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authorAl Viro <viro@ZenIV.linux.org.uk>2016-06-20 13:14:36 -0400
committerAnna Schumaker <Anna.Schumaker@Netapp.com>2016-06-27 08:59:08 -0400
commitd20cb71dbf3487f24549ede1a8e2d67579b4632e (patch)
tree2f602eb69205f724fe404f6f021c21044b560804
parent1b982ea2ca398bdaeab6cf2aba459a9ca808f1f3 (diff)
downloadlinux-d20cb71dbf3487f24549ede1a8e2d67579b4632e.tar.gz
make nfs_atomic_open() call d_drop() on all ->open_context() errors.
In "NFSv4: Move dentry instantiation into the NFSv4-specific atomic open code" unconditional d_drop() after the ->open_context() had been removed. It had been correct for success cases (there ->open_context() itself had been doing dcache manipulations), but not for error ones. Only one of those (ENOENT) got a compensatory d_drop() added in that commit, but in fact it should've been done for all errors. As it is, the case of O_CREAT non-exclusive open on a hashed negative dentry racing with e.g. symlink creation from another client ended up with ->open_context() getting an error and proceeding to call nfs_lookup(). On a hashed dentry, which would've instantly triggered BUG_ON() in d_materialise_unique() (or, these days, its equivalent in d_splice_alias()). Cc: stable@vger.kernel.org # v3.10+ Tested-by: Oleg Drokin <green@linuxhacker.ru> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
-rw-r--r--fs/nfs/dir.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 2817cce7a9f4..d8015a03db4c 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1539,9 +1539,9 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
err = PTR_ERR(inode);
trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
put_nfs_open_context(ctx);
+ d_drop(dentry);
switch (err) {
case -ENOENT:
- d_drop(dentry);
d_add(dentry, NULL);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
break;