In xfs_buffered_write_iomap_begin, @icur is the iext cursor for the data
fork and @ccur is the cursor for the cow fork. Pass in whichever cursor
corresponds to allocfork, because otherwise the xfs_iext_prev_extent
call can use the data fork cursor to walk off the end of the cow fork
structure. Best case it returns the wrong results, worst case it does
this:
stack segment: 0000 [#1] PREEMPT SMP
CPU: 2 PID: 3141909 Comm: fsstress Tainted: G W 6.3.0-rc2-xfsx #6.3.0-rc2 7bf5cc2e98997627cae5c930d890aba3aeec65dd
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20171121_152543-x86-ol7-builder-01.us.oracle.com-4.el7.1 04/01/2014
RIP: 0010:xfs_iext_prev+0x71/0x150 [xfs]
RSP: 0018:ffffc90002233aa8 EFLAGS: 00010297
RAX: 000000000000000f RBX: 000000000000000e RCX: 000000000000000c
RDX: 0000000000000002 RSI: 000000000000000e RDI: ffff8883d0019ba0
RBP: 989642409af8a7a7 R08: ffffea0000000001 R09: 0000000000000002
R10: 0000000000000000 R11: 000000000000000c R12: ffffc90002233b00
R13: ffff8883d0019ba0 R14: 989642409af8a6bf R15: 000ffffffffe0000
FS: 00007fdf8115f740(0000) GS:ffff88843fd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdf8115e000 CR3: 0000000357256000 CR4: 00000000003506e0
Call Trace:
<TASK>
xfs_iomap_prealloc_size.constprop.0.isra.0+0x1a6/0x410 [xfs 619a268fb2406d68bd34e007a816b27e70abc22c]
xfs_buffered_write_iomap_begin+0xa87/0xc60 [xfs 619a268fb2406d68bd34e007a816b27e70abc22c]
iomap_iter+0x132/0x2f0
iomap_file_buffered_write+0x92/0x330
xfs_file_buffered_write+0xb1/0x330 [xfs 619a268fb2406d68bd34e007a816b27e70abc22c]
vfs_write+0x2eb/0x410
ksys_write+0x65/0xe0
do_syscall_64+0x2b/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
Found by xfs/538 in alwayscow mode, but this doesn't seem particular to
that test.
Fixes: 590b16516e ("xfs: refactor xfs_iomap_prealloc_size")
Actually-Fixes: 66ae56a53f ("xfs: introduce an always_cow mode")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
The operations in struct page_ops all operate on folios, so rename
struct page_ops to struct folio_ops.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[djwong: port around not removing iomap_valid]
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Shut up the sparse warnings about this variable that isn't referenced
anywhere else.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
- Fix a race condition w.r.t. percpu inode free counters
- Fix a broken error return in xfs_remove
- Print FS UUID at mount/unmount time
- Numerous fixes to the online fsck code
- Fix inode locking inconsistency problems when dealing with realtime
metadata files
- Actually merge pull requests so that we capture the cover letter
contents
- Fix a race between rebuilding VFS inode state and the AIL flushing
inodes that could cause corrupt inodes to be written to the
filesystem
- Fix a data corruption problem resulting from a write() to an
unwritten extent racing with writeback started on behalf of memory
reclaim changing the extent state
- Add debugging knobs so that we can test iomap invalidation
- Fix the blockdev pagecache contents being stale after unmounting the
filesystem, leading to spurious xfs_db errors and corrupt metadumps
- Fix a file mapping corruption bug due to ilock cycling when attaching
dquots to a file during delalloc reservation
- Fix a refcount btree corruption problem due to the refcount
adjustment code not handling MAXREFCOUNT correctly, resulting in
unnecessary record splits
- Fix COW staging extent alloctions not being classified as USERDATA,
which results in filestreams being ignored and possible data
corruption if the allocation was filled from the AGFL and the block
buffer is still being tracked in the AIL
- Fix new duplicated includes
- Fix a race between the dquot shrinker and dquot freeing that could
cause a UAF
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Merge tag 'xfs-6.2-merge-8' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull XFS updates from Darrick Wong:
"The highlight of this is a batch of fixes for the online metadata
checking code as we start the loooong march towards merging online
repair. I aim to merge that in time for the 2023 LTS.
There are also a large number of data corruption and race condition
fixes in this patchset. Most notably fixed are write() calls to
unwritten extents racing with writeback, which required some late(r
than I prefer) code changes to iomap to support the necessary
revalidations. I don't really like iomap changes going in past -rc4,
but Dave and I have been working on it long enough that I chose to
push it for 6.2 anyway.
