mirror_ubuntu-kernels/include
Andreas Gruenbacher 334fd34d76 vfs: Add page_cache_seek_hole_data helper
Both ext4 and xfs implement seeking for the next hole or piece of data
in unwritten extents by scanning the page cache, and both versions share
the same bug when iterating the buffers of a page: the start offset into
the page isn't taken into account, so when a page fits more than two
filesystem blocks, things will go wrong.  For example, on a filesystem
with a block size of 1k, the following command will fail:

  xfs_io -f -c "falloc 0 4k" \
            -c "pwrite 1k 1k" \
            -c "pwrite 3k 1k" \
            -c "seek -a -r 0" foo

In this example, neither lseek(fd, 1024, SEEK_HOLE) nor lseek(fd, 2048,
SEEK_DATA) will return the correct result.

Introduce a generic vfs helper for seeking in the page cache that gets
this right.  The next commits will replace the filesystem specific
implementations.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
[hch: dropped the export]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-07-02 22:46:13 -07:00
..
acpi Merge branch 'acpica-fixes' 2017-06-15 01:52:32 +02:00
asm-generic Kbuild UAPI header export updates for v4.12 2017-05-10 20:45:36 -07:00
clocksource
crypto Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2017-05-03 08:50:52 -07:00
drm drm/dp: start a DPCD based DP sink/branch device quirk database 2017-05-29 13:43:26 +03:00
dt-bindings Sort of on the quieter side this time, which is probably due more 2017-05-10 13:38:18 -07:00
keys
kvm KVM: arm/arm64: Fix bug when registering redist iodevs 2017-05-18 11:18:12 +02:00
linux vfs: Add page_cache_seek_hole_data helper 2017-07-02 22:46:13 -07:00
math-emu
media [media] media/cec.h: use IS_REACHABLE instead of IS_ENABLED 2017-06-08 16:52:28 -03:00
memory
misc
net net: Update TCP congestion control documentation 2017-06-05 10:53:24 -04:00
pcmcia
ras
rdma RDMA/SA: Fix kernel panic in CMA request handler flow 2017-06-01 17:20:14 -04:00
rxrpc
scsi Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2017-05-12 11:44:13 -07:00
soc powerpc updates for 4.12 part 2 2017-05-12 10:04:09 -07:00
sound ASoC: Updates for v4.12 2017-05-02 08:25:25 +02:00
target iscsi-target: Fix initial login PDU asynchronous socket close OOPs 2017-05-31 15:12:31 -07:00
trace Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2017-05-12 11:58:45 -07:00
uapi Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-15 18:09:47 +09:00
video uapi: export all headers under uapi directories 2017-05-11 00:21:54 +09:00
xen xen: Implement EFI reset_system callback 2017-05-02 12:06:50 +02:00