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authorIan Kent <raven@themaw.net>2008-07-23 21:30:14 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-24 10:47:31 -0700
commitc432c2586a0811c7d0030d78f0993568bc889a6f (patch)
treeb5d711345120af6cc6ae67836d0773a5857e3e8c
parentef581a742874ebc4c28d24b374c78b762144ebdc (diff)
autofs4: don't release directory mutex if called in oz_mode
Since we now delay hashing of dentrys until the ->mkdir() call, droping and re-taking the directory mutex within the ->lookup() function when we are being called by user space is not needed. This can lead to a race when other processes are attempting to access the same directory during mount point directory creation. In this case we need to hang onto the mutex to ensure we don't get user processes trying to create a mount request for a newly created dentry after the mount point entry has already been created. This ensures that when we need to check a dentry passed to autofs4_wait(), if it is hashed, it is always the mount point dentry and not a new dentry created by another lookup during directory creation. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/autofs4/root.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 324290c6827..1e901e5ea01 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -686,12 +686,11 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
- }
-
- if (dentry->d_op && dentry->d_op->d_revalidate) {
- mutex_unlock(&dir->i_mutex);
- (dentry->d_op->d_revalidate)(dentry, nd);
- mutex_lock(&dir->i_mutex);
+ if (dentry->d_op && dentry->d_op->d_revalidate) {
+ mutex_unlock(&dir->i_mutex);
+ (dentry->d_op->d_revalidate)(dentry, nd);
+ mutex_lock(&dir->i_mutex);
+ }
}
/*