glusterfs.git/xlators/performance/md-cache, branch release-3.9

ec: Invalidations in disperse volume should not update the stat

2017-01-17T14:55:46+00:00

Backport of http://review.gluster.org/16329

Issue:
In disperse volume, the file is present across bricks, hence the stat
from one brick doesn't carry the valid size of the file. Therefore
the upcall from one brick updating the md-cache results in wrong size
being updated.

Fix:
If the notification is cache invalidation then, indicate md-cache that
the attributes is invalid.

>Reviewed-on: http://review.gluster.org/16329
>Smoke: Gluster Build System 
>NetBSD-regression: NetBSD Build System 
>Reviewed-by: Xavier Hernandez 
>CentOS-regression: Gluster Build System 
>Reviewed-by: Pranith Kumar Karampuri 
(cherry picked from commit 95d07a3d2d68805d93d36a447436e27c48777939)

BUG: 1410688
Change-Id: Id89d2283478e70b62b435a8891fffc86d2be8cb2
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/16341
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Pranith Kumar Karampuri

dht/md-cache: Filter invalidate if the file is made a linkto file

2017-01-05T06:10:12+00:00

Backport of http://review.gluster.org/15789

Upcall as a part of setattr, sends an invalidation and the
invalidation carries the resulting stat value. When a file
is converted to linkto files, even then an invalidation
is set and as a result the mountpoint shows the sticky
bit in the stat of the file.
eg: ---------T. 945 root root 0 Nov  8 10:14 hardlink.999

Fix:
When dht recieves a notification of sticky bit change, it updates
the flag, to indicate md-cache to send the subsequent lookup.

>Reviewed-on: http://review.gluster.org/15789
>Smoke: Gluster Build System 
>NetBSD-regression: NetBSD Build System 
>Reviewed-by: Niels de Vos 
>CentOS-regression: Gluster Build System 
>Reviewed-by: Susant Palai 
>Reviewed-by: Rajesh Joseph 
>(cherry picked from commit 4536f7bdf16f8286d67598eda9a46c029f0c0bf4)

Change-Id: Ic2fd7a5b196db0754f9b97072e644e6bf69da606
BUG: 1401376
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/16022
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Raghavendra G

afr,dht,ec: Replace GF_EVENT_CHILD_MODIFIED with event SOME_DESCENDENT_DOWN/UP

2016-12-13T09:46:14+00:00

Backport of http://review.gluster.org/#/c/15764/

Currently these are few events related to child_up/down:
GF_EVENT_CHILD_UP :  Issued when any of the protocol client
connects.
GF_EVENT_CHILD_MODIFIED : Issued by afr/dht/ec
GF_EVENT_CHILD_DOWN : Issued when any of the protocol client
disconnects.
These events get modified at the dht/afr/ec layers. Here is a
brief on the same.

DHT:
- All the subvolumes reported once, and atleast one child came
  up, then GF_EVENT_CHILD_UP is issued
- connect GF_EVENT_CHILD_UP is issued
- disconnect GF_EVENT_CHILD_MODIFIED is issued
- All the subvolumes disconnected, GF_EVENT_CHILD_DOWN is issued

AFR:
- First subvolume came up, then GF_EVENT_CHILD_UP is issued
- Subsequent subvolumes coming up, results in GF_EVENT_CHILD_MODIFIED
- Any of the subvolumes go down, then GF_EVENT_SOME_CHILD_DOWN is issued
- Last up subvolume goes down, then GF_EVENT_CHILD_DOWN is issued

Until the patch [1] introduced GF_EVENT_SOME_CHILD_UP,
GF_EVENT_CHILD_MODIFIED was issued by afr/dht when any of the subvolumes
go up or down.

Now with md-cache changes, there is a necessity to differentiate between
child up and down. Hence, introducing GF_EVENT_SOME_DESCENDENT_DOWN/UP and
getting rid of GF_EVENT_CHILD_MODIFIED.

