glusterfs.git/api/src/glfs-handleops.c, branch v3.6.3beta1

api: versioned symbols in libgfapi.so for compatibility

2014-11-07T10:17:56+00:00

Use versioned symbols to keep libgfapi at libgfapi.so.0.0.0

Some nits uncovered:

+ there are a couple functions declared that do not have an
  associated definition, e.g. glfs_truncate(), glfs_caller_specific_init()

+ there are seven private/internal functions used by heal/src/glfsheal
  and the gfapi master xlator (glfs-master.c): glfs_loc_touchup(),
  glfs_active_subvol(), and glfs_subvol_done(), glfs_init_done(),
  glfs_resolve_at(), glfs_free_from_ctx(), and glfs_new_from_ctx();
  which are not declared in glfs.h;

+ for this initial pass at versioned symbols, we use the earliest version
  of all public symbols, i.e. those for which there are declarations in
  glfs.h or glfs-handles.h.
  Further investigation as we do backports to 3.6, 3.4, and 3.4
  will be required to determine if older implementations need to
  be preserved (forward ported) and their associated alias(es) and
  symbol version(s) defined.

FWIW, we should consider linking all of our libraries with a map, it'll
result in a cleaner ABI. Perhaps something for an intern to do or a
Google Summer of Code project.

Change-Id: Ie3323e62bb125a3b26214153278b4e998804de0e
BUG: 1160710
Signed-off-by: Kaleb S. KEITHLEY 
Reviewed-on: http://review.gluster.org/9055
Tested-by: Gluster Build System 
Reviewed-by: Niels de Vos 
Tested-by: Niels de Vos 
Reviewed-by: Vijay Bellur

make snapview-server more compatible with NFS server

2014-07-16T09:27:50+00:00

* There was no handle based API for listxattr. With this change, glfs_h_getxattrs
  also handles the listxattr functionality by checking whether the name is NULL
  or not (like posix). But all the gfapi functions for listxattr
  (glfs_h_getxattrs AND glfs_listxattr AND glfs_flistxattr) returns the names of
  the xattrs in a buffer provided by the caller. But snapview-server has to
  return the list of xattrs in a dict itself (similar to posix xlator). But
  the buffer just contains the names of the xattrs. So for each xattr, a zero
  byte value is set (i.e. "") into the dict and sent back. Translators which
  do xattr caching (as of now md-cache which caches selinux and acl related
  xattrs) should not cache those xattrs whose value is a zero byte data ("").
  So made changes in md-cache to ignore zero byte values.

* NFS server was not linking the inodes to inode table in readdirp. This was
  leading to applications getting errors. The below set of operations would
  lead to applications getting error
  1) ls -l in one of the snaopshots (snapview-server would generate gfids for
     each entry on the fly and link the inodes associated with those entries)
  2) NFS server upon getting readdirp reply would not link the inodes of the
     entries. But it used to generate filehandles for each entry and associate
     the gfid of that entry with the filehandle and send it as part of the
     reply to nfs client.
  3) NFS client would send the filehandle of one of those entries when some
     activity is done on it.
  4) NFS server would not be able to find the inode for the gfid present in the
     filehandle (as the inode was not linked) and would go for hard resolution
     by sending a lookup on the gfid by creating a new inode.
  5) snapview-client will not able to identify whether the inode is a real inode
     existing in the main volume or a virtual inode existing in the snapshots
     as there would not be any inode context.
  6) Since the gfid upon which lookup is sent is a virtual gfid which is not
     present in the disk, lookup would fail and the application would get an
     error.

  To handle above situation, now nfs server also does inode linking in readdirp.

Change-Id: Ibb191408347b6b5f21cff72319ccee619ea77bcd
BUG: 1115949
Signed-off-by: Raghavendra Bhat 
Reviewed-on: http://review.gluster.org/8230
Tested-by: Gluster Build System 
Reviewed-by: Niels de Vos 
Reviewed-by: Raghavendra G 
Reviewed-by: Vijay Bellur

libgfapi: Fixed few memory leaks in glfs_h_getxattr, glfs_h_setxattr calls.

