linux/fs/ceph
majianpeng 02ae66d8b2 ceph: fix bugs about handling short-read for sync read mode.
cephfs . show_layout
>layyout.data_pool:     0
>layout.object_size:   4194304
>layout.stripe_unit:   4194304
>layout.stripe_count:  1

TestA:
>dd if=/dev/urandom of=test bs=1M count=2 oflag=direct
>dd if=/dev/urandom of=test bs=1M count=2 seek=4  oflag=direct
>dd if=test of=/dev/null bs=6M count=1 iflag=direct
The messages from func striped_read are:
ceph:           file.c:350  : striped_read 0~6291456 (read 0) got 2097152 HITSTRIPE SHORT
ceph:           file.c:350  : striped_read 2097152~4194304 (read 2097152) got 0 HITSTRIPE SHORT
ceph:           file.c:381  : zero tail 4194304
ceph:           file.c:390  : striped_read returns 6291456
The hole of file is from 2M--4M.But actualy it zero the last 4M include
the last 2M area which isn't a hole.
Using this patch, the messages are:
ceph:           file.c:350  : striped_read 0~6291456 (read 0) got 2097152 HITSTRIPE SHORT
ceph:           file.c:358  :  zero gap 2097152 to 4194304
ceph:           file.c:350  : striped_read 4194304~2097152 (read 4194304) got 2097152
ceph:           file.c:384  : striped_read returns 6291456

TestB:
>echo majianpeng > test
>dd if=test of=/dev/null bs=2M count=1 iflag=direct
The messages are:
ceph:           file.c:350  : striped_read 0~6291456 (read 0) got 11 HITSTRIPE SHORT
ceph:           file.c:350  : striped_read 11~6291445 (read 11) got 0 HITSTRIPE SHORT
ceph:           file.c:390  : striped_read returns 11
For this case,it did once more striped_read.It's no meaningless.
Using this patch, the message are:
ceph:           file.c:350  : striped_read 0~6291456 (read 0) got 11 HITSTRIPE SHORT
ceph:           file.c:384  : striped_read returns 11

Big thanks to Yan Zheng for the patch.

Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
2013-08-27 12:28:45 -07:00
..
addr.c ceph: cleanup the logic in ceph_invalidatepage 2013-08-15 11:12:02 -07:00
caps.c ceph: remove useless variable revoked_rdcache 2013-08-27 12:28:44 -07:00
ceph_frag.c
debugfs.c libceph: delay debugfs initialization until we learn global_id 2012-08-20 10:03:15 -07:00
dir.c Merge remote-tracking branch 'linus/master' into testing 2013-08-15 11:11:45 -07:00
export.c fs: encode_fh: return FILEID_INVALID if invalid fid_type 2013-02-26 02:46:10 -05:00
file.c ceph: fix bugs about handling short-read for sync read mode. 2013-08-27 12:28:45 -07:00
inode.c ceph: introduce i_truncate_mutex 2013-08-15 11:12:06 -07:00
ioctl.c ceph: Add check returned value on func ceph_calc_ceph_pg. 2013-08-09 17:55:21 -07:00
ioctl.h ceph: fully initialize new layout 2012-05-16 14:28:27 -05:00
Kconfig fs/ceph: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:39:04 -08:00
locks.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2013-07-09 12:39:10 -07:00
Makefile ceph: Makefile: Remove unnessary code 2011-01-12 15:15:13 -08:00
mds_client.c Merge remote-tracking branch 'linus/master' into testing 2013-08-15 11:11:45 -07:00
mds_client.h Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2013-02-28 17:43:09 -08:00
mdsmap.c ceph: tidy ceph_mdsmap_decode() a little 2013-07-01 09:52:02 -07:00
snap.c ceph: use ceph_create_snap_context() 2013-05-01 21:20:09 -07:00
strings.c libceph: update ceph_mds_state_name() and ceph_mds_op_name() 2013-02-18 12:20:34 -06:00
super.c ceph: avoid accessing invalid memory 2013-07-03 15:32:55 -07:00
super.h ceph: introduce i_truncate_mutex 2013-08-15 11:12:06 -07:00
xattr.c ceph: fix sleeping function called from invalid context. 2013-07-03 15:32:51 -07:00