ceph: handle frag mismatch between readdir request and reply
If client has outdated directory fragments information, it may request
readdir an non-existent directory fragment. In this case, the MDS finds
an approximate directory fragment and sends its contents back to the
client. When receiving a reply with fragment that is different than the
requested one, the client need to reset the 'readdir offset'.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 868b61d..2a0bcae 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -352,8 +352,18 @@
}
/* note next offset and last dentry name */
+ rinfo = &req->r_reply_info;
+ if (le32_to_cpu(rinfo->dir_dir->frag) != frag) {
+ frag = le32_to_cpu(rinfo->dir_dir->frag);
+ if (ceph_frag_is_leftmost(frag))
+ fi->next_offset = 2;
+ else
+ fi->next_offset = 0;
+ off = fi->next_offset;
+ }
fi->offset = fi->next_offset;
fi->last_readdir = req;
+ fi->frag = frag;
if (req->r_reply_info.dir_end) {
kfree(fi->last_name);
@@ -363,7 +373,6 @@
else
fi->next_offset = 0;
} else {
- rinfo = &req->r_reply_info;
err = note_last_dentry(fi,
rinfo->dir_dname[rinfo->dir_nr-1],
rinfo->dir_dname_len[rinfo->dir_nr-1]);
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 1c9fea0..9a8e396 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1275,8 +1275,20 @@
int err = 0, i;
struct inode *snapdir = NULL;
struct ceph_mds_request_head *rhead = req->r_request->front.iov_base;
- u64 frag = le32_to_cpu(rhead->args.readdir.frag);
struct ceph_dentry_info *di;
+ u64 r_readdir_offset = req->r_readdir_offset;
+ u32 frag = le32_to_cpu(rhead->args.readdir.frag);
+
+ if (rinfo->dir_dir &&
+ le32_to_cpu(rinfo->dir_dir->frag) != frag) {
+ dout("readdir_prepopulate got new frag %x -> %x\n",
+ frag, le32_to_cpu(rinfo->dir_dir->frag));
+ frag = le32_to_cpu(rinfo->dir_dir->frag);
+ if (ceph_frag_is_leftmost(frag))
+ r_readdir_offset = 2;
+ else
+ r_readdir_offset = 0;
+ }
if (req->r_aborted)
return readdir_prepopulate_inodes_only(req, session);
@@ -1340,7 +1352,7 @@
}
di = dn->d_fsdata;
- di->offset = ceph_make_fpos(frag, i + req->r_readdir_offset);
+ di->offset = ceph_make_fpos(frag, i + r_readdir_offset);
/* inode */
if (dn->d_inode) {
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index b7bda5d..f51ab26 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2238,8 +2238,7 @@
err = ceph_fill_trace(mdsc->fsc->sb, req, req->r_session);
if (err == 0) {
if (result == 0 && (req->r_op == CEPH_MDS_OP_READDIR ||
- req->r_op == CEPH_MDS_OP_LSSNAP) &&
- rinfo->dir_nr)
+ req->r_op == CEPH_MDS_OP_LSSNAP))
ceph_readdir_prepopulate(req, req->r_session);
ceph_unreserve_caps(mdsc, &req->r_caps_reservation);
}