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authorTrond Myklebust <Trond.Myklebust@netapp.com>2008-01-25 16:38:17 -0500
committerTrond Myklebust <Trond.Myklebust@netapp.com>2008-01-30 02:06:12 -0500
commit6f23e3872cff238589f9bf39c71db2ea880c9a26 (patch)
tree7b118601dcd65ae2bee7eddbeae6bdd6d64f4423 /fs
parente6f810759505bc86c009854b82cc495ffd8eb020 (diff)
downloadlinux-6f23e3872cff238589f9bf39c71db2ea880c9a26.tar.gz
NFS: Fix a potential race between umount and nfs_access_cache_shrinker()
Thanks to Yawei Niu for spotting the race. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/nfs/dir.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 5ca762de88b..476cb0f837f 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1694,13 +1694,19 @@ int nfs_access_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
restart:
spin_lock(&nfs_access_lru_lock);
list_for_each_entry(nfsi, &nfs_access_lru_list, access_cache_inode_lru) {
+ struct rw_semaphore *s_umount;
struct inode *inode;
if (nr_to_scan-- == 0)
break;
+ s_umount = &nfsi->vfs_inode.i_sb->s_umount;
+ if (!down_read_trylock(s_umount))
+ continue;
inode = igrab(&nfsi->vfs_inode);
- if (inode == NULL)
+ if (inode == NULL) {
+ up_read(s_umount);
continue;
+ }
spin_lock(&inode->i_lock);
if (list_empty(&nfsi->access_cache_entry_lru))
goto remove_lru_entry;
@@ -1719,6 +1725,7 @@ remove_lru_entry:
spin_unlock(&inode->i_lock);
spin_unlock(&nfs_access_lru_lock);
iput(inode);
+ up_read(s_umount);
goto restart;
}
spin_unlock(&nfs_access_lru_lock);