From 8909c28c1173e10fd2f10706bd8a0f2ca5b5d685 Mon Sep 17 00:00:00 2001 From: Anand Avati Date: Wed, 27 Mar 2013 19:55:58 -0700 Subject: cluster/afr: fsync() guarantees POST-OP completion AFR now provides a stronger guarantee that fsync() returns only after completely finishing all the deferred/delayed POST-OP on that open file. To acheive this we make a stub out of the returning fsync and register it with the "delayed" frame in afr_changelog_wake_resume(). The delayed frame, after getting woken up and finishing the POST-OP will call_resume() the registered stub (which UNWINDs the fsync) at the time of frame destruction. This provides a guarantee that an application's (or FUSE) fsync() returns only after finishing up all the previous transactions, including delayed POST-OPs and UNLOCK. Change-Id: Iaa955457e2f25088a144fde37ad0444277b5cf49 BUG: 927146 Signed-off-by: Anand Avati Reviewed-on: http://review.gluster.org/4737 Tested-by: Gluster Build System Reviewed-by: Pranith Kumar Karampuri --- xlators/cluster/afr/src/afr-common.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-) (limited to 'xlators/cluster/afr/src/afr-common.c') diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c index 5b96a7789f9..c55adc1ee9c 100644 --- a/xlators/cluster/afr/src/afr-common.c +++ b/xlators/cluster/afr/src/afr-common.c @@ -852,6 +852,11 @@ afr_local_transaction_cleanup (afr_local_t *local, xlator_t *this) loc_wipe (&local->transaction.new_parent_loc); GF_FREE (local->transaction.postop_piggybacked); + + if (local->transaction.resume_stub) { + call_resume (local->transaction.resume_stub); + local->transaction.resume_stub = NULL; + } } @@ -2643,6 +2648,7 @@ afr_fsync_cbk (call_frame_t *frame, void *cookie, xlator_t *this, int call_count = -1; int child_index = (long) cookie; int read_child = 0; + call_stub_t *stub = NULL; local = frame->local; @@ -2677,18 +2683,29 @@ afr_fsync_cbk (call_frame_t *frame, void *cookie, xlator_t *this, call_count = afr_frame_return (frame); if (call_count == 0) { + /* Make a stub out of the frame, and register it + with the waking up post-op. When the call-stub resumes, + we are guaranteed that there was no post-op pending + (i.e changelogs were unset in the server). This is an + essential "guarantee", that fsync() returns only after + completely finishing EVERYTHING, including the delayed + post-op. This guarantee is expected by FUSE graph switching + for example. + */ + stub = fop_fsync_cbk_stub (frame, default_fsync_cbk, op_ret, + op_errno, prebuf, postbuf, xdata); + if (!stub) { + AFR_STACK_UNWIND (fsync, frame, -1, ENOMEM, 0, 0, 0); + return 0; + } + /* If no new unstable writes happened between the time we cleared the unstable write witness flag in afr_fsync and now, calling afr_delayed_changelog_wake_up() should wake up and skip over the fsync phase and go straight to afr_changelog_post_op_now() */ - afr_delayed_changelog_wake_up (this, local->fd); - - AFR_STACK_UNWIND (fsync, frame, local->op_ret, local->op_errno, - &local->cont.fsync.prebuf, - &local->cont.fsync.postbuf, - NULL); + afr_delayed_changelog_wake_resume (this, local->fd, stub); } return 0; -- cgit