glusterfs.git/tests/basic/afr, branch v3.5.9 afr: Don't write to sparse regions of sink. 2015-02-12T12:09:13+00:00 Ravishankar N ravishankar@redhat.com 2015-02-09T03:01:10+00:00 b6c37bd9954fb3b7aee79dbe453f875b70a03e71 Corresponding afr-v2 fix: http://review.gluster.org/#/c/9480/ Problem: When data-self-heal-algorithm is set to 'full', shd just reads from source and writes to sink. If source file happened to be sparse (VM workloads), we end up actually writing 0s to the corresponding regions of the sink causing it to lose its sparseness. Fix: If the source file is sparse, and the data read from source and sink are both zeros for that range, skip writing that range to the sink. Change-Id: Iade957e4173c87e45a2881df501ba2ad3eb1a172 BUG: 1190633 Signed-off-by: Ravishankar N <ravishankar@redhat.com> Reviewed-on: http://review.gluster.org/9611 Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com> Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com> Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Niels de Vos <ndevos@redhat.com> 
Corresponding afr-v2 fix: http://review.gluster.org/#/c/9480/

Problem:
When data-self-heal-algorithm is set to 'full', shd just reads from
source and writes to sink. If source file happened to be sparse (VM
workloads), we end up actually writing 0s to the corresponding regions
of the sink causing it to lose its sparseness.

Fix:
If the source file is sparse, and the data read from source and sink are
both zeros for that range, skip writing that range to the sink.

Change-Id: Iade957e4173c87e45a2881df501ba2ad3eb1a172
BUG: 1190633
Signed-off-by: Ravishankar N <ravishankar@redhat.com>
Reviewed-on: http://review.gluster.org/9611
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
cluster/afr: Fix resolution issues with afr 2014-06-24T16:26:13+00:00 Pranith Kumar K pkarampu@redhat.com 2014-06-23T16:05:29+00:00 5d2603c75bfd78c8b33903a20e844430276e7539 Problem with afr: Lets say there is a directory hierarchy a/b/c/d on the mount and the user is cd'ed into the directory. Bring down one of the bricks of replica and remove all directories/files to simulate disk replacement on that brick. Now this brick is brought back up. Creates on the cd'ed directory fail with ESTALE. Basically before sending a create of 'f' inside 'd', fuse sends a lookup to make sure the file is not present. On one of the bricks 'd' is present and 'f' is not so it sends ENOENT as response. On the new brick 'd' itself is not present. So it sends ESTALE. In afr ESTALE is considered to be special errno on witnessing which lookup has to fail. And ESTALE is given more priority than ENOENT. Due to these reasons lookup fails with ESTALE rather than ENOENT. Since lookup didn't fail with ENOENT, 'create' can't be issued so the command is failed with ESTALE. Solution: Afr needs to consider ESTALE errno normally and ENOENT needs to be given more priority so that operations like create can proceed even when only one of the brick is up and running. Whenever client xlator identifies that gfid-changed, it sets that information in lookup xdata. Afr uses this information to fail the lookup with ESTALE so that top xlator can send fresh lookup. Change-Id: Ie8e0e327542fd644409eb5dadf451679afa1c0e5 BUG: 1112348 Signed-off-by: Pranith Kumar K <pkarampu@redhat.com> Reviewed-on: http://review.gluster.org/8154 Tested-by: Justin Clift <justin@gluster.org> Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Ravishankar N <ravishankar@redhat.com> Reviewed-by: Niels de Vos <ndevos@redhat.com> 
Problem with afr:
Lets say there is a directory hierarchy a/b/c/d on the mount and the
user is cd'ed into the directory. Bring down one of the bricks of replica and
remove all directories/files to simulate disk replacement on that brick. Now
this brick is brought back up. Creates on the cd'ed directory fail with ESTALE.
Basically before sending a create of 'f' inside 'd', fuse sends a lookup to
make sure the file is not present.  On one of the bricks  'd' is present and
'f' is not so it sends ENOENT as response. On the new brick 'd' itself is not
present. So it sends ESTALE. In afr ESTALE is considered to be special errno on
witnessing which lookup has to fail. And ESTALE is given more priority than
ENOENT. Due to these reasons lookup fails with ESTALE rather than ENOENT. Since
lookup didn't fail with ENOENT, 'create' can't be issued so the command is
failed with ESTALE.

Solution:
Afr needs to consider ESTALE errno normally and ENOENT needs to
be given more priority so that operations like create can proceed even when
only one of the brick is up and running. Whenever client xlator identifies
that gfid-changed, it sets that information in lookup xdata. Afr uses this
information to fail the lookup with ESTALE so that top xlator can send
fresh lookup.

Change-Id: Ie8e0e327542fd644409eb5dadf451679afa1c0e5
BUG: 1112348
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/8154
Tested-by: Justin Clift <justin@gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Ravishankar N <ravishankar@redhat.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>