ceph: fix LSSNAP regression

commit 6e8575faa8 makes parse_reply_info_extra() return -EIO for LSSNAP

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: queue cap release when trimming cap

So the client will later send cap release message to MDS

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: set mds_want according to cap import message

MDS ignores cap update message if migrate_seq mismatch, so when
receiving a cap import message with higher migrate_seq, set mds_want
according to the cap import message.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: use I_COMPLETE inode flag instead of D_COMPLETE flag

commit c6ffe10015 moved the flag that tracks if the dcache contents
for a directory are complete to dentry. The problem is there are
lots of places that use ceph_dir_{set,clear,test}_complete() while
holding i_ceph_lock. but ceph_dir_{set,clear,test}_complete() may
sleep because they call dput().

This patch basically reverts that commit. For ceph_d_prune(), it's
called with both the dentry to prune and the parent dentry are
locked. So it's safe to access the parent dentry's d_inode and
clear I_COMPLETE flag.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: revert commit 22cddde104

commit 22cddde104 breaks the atomicity of write operation, it also
introduces a deadlock between write and truncate.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: don't early drop Fw cap

ceph_aio_write() has an optimization that marks CEPH_CAP_FILE_WR
cap dirty before data is copied to page cache and inode size is
updated. The optimization avoids slow cap revocation caused by
balance_dirty_pages(), but introduces inode size update race. If
ceph_check_caps() flushes the dirty cap before the inode size is
updated, MDS can miss the new inode size. So just remove the
optimization.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: acquire i_mutex in __ceph_do_pending_vmtruncate

make __ceph_do_pending_vmtruncate() acquire the i_mutex if the caller
does not hold the i_mutex, so ceph_aio_read() can call safely.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>