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| author | Miklos Szeredi <mszeredi@suse.cz> | 2013-09-05 11:44:36 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-09-05 16:23:41 -0400 |
| commit | 848ac114e847af3f1f9141c90a39ebe79bdb13b3 (patch) | |
| tree | 3673b97171b0e0bc5b179908b4ad15ede9a91b35 /include/linux/dcache.h | |
| parent | db14fc3abcd5dcc9b32ad5b9dd5b8f9e16295a39 (diff) | |
| download | talos-obmc-linux-848ac114e847af3f1f9141c90a39ebe79bdb13b3.tar.gz talos-obmc-linux-848ac114e847af3f1f9141c90a39ebe79bdb13b3.zip | |
vfs: check submounts and drop atomically
We check submounts before doing d_drop() on a non-empty directory dentry in
NFS (have_submounts()), but we do not exclude a racing mount.
Process A: have_submounts() -> returns false
Process B: mount() -> success
Process A: d_drop()
This patch prepares the ground for the fix by doing the following
operations all under the same rename lock:
have_submounts()
shrink_dcache_parent()
d_drop()
This is actually an optimization since have_submounts() and
shrink_dcache_parent() both traverse the same dentry tree separately.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: David Howells <dhowells@redhat.com>
CC: Steven Whitehouse <swhiteho@redhat.com>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/dcache.h')
| -rw-r--r-- | include/linux/dcache.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 9169b91ea2d2..c6d3fe50ff96 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -253,6 +253,7 @@ extern void d_prune_aliases(struct inode *); /* test whether we have any submounts in a subdir tree */ extern int have_submounts(struct dentry *); +extern int check_submounts_and_drop(struct dentry *); /* * This adds the entry to the hash queues. |