[1] http://review.gluster.org/12573

>Reviewed-on: http://review.gluster.org/15764
>CentOS-regression: Gluster Build System 
>NetBSD-regression: NetBSD Build System 
>Smoke: Gluster Build System 
>Reviewed-by: N Balachandran 
>Reviewed-by: Pranith Kumar Karampuri  
>Reviewed-by: Rajesh Joseph 
(cherry picked from commit f7ab6c45963fa0da68acedfb14281cd2456abc68)

Change-Id: I704140b6598f7ec705493251d2dbc4191c965a58
BUG: 1396880
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15890
NetBSD-regression: NetBSD Build System 
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Pranith Kumar Karampuri

md-cache: Invalidate cache entry for open() with O_TRUNC

2016-11-04T03:19:55+00:00

When a file is opened with O_TRUNC flag set, its size gets
set to '0'. This case needs to be handled in md-cache to
avoid sending incorrect cached stat.

This is backport of below mainline patch -
http://review.gluster.org/#/c/15618/

> Change-Id: I95d1f8a6634734898883ede010c3e7b0b7eb97d9
> BUG: 1382266
> Signed-off-by: Soumya Koduri 
> Reviewed-on: http://review.gluster.org/15618
> Smoke: Gluster Build System 
> Reviewed-by: jiffin tony Thottan 
> Tested-by: jiffin tony Thottan 
> NetBSD-regression: NetBSD Build System 
> CentOS-regression: Gluster Build System 
> Reviewed-by: Kaleb KEITHLEY 
> (cherry picked from commit 6ca5d6382f03685b31b12accb095093cf1486603)

Change-Id: I9780a4051adaa9030bd33da68dbc0a31212de054
BUG: 1391448
Signed-off-by: Soumya Koduri 
Reviewed-on: http://review.gluster.org/15770
Reviewed-by: jiffin tony Thottan 
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Kaleb KEITHLEY

md-cache: Process all the cache invalidation flags

2016-08-31T06:40:52+00:00

Currently, md-cache only processes IATT_UPDATE_FLAGS, UP_XATTR and
UP_XATTR_RM. We also need to process UP_RENAME_FLAGS, UP_FORGET,
UP_PARENT_DENTRY_FLAGS and UP_NLINK_FLAGS. Otherwise the files
unlinked or renamed will not be reflected on other mounts.

Change-Id: Icb8b03da51482c3fc2e2a7292d16d56e11a341d9
BUG: 1211863
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15324
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Raghavendra G

dht, md-cache, upcall: Add invalidation of IATT when the layout changes

2016-08-31T06:08:54+00:00

Issue:
dht_layout is built as a part of lookup only. The layout can be
modified by rebalance process. Since every IO fop is preceded
by a lookup, there are very less issues of stale layout. But
with enhancements of aggressive caching of stats in md-cache,
the lookup will reduce and expose the stale layout issue often.

Solution:
Since stale layout is already an issue on dht, there is already
a plan to fix this at the dht layer, but this fix is not currently
planned for any release. Until this fix comes out, we can have
a workaround where, the upcall will send a notification to md-cache
when a layout xattr is changed. As a part of layout change notification
the existing cache is invalidated and the next lookup will fetch the
latest layout.

This is not a foolproof solution as the window between the layout change
and the next lookup(after invalidation of stat), where there will be stale
layout. But until the final fix comes in, this reduces the stale layout
window.

Change-Id: Iacf871a38b35880c1fc0bc68fe7ce291265e71d4
BUG: 1369638
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15300
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Smoke: Gluster Build System 
Reviewed-by: Raghavendra G

md-cache: Register the list of xattrs with cache-invalidation

2016-08-31T06:07:01+00:00

Issue:
md-cache caches a specified list of xattrs, and when cache invalidation
is enabled, it makes sense to recieve invalidation only when those xattrs
are modified by other clients. But the current implementation of upcall
is that, it will send invalidation when any of the on-disk xattrs is modified.