There are also a number of other subtle problems fixed, including the
log racing with inode writeback to write inodes with incorrect link
count to disk; file data mapping corruptions as a result of incorrect
lock cycling when attaching dquots; refcount metadata corruption if
one actually manages to share a block 2^32 times; and the log
clobbering cow staging extents if they were formerly metadata blocks.
Summary:
- Fix a race condition w.r.t. percpu inode free counters
- Fix a broken error return in xfs_remove
- Print FS UUID at mount/unmount time
- Numerous fixes to the online fsck code
- Fix inode locking inconsistency problems when dealing with realtime
metadata files
- Actually merge pull requests so that we capture the cover letter
contents
- Fix a race between rebuilding VFS inode state and the AIL flushing
inodes that could cause corrupt inodes to be written to the
filesystem
- Fix a data corruption problem resulting from a write() to an
unwritten extent racing with writeback started on behalf of memory
reclaim changing the extent state
- Add debugging knobs so that we can test iomap invalidation
- Fix the blockdev pagecache contents being stale after unmounting
the filesystem, leading to spurious xfs_db errors and corrupt
metadumps
- Fix a file mapping corruption bug due to ilock cycling when
attaching dquots to a file during delalloc reservation
- Fix a refcount btree corruption problem due to the refcount
adjustment code not handling MAXREFCOUNT correctly, resulting in
unnecessary record splits
- Fix COW staging extent alloctions not being classified as USERDATA,
which results in filestreams being ignored and possible data
corruption if the allocation was filled from the AGFL and the block
buffer is still being tracked in the AIL
- Fix new duplicated includes
- Fix a race between the dquot shrinker and dquot freeing that could
cause a UAF"
* tag 'xfs-6.2-merge-8' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (50 commits)
xfs: dquot shrinker doesn't check for XFS_DQFLAG_FREEING
xfs: Remove duplicated include in xfs_iomap.c
xfs: invalidate xfs_bufs when allocating cow extents
xfs: get rid of assert from xfs_btree_islastblock
xfs: estimate post-merge refcounts correctly
xfs: hoist refcount record merge predicates
xfs: fix super block buf log item UAF during force shutdown
xfs: wait iclog complete before tearing down AIL
xfs: attach dquots to inode before reading data/cow fork mappings
xfs: shut up -Wuninitialized in xfsaild_push
xfs: use memcpy, not strncpy, to format the attr prefix during listxattr
xfs: invalidate block device page cache during unmount
xfs: add debug knob to slow down write for fun
xfs: add debug knob to slow down writeback for fun
xfs: drop write error injection is unfixable, remove it
xfs: use iomap_valid method to detect stale cached iomaps
iomap: write iomap validity checks
xfs: xfs_bmap_punch_delalloc_range() should take a byte range
iomap: buffered write failure should not truncate the page cache
xfs,iomap: move delalloc punching to iomap
...
Zero and truncate on a dax file may execute CoW. So use dax ops which
contains end work for CoW.
Link: https://lkml.kernel.org/r/1669908730-131-1-git-send-email-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If a dax page is shared, mapread at different offsets can also trigger
page fault on same dax page. So, change the flag from "cow" to "shared".
And get the shared flag from filesystem when read.
Link: https://lkml.kernel.org/r/1669908538-55-5-git-send-email-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
./fs/xfs/xfs_iomap.c: xfs_error.h is included more than once.
./fs/xfs/xfs_iomap.c: xfs_errortag.h is included more than once.
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=3337
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
I've been running near-continuous integration testing of online fsck,
and I've noticed that once a day, one of the ARM VMs will fail the test
with out of order records in the data fork.
xfs/804 races fsstress with online scrub (aka scan but do not change
anything), so I think this might be a bug in the core xfs code. This
also only seems to trigger if one runs the test for more than ~6 minutes
via TIME_FACTOR=13 or something.
https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfstests-dev.git/tree/tests/xfs/804?h=djwong-wtf
I added a debugging patch to the kernel to check the data fork extents
after taking the ILOCK, before dropping ILOCK, and before and after each
bmapping operation. So far I've narrowed it down to the delalloc code
inserting a record in the wrong place in the iext tree:
xfs_bmap_add_extent_hole_delay, near line 2691:
case 0:
/*
* New allocation is not contiguous with another
* delayed allocation.
* Insert a new entry.
