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authorJeff Layton2019-10-30 12:15:10 -0400
committerIlya Dryomov2019-11-05 15:42:44 +0100
commit5bb5e6ee6f5c557dcd19822eccd7bcced1e1a410 (patch)
treef8a1b79914122633ee4e1ec4139d9b8ff751f4bd /fs/ceph
parent1f08529c84cfecaf1261ed9b7e17fab18541c58f (diff)
ceph: don't try to handle hashed dentries in non-O_CREAT atomic_open
If ceph_atomic_open is handed a !d_in_lookup dentry, then that means that it already passed d_revalidate so we *know* that it's negative (or at least was very recently). Just return -ENOENT in that case. This also addresses a subtle bug in dentry handling. Non-O_CREAT opens call atomic_open with the parent's i_rwsem shared, but calling d_splice_alias on a hashed dentry requires the exclusive lock. If ceph_atomic_open receives a hashed, negative dentry on a non-O_CREAT open, and another client were to race in and create the file before we issue our OPEN, ceph_fill_trace could end up calling d_splice_alias on the dentry with the new inode with insufficient locks. Cc: stable@vger.kernel.org Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph')
-rw-r--r--fs/ceph/file.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index d277f71abe0b..d2854cd2f4f5 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -462,6 +462,9 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
err = ceph_security_init_secctx(dentry, mode, &as_ctx);
if (err < 0)
goto out_ctx;
+ } else if (!d_in_lookup(dentry)) {
+ /* If it's not being looked up, it's negative */
+ return -ENOENT;
}
/* do the open */