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authorDavid Howells <dhowells@redhat.com>2019-11-14 21:41:03 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2019-11-15 21:28:02 +0300
commita28f239e296767ebf4ec4ae8a9ecb57d0d444b3f (patch)
treeef51943b4312f2e0c9d692a61cdb8ba737c9d2fc /fs
parenteb70e26cd79da8068dc7a9d013cd78fbba483038 (diff)
downloadlinux-a28f239e296767ebf4ec4ae8a9ecb57d0d444b3f.tar.xz
afs: Fix race in commit bulk status fetch
When a lookup is done, the afs filesystem will perform a bulk status-fetch operation on the requested vnode (file) plus the next 49 other vnodes from the directory list (in AFS, directory contents are downloaded as blobs and parsed locally). When the results are received, it will speculatively populate the inode cache from the extra data. However, if the lookup races with another lookup on the same directory, but for a different file - one that's in the 49 extra fetches, then if the bulk status-fetch operation finishes first, it will try and update the inode from the other lookup. If this other inode is still in the throes of being created, however, this will cause an assertion failure in afs_apply_status(): BUG_ON(test_bit(AFS_VNODE_UNSET, &vnode->flags)); on or about fs/afs/inode.c:175 because it expects data to be there already that it can compare to. Fix this by skipping the update if the inode is being created as the creator will presumably set up the inode with the same information. Fixes: 39db9815da48 ("afs: Fix application of the results of a inline bulk status fetch") Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/afs/dir.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index cc12772d0a4d..497f979018c2 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -803,7 +803,12 @@ success:
continue;
if (cookie->inodes[i]) {
- afs_vnode_commit_status(&fc, AFS_FS_I(cookie->inodes[i]),
+ struct afs_vnode *iv = AFS_FS_I(cookie->inodes[i]);
+
+ if (test_bit(AFS_VNODE_UNSET, &iv->flags))
+ continue;
+
+ afs_vnode_commit_status(&fc, iv,
scb->cb_break, NULL, scb);
continue;
}