Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock. In the most basic scenario, that buffer will not be
resident and it will be mapped to the same file. Accessing the buffer
will trigger a page fault, and gfs2 will deadlock trying to take the
same inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled.
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Merge tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 mmap + page fault deadlocks fixes from Andreas Gruenbacher:
"Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock.
In the most basic deadlock scenario, that buffer will not be resident
and it will be mapped to the same file. Accessing the buffer will
trigger a page fault, and gfs2 will deadlock trying to take the same
inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled"
* tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: Fix mmap + page fault deadlocks for direct I/O
iov_iter: Introduce nofault flag to disable page faults
gup: Introduce FOLL_NOFAULT flag to disable page faults
iomap: Add done_before argument to iomap_dio_rw
iomap: Support partial direct I/O on user copy failures
iomap: Fix iomap_dio_rw return value for user copies
gfs2: Fix mmap + page fault deadlocks for buffered I/O
gfs2: Eliminate ip->i_gh
gfs2: Move the inode glock locking to gfs2_file_buffered_write
gfs2: Introduce flag for glock holder auto-demotion
gfs2: Clean up function may_grant
gfs2: Add wrapper for iomap_file_buffered_write
iov_iter: Introduce fault_in_iov_iter_writeable
iov_iter: Turn iov_iter_fault_in_readable into fault_in_iov_iter_readable
gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable}
powerpc/kvm: Fix kvm_use_magic_page
iov_iter: Fix iov_iter_get_pages{,_alloc} page fault return value
The second argument was only used by the USB gadget code, yet everyone
pays the overhead of passing a zero to be passed into aio, where it
ends up being part of the aio res2 value.
Now that everybody is passing in zero, kill off the extra argument.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a done_before argument to iomap_dio_rw that indicates how much of
the request has already been transferred. When the request succeeds, we
report that done_before additional bytes were tranferred. This is
useful for finishing a request asynchronously when part of the request
has already been completed synchronously.
We'll use that to allow iomap_dio_rw to be used with page faults
disabled: when a page fault occurs while submitting a request, we
synchronously complete the part of the request that has already been
submitted. The caller can then take care of the page fault and call
iomap_dio_rw again for the rest of the request, passing in the number of
bytes already tranferred.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
In iomap_dio_rw, when iomap_apply returns an -EFAULT error and the
IOMAP_DIO_PARTIAL flag is set, complete the request synchronously and
return a partial result. This allows the caller to deal with the page
fault and retry the remainder of the request.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
When a user copy fails in one of the helpers of iomap_dio_rw, fail with
-EFAULT instead of returning 0. This matches what iomap_dio_bio_actor
returns when it gets an -EFAULT from bio_iov_iter_get_pages. With these
changes, iomap_dio_actor now consistently fails with -EFAULT when a user
page cannot be faulted in.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
struct io_comp_batch contains a list head and a completion handler, which
will allow completions to more effciently completed batches of IO.
For now, no functional changes in this patch, we just define the
io_comp_batch structure and add the argument to the file_operations iopoll
handler.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the blk_poll interface that requires the caller to keep a queue
and cookie from the submissions with polling based on the bio.
Polling for the bio itself leads to a few advantages:
- the cookie construction can made entirely private in blk-mq.c
- the caller does not need to remember the request_queue and cookie
separately and thus sidesteps their lifetime issues
- keeping the device and the cookie inside the bio allows to trivially
support polling BIOs remapping by stacking drivers
- a lot of code to propagate the cookie back up the submission path can
be removed entirely.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Switch the boolean spin argument to blk_poll to passing a set of flags
instead. This will allow to control polling behavior in a more fine
grained way.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-10-hch@lst.de
[axboe: adapt to changed io_uring iopoll]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If an iocb is split into multiple bios we can't poll for both. So don't
bother to even try to poll in that case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Switch __iomap_dio_rw to use iomap_iter.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
The existing inline data support only works for cases where the entire
file is stored as inline data. For larger files, EROFS stores the
initial blocks separately and the remainder of the file ("file tail")
adjacent to the inode. Generalise inline data to allow reading the
inline file tail. Tails may not cross a page boundary in memory.
We currently have no filesystems that support tails and writing,
so that case is currently disabled (see iomap_write_begin_inline).
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
For reads, use the better variant of checking for the need to call
filemap_write_and_wait_range() when doing O_DIRECT. This avoids falling
back to the slow path for IOCB_NOWAIT, if there are no pages to wait for
(or write out).
