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authorJeff Layton <jlayton@redhat.com>2014-01-28 13:47:46 -0500
committerTrond Myklebust <trond.myklebust@primarydata.com>2014-01-28 14:48:18 -0500
commit4db72b40fdbc706f8957e9773ae73b1574b8c694 (patch)
tree7ccf6324c0643b0b35c1ccc0895292f51000685e /fs/nfs/dir.c
parent17dfeb9113397a6119091a491ef7182649f0c5a9 (diff)
downloadlinux-4db72b40fdbc706f8957e9773ae73b1574b8c694.tar.bz2
nfs: add memory barriers around NFS_INO_INVALID_DATA and NFS_INO_INVALIDATING
If the setting of NFS_INO_INVALIDATING gets reordered to before the clearing of NFS_INO_INVALID_DATA, then another task may hit a race window where both appear to be clear, even though the inode's pages are still in need of invalidation. Fix this by adding the appropriate memory barriers. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs/dir.c')
-rw-r--r--fs/nfs/dir.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index b39a0468829b..be38b573495a 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -274,6 +274,15 @@ out_eof:
return -EBADCOOKIE;
}
+static bool
+nfs_readdir_inode_mapping_valid(struct nfs_inode *nfsi)
+{
+ if (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA))
+ return false;
+ smp_rmb();
+ return !test_bit(NFS_INO_INVALIDATING, &nfsi->flags);
+}
+
static
int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc)
{
@@ -287,9 +296,8 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des
struct nfs_open_dir_context *ctx = desc->file->private_data;
new_pos = desc->current_index + i;
- if (ctx->attr_gencount != nfsi->attr_gencount
- || (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA))
- || test_bit(NFS_INO_INVALIDATING, &nfsi->flags)) {
+ if (ctx->attr_gencount != nfsi->attr_gencount ||
+ !nfs_readdir_inode_mapping_valid(nfsi)) {
ctx->duped = 0;
ctx->attr_gencount = nfsi->attr_gencount;
} else if (new_pos < desc->ctx->pos) {