Reviewed-by: Sage Weil <sage@xxxxxxxxxxx>
On Sat, 21 Sep 2013, Yan, Zheng wrote:
> From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx>
>
> If client has outdated directory fragments information, it may request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@xxxxxxxxx>
> ---
> fs/ceph/dir.c | 11 ++++++++++-
> fs/ceph/inode.c | 15 +++++++++++++--
> fs/ceph/mds_client.c | 3 +--
> 3 files changed, 24 insertions(+), 5 deletions(-)
>
> 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 @@ more:
> }
>
> /* 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 @@ more:
> 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 cf12ea6..833a4d5 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -1274,8 +1274,19 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
> 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 (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);
> @@ -1339,7 +1350,7 @@ retry_lookup:
> }
>
> 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 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
> 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);
> }
> --
> 1.8.1.4
>
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