Solution:
md-cache sends a list of xattrs that it is interested in, to upcall by
issuing an ipc(). The challenge here is to make sure everytime a brick
goes offline and comes back up, the ipc() needs to be issued to the
bricks. Hence ipc() is sent from md-cache every time there is a
CHILD_UP/CHILD_MODIFIED event.

TODO:
There will be patches following, in cluster xlators, to implement ipc fop.

Change-Id: I6efcf3df474f5ce6eabd3d6694c00c7bd89bc25d
BUG: 1211863
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15002
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Rajesh Joseph 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Prashanth Pai 
Reviewed-by: Raghavendra G

md-cache: Fix wrong cache time update for xattrs

2016-08-27T12:56:35+00:00

In md-cache, the cache has two times:
1. Time when the stat was last fetched for that inode
2. Time when the xattrs were last fetched for that inode. This
time should not be updated when only one of the xattrs is updated.
If, its updated when one of the cached xattr is changed, it can so
happen that the other xattrs have past their cache timeout, but are
still served from cache.

Solution:
Do not update the xattr cache time, when one of the xattrs being cached
is changed. With this, we may end up in cache timeout though it was
updated recently, but it is not a harm. The other way is to have
timeout for every xattr that is being cached. Its more complicated, and
may be not worth it, as we have lot of lookup fops, that are overloaded to
get all the xattrs.

Change-Id: Id77e547f403fc792348f1ea56b468b9260a5a34f
BUG: 1211863
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15045
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Raghavendra G

md-cache: Do not use features.cache-invalidation for both md-cache and upcall

2016-08-27T12:18:49+00:00

Currently, the volume set option features.cache-invalidation enables upcall
feature on server side and md-cache cache-invalidation on client side.
There are multiple problems that can arise from this:
1. The scenario when user wants to, enable upcall for nfs-ganesha setup,
   but do not want to enable md-cache cache-invalidation, as the
   nfs-clients have already cached the metadata and upcall is used to
   to invalidate the nfs-client cache. In this case, users should have
   a way of disabling md-cache invalidation without disabling upcall.

2. Upcall requires a op-version of GD_OP_VERSION_3_7_0, where as
   md-cache invalidation requires an op version of GD_OP_VERSION_3_9_0.
   Consider a setup where the servers are in op-version GD_OP_VERSION_3_7_0,
   and th clients are in op-version GD_OP_VERSION_3_9_0. if there is one
   single volume set option, user can enable this feature in this setup.
   But it can lead to stale xattr cache as the xattr invalidation was
   introduced in upcall only in release 3.8. Hence, we should not be
   able to enable md-cache invalidation, if all the servers and clients
   are not on opversion >= GD_OP_VERSION_3_9_0.

To solve the above mentioned issues, we have seperate volume options
for enabling md-cache invalidation and upcall. But this can lead to
issues when user enable md-cache invalidation and forgets to enable
upcall. Probably in the next release, these can be enables by default.

Change-Id: Ie70eff97fe12fcb623eec8f4f5861ac065bf483e
BUG: 1211863
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15314
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Smoke: Gluster Build System 
Reviewed-by: soumya k 
Reviewed-by: Raghavendra G

md-cache: Add cache hit and miss counters

2016-08-27T11:14:36+00:00

These counters can be accessed either by .meta interface
or statedump.

From meta: cat on the private file in md-cache directory.
Eg: cat /mnt/glusterfs/0/.meta/graphs/active/patchy-md-cache/private
[performance/md-cache.patchy-md-cache]
stat_hit_count = 2
stat_miss_count = 8
xattr_hit_count = 4
xattr_miss_count = 3
nameless_lookup_count = 1
negative_lookup_count = 0
stat_invalidations_recieved = 1
xattr_invalidations_recieved = 1

Change-Id: Ib62a8822f263a9f75858b15832d0119fbe382629
BUG: 1211863
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15185
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Raghavendra G