- 05 10月, 2016 2 次提交
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由 Darrick J. Wong 提交于
Modify the writepage handler to find and convert pending delalloc extents to real allocations. Furthermore, when we're doing non-cow writes to a part of a file that already has a CoW reservation (the cowextsz hint that we set up in a subsequent patch facilitates this), promote the write to copy-on-write so that the entire extent can get written out as a single extent on disk, thereby reducing post-CoW fragmentation. Christoph moved the CoW support code in _map_blocks to a separate helper function, refactored other functions, and reduced the number of CoW fork lookups, so I merged those changes here to reduce churn. Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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由 Darrick J. Wong 提交于
Modify xfs_bmap_add_extent_delay_real() so that we can convert delayed allocation extents in the CoW fork to real allocations, and wire this up all the way back to xfs_iomap_write_allocate(). In a subsequent patch, we'll modify the writepage handler to call this. Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com> Reviewed-by: NChristoph Hellwig <hch@lst.de>
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- 19 9月, 2016 1 次提交
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由 Christoph Hellwig 提交于
Rename the current function to __xfs_setfilesize and add a non-static wrapper that also takes care of creating the transaction. This new helper will be used by the new iomap-based DAX path. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NDave Chinner <dchinner@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 22 7月, 2016 2 次提交
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由 Dave Chinner 提交于
In xfs_finish_page_writeback(), we have a loop that looks like this: do { if (off < bvec->bv_offset) goto next_bh; if (off > end) break; bh->b_end_io(bh, !error); next_bh: off += bh->b_size; } while ((bh = bh->b_this_page) != head); The b_end_io function is end_buffer_async_write(), which will call end_page_writeback() once all the buffers have marked as no longer under IO. This issue here is that the only thing currently protecting both the bufferhead chain and the page from being reclaimed is the PageWriteback state held on the page. While we attempt to limit the loop to just the buffers covered by the IO, we still read from the buffer size and follow the next pointer in the bufferhead chain. There is no guarantee that either of these are valid after the PageWriteback flag has been cleared. Hence, loops like this are completely unsafe, and result in use-after-free issues. One such problem was caught by Calvin Owens with KASAN: ..... INFO: Freed in 0x103fc80ec age=18446651500051355200 cpu=2165122683 pid=-1 free_buffer_head+0x41/0x90 __slab_free+0x1ed/0x340 kmem_cache_free+0x270/0x300 free_buffer_head+0x41/0x90 try_to_free_buffers+0x171/0x240 xfs_vm_releasepage+0xcb/0x3b0 try_to_release_page+0x106/0x190 shrink_page_list+0x118e/0x1a10 shrink_inactive_list+0x42c/0xdf0 shrink_zone_memcg+0xa09/0xfa0 shrink_zone+0x2c3/0xbc0 ..... Call Trace: <IRQ> [<ffffffff81e8b8e4>] dump_stack+0x68/0x94 [<ffffffff8153a995>] print_trailer+0x115/0x1a0 [<ffffffff81541174>] object_err+0x34/0x40 [<ffffffff815436e7>] kasan_report_error+0x217/0x530 [<ffffffff81543b33>] __asan_report_load8_noabort+0x43/0x50 [<ffffffff819d651f>] xfs_destroy_ioend+0x3bf/0x4c0 [<ffffffff819d69d4>] xfs_end_bio+0x154/0x220 [<ffffffff81de0c58>] bio_endio+0x158/0x1b0 [<ffffffff81dff61b>] blk_update_request+0x18b/0xb80 [<ffffffff821baf57>] scsi_end_request+0x97/0x5a0 [<ffffffff821c5558>] scsi_io_completion+0x438/0x1690 [<ffffffff821a8d95>] scsi_finish_command+0x375/0x4e0 [<ffffffff821c3940>] scsi_softirq_done+0x280/0x340 Where the access is occuring during IO completion after the buffer had been freed from direct memory reclaim. Prevent use-after-free accidents in this end_io processing loop by pre-calculating the loop conditionals before calling bh->b_end_io(). The loop is already limited to just the bufferheads covered by the IO in progress, so the offset checks are sufficient to prevent accessing buffers in the chain after end_page_writeback() has been called by the the bh->b_end_io() callout. Yet another example of why Bufferheads Must Die. cc: <stable@vger.kernel.org> # 4.7 Signed-off-by: NDave Chinner <dchinner@redhat.com> Reported-and-Tested-by: NCalvin Owens <calvinowens@fb.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NBrian Foster <bfoster@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Brian Foster 提交于