2014-06-02T08:56:41+00:00

          Also replaced the tabs with spaces in that entire file.

Change-Id: Iee6dc031d27fe8d26caf90736d4b2ac7bc8c5206
BUG: 1089414
Signed-off-by: Soumya Koduri 
Reviewed-on: http://review.gluster.org/7841
Reviewed-by: Raghavendra G 
Tested-by: Gluster Build System 
Reviewed-by: Meghana M 
Reviewed-by: Vijay Bellur

user servicable snapshots

2014-05-29T16:25:46+00:00

Change-Id: Idbf27dbe088e646a8ab81cedc5818413795895ea
Signed-off-by: Raghavendra Bhat 
Signed-off-by: Anand Subramanian 
Signed-off-by: Raghavendra Bhat 
Reviewed-on: http://review.gluster.org/7700
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

libgfapi: A minor bug-fix in glfs_h_setxattr and glfs_h_removexattr calls.

2014-04-29T01:21:47+00:00

Change-Id: I62f63da37edf722d6d79c75f72ee7403e93e4936
BUG: 1089414
Signed-off-by: Soumya Koduri 
Reviewed-on: http://review.gluster.org/7529
Reviewed-by: Santosh Pradhan 
Tested-by: Meghana M 
Reviewed-by: Humble Devassy Chirammal 
Reviewed-by: Pranith Kumar Karampuri 
Reviewed-by: Anand Avati

Added Handle-based ops to get/set/remove extended attributes in the libgfapi.

2014-04-18T20:21:05+00:00

Change-Id: I1a8e666018d7b93e0bba2d9882935681da909980
BUG: 1089414
Signed-off-by: Soumya Koduri 
Reviewed-on: http://review.gluster.org/7308
Reviewed-by: Vijay Bellur 
Tested-by: Vijay Bellur

Changing the errno in glfs_h_rename

2014-03-12T21:28:21+00:00

Change-Id: I006215d910ee854aee488f3880f39ed425f294cc
BUG: 1075488
Reviewed-on: http://review.gluster.org/7226
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

syncop: Change return value of syncop

2014-01-20T07:05:15+00:00

Problem:
We found a day-1 bug when syncop_xxx() infra is used inside a synctask with
compilation optimization (CFLAGS -O2).

Detailed explanation of the Root cause:
We found the bug in 'gf_defrag_migrate_data' in rebalance operation:

Lets look at interesting parts of the function:

int
gf_defrag_migrate_data (xlator_t *this, gf_defrag_info_t *defrag, loc_t *loc,
                        dict_t *migrate_data)
{
.....
code section - [ Loop ]
        while ((ret = syncop_readdirp (this, fd, 131072, offset, NULL,
                                       &entries)) != 0) {
.....
code section - [ ERRNO-1 ] (errno of readdirp is stored in readdir_operrno by a
thread)
                /* Need to keep track of ENOENT errno, that means, there is no
                   need to send more readdirp() */
                readdir_operrno = errno;
.....
code section - [ SYNCOP-1 ] (syncop_getxattr is called by a thread)
                        ret = syncop_getxattr (this, &entry_loc, &dict,
                                               GF_XATTR_LINKINFO_KEY);
code section - [ ERRNO-2]   (checking for failures of syncop_getxattr(). This
may not always be executed in same thread which executed [SYNCOP-1])
                        if (ret < 0) {
                                if (errno != ENODATA) {
                                        loglevel = GF_LOG_ERROR;
                                        defrag->total_failures += 1;
.....
}

the function above could be executed by thread(t1) till [SYNCOP-1] and code
from [ERRNO-2] can be executed by a different thread(t2) because of the way
syncop-infra schedules the tasks.