Link: https://lkml.kernel.org/r/20210224164455.1096727-4-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ever since the addition of multipage bio_vecs BIO_MAX_PAGES has been
horribly confusingly misnamed. Rename it to BIO_MAX_VECS to stop
confusing users of the bio API.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20210311110137.1132391-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-block
Pull core block updates from Jens Axboe:
"Another nice round of removing more code than what is added, mostly
due to Christoph's relentless pursuit of tech debt removal/cleanups.
This pull request contains:
- Two series of BFQ improvements (Paolo, Jan, Jia)
- Block iov_iter improvements (Pavel)
- bsg error path fix (Pan)
- blk-mq scheduler improvements (Jan)
- -EBUSY discard fix (Jan)
- bvec allocation improvements (Ming, Christoph)
- bio allocation and init improvements (Christoph)
- Store bdev pointer in bio instead of gendisk + partno (Christoph)
- Block trace point cleanups (Christoph)
- hard read-only vs read-only split (Christoph)
- Block based swap cleanups (Christoph)
- Zoned write granularity support (Damien)
- Various fixes/tweaks (Chunguang, Guoqing, Lei, Lukas, Huhai)"
* tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-block: (104 commits)
mm: simplify swapdev_block
sd_zbc: clear zone resources for non-zoned case
block: introduce blk_queue_clear_zone_settings()
zonefs: use zone write granularity as block size
block: introduce zone_write_granularity limit
block: use blk_queue_set_zoned in add_partition()
nullb: use blk_queue_set_zoned() to setup zoned devices
nvme: cleanup zone information initialization
block: document zone_append_max_bytes attribute
block: use bi_max_vecs to find the bvec pool
md/raid10: remove dead code in reshape_request
block: mark the bio as cloned in bio_iov_bvec_set
block: set BIO_NO_PAGE_REF in bio_iov_bvec_set
block: remove a layer of indentation in bio_iov_iter_get_pages
block: turn the nr_iovecs argument to bio_alloc* into an unsigned short
block: remove the 1 and 4 vec bvec_slabs entries
block: streamline bvec_alloc
block: factor out a bvec_alloc_gfp helper
block: move struct biovec_slab to bio.c
block: reuse BIO_INLINE_VECS for integrity bvecs
...
- Adjust the final parameter of iomap_dio_rw.
- Add a new flag to request that iomap directio writes return EAGAIN if
the write is not a pure overwrite within EOF; this will be used to
reduce lock contention with unaligned direct writes on XFS.
- Amend XFS' directio code to eliminate exclusive locking for unaligned
direct writes if the circumstances permit
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Merge tag 'iomap-5.12-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull iomap updates from Darrick Wong:
"The big change in this cycle is some new code to make it possible for
XFS to try unaligned directio overwrites without taking locks. If the
block is fully written and within EOF (i.e. doesn't require any
further fs intervention) then we can let the unlocked write proceed.
If not, we fall back to synchronizing direct writes.
Summary:
- Adjust the final parameter of iomap_dio_rw.
- Add a new flag to request that iomap directio writes return EAGAIN
if the write is not a pure overwrite within EOF; this will be used
to reduce lock contention with unaligned direct writes on XFS.
- Amend XFS' directio code to eliminate exclusive locking for
unaligned direct writes if the circumstances permit"
* tag 'iomap-5.12-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: reduce exclusive locking on unaligned dio
xfs: split the unaligned DIO write code out
xfs: improve the reflink_bounce_dio_write tracepoint
xfs: simplify the read/write tracepoints
xfs: remove the buffered I/O fallback assert
xfs: cleanup the read/write helper naming
xfs: make xfs_file_aio_write_checks IOCB_NOWAIT-aware
xfs: factor out a xfs_ilock_iocb helper
iomap: add a IOMAP_DIO_OVERWRITE_ONLY flag
iomap: pass a flags argument to iomap_dio_rw
iomap: rename the flags variable in __iomap_dio_rw
A ZONE_APPEND bio must follow hardware restrictions (e.g. not exceeding
max_zone_append_sectors) not to be split. bio_iov_iter_get_pages builds
such restricted bio using __bio_iov_append_get_pages if bio_op(bio) ==
REQ_OP_ZONE_APPEND.
To utilize it, we need to set the bio_op before calling
bio_iov_iter_get_pages(). This commit introduces IOMAP_F_ZONE_APPEND, so
that iomap user can set the flag to indicate they want REQ_OP_ZONE_APPEND
and restricted bio.