XFS has had scattered reports of delalloc blocks present at ->releasepage() time. This results in a warning with a stack trace similar to the following: ... Call Trace: [<ffffffffa23c5b8f>] dump_stack+0x63/0x84 [<ffffffffa20837a7>] warn_slowpath_common+0x97/0xe0 [<ffffffffa208380a>] warn_slowpath_null+0x1a/0x20 [<ffffffffa2326caf>] xfs_vm_releasepage+0x10f/0x140 [<ffffffffa218c680>] ? page_mkclean_one+0xd0/0xd0 [<ffffffffa218d3a0>] ? anon_vma_prepare+0x150/0x150 [<ffffffffa21521c2>] try_to_release_page+0x32/0x50 [<ffffffffa2166b2e>] shrink_active_list+0x3ce/0x3e0 [<ffffffffa21671c7>] shrink_lruvec+0x687/0x7d0 [<ffffffffa21673ec>] shrink_zone+0xdc/0x2c0 [<ffffffffa2168539>] kswapd+0x4f9/0x970 [<ffffffffa2168040>] ? mem_cgroup_shrink_node_zone+0x1a0/0x1a0 [<ffffffffa20a0d99>] kthread+0xc9/0xe0 [<ffffffffa20a0cd0>] ? kthread_stop+0x100/0x100 [<ffffffffa26b404f>] ret_from_fork+0x3f/0x70 [<ffffffffa20a0cd0>] ? kthread_stop+0x100/0x100 This occurs because it is possible for shrink_active_list() to send pages marked dirty to ->releasepage() when certain buffer_head threshold conditions are met. shrink_active_list() doesn't check the page dirty state apparently to handle an old ext3 corner case where in some cases clean pages would not have the dirty bit cleared, thus it is up to the filesystem to determine how to handle the page. XFS currently handles the delalloc case properly, but this behavior makes the warning spurious. Update the XFS ->releasepage() handler to explicitly skip dirty pages. Retain the existing delalloc/unwritten checks so we continue to warn if such buffers exist on clean pages when they shouldn't. Diagnosed-by: NDave Chinner <david@fromorbit.com> Signed-off-by: NBrian Foster <bfoster@redhat.com> Reviewed-by: NDave Chinner <dchinner@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 20 7月, 2016 1 次提交
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由 Christoph Hellwig 提交于
We control both the callers and callees of ->direct_IO, so remove the indirect calls. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NDave Chinner <dchinner@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 21 6月, 2016 2 次提交
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由 Christoph Hellwig 提交于
Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NBob Peterson <rpeterso@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Christoph Hellwig 提交于
Convert XFS to use the new iomap based multipage write path. This involves implementing the ->iomap_begin and ->iomap_end methods, and switching the buffered file write, page_mkwrite and xfs_iozero paths to the new iomap helpers. With this change __xfs_get_blocks will never be used for buffered writes, and the code handling them can be removed. Based on earlier code from Dave Chinner. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NBob Peterson <rpeterso@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 08 6月, 2016 2 次提交
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由 Mike Christie 提交于
Separate the op from the rq_flag_bits and have xfs set/get the bio using bio_set_op_attrs/bio_op. Signed-off-by: NMike Christie <mchristi@redhat.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Mike Christie 提交于
This has callers of submit_bio/submit_bio_wait set the bio->bi_rw instead of passing it in. This makes that use the same as generic_make_request and how we set the other bio fields. Signed-off-by: NMike Christie <mchristi@redhat.com> Fixed up fs/ext4/crypto.c Signed-off-by: NJens Axboe <axboe@fb.com>
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- 20 5月, 2016 1 次提交
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由 Christoph Hellwig 提交于
blockmask is unused if ASSERTs are disabled. Reported-by: Nkbuild test robot <fengguang.wu@intel.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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- 02 5月, 2016 1 次提交
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由 Christoph Hellwig 提交于
Including blkdev_direct_IO and dax_do_io. It has to be ki_pos to actually work, so eliminate the superflous argument. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 06 4月, 2016 4 次提交
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由 Christoph Hellwig 提交于
Merge xfs_trans_reserve and xfs_trans_alloc into a single function call that returns a transaction with all the required log and block reservations, and which allows passing transaction flags directly to avoid the cumbersome _xfs_trans_alloc interface. While we're at it we also get rid of the transaction type argument that has been superflous since we stopped supporting the non-CIL logging mode. The guts of it will be removed in another patch. [dchinner: fixed transaction leak in error path in xfs_setattr_nonsize] Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NDave Chinner <dchinner@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Christoph Hellwig 提交于