when the code is compiled with -O2 optimization this is the assembly code that
is generated:
 [ERRNO-1]
1165                        readdir_operrno = errno; <<---- errno gets expanded
as *(__errno_location())
   0x00007fd149d48b60 <+496>:        callq  0x7fd149d410c0 
   0x00007fd149d48b72 <+514>:        mov    %rax,0x50(%rsp) <<------ Address
returned by __errno_location() is stored in a special location in stack for
later use.
   0x00007fd149d48b77 <+519>:        mov    (%rax),%eax
   0x00007fd149d48b79 <+521>:        mov    %eax,0x78(%rsp)
....
 [ERRNO-2]
1281                                        if (errno != ENODATA) {
   0x00007fd149d492ae <+2366>:        mov    0x50(%rsp),%rax <<-----  Because
it already stored the address returned by __errno_location(), it just
dereferences the address to get the errno value. BUT THIS CODE NEED NOT BE
EXECUTED BY SAME THREAD!!!
   0x00007fd149d492b3 <+2371>:        mov    $0x9,%ebp
   0x00007fd149d492b8 <+2376>:        mov    (%rax),%edi
   0x00007fd149d492ba <+2378>:        cmp    $0x3d,%edi

The problem is that __errno_location() value of t1 and t2 are different. So
[ERRNO-2] ends up reading errno of t1 instead of errno of t2 even though t2 is
executing [ERRNO-2] code section.

When code is compiled without any optimization for [ERRNO-2]:
1281                                        if (errno != ENODATA) {
   0x00007fd58e7a326f <+2237>:        callq  0x7fd58e797300
<<--- As it is calling __errno_location() again it gets the
location from t2 so it works as intended.
   0x00007fd58e7a3274 <+2242>:        mov    (%rax),%eax
   0x00007fd58e7a3276 <+2244>:        cmp    $0x3d,%eax
   0x00007fd58e7a3279 <+2247>:        je     0x7fd58e7a32a1


Fix:
Make syncop_xxx() return (-errno) value as the return value in
case of errors and all the functions which make syncop_xxx() will need to use
(-ret) to figure out the reason for failure in case of syncop_xxx() failures.

Change-Id: I314d20dabe55d3e62ff66f3b4adb1cac2eaebb57
BUG: 1040356
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/6475
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

syncops: expose @flags in syncop_rmdir()

2013-11-21T21:08:32+00:00

Change-Id: I9b73c1db728e4cb3948fc118cceb292b21d48b96
BUG: 1021686
Signed-off-by: Anand Avati 
Reviewed-on: http://review.gluster.org/6112
Reviewed-by: Amar Tumballi 
Tested-by: Gluster Build System

gfapi: object handle based API extensions

2013-10-11T19:16:46+00:00

There is an ongoing effort to integrate NFS Ganesha (
https://github.com/nfs-ganesha/nfs-ganesha/wiki ) with GlusterFS as one of
the file system back ends.

Towards this we need extensions to gfapi that can handle object based
operations. Meaning, instead of using full paths or relative paths from
cwd, it is required that we can work with APIs, like the *at POSIX
variants, to be able to create, lookup, open etc. files and directories.
Hence the objects are the files or directories themselves and we give out
handles to these objects that can be used for further operations.

This code drop is an initial implementation of the proposed APIs.

The new APIs are implemented as glfs_h_XXX variants in the file
glfs-handleops.c to mirror glfs-fops.c style. The code leverages holding
onto inode references and doling these out as opaque/cookie type objects to
the callers, to enable them to be used as handles in other operations.

An fd based approach was considered, but due to the extra footprint that
the fd structure and its counterparts would incur, this was dropped to take
the approach of holding inode references themselves.

Tested by extending glfsxmp.c to invoke and exercise the added APIs, and
further tested with a reference integration of the same as an FSAL with NFS
Ganesha.

Change-Id: I23629c99e905b54070fa2e6565147812e5f3fa5d
BUG: 1016000
Signed-off-by: R.Shyamsundar 
Reviewed-on: http://review.gluster.org/5936
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati