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authorTrond Myklebust <trond.myklebust@primarydata.com>2014-01-28 18:37:16 +0400
committerTrond Myklebust <trond.myklebust@primarydata.com>2014-01-28 19:47:08 +0400
commit17dfeb9113397a6119091a491ef7182649f0c5a9 (patch)
tree26024381114970fa3ab1844f55b30755e7a32af3 /fs/nfs/inode.c
parent0ea9de0ea6a4e4a1d343130b2a159b4f986e288e (diff)
downloadlinux-17dfeb9113397a6119091a491ef7182649f0c5a9.tar.xz
NFS: Fix races in nfs_revalidate_mapping
Commit d529ef83c355f97027ff85298a9709fe06216a66 (NFS: fix the handling of NFS_INO_INVALID_DATA flag in nfs_revalidate_mapping) introduces a potential race, since it doesn't test the value of nfsi->cache_validity and set the bitlock in nfsi->flags atomically. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Cc: Jeff Layton <jlayton@redhat.com>
Diffstat (limited to 'fs/nfs/inode.c')
-rw-r--r--fs/nfs/inode.c28
1 files changed, 14 insertions, 14 deletions
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 0a972ee9ccc1..e5070aa5f175 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1038,24 +1038,24 @@ int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
nfs_wait_bit_killable, TASK_KILLABLE);
if (ret)
goto out;
- if (!(nfsi->cache_validity & NFS_INO_INVALID_DATA))
- goto out;
- if (!test_and_set_bit_lock(NFS_INO_INVALIDATING, bitlock))
+ spin_lock(&inode->i_lock);
+ if (test_bit(NFS_INO_INVALIDATING, bitlock)) {
+ spin_unlock(&inode->i_lock);
+ continue;
+ }
+ if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
break;
- }
-
- spin_lock(&inode->i_lock);
- if (nfsi->cache_validity & NFS_INO_INVALID_DATA) {
- nfsi->cache_validity &= ~NFS_INO_INVALID_DATA;
- spin_unlock(&inode->i_lock);
- trace_nfs_invalidate_mapping_enter(inode);
- ret = nfs_invalidate_mapping(inode, mapping);
- trace_nfs_invalidate_mapping_exit(inode, ret);
- } else {
- /* something raced in and cleared the flag */
spin_unlock(&inode->i_lock);
+ goto out;
}
+ set_bit(NFS_INO_INVALIDATING, bitlock);
+ nfsi->cache_validity &= ~NFS_INO_INVALID_DATA;
+ spin_unlock(&inode->i_lock);
+ trace_nfs_invalidate_mapping_enter(inode);
+ ret = nfs_invalidate_mapping(inode, mapping);
+ trace_nfs_invalidate_mapping_exit(inode, ret);
+
clear_bit_unlock(NFS_INO_INVALIDATING, bitlock);
smp_mb__after_clear_bit();
wake_up_bit(bitlock, NFS_INO_INVALIDATING);