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add a helper function calculating the number of bvec segments we need to
allocate to construct a bio. It doesn't change anything functionally,
but will be used to not duplicate special cases in the future.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a flag to signal that only pure overwrites are allowed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Pass a set of flags to iomap_dio_rw instead of the boolean
wait_for_completion argument. The IOMAP_DIO_FORCE_WAIT flag
replaces the wait_for_completion, but only needs to be passed
when the iocb isn't synchronous to start with to simplify the
callers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
[djwong: rework xfs_file.c so that we can push iomap changes separately]
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Rename flags to iomap_flags to make the usage a little more clear.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
iomap complete routine can deadlock with btrfs_fallocate because of the
call to generic_write_sync().
P0 P1
inode_lock() fallocate(FALLOC_FL_ZERO_RANGE)
__iomap_dio_rw() inode_lock()
<block>
<submits IO>
<completes IO>
inode_unlock()
<gets inode_lock()>
inode_dio_wait()
iomap_dio_complete()
generic_write_sync()
btrfs_file_fsync()
inode_lock()
<deadlock>
inode_dio_end() is used to notify the end of DIO data in order
to synchronize with truncate. Call inode_dio_end() before calling
generic_write_sync(), so filesystems can lock i_rwsem during a sync.
This matches the way it is done in fs/direct-io.c:dio_complete().
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This is to avoid the deadlock caused in btrfs because of O_DIRECT |
O_DSYNC.
Filesystems such as btrfs require i_rwsem while performing sync on a
file. iomap_dio_rw() is called under i_rw_sem. This leads to a
deadlock because of:
iomap_dio_complete()
generic_write_sync()
btrfs_sync_file()
Separate out iomap_dio_complete() from iomap_dio_rw(), so filesystems
can call iomap_dio_complete() after unlocking i_rwsem.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
When a direct I/O write falls back to buffered I/O entirely, dio->size
will be 0 in iomap_dio_complete. Function invalidate_inode_pages2_range
will try to invalidate the rest of the address space. If there are any
dirty pages in that range, the write will fail and a "Page cache
invalidation failure on direct I/O" error will be logged.
On gfs2, this can be reproduced as follows:
xfs_io \
-c "open -ft foo" -c "pwrite 4k 4k" -c "close" \
-c "open -d foo" -c "pwrite 0 4k"
Fix this by recognizing 0-length writes.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
It is trivial to trigger a WARN_ON_ONCE(1) in iomap_dio_actor() by
unprivileged users which would taint the kernel, or worse - panic if
panic_on_warn or panic_on_taint is set. Hence, just convert it to
pr_warn_ratelimited() to let users know their workloads are racing.
Thank Dave Chinner for the initial analysis of the racing reproducers.
Signed-off-by: Qian Cai <cai@lca.pw>
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>
Failing to invalid the page cache means data in incoherent, which is
a very bad state for the system. Always fall back to buffered I/O
through the page cache if we can't invalidate mappings.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu> # for ext4
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com> # for gfs2
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
The historic requirement for XFS to invalidate cached pages on
direct IO reads has been lost in the twisty pages of history - it was
inherited from Irix, which implemented page cache invalidation on
read as a method of working around problems synchronising page
cache state with uncached IO.
XFS has carried this ever since. In the initial linux ports it was
necessary to get mmap and DIO to play "ok" together and not
immediately corrupt data. This was the state of play until the linux
kernel had infrastructure to track unwritten extents and synchronise
page faults with allocations and unwritten extent conversions
(->page_mkwrite infrastructure). IOws, the page cache invalidation
on DIO read was necessary to prevent trivial data corruptions. This
didn't solve all the problems, though.
There were peformance problems if we didn't invalidate the entire
page cache over the file on read - we couldn't easily determine if
the cached pages were over the range of the IO, and invalidation
required taking a serialising lock (i_mutex) on the inode. This
serialising lock was an issue for XFS, as it was the only exclusive
lock in the direct Io read path.
Hence if there were any cached pages, we'd just invalidate the
entire file in one go so that subsequent IOs didn't need to take the
serialising lock. This was a problem that prevented ranged
invalidation from being particularly useful for avoiding the
remaining coherency issues. This was solved with the conversion of
i_mutex to i_rwsem and the conversion of the XFS inode IO lock to
use i_rwsem. Hence we could now just do ranged invalidation and the
performance problem went away.
