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* fs: fix data invalidation in the cleancache during direct IOAndrey Ryabinin2017-05-031-10/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "Properly invalidate data in the cleancache", v2. We've noticed that after direct IO write, buffered read sometimes gets stale data which is coming from the cleancache. The reason for this is that some direct write hooks call call invalidate_inode_pages2[_range]() conditionally iff mapping->nrpages is not zero, so we may not invalidate data in the cleancache. Another odd thing is that we check only for ->nrpages and don't check for ->nrexceptional, but invalidate_inode_pages2[_range] also invalidates exceptional entries as well. So we invalidate exceptional entries only if ->nrpages != 0? This doesn't feel right. - Patch 1 fixes direct IO writes by removing ->nrpages check. - Patch 2 fixes similar case in invalidate_bdev(). Note: I only fixed conditional cleancache_invalidate_inode() here. Do we also need to add ->nrexceptional check in into invalidate_bdev()? - Patches 3-4: some optimizations. This patch (of 4): Some direct IO write fs hooks call invalidate_inode_pages2[_range]() conditionally iff mapping->nrpages is not zero. This can't be right, because invalidate_inode_pages2[_range]() also invalidate data in the cleancache via cleancache_invalidate_inode() call. So if page cache is empty but there is some data in the cleancache, buffered read after direct IO write would get stale data from the cleancache. Also it doesn't feel right to check only for ->nrpages because invalidate_inode_pages2[_range] invalidates exceptional entries as well. Fix this by calling invalidate_inode_pages2[_range]() regardless of nrpages state. Note: nfs,cifs,9p doesn't need similar fix because the never call cleancache_get_page() (nor directly, nor via mpage_readpage[s]()), so they are not affected by this bug. Fixes: c515e1fd361c ("mm/fs: add hooks to support cleancache") Link: http://lkml.kernel.org/r/20170424164135.22350-2-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Alexey Kuznetsov <kuznet@virtuozzo.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Nikolay Borisov <n.borisov.lkml@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* iomap: invalidate page caches should be after iomap_dio_complete() in direct ↵Eryu Guan2017-03-061-7/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | write After XFS switching to iomap based DIO (commit acdda3aae146 ("xfs: use iomap_dio_rw")), I started to notice dio29/dio30 tests failures from LTP run on ppc64 hosts, and they can be reproduced on x86_64 hosts with 512B/1k block size XFS too. dio29 diotest3 -b 65536 -n 100 -i 1000 -o 1024000 dio30 diotest6 -b 65536 -n 100 -i 1000 -o 1024000 The failure message is like: bufcmp: offset 0: Expected: 0x62, got 0x0 diotest03 1 TPASS : Read with Direct IO, Write without diotest03 2 TFAIL : diotest3.c:142: comparsion failed; child=98 offset=1425408 diotest03 3 TFAIL : diotest3.c:194: Write Direct-child 98 failed Direct write wrote 0x62 but buffer read got zero. This is because, when doing direct write to a hole or preallocated file, we invalidate the page caches before converting the extent from unwritten state to normal state, which is done by iomap_dio_complete(), thus leave a window for other buffer reader to cache the unwritten state extent. Consider this case, with sub-page blocksize XFS, two processes are direct writing to different blocksize-aligned regions (say 512B) of the same preallocated file, and reading the region back via buffered I/O to compare contents. process A, region [0,512] process B, region [512,1024] xfs_file_write_iter xfs_file_aio_dio_write iomap_dio_rw iomap_apply invalidate_inode_pages2_range xfs_file_write_iter xfs_file_aio_dio_write iomap_dio_rw iomap_apply invalidate_inode_pages2_range iomap_dio_complete xfs_file_read_iter xfs_file_buffered_aio_read generic_file_read_iter do_generic_file_read <readahead fills pagecache with 0> iomap_dio_complete xfs_file_read_iter <read gets 0 from pagecache> Process A first invalidates page caches, at this point the underlying extent is still in unwritten state (iomap_dio_complete not called yet), and process B finishs direct write and populates page caches via readahead, which caches zeros in page for region A, then process A reads zeros from page cache, instead of the actual data. Fix it by invalidating page caches after converting unwritten extent to make sure we read content from disk after extent state changed, as what we did before switching to iomap based dio. Also introduce a new 'start' variable to save the original write offset (iomap_dio_complete() updates iocb->ki_pos), and a 'err' variable for invalidating caches result, cause we can't reuse 'ret' anymore. Signed-off-by: Eryu Guan <eguan@redhat.com> Reviewed-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>
