diff options
| author | Jeff Layton <jlayton@kernel.org> | 2021-03-01 08:01:54 -0500 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2021-04-27 23:52:23 +0200 |
| commit | aa60cfc3f7ee32766766f71e6bfbea963b4f94bc (patch) | |
| tree | eab5168f12d68b2371ace2eb91a5eea95e560d7d /fs/ceph/dir.c | |
| parent | d3c51ae1b8cce5bdaf91a1ce32b33cf5626075dc (diff) | |
ceph: don't use d_add in ceph_handle_snapdir
It's possible ceph_get_snapdir could end up finding a (disconnected)
inode that already exists in the cache. Change the prototype for
ceph_handle_snapdir to return a dentry pointer and have it use
d_splice_alias so we don't end up with an aliased dentry in the cache.
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/dir.c')
| -rw-r--r-- | fs/ceph/dir.c | 30 |
1 files changed, 19 insertions, 11 deletions
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c index 3e575656713e..5624fae7a603 100644 --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -667,8 +667,8 @@ out: /* * Handle lookups for the hidden .snap directory. */ -int ceph_handle_snapdir(struct ceph_mds_request *req, - struct dentry *dentry, int err) +struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req, + struct dentry *dentry, int err) { struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb); struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */ @@ -676,16 +676,17 @@ int ceph_handle_snapdir(struct ceph_mds_request *req, /* .snap dir? */ if (err == -ENOENT && ceph_snap(parent) == CEPH_NOSNAP && - strcmp(dentry->d_name.name, - fsc->mount_options->snapdir_name) == 0) { + strcmp(dentry->d_name.name, fsc->mount_options->snapdir_name) == 0) { + struct dentry *res; struct inode *inode = ceph_get_snapdir(parent); - dout("ENOENT on snapdir %p '%pd', linking to snapdir %p\n", - dentry, dentry, inode); - BUG_ON(!d_unhashed(dentry)); - d_add(dentry, inode); - err = 0; + + res = d_splice_alias(inode, dentry); + dout("ENOENT on snapdir %p '%pd', linking to snapdir %p. Spliced dentry %p\n", + dentry, dentry, inode, res); + if (res) + dentry = res; } - return err; + return dentry; } /* @@ -741,6 +742,7 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry, struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb); struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb); struct ceph_mds_request *req; + struct dentry *res; int op; int mask; int err; @@ -791,7 +793,13 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry, req->r_parent = dir; set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags); err = ceph_mdsc_do_request(mdsc, NULL, req); - err = ceph_handle_snapdir(req, dentry, err); + res = ceph_handle_snapdir(req, dentry, err); + if (IS_ERR(res)) { + err = PTR_ERR(res); + } else { + dentry = res; + err = 0; + } dentry = ceph_finish_lookup(req, dentry, err); ceph_mdsc_put_request(req); /* will dput(dentry) */ dout("lookup result=%p\n", dentry); |