However, page cache invalidation was still needed to serialise
sub-page/sub-block zeroing via direct IO against buffered IO because
bufferhead state attached to the cached page could get out of whack
when direct IOs were issued. We've removed bufferheads from the
XFS code, and we don't carry any extent state on the cached pages
anymore, and so this problem has gone away, too.
IOWs, it would appear that we don't have any good reason to be
invalidating the page cache on DIO reads anymore. Hence remove the
invalidation on read because it is unnecessary overhead,
not needed to maintain coherency between mmap/buffered access and
direct IO anymore, and prevents anyone from using direct IO reads
from intentionally invalidating the page cache of a file.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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Merge tag 'for-5.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"Highlights:
- speedup dead root detection during orphan cleanup, eg. when there
are many deleted subvolumes waiting to be cleaned, the trees are
now looked up in radix tree instead of a O(N^2) search
- snapshot creation with inherited qgroup will mark the qgroup
inconsistent, requires a rescan
- send will emit file capabilities after chown, this produces a
stream that does not need postprocessing to set the capabilities
again
- direct io ported to iomap infrastructure, cleaned up and simplified
code, notably removing last use of struct buffer_head in btrfs code
Core changes:
- factor out backreference iteration, to be used by ordinary
backreferences and relocation code
- improved global block reserve utilization
* better logic to serialize requests
* increased maximum available for unlink
* improved handling on large pages (64K)
- direct io cleanups and fixes
* simplify layering, where cloned bios were unnecessarily created
for some cases
* error handling fixes (submit, endio)
* remove repair worker thread, used to avoid deadlocks during
repair
- refactored block group reading code, preparatory work for new type
of block group storage that should improve mount time on large
filesystems
Cleanups:
- cleaned up (and slightly sped up) set/get helpers for metadata data
structure members
- root bit REF_COWS got renamed to SHAREABLE to reflect the that the
blocks of the tree get shared either among subvolumes or with the
relocation trees
Fixes:
- when subvolume deletion fails due to ENOSPC, the filesystem is not
turned read-only
- device scan deals with devices from other filesystems that changed
ownership due to overwrite (mkfs)
- fix a race between scrub and block group removal/allocation
- fix long standing bug of a runaway balance operation, printing the
same line to the syslog, caused by a stale status bit on a reloc
tree that prevented progress
- fix corrupt log due to concurrent fsync of inodes with shared
extents
- fix space underflow for NODATACOW and buffered writes when it for
some reason needs to fallback to COW mode"
* tag 'for-5.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (133 commits)
btrfs: fix space_info bytes_may_use underflow during space cache writeout
btrfs: fix space_info bytes_may_use underflow after nocow buffered write
btrfs: fix wrong file range cleanup after an error filling dealloc range
btrfs: remove redundant local variable in read_block_for_search
btrfs: open code key_search
btrfs: split btrfs_direct_IO to read and write part
btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK
fs: remove dio_end_io()
btrfs: switch to iomap_dio_rw() for dio
iomap: remove lockdep_assert_held()
iomap: add a filesystem hook for direct I/O bio submission
fs: export generic_file_buffered_read()
btrfs: turn space cache writeout failure messages into debug messages
btrfs: include error on messages about failure to write space/inode caches
btrfs: remove useless 'fail_unlock' label from btrfs_csum_file_blocks()
btrfs: do not ignore error from btrfs_next_leaf() when inserting checksums
btrfs: make checksum item extension more efficient
btrfs: fix corrupt log due to concurrent fsync of inodes with shared extents
btrfs: unexport btrfs_compress_set_level()
btrfs: simplify iget helpers
...
Filesystems such as btrfs can perform direct I/O without holding the
inode->i_rwsem in some of the cases like writing within i_size. So,
remove the check for lockdep_assert_held() in iomap_dio_rw().
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This helps filesystems to perform tasks on the bio while submitting for
I/O. This could be post-write operations such as data CRC or data
replication for fs-handled RAID.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Sync dio could be big, or may take long time in discard or in case of
IO failure.
We have prevented task hung in submit_bio_wait() and blk_execute_rq(),
so apply the same trick for prevent task hung from happening in sync dio.
Add helper of blk_io_schedule() and use io_schedule_timeout() to prevent
task hung warning.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Cc: Salman Qazi <sqazi@google.com>
Cc: Jesse Barnes <jsbarnes@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Double 'three' exists in the comments of iomap_dio_rw.
Signed-off-by: yangerkun <yangerkun@huawei.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>
The 'start' variable indicates the start of a filemap and is set to the
iocb's position, which we have already cached as 'pos', upon function
entry.
'pos' is used as a cursor indicating the current position and updated
later in iomap_dio_rw(), but not before the last use of 'start'.
Remove 'start' as it's synonym for 'pos' before we're entering the loop
calling iomapp_apply().
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
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>
iomap_dio_bio_actor() copies iter to a local variable and then limits it
to a file extent we have mapped. When IO is submitted,
iomap_dio_bio_actor() advances the original iter while the copied iter
is advanced inside bio_iov_iter_get_pages(). This logic is non-obvious
especially because both iters still point to same shared structures
(such as pipe info) so if iov_iter_advance() changes anything in the
shared structure, this scheme breaks. Let's just truncate and reexpand
the original iter as needed instead of playing games with copying iters
and keeping them in sync.
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
When splicing using iomap_dio_rw() to a pipe, we may leak pipe pages
because bio_iov_iter_get_pages() records that the pipe will have full
extent worth of data however if file size is not block size aligned
iomap_dio_rw() returns less than what bio_iov_iter_get_pages() set up
and splice code gets confused leaking a pipe page with the file tail.
Handle the situation similarly to the old direct IO implementation and
revert iter to actually returned read amount which makes iter consistent
with value returned from iomap_dio_rw() and thus the splice code is
happy.
Fixes: ff6a9292e6 ("iomap: implement direct I/O")
CC: stable@vger.kernel.org
Reported-by: syzbot+991400e8eba7e00a26e1@syzkaller.appspotmail.com
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Naresh reported LTP diotest4 failing for 32bit x86 and arm -next
kernels on ext4. Same problem exists in 5.4-rc7 on xfs.
The failure comes down to:
openat(AT_FDCWD, "testdata-4.5918", O_RDWR|O_DIRECT) = 4
mmap2(NULL, 4096, PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7f7b000
read(4, 0xb7f7b000, 4096) = 0 // expects -EFAULT
Problem is conversion at iomap_dio_bio_actor() return. Ternary
operator has a return type and an attempt is made to convert each
of operands to the type of the other. In this case "ret" (int)
is converted to type of "copied" (unsigned long). Both have size
of 4 bytes:
size_t copied = 0;
int ret = -14;
long long actor_ret = copied ? copied : ret;
On x86_64: actor_ret == -14;
On x86 : actor_ret == 4294967282
Replace ternary operator with 2 return statements to avoid this
unwanted conversion.
Fixes: 4721a60109 ("iomap: dio data corruption and spurious errors when pipes fill")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Jan Stancek <jstancek@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>
We've already check if it is READ iov_iter, no need check again.
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
The srcmap is used to identify where the read is to be performed from.
It is passed to ->iomap_begin, which can fill it in if we need to read
data for partially written blocks from a different location than the
write target. The srcmap is only supported for buffered writes so far.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
[hch: merged two patches, removed the IOMAP_F_COW flag, use iomap as
srcmap if not set, adjust length down to srcmap end as well]
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>
Acked-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Filesystems do not support doing IO as asynchronous in some cases. For
example in case of unaligned writes or in case file size needs to be
extended (e.g. for ext4). Instead of forcing filesystem to wait for AIO
in such cases, add argument to iomap_dio_rw() which makes the function
wait for IO completion. This also results in executing
iomap_dio_complete() inline in iomap_dio_rw() providing its return value
to the caller as for ordinary sync IO.
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Add a new iomap_dio_ops structure that for now just contains the end_io
handler. This avoid storing the function pointer in a mutable structure,
which is a possible exploit vector for kernel code execution, and prepares
for adding a submit_io handler that btrfs needs.
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>
Modify the calling convention for the iomap_dio_rw ->end_io() callback.
Rather than passing either dio->error or dio->size as the 'size' argument,
instead pass both the dio->error and the dio->size value separately.
In the instance that an error occurred during a write, we currently cannot
determine whether any blocks have been allocated beyond the current EOF and
data has subsequently been written to these blocks within the ->end_io()
callback. As a result, we cannot judge whether we should take the truncate
failed write path. Having both dio->error and dio->size will allow us to
perform such checks within this callback.
Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
[hch: minor cleanups]
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>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Move the direct IO code into a separate file so that we can group
related functions in a single file instead of having a single enormous
source file.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Linus Torvalds