This patch implements two closely related changes: First it embeds a bio the ioend structure so that we don't have to allocate one separately. Second it uses the block layer bio chaining mechanism to chain additional bios off this first one if needed instead of manually accounting for multiple bio completions in the ioend structure. Together this removes a memory allocation per ioend and greatly simplifies the ioend setup and I/O completion path. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NBrian Foster <bfoster@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Dave Chinner 提交于
Completion of an ioend requires us to walk the bufferhead list to end writback on all the bufferheads. This, in turn, is needed so that we can end writeback on all the pages we just did IO on. To remove our dependency on bufferheads in writeback, we need to turn this around the other way - we need to walk the pages we've just completed IO on, and then walk the buffers attached to the pages and complete their IO. In doing this, we remove the requirement for the ioend to track bufferheads directly. To enable IO completion to walk all the pages we've submitted IO on, we need to keep the bios that we used for IO around until the ioend has been completed. We can do this simply by chaining the bios to the ioend at completion time, and then walking their pages directly just before destroying the ioend. Signed-off-by: NDave Chinner <dchinner@redhat.com> [hch: changed the xfs_finish_page_writeback calling convention] Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NBrian Foster <bfoster@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Dave Chinner 提交于
Currently adding a buffer to the ioend and then building a bio from the buffer list are two separate operations. We don't build the bios and submit them until the ioend is submitted, and this places a fixed dependency on bufferhead chaining in the ioend. The first step to removing the bufferhead chaining in the ioend is on the IO submission side. We can build the bio directly as we add the buffers to the ioend chain, thereby removing the need for a latter "buffer-to-bio" submission loop. This allows us to submit bios on large ioends as soon as we cannot add more data to the bio. These bios then get captured by the active plug, and hence will be dispatched as soon as either the plug overflows or we schedule away from the writeback context. This will reduce submission latency for large IOs, but will also allow more timely request queue based writeback blocking when the device becomes congested. Signed-off-by: NDave Chinner <dchinner@redhat.com> [hch: various small updates] Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NBrian Foster <bfoster@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 05 4月, 2016 2 次提交
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由 Kirill A. Shutemov 提交于
Mostly direct substitution with occasional adjustment or removing outdated comments. Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: NMichal Hocko <mhocko@suse.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill A. Shutemov 提交于
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: NMichal Hocko <mhocko@suse.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 16 3月, 2016 2 次提交
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由 Johannes Weiner 提交于
Now that migration doesn't clear page->mem_cgroup of live pages anymore, it's safe to make lock_page_memcg() and the memcg stat functions take pages, and spare the callers from memcg objects. [akpm@linux-foundation.org: fix warnings] Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Suggested-by: NVladimir Davydov <vdavydov@virtuozzo.com> Acked-by: NVladimir Davydov <vdavydov@virtuozzo.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Johannes Weiner 提交于
These patches tag the page cache radix tree eviction entries with the memcg an evicted page belonged to, thus making per-cgroup LRU reclaim work properly and be as adaptive to new cache workingsets as global reclaim already is. This should have been part of the original thrash detection patch series, but was deferred due to the complexity of those patches. This patch (of 5): So far the only sites that needed to exclude charge migration to stabilize page->mem_cgroup have been per-cgroup page statistics, hence the name mem_cgroup_begin_page_stat(). But per-cgroup thrash detection will add another site that needs to ensure page->mem_cgroup lifetime. Rename these locking functions to the more generic lock_page_memcg() and unlock_page_memcg(). Since charge migration is a cgroup1 feature only, we might be able to delete it at some point, and these now easy to identify locking sites along with it. Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Suggested-by: NVladimir Davydov <vdavydov@virtuozzo.com> Acked-by: NVladimir Davydov <vdavydov@virtuozzo.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 3月, 2016 1 次提交
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由 Brian Foster 提交于
