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authorNick Piggin <npiggin@kernel.dk>2011-01-07 09:49:34 +0300
committerNick Piggin <npiggin@kernel.dk>2011-01-07 09:50:21 +0300
commit2fd6b7f50797f2e993eea59e0a0b8c6399c811dc (patch)
treece33b94b34844c09103836cf4cfa4364b742f217 /fs/notify/fsnotify.c
parentda5029563a0a026c64821b09e8e7b4fd81d3fe1b (diff)
downloadlinux-2fd6b7f50797f2e993eea59e0a0b8c6399c811dc.tar.xz
fs: dcache scale subdirs
Protect d_subdirs and d_child with d_lock, except in filesystems that aren't using dcache_lock for these anyway (eg. using i_mutex). Note: if we change the locking rule in future so that ->d_child protection is provided only with ->d_parent->d_lock, it may allow us to reduce some locking. But it would be an exception to an otherwise regular locking scheme, so we'd have to see some good results. Probably not worthwhile. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Diffstat (limited to 'fs/notify/fsnotify.c')
-rw-r--r--fs/notify/fsnotify.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 20dc218707ca..aa4f25e803f6 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -68,17 +68,19 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode)
/* run all of the children of the original inode and fix their
* d_flags to indicate parental interest (their parent is the
* original inode) */
+ spin_lock(&alias->d_lock);
list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
if (!child->d_inode)
continue;
- spin_lock(&child->d_lock);
+ spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
if (watched)
child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
else
child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
spin_unlock(&child->d_lock);
}
+ spin_unlock(&alias->d_lock);
}
spin_unlock(&dcache_lock);
}