* sched/headers: Prepare for the reduction of <linux/sched.h>'s signal API ↵Ingo Molnar2017-03-021-0/+2
| | | | | | | | | | | | | | | | | | | | dependency Instead of including the full <linux/signal.h>, we are going to include the types-only <linux/signal_types.h> header in <linux/sched.h>, to further decouple the scheduler header from the signal headers. This means that various files which relied on the full <linux/signal.h> need to be updated to gain an explicit dependency on it. Update the code that relies on sched.h's inclusion of the <linux/signal.h> header. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* fs: add i_blocksize()Fabian Frederick2017-02-271-5/+5
| | | | | | | | | | | | | | | | | | | | | Replace all 1 << inode->i_blkbits and (1 << inode->i_blkbits) in fs branch. This patch also fixes multiple checkpatch warnings: WARNING: Prefer 'unsigned int' to bare use of 'unsigned' Thanks to Andrew Morton for suggesting more appropriate function instead of macro. [geliangtang@gmail.com: truncate: use i_blocksize()] Link: http://lkml.kernel.org/r/9c8b2cd83c8f5653805d43debde9fa8817e02fc4.1484895804.git.geliangtang@gmail.com Link: http://lkml.kernel.org/r/1481319905-10126-1-git-send-email-fabf@skynet.be Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Geliang Tang <geliangtang@gmail.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmfDave Jiang2017-02-241-3/+2
| | | | | | | | | | | | | | | | | | | | | | | ->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to take a vma and vmf parameter when the vma already resides in vmf. Remove the vma parameter to simplify things. [arnd@arndb.de: fix ARM build] Link: http://lkml.kernel.org/r/20170125223558.1451224-1-arnd@arndb.de Link: http://lkml.kernel.org/r/148521301778.19116.10840599906674778980.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'xfs-4.11-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds2017-02-221-9/+9
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull xfs updates from Darrick Wong: "Here are the XFS changes for 4.11. We aren't introducing any major features in this release cycle except for this being the first merge window I've managed on my own. :) Changes since last update: - Various cleanups - Livelock fixes for eofblocks scanning - Improved input verification for on-disk metadata - Fix races in the copy on write remap mechanism - Fix buffer io error timeout controls - Streamlining of directio copy on write - Asynchronous discard support - Fix asserts when splitting delalloc reservations - Don't bloat bmbt when right shifting extents - Inode alignment fixes for 32k block sizes" * tag 'xfs-4.11-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (39 commits) xfs: remove XFS_ALLOCTYPE_ANY_AG and XFS_ALLOCTYPE_START_AG xfs: simplify xfs_rtallocate_extent xfs: tune down agno asserts in the bmap code xfs: Use xfs_icluster_size_fsb() to calculate inode chunk alignment xfs: don't reserve blocks for right shift transactions xfs: fix len comparison in xfs_extent_busy_trim xfs: fix uninitialized variable in _reflink_convert_cow xfs: split indlen reservations fairly when under reserved xfs: handle indlen shortage on delalloc extent merge xfs: resurrect debug mode drop buffered writes mechanism xfs: clear delalloc and cache on buffered write failure xfs: don't block the log commit handler for discards xfs: improve busy extent sorting xfs: improve handling of busy extents in the low-level allocator xfs: don't fail xfs_extent_busy allocation xfs: correct null checks and error processing in xfs_initialize_perag xfs: update ctime and mtime on clone destinatation inodes xfs: allocate direct I/O COW blocks in iomap_begin xfs: go straight to real allocations for direct I/O COW writes xfs: return the converted extent in __xfs_reflink_convert_cow ...