*/
oldlen = newlen = 0;
xfs_iunlock_check_datafork(ip); <-- ok here
xfs_iext_insert(ip, icur, new, state);
xfs_iunlock_check_datafork(ip); <-- bad here
break;
}
I recorded the state of the data fork mappings and iext cursor state
when a corrupt data fork is detected immediately after the
xfs_bmap_add_extent_hole_delay call in xfs_bmapi_reserve_delalloc:
ino 0x140bb3 func xfs_bmapi_reserve_delalloc line 4164 data fork:
ino 0x140bb3 nr 0x0 nr_real 0x0 offset 0xb9 blockcount 0x1f startblock 0x935de2 state 1
ino 0x140bb3 nr 0x1 nr_real 0x1 offset 0xe6 blockcount 0xa startblock 0xffffffffe0007 state 0
ino 0x140bb3 nr 0x2 nr_real 0x1 offset 0xd8 blockcount 0xe startblock 0x935e01 state 0
Here we see that a delalloc extent was inserted into the wrong position
in the iext leaf, same as all the other times. The extra trace data I
collected are as follows:
ino 0x140bb3 fork 0 oldoff 0xe6 oldlen 0x4 oldprealloc 0x6 isize 0xe6000
ino 0x140bb3 oldgotoff 0xea oldgotstart 0xfffffffffffffffe oldgotcount 0x0 oldgotstate 0
ino 0x140bb3 crapgotoff 0x0 crapgotstart 0x0 crapgotcount 0x0 crapgotstate 0
ino 0x140bb3 freshgotoff 0xd8 freshgotstart 0x935e01 freshgotcount 0xe freshgotstate 0
ino 0x140bb3 nowgotoff 0xe6 nowgotstart 0xffffffffe0007 nowgotcount 0xa nowgotstate 0
ino 0x140bb3 oldicurpos 1 oldleafnr 2 oldleaf 0xfffffc00f0609a00
ino 0x140bb3 crapicurpos 2 crapleafnr 2 crapleaf 0xfffffc00f0609a00
ino 0x140bb3 freshicurpos 1 freshleafnr 2 freshleaf 0xfffffc00f0609a00
ino 0x140bb3 newicurpos 1 newleafnr 3 newleaf 0xfffffc00f0609a00
The first line shows that xfs_bmapi_reserve_delalloc was called with
whichfork=XFS_DATA_FORK, off=0xe6, len=0x4, prealloc=6.
The second line ("oldgot") shows the contents of @got at the beginning
of the call, which are the results of the first iext lookup in
xfs_buffered_write_iomap_begin.
Line 3 ("crapgot") is the result of duplicating the cursor at the start
of the body of xfs_bmapi_reserve_delalloc and performing a fresh lookup
at @off.
Line 4 ("freshgot") is the result of a new xfs_iext_get_extent right
before the call to xfs_bmap_add_extent_hole_delay. Totally garbage.
Line 5 ("nowgot") is contents of @got after the
xfs_bmap_add_extent_hole_delay call.
Line 6 is the contents of @icur at the beginning fo the call. Lines 7-9
are the contents of the iext cursors at the point where the block
mappings were sampled.
I think @oldgot is a HOLESTARTBLOCK extent because the first lookup
didn't find anything, so we filled in imap with "fake hole until the
end". At the time of the first lookup, I suspect that there's only one
32-block unwritten extent in the mapping (hence oldicurpos==1) but by
the time we get to recording crapgot, crapicurpos==2.
Dave then added:
Ok, that's much simpler to reason about, and implies the smoke is
coming from xfs_buffered_write_iomap_begin() or
xfs_bmapi_reserve_delalloc(). I suspect the former - it does a lot
of stuff with the ILOCK_EXCL held.....
.... including calling xfs_qm_dqattach_locked().
xfs_buffered_write_iomap_begin
ILOCK_EXCL
look up icur
xfs_qm_dqattach_locked
xfs_qm_dqattach_one
xfs_qm_dqget_inode
dquot cache miss
xfs_iunlock(ip, XFS_ILOCK_EXCL);
error = xfs_qm_dqread(mp, id, type, can_alloc, &dqp);
xfs_ilock(ip, XFS_ILOCK_EXCL);
....
xfs_bmapi_reserve_delalloc(icur)
Yup, that's what is letting the magic smoke out -
xfs_qm_dqattach_locked() can cycle the ILOCK. If that happens, we
can pass a stale icur to xfs_bmapi_reserve_delalloc() and it all
goes downhill from there.
Back to Darrick now:
So. Fix this by moving the dqattach_locked call up before we take the
ILOCK, like all the other callers in that file.
