From 9358c6d4c0264b1572554c49c4b92673ea9a5c72 Mon Sep 17 00:00:00 2001 From: Sage Weil Date: Tue, 30 Mar 2010 13:54:41 -0700 Subject: [PATCH] ceph: fix dentry rehashing on virtual .snap dir If a lookup fails on the magic .snap directory, we bind it to a magic snap directory inode in ceph_lookup_finish(). That code assumes the dentry is unhashed, but a recent server-side change started returning NULL leases on lookup failure, causing the .snap dentry to be hashed and NULL by ceph_fill_trace(). This causes dentry hash chain corruption, or a dies when d_rehash() includes BUG_ON(!d_unhashed(entry)); So, avoid processing the NULL dentry lease if it the dentry matches the snapdir name in ceph_fill_trace(). That allows the lookup completion to properly bind it to the snapdir inode. BUG there if dentry is hashed to be sure. Signed-off-by: Sage Weil --- fs/ceph/dir.c | 1 + fs/ceph/inode.c | 10 +++++++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c index 8a9116e15b70..aed8fda33024 100644 --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -488,6 +488,7 @@ struct dentry *ceph_finish_lookup(struct ceph_mds_request *req, struct inode *inode = ceph_get_snapdir(parent); dout("ENOENT on snapdir %p '%.*s', linking to snapdir %p\n", dentry, dentry->d_name.len, dentry->d_name.name, inode); + BUG_ON(!d_unhashed(dentry)); d_add(dentry, inode); err = 0; } diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index aca82d55cc53..26f883c275e8 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -886,6 +886,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req, struct inode *in = NULL; struct ceph_mds_reply_inode *ininfo; struct ceph_vino vino; + struct ceph_client *client = ceph_sb_to_client(sb); int i = 0; int err = 0; @@ -949,7 +950,14 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req, return err; } - if (rinfo->head->is_dentry && !req->r_aborted) { + /* + * ignore null lease/binding on snapdir ENOENT, or else we + * will have trouble splicing in the virtual snapdir later + */ + if (rinfo->head->is_dentry && !req->r_aborted && + (rinfo->head->is_target || strncmp(req->r_dentry->d_name.name, + client->mount_args->snapdir_name, + req->r_dentry->d_name.len))) { /* * lookup link rename : null -> possibly existing inode * mknod symlink mkdir : null -> new inode -- 2.30.2