Commit 7c3ea987 authored by Xiubo Li's avatar Xiubo Li Committed by Ilya Dryomov
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ceph: no need to wait for transition RDCACHE|RD -> RD 



For write when trying to get the Fwb caps we need to keep waiting
on transition from WRBUFFER|WR -> WR to avoid a new WR sync write
from going before a prior buffered writeback happens.

While for read there is no need to wait on transition from
RDCACHE|RD -> RD, and we can just exclude the revoking caps and
force to sync read.

Signed-off-by: default avatarXiubo Li <xiubli@redhat.com>
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent 6eb06c46

fs/ceph/caps.c

+6 −2
Original line number Diff line number Diff line
@@ -2760,13 +2760,17 @@ static int try_get_cap_refs(struct inode *inode, int need, int want, 
		 * on transition from wanted -> needed caps.  This is needed

		 * for WRBUFFER|WR -> WR to avoid a new WR sync write from

		 * going before a prior buffered writeback happens.

		 *

		 * For RDCACHE|RD -> RD, there is not need to wait and we can

		 * just exclude the revoking caps and force to sync read.

		 */

		int not = want & ~(have & need);

		int revoking = implemented & ~have;

		int exclude = revoking & not;

		dout("get_cap_refs %p have %s but not %s (revoking %s)\n",

		     inode, ceph_cap_string(have), ceph_cap_string(not),

		     ceph_cap_string(revoking));

		if ((revoking & not) == 0) {

		if (!exclude || !(exclude & CEPH_CAP_FILE_BUFFER)) {

			if (!snap_rwsem_locked &&

			    !ci->i_head_snapc &&

			    (need & CEPH_CAP_FILE_WR)) {
@@ -2788,7 +2792,7 @@ static int try_get_cap_refs(struct inode *inode, int need, int want, 
				snap_rwsem_locked = true;

			}

			if ((have & want) == want)

				*got = need | want;

				*got = need | (want & ~exclude);

			else

				*got = need;

			ceph_take_cap_refs(ci, *got, true);