glusterfs-snapshot.git/xlators/storage, branch development

bd: Add support to create clone, snapshot and merge of LV images.

2013-11-13T19:39:22+00:00

Special xattr names "clone" & "snapshot" can be used to create full and
linked clone of the LV images. GFID of destination posix file (to be
mapped) is passed as a value to the xattr. Destination posix file must
exist before running this operation.

These operations form a basis for offloading storage related operations
from QEMU to GlusterFS.

Syntax for full clone: xattr name: "clone" value: "gfid-of-dest-file"
Syntax for linked clone: xattr name: "snapshot" value: "gfid-of-dest-file"
Syntax for merging: xattr name: "merge" value: "path-to-snapshot-file"

Example:
	setfattr -n clone -v  /media/source
	setfattr -n snapshot -v  /media/source
	setfattr -n merge -v "/media/sn" /media/sn

Change-Id: Id9f984a709d4c2e52a64ae75bb12a8ecb01f8776
BUG: 1028672
Signed-off-by: M. Mohan Kumar 
Reviewed-on: http://review.gluster.org/5626
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

bd: Add aio support to BD xlator

2013-11-13T19:39:11+00:00

Volume option bd-aio controls AIO feature for BD xlator. Code taken from
posix-aio.c

Change-Id: Ib049bd59c9d3f9101d33939838322cfa808de053
BUG: 1028672
Signed-off-by: M. Mohan Kumar 
Reviewed-on: http://review.gluster.org/5748
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

bd: posix/multi-brick support to BD xlator

2013-11-13T19:38:42+00:00

Current BD xlator (block backend) has a few limitations such as
* Creation of directories not supported
* Supports only single brick
* Does not use extended attributes (and client gfid) like posix xlator
* Creation of special files (symbolic links, device nodes etc) not
  supported

Basic limitation of not allowing directory creation is blocking
oVirt/VDSM to consume BD xlator as part of Gluster domain since VDSM
creates multi-level directories when GlusterFS is used as storage
backend for storing VM images.

To overcome these limitations a new BD xlator with following
improvements is suggested.

* New hybrid BD xlator that handles both regular files and block device
  files
* The volume will have both POSIX and BD bricks. Regular files are
  created on POSIX bricks, block devices are created on the BD brick (VG)
* BD xlator leverages exiting POSIX xlator for most POSIX calls and
  hence sits above the POSIX xlator
* Block device file is differentiated from regular file by an extended
  attribute
* The xattr 'user.glusterfs.bd' (BD_XATTR) plays a role in mapping a
  posix file to Logical Volume (LV).
* When a client sends a request to set BD_XATTR on a posix file, a new
  LV is created and mapped to posix file. So every block device will
  have a representative file in POSIX brick with 'user.glusterfs.bd'
  (BD_XATTR) set.
* Here after all operations on this file results in LV related
  operations.

For example opening a file that has BD_XATTR set results in opening
the LV block device, reading results in reading the corresponding LV
block device.

When BD xlator gets request to set BD_XATTR via setxattr call, it
creates a LV and information about this LV is placed in the xattr of the
posix file. xattr "user.glusterfs.bd" used to identify that posix file
is mapped to BD.

Usage:
Server side:
[root@host1 ~]# gluster volume create bdvol host1:/storage/vg1_info?vg1 host2:/storage/vg2_info?vg2
It creates a distributed gluster volume 'bdvol' with Volume Group vg1
using posix brick /storage/vg1_info in host1 and Volume Group vg2 using
/storage/vg2_info in host2.

[root@host1 ~]# gluster volume start bdvol

Client side:
[root@node ~]# mount -t glusterfs host1:/bdvol /media
[root@node ~]# touch /media/posix
It creates regular posix file 'posix' in either host1:/vg1 or host2:/vg2 brick
[root@node ~]# mkdir /media/image
[root@node ~]# touch /media/image/lv1
It also creates regular posix file 'lv1' in either host1:/vg1 or
host2:/vg2 brick
[root@node ~]# setfattr -n "user.glusterfs.bd" -v "lv" /media/image/lv1
[root@node ~]#
Above setxattr results in creating a new LV in corresponding brick's VG
and it sets 'user.glusterfs.bd' with value 'lv: --deltag
>

Changes from previous version V5:
* Removed support for delayed deleting of LVs

Changes from previous version V4:
* Consolidated the patches
* Removed usage of BD_XATTR_SIZE and consolidated it in BD_XATTR.

