glusterfs.git/api/src/glfs-internal.h, branch v3.6.9

api: versioned symbols in libgfapi.so for compatibility

2015-03-04T07:32:16+00:00

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

Revisited to address broken build on Mac OS X

See http://review.gluster.org/9055

Change-Id: I0f26668898749f57b61490b18f1f04c42996225d
BUG: 1165129
Signed-off-by: Kaleb S. KEITHLEY 
Reviewed-on: http://review.gluster.org/9145
Reviewed-by: Shyamsundar Ranganathan 
Tested-by: Gluster Build System 
Reviewed-by: Ravishankar N 
Reviewed-by: Raghavendra Bhat

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

libgfapi: Added support to fetch volume info from glusterd and store in glfs object.

2014-05-11T09:47:42+00:00

Defined new APIs in the libgfapi module, given a glfs object,
 * to send handshake RPC call to glusterd process to fetch UUID of the volume
 * store it in the glusterfs_context linked to the glfs object.
 * to parse UUID from its cannonical string format into 16-byte array
   before sending it to the libgfapi users.

Defined a RPC call in glusterd which can be used to query volume related
info by other processes using 'clnt_handshake_procs'.

Note - Currently this RPC call to glusterd process is used only to fetch UUID.
But it can be extended to get other volume related structures as well.

In addition to the above, defined a new variable to keep track of such handshake
RPCs still in progress to make sure all the corresponding RPC callbacks have been
processed before libgfapi returns the glfs object initialized.

Also bumping up the GFAPI current version number since there is a new API
"glfs_get_volume_id" defined and exposed by libgfapi as part of these changes.

Change-Id: I303f76d7177d32d25bdb301b1dbcf5cd73f42807
BUG: 1090363
Signed-off-by: Soumya Koduri 
Reviewed-on: http://review.gluster.org/7218
Reviewed-by: Anand Avati 
Reviewed-by: Harshavardhana 
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

logging: Introduce suppression of repetitive log messages

2014-05-01T06:52:28+00:00

Change-Id: I8efa08cc9832ad509fba65a88bb0cddbaf056404
BUG: 1075611
Signed-off-by: Krutika Dhananjay 
Reviewed-on: http://review.gluster.org/7475
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

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

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

gfapi: introduce glfs_readdir() and glfs_readdirplus() APIs

2013-11-13T18:48:18+00:00

Change-Id: I6b233bf647585675f233898351bf593f251716cc
BUG: 839950
Signed-off-by: Anand Avati 
Reviewed-on: http://review.gluster.org/6201
Tested-by: Gluster Build System 
Reviewed-by: Raghavendra Talur

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

gfapi: apply an upper bound on nested symlink resolution

2013-09-05T12:26:30+00:00

In case of nested symlink resolution, implement an upper
bound on the number of such nested levels the resolver will
descend. This limit is arbitrary, and set to 2048 nested
levels.

Change-Id: I264e5bd60d317eda97f4e6f49bd5d8694f8664a9
BUG: 1004100
Signed-off-by: Anand Avati 
Reviewed-on: http://review.gluster.org/5768
Tested-by: Gluster Build System 
Reviewed-by: Raghavendra Talur 
Reviewed-by: Vijay Bellur

gfapi: handle graph switch (cwd, fds, locks)

2013-05-28T07:08:57+00:00

- Migrate open fds to new graph
- Migrate locks held in open fd to new fd
- Refresh CWD, so resolution of relative paths happens on refreshed
  inode (on new graph).

Change-Id: I4b18083b9b290107ebda1f917fc85b635ab72fb4
BUG: 953694
Signed-off-by: Anand Avati 
Reviewed-on: http://review.gluster.org/5059
Tested-by: Gluster Build System 
Reviewed-by: Raghavendra G