Add a DEBUG mode-only sysfs knob to enable forced buffered write failure. An additional side effect of this mode is brute force killing of delayed allocation blocks in the range of the write. The latter is the prime motiviation behind this patch, as userspace test infrastructure requires a reliable mechanism to create and split delalloc extents without causing extent conversion. Certain fallocate operations (i.e., zero range) were used for this in the past, but the implementations have changed such that delalloc extents are flushed and converted to real blocks, rendering the test useless. Signed-off-by: NBrian Foster <bfoster@redhat.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 07 3月, 2016 1 次提交
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由 Darrick J. Wong 提交于
We need to create a new ioend if the current writepage call isn't logically contiguous with the range contained in the previous ioend. Hopefully writepage gets called in order of increasing file offset. Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com> Reviewed-by: NDave Chinner <dchinner@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 28 2月, 2016 2 次提交
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由 Ross Zwisler 提交于
Previously calls to dax_writeback_mapping_range() for all DAX filesystems (ext2, ext4 & xfs) were centralized in filemap_write_and_wait_range(). dax_writeback_mapping_range() needs a struct block_device, and it used to get that from inode->i_sb->s_bdev. This is correct for normal inodes mounted on ext2, ext4 and XFS filesystems, but is incorrect for DAX raw block devices and for XFS real-time files. Instead, call dax_writeback_mapping_range() directly from the filesystem ->writepages function so that it can supply us with a valid block device. This also fixes DAX code to properly flush caches in response to sync(2). Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: NJan Kara <jack@suse.cz> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@fb.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Ross Zwisler 提交于
dax_clear_blocks() needs a valid struct block_device and previously it was using inode->i_sb->s_bdev in all cases. This is correct for normal inodes on mounted ext2, ext4 and XFS filesystems, but is incorrect for DAX raw block devices and for XFS real-time devices. Instead, rename dax_clear_blocks() to dax_clear_sectors(), and change its arguments to take a bdev and a sector instead of an inode and a block. This better reflects what the function does, and it allows the filesystem and raw block device code to pass in an appropriate struct block_device. Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Suggested-by: NDan Williams <dan.j.williams@intel.com> Reviewed-by: NJan Kara <jack@suse.cz> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@fb.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 2月, 2016 6 次提交
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由 Dave Chinner 提交于
Currently we can build a long ioend chain during ->writepages that gets attached to the writepage context. IO submission only then occurs when we finish all the writepage processing. This means we can have many ioends allocated and pending, and this violates the mempool guarantees that we need to give about forwards progress. i.e. we really should only have one ioend being built at a time, otherwise we may drain the mempool trying to allocate a new ioend and that blocks submission, completion and freeing of ioends that are already in progress. To prevent this situation from happening, we need to submit ioends for IO as soon as they are ready for dispatch rather than queuing them for later submission. This means the ioends have bios built immediately and they get queued on any plug that is current active. Hence if we schedule away from writeback, the ioends that have been built will make forwards progress due to the plug flushing on context switch. This will also prevent context switches from creating unnecessary IO submission latency. We can't completely avoid having nested IO allocation - when we have a block size smaller than a page size, we still need to hold the ioend submission until after we have marked the current page dirty. Hence we may need multiple ioends to be held while the current page is completely mapped and made ready for IO dispatch. We cannot avoid this problem - the current code already has this ioend chaining within a page so we can mostly ignore that it occurs. Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Dave Chinner 提交于
Separate out the bufferhead based mapping from the writepage code so that we have a clear separation of the page operations and the bufferhead state. Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Dave Chinner 提交于
xfs_cluster_write() is not necessary now that xfs_vm_writepages() aggregates writepage calls across a single mapping. This means we no longer need to do page lookups in xfs_cluster_write, so writeback only needs to look up th epage cache once per page being written. This also removes a large amount of mostly duplicate code between xfs_do_writepage() and xfs_convert_page(). Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Dave Chinner 提交于
xfs_vm_writepages() calls generic_writepages to writeback a range of a file, but then xfs_vm_writepage() clusters pages itself as it does not have any context it can pass between->writepage calls from __write_cache_pages(). Introduce a writeback context for xfs_vm_writepages() and call __write_cache_pages directly with our own writepage callback so that we can pass that context to each writepage invocation. This encapsulates the current mapping, whether it is valid or not, the current ioend and it's IO type and the ioend chain being built. This requires us to move the ioend submission up to the level where the writepage context is declared. This does mean we do not submit IO until we packaged the entire writeback range, but with the block plugging in the writepages call this is the way IO is submitted, anyway. It also means that we need to handle discontiguous page ranges. If the pages sent down by write_cache_pages to the writepage callback are discontiguous, we need to detect this and put each discontiguous page range into individual ioends. This is needed to ensure that the ioend accurately represents the range of the file that it covers so that file size updates during IO completion set the size correctly. Failure to take into account the discontiguous ranges results in files being too small when writeback patterns are non-sequential. Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Dave Chinner 提交于
We currently have code to cancel ioends being built because we change bufferhead state as we build the ioend. On error, this needs to be unwound and so we have cancelling code that walks the buffers on the ioend chain and undoes these state changes. However, the IO submission path already handles state changes for buffers when a submission error occurs, so we don't really need a separate cancel function to do this - we can simply submit the ioend chain with the specific error and it will be cancelled rather than submitted. Hence we can remove the explicit cancel code and just rely on submission to deal with the error correctly. Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Dave Chinner 提交于
Remove the nonblocking optimisation done for mapping lookups during writeback. It's not clear that leaving a hole in the writeback range just because we couldn't get a lock is really a win, as it makes us do another small random IO later on rather than a large sequential IO now. As this gets in the way of sane error handling later on, just remove for the moment and we can re-introduce an equivalent optimisation in future if we see problems due to extent map lock contention. Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 08 2月, 2016 5 次提交
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由 Brian Foster 提交于
If the filesystem has shut down, xfs_end_io() currently sets an error on the ioend and proceeds to ioend destruction. The ioend might contain a truncate transaction if the I/O extended the size of the file. This transaction is only cleaned up in xfs_setfilesize_ioend(), however, which is skipped in this case. This results in an xfs_log_ticket leak message when the associate cache slab is destroyed (e.g., on rmmod). This was originally reproduced by xfs/141 on a distro kernel. The problem is reproducible on an upstream kernel, but not easily detected in current upstream if the xfs_log_ticket cache happens to be merged with another cache. This can be reproduced more deterministically with the 'slab_nomerge' kernel boot option. Update xfs_end_io() to proceed with normal end I/O processing after an error is set on an ioend due to fs shutdown. The I/O type-based processing is already designed to handle an I/O error and ensure that the ioend is cleaned up correctly. Signed-off-by: NBrian Foster <bfoster@redhat.com> Reviewed-by: NDave Chinner <dchinner@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Brian Foster 提交于