Changes from previous version V3:
* Added support in FUSE to support full/linked clone
* Added support to merge snapshots and provide information about origin
* bd_map xlator removed
* iatt structure used in inode_ctx. iatt is cached and updated during
fsync/flush
* aio support
* Type and capabilities of volume are exported through getxattr

Changes from version 2:
* Used inode_context for caching BD size and to check if loc/fd is BD or
  not.
* Added GlusterFS server offloaded copy and snapshot through setfattr
  FOP. As part of this libgfapi is modified.
* BD xlator supports stripe
* During unlinking if a LV file is already opened, its added to delete
  list and bd_del_thread tries to delete from this list when a last
  reference to that file is closed.

Changes from previous version:
* gfid is used as name of LV
* ? is used to specify VG name for creating BD volume in volume
  create, add-brick. gluster volume create volname host:/path?vg
* open-behind issue is fixed
* A replicate brick can be added dynamically and LVs from source brick
  are replicated to destination brick
* A distribute brick can be added dynamically and rebalance operation
  distributes existing LVs/files to the new brick
* Thin provisioning support added.
* bd_map xlator support retained
* setfattr -n user.glusterfs.bd -v "lv" creates a regular LV and
  setfattr -n user.glusterfs.bd -v "thin" creates thin LV
* Capability and backend information added to gluster volume info (and
--xml) so
  that management tools can exploit BD xlator.
* tracing support for bd xlator added

TODO:
* Add support to display snapshots for a given LV
* Display posix filename for list-origin instead of gfid

Change-Id: I00d32dfbab3b7c806e0841515c86c3aa519332f2
BUG: 1028672
Signed-off-by: M. Mohan Kumar 
Reviewed-on: http://review.gluster.org/4809
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

bd_map: Remove bd_map xlator

2013-11-13T19:38:28+00:00

Remove bd_map xlator and CLI related changes.

Change-Id: If7086205df1907127c1a1fa4ba603f1c48421d09
BUG: 1028672
Signed-off-by: M. Mohan Kumar 
Reviewed-on: http://review.gluster.org/5747
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

glusterfs: zerofill support

2013-11-11T05:25:49+00:00

Add support for a new ZEROFILL fop. Zerofill writes zeroes to a file in
the specified range. This fop will be useful when a whole file needs to
be initialized with zero (could be useful for zero filled VM disk image
provisioning or  during scrubbing of VM disk images).

Client/application can issue this FOP for zeroing out. Gluster server
will zero out required range of bytes ie server offloaded zeroing. In
the absence of this fop,  client/application has to repetitively issue
write (zero) fop to the server, which is very inefficient method because
of the overheads involved in RPC calls  and acknowledgements.

WRITESAME is a  SCSI T10 command that takes a block of data as input and
writes the same data to other blocks and this write is handled
completely within the storage and hence is known as offload . Linux ,now
has support for SCSI WRITESAME command which is exposed to the user in
the form of BLKZEROOUT ioctl.  BD Xlator can exploit BLKZEROOUT ioctl to
implement this fop. Thus zeroing out operations can be completely
offloaded to the storage device , making it highly efficient.

The fop takes two arguments offset and size. It zeroes out 'size' number
of bytes in an opened file starting from 'offset' position.

This patch adds zerofill support to the following areas:
	- libglusterfs
	- io-stats
	- performance/md-cache,open-behind
	- quota
	- cluster/afr,dht,stripe
	- rpc/xdr
	- protocol/client,server
	- io-threads
	- marker
	- storage/posix
	- libgfapi

Client applications can exloit this fop by using glfs_zerofill introduced in
libgfapi.FUSE support to this fop has not been added as there is no system call
for this fop.

