linux/include
Christoph Hellwig 456be1484f loop: remove the incorrect write_begin/write_end shortcut
Currently the loop device tries to call directly into write_begin/write_end
instead of going through ->write if it can.  This is a fairly nasty shortcut
as write_begin and write_end are only callbacks for the generic write code
and expect to be called with filesystem specific locks held.

This code currently causes various issues for clustered filesystems as it
doesn't take the required cluster locks, and it also causes issues for XFS
as it doesn't properly lock against the swapext ioctl as called by the
defragmentation tools.  This in case causes data corruption if
defragmentation hits a busy loop device in the wrong time window, as
reported by RH QA.

The reason why we have this shortcut is that it saves a data copy when
doing a transformation on the loop device, which is the technical term
for using cryptoloop (or an XOR transformation).  Given that cryptoloop
has been deprecated in favour of dm-crypt my opinion is that we should
simply drop this shortcut instead of finding complicated ways to to
introduce a formal interface for this shortcut.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-10-17 12:57:20 +02:00
..
acpi Merge branch 'apei-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2011-08-03 21:53:27 -10:00
asm-generic All Arch: remove linkage for sys_nfsservctl system call 2011-08-26 15:09:58 -07:00
crypto
drm drm: Separate EDID Header Check from EDID Block Check 2011-08-04 14:39:35 +01:00
keys
linux loop: remove the incorrect write_begin/write_end shortcut 2011-10-17 12:57:20 +02:00
math-emu
media
mtd
net tcp: fix build error if !CONFIG_SYN_COOKIES 2011-09-18 21:48:01 -04:00
pcmcia Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 2011-07-31 06:23:08 -10:00
rdma
rxrpc
scsi Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osd 2011-08-06 22:56:03 -07:00
sound ASoC: omap: Update e-mail address of Jarkko Nikula 2011-08-12 11:45:10 +09:00
target target: Make standard INQUIRY return 'not connected' for tpg_virt_lun0 2011-08-22 19:25:35 +00:00
trace writeback: show raw dirtied_when in trace writeback_single_inode 2011-08-31 08:48:15 +08:00
video
xen
Kbuild