ceph: introduce global empty snap context

Current snaphost code does not properly handle moving inode from one
empty snap realm to another empty snap realm. After changing inode's
snap realm, some dirty pages' snap context can be not equal to inode's
i_head_snap. This can trigger BUG() in ceph_put_wrbuffer_cap_refs()

The fix is introduce a global empty snap context for all empty snap
realm. This avoids triggering the BUG() for filesystem with no snapshot.

Fixes: http://tracker.ceph.com/issues/9928
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@redhat.com>
libceph: require cephx message signature by default

Signed-off-by: Yan, Zheng <zyan@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@redhat.com>
ceph: remove unused stringification macros

These were used to report git versions a long time ago.

Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
rbd: don't treat CEPH_OSD_OP_DELETE as extent op

CEPH_OSD_OP_DELETE is not an extent op, stop treating it as such.  This
sneaked in with discard patches - it's one of the three osd ops (the
other two are CEPH_OSD_OP_TRUNCATE and CEPH_OSD_OP_ZERO) that discard
is implemented with.

Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Reviewed-by: Alex Elder <elder@linaro.org>
libceph: add SETXATTR/CMPXATTR osd operations support

Signed-off-by: Yan, Zheng <zyan@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@redhat.com>
libceph: add CREATE osd operation support

Add CEPH_OSD_OP_CREATE support.  Also change libceph to not treat
CEPH_OSD_OP_DELETE as an extent op and add an assert to that end.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@redhat.com>
libceph: specify position of extent operation

allow specifying position of extent operation in multi-operations
osd request. This is required for cephfs to convert inline data to
normal data (compare xattr, then write object).

Signed-off-by: Yan, Zheng <zyan@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@redhat.com>
ceph: parse inline data in MClientReply and MClientCaps

Signed-off-by: Yan, Zheng <zyan@redhat.com>
ceph: add inline data to pagecache

Request reply and cap message can contain inline data. add inline data
to the page cache if there is Fc cap.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
ceph: use getattr request to fetch inline data

Add a new parameter 'locked_page' to ceph_do_getattr(). If inline data
in getattr reply will be copied to the page.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
ceph: fetch inline data when getting Fcr cap refs

we can't use getattr to fetch inline data after getting Fcr caps,
because it can cause deadlock. The solution is try bringing inline
data to page cache when not holding any cap, and hope the inline
data page is still there after getting the Fcr caps. If the page
is still there, pin it in page cache for later IO.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
ceph: sync read inline data

we can't use getattr to fetch inline data while holding Fr cap,
because it can cause deadlock. If we need to sync read inline data,
drop cap refs first, then use getattr to fetch inline data.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
ceph: convert inline data to normal data before data write

Before any data write, convert inline data to normal data and set
i_inline_version to CEPH_INLINE_NONE. The OSD request that saves
inline data to object contains 3 operations (CMPXATTR, WRITE and
SETXATTR). It compares a xattr named 'inline_version' to prevent
old data overwrites newer data.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
ceph: flush inline version

After converting inline data to normal data, client need to flush
the new i_inline_version (CEPH_INLINE_NONE) to MDS. This commit makes
cap messages (sent to MDS) contain inline_version and inline_data.
Client always converts inline data to normal data before data write,
so the inline data length part is always zero.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
ceph: support inline data feature

Signed-off-by: Yan, Zheng <zyan@redhat.com>
libceph: fixup includes in pagelist.h

pagelist.h needs to include linux/types.h and asm/byteorder.h and not
rely on other headers pulling yet another set of headers.

Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
ceph: do_sync is never initialized

Probably this code was syncing a lot more often then intended because
the do_sync variable wasn't set to zero.

Cc: stable@vger.kernel.org # v3.11+
Fixes: c62988ec0910 ('ceph: avoid meaningless calling ceph_caps_revoking if sync_mode == WB_SYNC_ALL.')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
ceph: fix mksnap crash

mksnap reply only contain 'target', does not contain 'dentry'. So
it's wrong to use req->r_reply_info.head->is_dentry to detect traceless
reply.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
Reviewed-by: Sage Weil <sage@redhat.com>