glusterfs.git/xlators/storage/posix/src/posix.c, branch v3.5beta1

posix: do not allow to set/get "trusted.glusterfs.volume-id" xattr

2013-11-26T19:00:18+00:00

Change-Id: I2e9a2264b1fd5ebc1ed0aff30225e89acbd0bcb4
BUG: 1034716
Signed-off-by: Vijaykumar M 
Reviewed-on: http://review.gluster.org/6361
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

core: fix errno for non-existent GFID

2013-11-26T18:29:23+00:00

When clients refer to a GFID which does not exist, the errno to
be returned in ESTALE (and not ENOENT). Even though ENOENT might
look "proper" most of the time, as the application eventually expects
ENOENT even if a parent directory does not exist, not returning
ESTALE results in resolvers (FUSE and GFAPI) to not retry resolution
in uncached mode. This can result in spurious ENOENTs during
concurrent path modification operations.

Change-Id: I7a06ea6d6a191739f2e9c6e333a1969615e05936
BUG: 1032894
Signed-off-by: Anand Avati 
Reviewed-on: http://review.gluster.org/6318
Tested-by: Gluster Build System 
Reviewed-by: Amar Tumballi 
Reviewed-by: Brian Foster 
Reviewed-by: Vijay Bellur

posix: placeholders for GFID to path conversion

2013-11-26T18:22:40+00:00

what?
=====
    The following is an attempt to generate the paths of a file when
    only its gfid is known.

    To find the path of a directory, the symlink handle to the
    directory maintained in  the ".glusterfs" backend directory is
    read. The symlink handle is generated using the gfid of the
    directory. It (handle) contains the directory's name and parent
    gfid, which are used to recursively construct the absolute path as
    seen by the user from the mount point.

    A similar approach cannot be used for a regular file or a symbolic
    link since its hardlink handle, generated using its gfid, doesn't
    contain its parent gfid and basename. So xattrs are set to store
    the parent gfids and the number of hardlinks to a file or a
    symlink having the same parent gfid.  When an user/application
    requests for the paths of a regular file or a symlink with
    multiple hardlinks, using the parent gfids stored in the xattrs,
    the paths of the parent directories are generated as mentioned
    earlier. The base names of the hardlinks (with the same parent
    gfid) are determined by matching the actual backend inode numbers
    of each entry in the parent directory with that of the hardlink
    handle.

    Xattr is set on a regular file, link, and symbolic link as
    follows, Xattr name : trusted.pgfid. Xattr value :
    

    If a regular file, hard link, symbolic link is created then an
    xattr in the above format is set in the backend.

how to use?
===========
    This functionality can be used through getxattr interface. Two
    keys - glusterfs.ancestry.dentry and glusterfs.ancestry.path - enable
    usage of this functionality. A successful getxattr will have the
    result stored under same keys. Values will be,

    glusterfs.ancestry.dentry:
    --------------------------
    A linked list of gf-dirent structures for all possible paths from
    root to this gfid. If there are multiple paths, the linked-list
    will be a series of paths one after another. Each path will be a
    series of dentries representing all components of the path. This
    key is primarily for internal usage within glusterfs.

    glusterfs.ancestry.path:
    ------------------------
    A string containing all possible paths from root to this gfid.
    Multiple hardlinks of a file or a symlink are displayed as a colon
    seperated list (this could interfere with path components
    containing ':').

    e.g. If there is a file "file1" in root directory with two hardlinks,
         "/dir2/link2tofile1" and "/dir1/link1tofile1", then

         [root@alpha gfsmntpt]# getfattr -n glusterfs.ancestry.path -e text
          file1
          glusterfs.ancestry.path="/file1:/dir2/link2tofile1:/dir1/link1tofile1"

    Thanks Amar, Avati and Venky for the inputs.

Original Author: Ramana Raja 
BUG: 990028
Signed-off-by: Raghavendra G 
Change-Id: I0eaa9101e333e0c1f66ccefd9e95944dd4a27497
Reviewed-on: http://review.gluster.org/5951
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

Build storage/posix xlator if fallocate() does not exists

2013-11-20T22:47:31+00:00

If fallocate() does not exists, just return EOPNOTSUPP

BUG: 764655
Change-Id: I808114f733c88985519dc47fb7537e1ced1db077
Signed-off-by: Emmanuel Dreyfus 
Reviewed-on: http://review.gluster.org/6289
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

Fixes for ZF reported by coverity

2013-11-19T17:57:37+00:00

BUG: 1028673
Change-Id: I7c75738cca22c81c5629d579ef5bea24000e622e
Signed-off-by: M. Mohan Kumar 
Reviewed-on: http://review.gluster.org/6291
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

zerofill: Change the type of len argument of glfs_zerofill() to off_t

2013-11-15T07:29:48+00:00

glfs_zerofill() can be potentially called to zero-out entire file and
hence allow for bigger value of length parameter.

Change-Id: I75f1d11af298915049a3f3a7cb3890a2d72fca63
BUG: 1028673
Signed-off-by: Bharata B Rao 
Reviewed-on: http://review.gluster.org/6266
Tested-by: Gluster Build System 
Reviewed-by: M. Mohan Kumar 
Tested-by: M. Mohan Kumar 
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