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authorAl Viro <viro@ZenIV.linux.org.uk>2016-06-20 13:14:36 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-07-27 08:42:12 -0700
commitc45ef6742072e8cdd680233c4b02aa01105f9b4d (patch)
tree58206d053667956c2acae08c4728f99b581c3dae /fs
parente7e4ce1e80cc01b48d14eeda1e7e10b592abdc5c (diff)
make nfs_atomic_open() call d_drop() on all ->open_context() errors.
commit d20cb71dbf3487f24549ede1a8e2d67579b4632e upstream. 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()). 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-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 33eb81738d03..a7dd1fee8f13 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1527,9 +1527,9 @@ 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;