| * iomap: constify struct iomap_opsChristoph Hellwig2017-01-301-9/+9
| | | | | | | | | | | | 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>
* | fs: break out of iomap_file_buffered_write on fatal signalsMichal Hocko2017-02-031-0/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Tetsuo has noticed that an OOM stress test which performs large write requests can cause the full memory reserves depletion. He has tracked this down to the following path __alloc_pages_nodemask+0x436/0x4d0 alloc_pages_current+0x97/0x1b0 __page_cache_alloc+0x15d/0x1a0 mm/filemap.c:728 pagecache_get_page+0x5a/0x2b0 mm/filemap.c:1331 grab_cache_page_write_begin+0x23/0x40 mm/filemap.c:2773 iomap_write_begin+0x50/0xd0 fs/iomap.c:118 iomap_write_actor+0xb5/0x1a0 fs/iomap.c:190 ? iomap_write_end+0x80/0x80 fs/iomap.c:150 iomap_apply+0xb3/0x130 fs/iomap.c:79 iomap_file_buffered_write+0x68/0xa0 fs/iomap.c:243 ? iomap_write_end+0x80/0x80 xfs_file_buffered_aio_write+0x132/0x390 [xfs] ? remove_wait_queue+0x59/0x60 xfs_file_write_iter+0x90/0x130 [xfs] __vfs_write+0xe5/0x140 vfs_write+0xc7/0x1f0 ? syscall_trace_enter+0x1d0/0x380 SyS_write+0x58/0xc0 do_syscall_64+0x6c/0x200 entry_SYSCALL64_slow_path+0x25/0x25 the oom victim has access to all memory reserves to make a forward progress to exit easier. But iomap_file_buffered_write and other callers of iomap_apply loop to complete the full request. We need to check for fatal signals and back off with a short write instead. As the iomap_apply delegates all the work down to the actor we have to hook into those. All callers that work with the page cache are calling iomap_write_begin so we will check for signals there. dax_iomap_actor has to handle the situation explicitly because it copies data to the userspace directly. Other callers like iomap_page_mkwrite work on a single page or iomap_fiemap_actor do not allocate memory based on the given len. Fixes: 68a9f5e7007c ("xfs: implement iomap based buffered write path") Link: http://lkml.kernel.org/r/20170201092706.9966-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <stable@vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'xfs-for-linus-4.10-rc1' of ↵Linus Torvalds2016-12-141-0/+373
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs Pull xfs updates from Dave Chinner: "There is quite a varied bunch of stuff in this update, and some of it you will have already merged through the ext4 tree which imported the dax-4.10-iomap-pmd topic branch from the XFS tree. There is also a new direct IO implementation that uses the iomap infrastructure. It's much simpler, faster, and has lower IO latency than the existing direct IO infrastructure. Summary: - DAX PMD faults via iomap infrastructure - Direct-io support in iomap infrastructure - removal of now-redundant XFS inode iolock, replaced with VFS i_rwsem - synchronisation with fixes and changes in userspace libxfs code - extent tree lookup helpers - lots of little corruption detection improvements to verifiers - optimised CRC calculations - faster buffer cache lookups - deprecation of barrier/nobarrier mount options - we always use REQ_FUA/REQ_FLUSH where appropriate for data integrity now - cleanups to speculative preallocation - miscellaneous minor bug fixes and cleanups" * tag 'xfs-for-linus-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (63 commits) xfs: nuke unused tracepoint definitions xfs: use GPF_NOFS when allocating btree cursors xfs: use xfs_vn_setattr_size to check on new size xfs: deprecate barrier/nobarrier mount option xfs: Always flush caches when integrity is required xfs: ignore leaf attr ichdr.count in verifier during log replay xfs: use rhashtable to track buffer cache xfs: optimise CRC updates xfs: make xfs btree stats less huge xfs: don't cap maximum dedupe request length xfs: don't allow di_size with high bit set xfs: error out if trying to add attrs and anextents > 0 xfs: don't crash if reading a directory results in an unexpected hole xfs: complain if we don't get nextents bmap records xfs: check for bogus values in btree block headers xfs: forbid AG btrees with level == 0 xfs: several xattr functions can be void xfs: handle cow fork in xfs_bmap_trace_exlist xfs: pass state not whichfork to trace_xfs_extlist xfs: Move AGI buffer type setting to xfs_read_agi ...
| * iomap: implement direct I/OChristoph Hellwig2016-11-301-0/+373
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds a full fledget direct I/O implementation using the iomap interface. Full fledged in this case means all features are supported: AIO, vectored I/O, any iov_iter type including kernel pointers, bvecs and pipes, support for hole filling and async apending writes. It does not mean supporting all the warts of the old generic code. We expect i_rwsem to be held over the duration of the call, and we expect to maintain i_dio_count ourselves, and we pass on any kinds of mapping to the file system for now. The algorithm used is very simple: We use iomap_apply to iterate over the range of the I/O, and then we use the new bio_iov_iter_get_pages helper to lock down the user range for the size of the extent. bio_iov_iter_get_pages can currently lock down twice as many pages as the old direct I/O code did, which means that we will have a better batch factor for everything but overwrites of badly fragmented files. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com> Tested-by: Jens Axboe <axboe@fb.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
| * Merge branch 'xfs-4.10-misc-fixes-2' into iomap-4.10-directioDave Chinner2016-11-301-3/+2
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* | | Merge branch 'dax-4.10-iomap-pmd' into originTheodore Ts'o2016-11-131-2/+3