Changes from previous version 3:
* Removed redundant memory failure log messages

Changes from previous version 2:
* Rebased and fixed build error

Changes from previous version 1:
* Rebased for latest master

TODO :
     * Add zerofill support to trace xlator
     * Expose zerofill capability as part of gluster volume info

Here is a performance comparison of server offloaded zeofill vs zeroing
out using repeated writes.

[root@llmvm02 remote]# time ./offloaded aakash-test log 20

real	3m34.155s
user	0m0.018s
sys	0m0.040s
[root@llmvm02 remote]# time ./manually aakash-test log 20

real	4m23.043s
user	0m2.197s
sys	0m14.457s
[root@llmvm02 remote]# time ./offloaded aakash-test log 25;

real	4m28.363s
user	0m0.021s
sys	0m0.025s
[root@llmvm02 remote]# time ./manually aakash-test log 25

real	5m34.278s
user	0m2.957s
sys	0m18.808s

The argument log is a file which we want to set for logging purpose and
the third argument is size in GB .

As we can see there is a performance improvement of around 20% with this
fop.

Change-Id: I081159f5f7edde0ddb78169fb4c21c776ec91a18
BUG: 1028673
Signed-off-by: Aakash Lal Das 
Signed-off-by: M. Mohan Kumar 
Reviewed-on: http://review.gluster.org/5327
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

posix: Fix excessive logging resulting from get_real_filename failure from samba

2013-11-08T07:53:11+00:00

Change-Id: I641d028165da7b8501bd372c62d2df89a9d4db1f
BUG: 1027174
Signed-off-by: Krutika Dhananjay 
Reviewed-on: http://review.gluster.org/6237
Reviewed-by: poornima g 
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

posix: Fix readv FOP

2013-10-17T11:15:24+00:00

Suggested by Anand Avati in BD xlator code review.

Change-Id: I31c353a26dfdeb3d0023c3f7e03ed25461d13c16
Signed-off-by: M. Mohan Kumar 
BUG: 837495
Reviewed-on: http://review.gluster.org/6077
Reviewed-by: Vijay Bellur 
Tested-by: Vijay Bellur

storage/posix: Lower log severity for ENODATA errors in getxattr()

2013-10-15T08:32:48+00:00

Change-Id: I101e329cce4c1305615c63ebcb42355f6c3e85e0
BUG: 918052
Signed-off-by: Vijay Bellur 
Reviewed-on: http://review.gluster.org/6084
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

gNFS: Incorrect NFS ACL encoding for XFS

2013-09-29T23:54:37+00:00

Problem:
Incorrect NFS ACL encoding causes "system.posix_acl_default"
setxattr failure on bricks on XFS file system. XFS (potentially
others?) doesn't understand when the 0x10 prefix is added to the
ACL type field for default ACLs (which the Linux NFS client adds)
which causes setfacl()->setxattr() to fail silently. NFS client
adds NFS_ACL_DEFAULT(0x1000) for default ACL.

FIX:
Mask the prefix (added by NFS client) OFF, so the setfacl is not
rejected when it hits the FS.

Original patch by: "Richard Wareing"

Change-Id: I17ad27d84f030cdea8396eb667ee031f0d41b396
BUG: 1009210
Signed-off-by: Santosh Kumar Pradhan 
Reviewed-on: http://review.gluster.org/5980
Reviewed-by: Amar Tumballi 
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

core: block unused signals in created threads

2013-09-25T08:33:16+00:00

Block all signal except those which are set for explicit handling
in glusterfs_signals_setup(). Since thread spawning code in
libglusterfs and xlators can get called from application threads
when used through libgfapi, it is necessary to do this blocking.

Change-Id: Ia320f80521a83d2edcda50b9ad414583a0175281
BUG: 1011662
Signed-off-by: Anand Avati 
Reviewed-on: http://review.gluster.org/5995
Tested-by: Gluster Build System 
Reviewed-by: Amar Tumballi 
Reviewed-by: Vijay Bellur