xemu/block
Jeff Cody 223a23c198 block/gluster: glfs_lseek() workaround
On current released versions of glusterfs, glfs_lseek() will sometimes
return invalid values for SEEK_DATA or SEEK_HOLE.  For SEEK_DATA and
SEEK_HOLE, the returned value should be >= the passed offset, or < 0 in
the case of error:

LSEEK(2):

    off_t lseek(int fd, off_t offset, int whence);

    [...]

    SEEK_HOLE
              Adjust  the file offset to the next hole in the file greater
              than or equal to offset.  If offset points into the middle of
              a hole, then the file offset is set to offset.  If there is no
              hole past offset, then the file offset is adjusted to the end
              of the file (i.e., there is  an implicit hole at the end of
              any file).

    [...]

    RETURN VALUE
              Upon  successful  completion,  lseek()  returns  the resulting
              offset location as measured in bytes from the beginning of the
              file.  On error, the value (off_t) -1 is returned and errno is
              set to indicate the error

However, occasionally glfs_lseek() for SEEK_HOLE/DATA will return a
value less than the passed offset, yet greater than zero.

For instance, here are example values observed from this call:

    offs = glfs_lseek(s->fd, start, SEEK_HOLE);
    if (offs < 0) {
        return -errno;          /* D1 and (H3 or H4) */
    }

start == 7608336384
offs == 7607877632

This causes QEMU to abort on the assert test.  When this value is
returned, errno is also 0.

This is a reported and known bug to glusterfs:
https://bugzilla.redhat.com/show_bug.cgi?id=1425293

Although this is being fixed in gluster, we still should work around it
in QEMU, given that multiple released versions of gluster behave this
way.