The xfs_vm_write_failed() handler is currently responsible for cleaning up any delalloc blocks over the range of a failed write beyond EOF. Failure to do so results in warning messages and other inconsistencies between buffer and extent state. The ->releasepage() handler currently warns in the event of a page being released with either unwritten or delalloc buffers, as neither is ever expected by the time a page is released. As has been reproduced by generic/083 on a -bsize=1k fs, it is currently possible to trigger the ->releasepage() warning for a page with unwritten buffers when a filesystem is near ENOSPC. This is reproduced by the following sequence: $ mkfs.xfs -f -b size=1k -d size=100m <dev> $ mount <dev> /mnt/ $ $ xfs_io -fc "falloc -k 0 1k" /mnt/file $ dd if=/dev/zero of=/mnt/enospc conv=notrunc oflag=append $ $ xfs_io -c "pwrite 512 1k" /mnt/file $ xfs_io -d -c "pwrite 16k 1k" /mnt/file The first pwrite command attempts a block unaligned write across an unwritten block and a hole. The delalloc for the hole fails with ENOSPC and the subsequent error handling does not clean up the unwritten buffer that was instantiated during the first ->get_block() call. The second pwrite triggers a warning as part of the inode mapping invalidation that occurs prior to direct I/O. The releasepage() handler detects the unwritten buffer at this time, warns and prevents the release of the page. To deal with this problem, update xfs_vm_write_failed() to clean up unwritten as well as delalloc buffers that are beyond EOF and within the range of the failed write. Signed-off-by: NBrian Foster <bfoster@redhat.com> Reviewed-by: NDave Chinner <dchinner@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Christoph Hellwig 提交于
Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NBrian Foster <bfoster@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Christoph Hellwig 提交于
We only need to communicate two bits of information to the direct I/O completion handler: (1) do we need to convert any unwritten extents in the range (2) do we need to check if we need to update the inode size based on the range passed to the completion handler We can use the private data passed to the get_block handler and the completion handler as a simple bitmask to communicate this information instead of the current complicated infrastructure reusing the ioends from the buffer I/O path, and thus avoiding a memory allocation and a context switch for any non-trivial direct write. As a nice side effect we also decouple the direct I/O path implementation from that of the buffered I/O path. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NBrian Foster <bfoster@redhat.com>
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由 Christoph Hellwig 提交于
This way we can pass back errors to the file system, and allow for cleanup required for all direct I/O invocations. Also allow the ->end_io handlers to return errors on their own, so that I/O completion errors can be passed on to the callers. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NDave Chinner <dchinner@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 08 1月, 2016 1 次提交
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由 Dave Chinner 提交于
This allows us to see page cache driven readahead in action as it passes through XFS. This helps to understand buffered read throughput problems such as readahead IO IO sizes being too small for the underlying device to reach max throughput. Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NBrian Foster <bfoster@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 03 11月, 2015 3 次提交
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由 Dave Chinner 提交于
For DAX, we are now doing block zeroing during allocation. This means we no longer need a special DAX fault IO completion callback to do unwritten extent conversion. Because mmap never extends the file size (it SEGVs the process) we don't need a callback to update the file size, either. Hence we can remove the completion callbacks from the __dax_fault and __dax_mkwrite calls. Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NBrian Foster <bfoster@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Dave Chinner 提交于
DAX has a page fault serialisation problem with block allocation. Because it allows concurrent page faults and does not have a page lock to serialise faults to the same page, it can get two concurrent faults to the page that race. When two read faults race, this isn't a huge problem as the data underlying the page is not changing and so "detect and drop" works just fine. The issues are to do with write faults. When two write faults occur, we serialise block allocation in get_blocks() so only one faul will allocate the extent. It will, however, be marked as an unwritten extent, and that is where the problem lies - the DAX fault code cannot differentiate between a block that was just allocated and a block that was preallocated and needs zeroing. The result is that both write faults end up zeroing the block and attempting to convert it back to written. The problem is that the first fault can zero and convert before the second fault starts zeroing, resulting in the zeroing for the second fault overwriting the data that the first fault wrote with zeros. The second fault then attempts to convert the unwritten extent, which is then a no-op because it's already written. Data loss occurs as a result of this race. Because there is no sane locking construct in the page fault code that we can use for serialisation across the page faults, we need to ensure block allocation and zeroing occurs atomically in the filesystem. This means we can still take concurrent page faults and the only time they will serialise is in the filesystem mapping/allocation callback. The page fault code will always see written, initialised extents, so we will be able to remove the unwritten extent handling from the DAX code when all filesystems are converted. Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NBrian Foster <bfoster@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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由 Dave Chinner 提交于
Both direct IO and DAX pass an offset and count into get_blocks that will overflow a s64 variable when an IO goes into the last supported block in a file (i.e. at offset 2^63 - 1FSB bytes). This can be seen from the tracing: xfs_get_blocks_alloc: [...] offset 0x7ffffffffffff000 count 4096 xfs_gbmap_direct: [...] offset 0x7ffffffffffff000 count 4096 xfs_gbmap_direct_none:[...] offset 0x7ffffffffffff000 count 4096 0x7ffffffffffff000 + 4096 = 0x8000000000000000, and hence that overflows the s64 offset and we fail to detect the need for a filesize update and an ioend is not allocated. This is *mostly* avoided for direct IO because such extending IOs occur with full block allocation, and so the "IS_UNWRITTEN()" check still evaluates as true and we get an ioend that way. However, doing single sector extending IOs to this last block will expose the fact that file size updates will not occur after the first allocating direct IO as the overflow will then be exposed. There is one further complexity: the DAX page fault path also exposes the same issue in block allocation. However, page faults cannot extend the file size, so in this case we want to allocate the block but do not want to allocate an ioend to enable file size update at IO completion. Hence we now need to distinguish between the direct IO patch allocation and dax fault path allocation to avoid leaking ioend structures. Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NBrian Foster <bfoster@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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- 12 10月, 2015 1 次提交
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由 Brian Foster 提交于
The iomap codepath (via get_blocks()) acquires and release the inode lock in the case of a direct write that requires block allocation. This is because xfs_iomap_write_direct() allocates a transaction, which means the ilock must be dropped and reacquired after the transaction is allocated and reserved. xfs_iomap_write_direct() invokes xfs_iomap_eof_align_last_fsb() before the transaction is created and thus before the ilock is reacquired. This can lead to calls to xfs_iread_extents() and reads of the in-core extent list without any synchronization (via xfs_bmap_eof() and xfs_bmap_last_extent()). xfs_iread_extents() assert fails if the ilock is not held, but this is not currently seen in practice as the current callers had already invoked xfs_bmapi_read(). What has been seen in practice are reports of crashes down in the xfs_bmap_eof() codepath on direct writes due to seemingly bogus pointer references from xfs_iext_get_ext(). While an explicit reproducer is not currently available to confirm the cause of the problem, crash analysis and code inspection from David Jeffrey had identified the insufficient locking. xfs_iomap_eof_align_last_fsb() is called from other contexts with the inode lock already held, so we cannot acquire it therein. __xfs_get_blocks() acquires and drops the ilock with variable flags to cover the event that the extent list must be read in. The common case is that __xfs_get_blocks() acquires the shared ilock. To provide locking around the last extent alignment call without adding more lock cycles to the dio path, update xfs_iomap_write_direct() to expect the shared ilock held on entry and do the extent alignment under its protection. Demote the lock, if necessary, from __xfs_get_blocks() and push the xfs_qm_dqattach() call outside of the shared lock critical section. Also, add an assert to document that the extent list is always expected to be present in this path. Otherwise, we risk a call to xfs_iread_extents() while under the shared ilock. This is safe as all current callers have executed an xfs_bmapi_read() call under the current iolock context. Reported-by: NDavid Jeffery <djeffery@redhat.com> Signed-off-by: NBrian Foster <bfoster@redhat.com> Reviewed-by: NDave Chinner <dchinner@redhat.com> Signed-off-by: NDave Chinner <david@fromorbit.com>
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