Problem: Before executing a fop in POSIX xlator it builds an internal
         path based on GFID.To validate the path it call's (l)stat
         system call and while .glusterfs is heavily loaded kernel takes
         time to lookup inode and due to that performance drops

Solution: In this patch we followed two ways to improve the performance.
          1) Keep open fd specific to first level directory(gfid[0])
             in .glusterfs, it would force to kernel keep the inodes
             from all those files in cache. In case of memory pressure
             kernel won't uncache first level inodes. We need to open
             256 fd's per brick to access the entry faster.
          2) Use at based call's to access relative path to reduce
             path based lookup time.

Note: To verify the patch we have executed kernel untar 100 times on 6
      different clients after enabling metadata group-cache and some
      other option.We were getting more than 20 percent improvement in
      kenel untar after applying the patch.

Credits: Xavi Hernandez <xhernandez@redhat.com>
Change-Id: I1643e6b01ed669b2bb148d02f4e6a8e08da45343
updates: #891
Signed-off-by: Mohit Agrawal <moagrawal@redhat.com>

Avoid one function call to set the gfid_path in buffer

Change-Id: If9b95801b05c34d262fac9a275492c794d12bf58
Updates #748
Signed-off-by: Mohit Agrawal <moagrawa@redhat.com>

In various places, we can re-use knowledge of string length
or result of snprintf() and such instead of strlen().

Change-Id: I4c9b1decf1169b3f8ac83699a0afbd7c38fad746
updates: bz#1193929
Signed-off-by: Yaniv Kaul <ykaul@redhat.com>

Server stack needs to have all the sort of validation, assuming
clients can be compromized. It is possible for a compromized
client to send basenames with paths with '/', and with that
create files without permission on server. By sanitizing the basename,
and not allowing anything other than actual directory as the parent
for any entry creation, we can mitigate the effects of clients
not able to exploit the server.

Fixes: CVE-2018-14651

Fixes: bz#1644755
Change-Id: I5dc0da0da2713452ff2b65ac2ddbccf1a267dc20
Signed-off-by: Amar Tumballi <amarts@redhat.com>

Change-Id: I6f5d8140a06f3c1b2d196849299f8d483028d33b

This will prevent any arbitrary file creation through glusterfs
by modifying the client bits.

Also check for the similar flaw inside posix too, so we prevent any
changes in layers in-between.

Fixes: bz#1625095

Signed-off-by: Amar Tumballi <amarts@redhat.com>
Change-Id: Id9fe0ef6e86459e8ed85ab947d977f058c5ae06e

This patch uses the ctime posix APIs to get consistent
time across replica. The time attributes are got from
from inode context or from on disk if not found and
merged with iatt to be returned.

Credits: Rafi KC <rkavunga@redhat.com>
Updates: #208
Change-Id: Id737038ce52468f1f5ebc8a42cbf9c6ffbd63850
Signed-off-by: Kotresh HR <khiremat@redhat.com>

Problem: storage.reserve option is not working correctly while
         disk space is allocate throguh fallocate

Solution: In posix_disk_space_check_thread_proc after every 5 sec interval
          it calls posix_disk_space_check to monitor disk space and set the
          flag in posix priv.In 5 sec timestamp user can create big file with
          fallocate that can reach posix reserve limit and no error is shown on
          terminal even limit has reached.
          To resolve the same call posix_disk_space for every fallocate fop
          instead to call by a thread after 5 second

BUG: 1560411
Signed-off-by: Mohit Agrawal <moagrawa@redhat.com>
Change-Id: I39ba9390e2e6d084eedbf3bcf45cd6d708591577

For more details on this issue see
https://github.com/gluster/glusterfs/issues/308

Solution:
This is a restrictive solution where a file will not be migrated
if a client writes to it during the migration. This does not
check if the writes from the rebalance and the client actually
do overlap.

If dht_writev_cbk finds that the file is being migrated (PHASE1)
it will set an xattr on the destination file indicating the file
was updated by a non-rebalance client.
Rebalance checks if any other client has written to the dst file
and aborts the file migration if it finds the xattr.

updates gluster/glusterfs#308

Change-Id: I73aec28bc9dbb8da57c7425ec88c6b6af0fbc9dd
Signed-off-by: Susant Palai <spalai@redhat.com>
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
Signed-off-by: N Balachandran <nbalacha@redhat.com>

1. Split out entry and inode/fd based FOPs into
separate files from posix.c
2. Split out common routines (init, fini, reconf,
and such) into its own file, from posix.c
3. Retain just the method assignments in posix.c
(such that posix2 for RIO can assign its own methods in
the future for entry operations and such)
4. Based on the split in (1) and (2) split out
posix-handle.h into 2 files, such that macros that are
needed for inode ops are in one and rest are in the other

If the split is done as above, posix2 can compile with
its own entry ops, and hence not compile, the entry ops
as split in (1) above.

The split described in (4) can again help posix2 to
define its own macros to make entry and inode handles,
thus not impact existing POSIX xlator code.

Noted problems
- There are path references in certain cases where
quota is used (in the xattr FOPs), and thus will fail
on reuse in posix2, this needs to be handled when we
get there.
- posix_init does set root GFID on the brick root,
and this is incorrect for posix2, again will need
handling later when posix2 evolves based on this
code (other init checks seem fine on current inspection)

Merge of experimental branch patches with the following
gerrit change-IDs
> Change-Id: I965ce6dffe70a62c697f790f3438559520e0af20
> Change-Id: I089a4d9cf470c2f9c121611e8ef18dea92b2be70
> Change-Id: I2cec103f6ba8f3084443f3066bcc70b2f5ecb49a

Fixes gluster/glusterfs#327

Change-Id: I0ccfa78559a7c5a68f5e861e144cf856f5c9e19c
Signed-off-by: ShyamsundarR <srangana@redhat.com>