_i->i_sb_list != list)) {
+ spin_lock(&next_i->i_lock);
+ if (next_i->i_count &&
+ !(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
+ inode_get_ilock(next_i);
+ need_iput = next_i;
+ }
+ spin_unlock(&next_i->i_lock);
}

/*


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