From c432c2586a0811c7d0030d78f0993568bc889a6f Mon Sep 17 00:00:00 2001 From: Ian Kent Date: Wed, 23 Jul 2008 21:30:14 -0700 Subject: 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/autofs4/root.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'fs/autofs4') diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 324290c68275..1e901e5ea013 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); + } } /* -- cgit v1.2.3