This patch treats the return case of (offs < start) the same as if an
error value other than ENXIO is returned; we will assume we learned
nothing, and there are no holes in the file.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Message-id: 87c0140e9407c08f6e74b04131b610f2e27c014c.1495560397.git.jcody@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
2017-05-24 16:44:46 -04:00
..
Makefile.objs block/vxhs.c: Add support for a new block device type called "vxhs" 2017-04-24 15:08:42 -04:00
accounting.c block: Clean up includes 2016-01-20 13:36:23 +01:00
backup.c blockjob: introduce block_job_early_fail 2017-05-24 16:38:51 -04:00
blkdebug.c blkdebug: Add ability to override unmap geometries 2017-05-11 14:28:06 +02:00
blkreplay.c block: Do not unref bs->file on error in BD's open 2017-04-27 16:12:13 +02:00
blkverify.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
block-backend.c block: Drop permissions when migration completes 2017-05-11 12:08:24 +02:00
bochs.c block: do not set BDS read_only if copy_on_read enabled 2017-04-24 15:09:33 -04:00
cloop.c block: do not set BDS read_only if copy_on_read enabled 2017-04-24 15:09:33 -04:00
commit.c blockjob: introduce block_job_early_fail 2017-05-24 16:38:51 -04:00
crypto.c crypto: move 'opaque' parameter to (nearly) the end of parameter list 2017-05-09 14:41:47 +01:00
curl.c curl: do not do aio_poll when waiting for a free CURLState 2017-05-16 10:34:50 -04:00
dirty-bitmap.c block: More operations for meta dirty bitmap 2016-10-24 17:56:07 +02:00
dmg-bz2.c dmg: Move libbz2 code to dmg-bz2.so 2016-10-07 14:14:06 +02:00
dmg.c block: do not set BDS read_only if copy_on_read enabled 2017-04-24 15:09:33 -04:00
dmg.h dmg: Move libbz2 code to dmg-bz2.so 2016-10-07 14:14:06 +02:00
file-posix.c file-posix: Remove .bdrv_inactivate/invalidate_cache 2017-05-11 12:08:24 +02:00
file-win32.c block/win32: fix 'ret not initialized' warning 2017-05-16 15:34:18 +01:00
gluster.c block/gluster: glfs_lseek() workaround 2017-05-24 16:44:46 -04:00
io.c blockjob: introduce block_job_pause/resume_all 2017-05-24 16:38:51 -04:00
iscsi-opts.c block/iscsi: statically link qemu_iscsi_opts 2017-01-27 18:07:58 +01:00
iscsi.c block: Add .bdrv_truncate() error messages 2017-04-28 16:02:03 +02:00
linux-aio.c block: explicitly acquire aiocontext in aio callbacks that need it 2017-02-21 11:39:39 +00:00
mirror.c blockjob: introduce block_job_early_fail 2017-05-24 16:38:51 -04:00
nbd-client.c nbd-client: fix handling of hungup connections 2017-03-27 16:50:36 +02:00
nbd-client.h nbd: drop unused NBDClientSession.is_unix field 2017-03-27 14:41:01 +02:00
nbd.c sockets: Limit SocketAddressLegacy to external interfaces 2017-05-09 09:14:40 +02:00
nfs.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
null.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
parallels.c block: Add errp to b{lk,drv}_truncate() 2017-04-28 16:02:02 +02:00
qapi.c block: Don't bother asserting type of output visitor's output 2017-02-22 19:52:20 +01:00
qcow.c migration: Create migration/blocker.h 2017-05-17 12:04:59 +02:00
qcow2-cache.c qcow2: Remove stale comment 2016-11-25 13:51:30 +01:00
qcow2-cluster.c qcow2: Discard/zero clusters by byte count 2017-05-11 14:28:07 +02:00
qcow2-refcount.c qcow2: Make distinction between zero cluster types obvious 2017-05-11 14:28:07 +02:00
qcow2-snapshot.c qcow2: Discard/zero clusters by byte count 2017-05-11 14:28:07 +02:00
qcow2.c qcow2: Discard/zero clusters by byte count 2017-05-11 14:28:07 +02:00
qcow2.h qcow2: Discard/zero clusters by byte count 2017-05-11 14:28:07 +02:00
qed-check.c qed: Use DIV_ROUND_UP 2016-06-07 18:19:24 +03:00
qed-cluster.c block: explicitly acquire aiocontext in aio callbacks that need it 2017-02-21 11:39:39 +00:00
qed-gencb.c block: Clean up includes 2016-01-20 13:36:23 +01:00
qed-l2-cache.c block: Clean up includes 2016-01-20 13:36:23 +01:00
qed-table.c block: explicitly acquire aiocontext in aio callbacks that need it 2017-02-21 11:39:39 +00:00
qed.c migration: migration.h was not needed 2017-05-18 19:20:59 +02:00
qed.h block: explicitly acquire aiocontext in timers that need it 2017-02-21 11:14:08 +00:00
quorum.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
raw-format.c block: Add .bdrv_truncate() error messages 2017-04-28 16:02:03 +02:00
rbd.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
replication.c block: Make 'replication_state' an enum 2017-05-07 09:57:51 +03:00
sheepdog.c sockets: Limit SocketAddressLegacy to external interfaces 2017-05-09 09:14:40 +02:00
snapshot.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
ssh.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
stream.c block: Add Error parameter to bdrv_set_backing_hd() 2017-02-28 20:47:51 +01:00
throttle-groups.c coroutine-lock: add mutex argument to CoQueue APIs 2017-02-21 11:39:40 +00:00
trace-events block/vxhs.c: Add support for a new block device type called "vxhs" 2017-04-24 15:08:42 -04:00
vdi.c migration: Create migration/blocker.h 2017-05-17 12:04:59 +02:00
vhdx-endian.c vhdx: Use QEMU UUID API 2016-09-23 11:42:52 +08:00
vhdx-log.c block: Add errp to b{lk,drv}_truncate() 2017-04-28 16:02:02 +02:00
vhdx.c migration: Create migration/blocker.h 2017-05-17 12:04:59 +02:00
vhdx.h block: vhdx - update PAYLOAD_BLOCK_UNMAPPED value to match 1.00 spec 2014-12-12 15:42:22 +00:00
vmdk.c migration: Create migration/blocker.h 2017-05-17 12:04:59 +02:00
vpc.c migration: Create migration/blocker.h 2017-05-17 12:04:59 +02:00
vvfat.c migration: Create migration/blocker.h 2017-05-17 12:04:59 +02:00
vxhs.c qobject: Use simpler QDict/QList scalar insertion macros 2017-05-09 09:13:51 +02:00
win32-aio.c block: explicitly acquire aiocontext in aio callbacks that need it 2017-02-21 11:39:39 +00:00
write-threshold.c block: use bdrv_add_before_write_notifier 2016-10-07 13:34:07 +02:00