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| * dax: Introduce IOMAP_FAULT flagJan Kara2016-11-101-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | Introduce a flag telling iomap operations whether they are handling a fault or other IO. That may influence behavior wrt inode size and similar things. Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
* | fs: Do to trim high file position bits in iomap_page_mkwrite_actorJan Kara2016-10-241-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | iomap_page_mkwrite_actor() calls __block_write_begin_int() with position masked as pos & ~PAGE_MASK which is equivalent to pos & (PAGE_SIZE-1). Thus it masks off high bits of file position. However __block_write_begin_int() expects full file position on input. This does not cause any visible issues because all __block_write_begin_int() really cares about are low file position bits but still it is a bug waiting to happen. Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
* | iomap: add IOMAP_REPORTChristoph Hellwig2016-10-201-1/+1
|/ | | | | | | | | | | | This allows the file system to tell a FIEMAP from a read operation, and thus avoids the need to report flags that aren't actually used in the read path. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
* Merge branch 'iomap-4.9-dax' into for-nextDave Chinner2016-10-031-4/+1
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| * iomap: expose iomap_apply outside iomap.cChristoph Hellwig2016-09-191-4/+1
| | | | | | | | | | | | | | | | | | This allows the DAX code to use it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
* | iomap: add a flag to report shared extentsDarrick J. Wong2016-09-191-0/+2
| | | | | | | | | | | | | | Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
* | fs: add iomap_file_dirtyChristoph Hellwig2016-09-191-0/+82
|/ | | | | | | | | | | | | Originally-From: Christoph Hellwig <hch@lst.de> This function uses the iomap infrastructure to re-write all pages in a given range. This is useful for doing a copy-up of COW ranges, and might be useful for scrubbing in the future. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
* iomap: don't set FIEMAP_EXTENT_MERGED for extent based filesystemsChristoph Hellwig2016-08-291-1/+4
| | | | | | | | | | | | | | | | Filesystems like XFS that use extents should not set the FIEMAP_EXTENT_MERGED flag in the fiemap extent structures. To allow for both behaviors for the upcoming gfs2 usage split the iomap type field into type and flags, and only set FIEMAP_EXTENT_MERGED if the IOMAP_F_MERGED flag is set. The flags field will also come in handy for future features such as shared extents on reflink-enabled file systems. Reported-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
* iomap: mark ->iomap_end as optionalChristoph Hellwig2016-08-171-2/+5
| | | | | | | | | | No need to implement it for read-only mappings. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
* iomap: prepare iomap_fiemap for attribute mappingsDave Chinner2016-08-171-0/+3
| | | | | | | | | | | | | By bassing through an -ENOENT, similar to the old XFS implementation of FIEMAP_FLAG_XATTR. Signed-off-by: Dave Chinner <dchinner@redhat.com> [hch: split from a larger patch] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
* iomap: fiemap should honor the FIEMAP_FLAG_SYNC flagDave Chinner2016-08-171-3/+5
| | | | | | | | | | | | The flag is checked as supported, but then we do an unconditional sync of the file, regardless of whether the flag is set or not. Make the sync conditional on having the FIEMAP_FLAG_SYNC flag set. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
* iomap: remove superflous pagefault_disable from iomap_write_actorChristoph Hellwig2016-08-171-2/+0
| | | | | | | | | | | | iov_iter_copy_from_user_atomic disables page faults internally, no need to do it around the call. This also brings the iomap code in line with the original filemap version. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
* iomap: remove superflous mark_page_accessed from iomap_write_actorChristoph Hellwig2016-08-171-1/+0
| | | | | | | | | | | | This catches up with commit 2457ae ("mm: non-atomically mark page accessed during page cache allocation where possible"), which moved the initial access marking into the pagecache allocator. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
* fs: iomap based fiemap implementationChristoph Hellwig2016-06-211-0/+90
| | | | | | | | | | | Add a simple fiemap implementation based on iomap_ops, partially based on a previous implementation from Bob Peterson <rpeterso@redhat.com>. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
* fs: support DAX based iomap zeroingChristoph Hellwig2016-06-211-1/+14
| | | | | | | | | | | This avoid needing a separate inefficient get_block based DAX zero_range implementation in file systems. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
* fs: introduce iomap infrastructureChristoph Hellwig2016-06-211-0/+394
Add infrastructure for multipage buffered writes. This is implemented using an main iterator that applies an actor function to a range that can be written. This infrastucture is used to implement a buffered write helper, one to zero file ranges and one to implement the ->page_mkwrite VM operations. All of them borrow a fair amount of code from fs/buffers. for now by using an internal version of __block_write_begin that gets passed an iomap and builds the corresponding buffer head. The file system is gets a set of paired ->iomap_begin and ->iomap_end calls which allow it to map/reserve a range and get a notification once the write code is finished with it. Based on earlier code from Dave Chinner. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
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