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authorSage Weil <sage@newdream.net>2010-03-30 13:54:41 -0700
committerSage Weil <sage@newdream.net>2010-03-30 13:55:22 -0700
commit9358c6d4c0264b1572554c49c4b92673ea9a5c72 (patch)
tree3d11a5021487dccf61b8d53c66c32df6b84223eb
parent2eaa9cfdf33b8d7fb7aff27792192e0019ae8fc6 (diff)
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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 <sage@newdream.net>
-rw-r--r--fs/ceph/dir.c1
-rw-r--r--fs/ceph/inode.c10
2 files changed, 10 insertions, 1 deletions
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 8a9116e15b7..aed8fda3302 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 aca82d55cc5..26f883c275e 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