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authorAl Viro <viro@ZenIV.linux.org.uk>2016-06-20 13:14:36 -0400
committerJiri Slaby <jslaby@suse.cz>2016-07-21 08:36:01 +0200
commit11d275361f3dfc42b338ca3a9d95fa39384ccd1f (patch)
tree630993f05efe3ffe10c1f44d8f56fddd79ce22eb /fs
parentda252e41f1931dc9b949ba45c08c9a7cae26ec23 (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: Jiri Slaby <jslaby@suse.cz>
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 cf6ede69a2e2..b9670301d7d3 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1483,9 +1483,9 @@ 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);
break;
case -EISDIR: