glusterfs.git/xlators/features/upcall/src/upcall.c, branch v3.10.8

marker: Fix inode value in loc, in setxattr fop

2017-02-20T12:24:01+00:00

On recieving a rename fop, marker_rename() stores the,
oldloc and newloc in its 'local' struct, once the rename
is done, the xtime marker(last updated time) is set on
the file, but sending a setxattr fop. When upcall
receives the setxattr fop, the loc->inode is NULL and
it crashes. The loc->inode can be NULL only in one valid
case, i.e. in rename case where the inode of new loc
can be NULL. Hence, marker should have filled the inode
of the new_loc before issuing a setxattr.

marker_rename_cbk was already fixed in a previous commit.
Fixing marker_rename_done to send valid inode in this commit.

Also in upcall check for NULL inode so that there is no crash.

>Reviewed-on: https://review.gluster.org/16633
>Reviewed-by: Kotresh HR 
>Smoke: Gluster Build System 
>CentOS-regression: Gluster Build System 
>Reviewed-by: soumya k 
>NetBSD-regression: NetBSD Build System 
>Reviewed-by: Raghavendra G 
>(cherry picked from commit 73defab8be16b73241225bb1c2588a61e3e425d5)

Change-Id: I3ed2a05118fed3367dfe3251ce4477310cb480d0
BUG: 1424937
Signed-off-by: Poornima G 
Reviewed-on: https://review.gluster.org/16684
Tested-by: Atin Mukherjee 
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Shyamsundar Ranganathan

upcall: Resolve dict leak from up_(f)removexattr in upcall code path

2017-01-16T09:32:13+00:00

Problem: In up_(f)removexattr() dict_for_key_value() is used to create a
         new dict. This dict is not correctly unref'd and gets leaked.

Solution: To avoid the leak up_(f)removexattr() now also does a
          dict_unref() on the newly created dict.

While reviewing the code in up_(f)setxattr() for a similar problem, it
was noticed that there is an extra dict created. There is no need for
this copy, upcall_local_init() can just take the dict that was passed as
argument to the FOP.

BUG: 1412917
Change-Id: I5bb9a7d99f5087af11c19ae722de62bdb5ad1498
Signed-off-by: Mohit Agrawal 
Reviewed-on: http://review.gluster.org/16392
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Niels de Vos 
Smoke: Gluster Build System

md-cache, afr: Reduce the window of stale read

2016-10-20T07:07:55+00:00

Problem:
Consider a replica setup, where one mount writes data to a
file and the other mount reads the file. In afr, read operations
are not transaction based, a brick(read subvolume) is chosen as
a part of lookup or other operations, read is always wound only
to the read subvolume, even if there was write from a different client
that failed on this brick. This stale read continues until there is
a lookup or any write operation from the mount point. Currently, this
is not a major issue, as a lookup is issued before every read and it will
switch the read subvolume to a correct one. But with the plan of
increasing md-cache timeout to 600s, the stale read problem will be
more pronounced, i.e. stale read can continue for 600s(or more if cascaded
with readdirp), as there will be no lookups.

Solution:
Afr doesn't have any built-in solution for stale read(without affecting
the performance). The solution that came up, was to use upcall. When a file
on any brick is marked bad for the first time, upcall sends a notification
to all the clients that had recently accessed the file. The solution has
2 parts:
- Identifying when a file is marked bad, on any of the bricks,
  for the first time
- Client side actions on recieving the notifications

Identifying when a file is marked bad on any of the bricks for the first time:
-----------------------------------------------------------------------------
The idea is to track xattrop in upcall. xattrop currently comes with 2 afr
xattrs - afr dirty bit and afr pending xattrs.
   Dirty xattr is set to 1 before every write, and is unset if write succeeds.
In certain scenarios, dirty xattr can be 0 and still the file could be bad
copy. Hence do not track dirty xattr.
   Pending xattr is set on the good copy, indicating the other bricks that have
bad copy. It is still not as simple as, notifying when any of the pending xattrs
change. It could lead to flood of notifcations, in case the other brick is
completely down or consistantly failing. Hence it is important to notify only
once, the first time a good copy is marked bad.

Client side actions on recieving pending xattr change, notification:
--------------------------------------------------------------------
md-cache will invalidate the cache of that file, so that further lookup is
passed down to afr and hence update the read subvolume. Invalidating only in
md-cache is not enough, consider the folling oder of opertaions:
- pending xattr invalidation - invalidate md-cache
- readdirp on the bad read subvolume - fill md-cache
- lookup (served from md-cache)
- read - wound to the old read subvol.
Hence, along with invalidating md-cache, it is very important to reset the
read subvolume for that file, in afr.

Design Credit: Anuradha Talur, Ravishankar N

1. xattrop doesn't carry info saying post op/pre op.
2. Pre xattrop will have 0 value for all pending xattrs,
   the cbk of pre xattrop carries the on-disk xattr value.
   Non zero indicated healing is required.
3. Post xattrop will have non zero value for any of the
   pending xattrs, if the fop failed on any of the bricks.

Change-Id: I469cbc111714c433984fe1c922be2ef113c25804
BUG: 1211863
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15398
Reviewed-by: Pranith Kumar Karampuri 
Tested-by: Pranith Kumar Karampuri 
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

upcall: Mark the clients as accessed on readdirp entries

2016-08-31T13:44:01+00:00

Currently when a client performs a readdirp it is not stored
in upcall, as one of the clients that have accessed the files.
Hence, when any other client modifies the file, the client that
had performed readdirp will not get any notifications.

Fix this by adding the clients to upcall database when they
perform readdirp.

Change-Id: I7767f1e26bf1bd1f67702a6d01f8aa64526ccc46
BUG: 1369430
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15313
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: soumya k 
Reviewed-by: Niels de Vos

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

features/upcall: segment fault while join thread reaper_thr in fini()

2016-08-29T12:13:49+00:00

reaper_thr thread may not be started according to option
'cache-invalidation', if it's not started, join it in fini will cause a
segment fault.

Change-Id: I1c145a5feb137767880a08e79f810537283fb6b9
BUG: 1369524
Signed-off-by: Ryan Ding 
[ndevos: check .reaper_init_done and make it a boolean]
Reviewed-on: http://review.gluster.org/15298
Smoke: Gluster Build System 
Reviewed-by: soumya k 
Reviewed-by: Niels de Vos 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

upcall: fix unused variable warnings/errors

2016-08-25T12:11:31+00:00

http://review.gluster.org/14085 fixes a/the "leak" - via the
generated rpc/xdr headers - of pragmas that mask these warnings.

However 14085 won't pass the smoke test until all the warnings are
fixed.

Change-Id: I887aa033f00ab67f73c7d7a7f1b3054d43bffc49
BUG: 1369124
Signed-off-by: Kaleb S. KEITHLEY 
Reviewed-on: http://review.gluster.org/15252
Reviewed-by: Niels de Vos 
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System

md-cache/upcall: In case of mode bit change invalidate xattr

2016-08-04T15:46:44+00:00

When the mode bits are changed, the ACL entries also do get affected.
Currently in upcall, setattr invalidates only the stat info.

With this patch, if mode bits are changed, the upcall will invalidate
all the xattrs.

Change-Id: Iccda2e1a7440ee845aa5442bf51970f74d9b0862
BUG: 1211863
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/15043
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Niels de Vos 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Prashanth Pai 
Reviewed-by: Jeff Darcy

dict: Don't expose get_new_dict/dict_destroy

2016-07-26T06:47:33+00:00

get_new_dict/dict_destroy is causing confusion where, dict_new/dict_destroy or
get_new_dict/dict_unref are used instead of dict_new/dict_unref.

Change-Id: I4cc69f5b6711d720823395e20fd624a0c6c1168c
BUG: 1296043
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/13183
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Jeff Darcy 
Reviewed-by: Krutika Dhananjay

upcall: Invalidation for xattr should also carry a valid stat

2016-07-05T11:53:03+00:00

xattr modification also impacts the ctime of the file, hence
include the new stat along with the new xattrs, in the
invalidation request

Change-Id: Ieaa4382fa62f397f61a995b926013b9207c6e9da
BUG: 1352671
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/14828
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Jeff Darcy