Fixes: a526c85c22 ("xfs: move xfs_file_iomap_begin_delay around") # goes further back than this
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Add a new error injection knob so that we can arbitrarily slow down
pagecache writes to test for race conditions and aberrant reclaim
behavior if the writeback mechanisms are slow to issue writeback. This
will enable functional testing for the ifork sequence counters
introduced in commit 304a68b9c6 ("xfs: use iomap_valid method to
detect stale cached iomaps") that fixes write racing with reclaim
writeback.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
With the changes to scan the page cache for dirty data to avoid data
corruptions from partial write cleanup racing with other page cache
operations, the drop writes error injection no longer works the same
way it used to and causes xfs/196 to fail. This is because xfs/196
writes to the file and populates the page cache before it turns on
the error injection and starts failing -overwrites-.
The result is that the original drop-writes code failed writes only
-after- overwriting the data in the cache, followed by invalidates
the cached data, then punching out the delalloc extent from under
that data.
On the surface, this looks fine. The problem is that page cache
invalidation *doesn't guarantee that it removes anything from the
page cache* and it doesn't change the dirty state of the folio. When
block size == page size and we do page aligned IO (as xfs/196 does)
everything happens to align perfectly and page cache invalidation
removes the single page folios that span the written data. Hence the
followup delalloc punch pass does not find cached data over that
range and it can punch the extent out.
IOWs, xfs/196 "works" for block size == page size with the new
code. I say "works", because it actually only works for the case
where IO is page aligned, and no data was read from disk before
writes occur. Because the moment we actually read data first, the
readahead code allocates multipage folios and suddenly the
invalidate code goes back to zeroing subfolio ranges without
changing dirty state.
Hence, with multipage folios in play, block size == page size is
functionally identical to block size < page size behaviour, and
drop-writes is manifestly broken w.r.t to this case. Invalidation of
a subfolio range doesn't result in the folio being removed from the
cache, just the range gets zeroed. Hence after we've sequentially
walked over a folio that we've dirtied (via write data) and then
invalidated, we end up with a dirty folio full of zeroed data.
And because the new code skips punching ranges that have dirty
folios covering them, we end up leaving the delalloc range intact
after failing all the writes. Hence failed writes now end up
writing zeroes to disk in the cases where invalidation zeroes folios
rather than removing them from cache.
This is a fundamental change of behaviour that is needed to avoid
the data corruption vectors that exist in the old write fail path,
and it renders the drop-writes injection non-functional and
unworkable as it stands.
As it is, I think the error injection is also now unnecessary, as
partial writes that need delalloc extent are going to be a lot more
common with stale iomap detection in place. Hence this patch removes
the drop-writes error injection completely. xfs/196 can remain for
testing kernels that don't have this data corruption fix, but those
that do will report:
xfs/196 3s ... [not run] XFS error injection drop_writes unknown on this kernel.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Now that iomap supports a mechanism to validate cached iomaps for
buffered write operations, hook it up to the XFS buffered write ops
so that we can avoid data corruptions that result from stale cached
iomaps. See:
https://lore.kernel.org/linux-xfs/20220817093627.GZ3600936@dread.disaster.area/
or the ->iomap_valid() introduction commit for exact details of the
corruption vector.
The validity cookie we store in the iomap is based on the type of
iomap we return. It is expected that the iomap->flags we set in
xfs_bmbt_to_iomap() is not perturbed by the iomap core and are
returned to us in the iomap passed via the .iomap_valid() callback.
This ensures that the validity cookie is always checking the correct
inode fork sequence numbers to detect potential changes that affect
the extent cached by the iomap.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
All the callers of xfs_bmap_punch_delalloc_range() jump through
hoops to convert a byte range to filesystem blocks before calling
xfs_bmap_punch_delalloc_range(). Instead, pass the byte range to
xfs_bmap_punch_delalloc_range() and have it do the conversion to
filesystem blocks internally.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Because that's what Christoph wants for this error handling path
only XFS uses.
It requires a new iomap export for handling errors over delalloc
ranges. This is basically the XFS code as is stands, but even though
Christoph wants this as iomap funcitonality, we still have
to call it from the filesystem specific ->iomap_end callback, and
call into the iomap code with yet another filesystem specific
callback to punch the delalloc extent within the defined ranges.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
xfs_buffered_write_iomap_end() currently converts the byte ranges
passed to it to filesystem blocks to pass them to the bmap code to
punch out delalloc blocks, but then has to convert filesytem
blocks back to byte ranges for page cache truncate.
We're about to make the page cache truncate go away and replace it
with a page cache walk, so having to convert everything to/from/to
filesystem blocks is messy and error-prone. It is much easier to
pass around byte ranges and convert to page indexes and/or
filesystem blocks only where those units are needed.
In preparation for the page cache walk being added, add a helper
that converts byte ranges to filesystem blocks and calls
xfs_bmap_punch_delalloc_range() and convert
xfs_buffered_write_iomap_end() to calculate limits in byte ranges.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
xfs_buffered_write_iomap_end() has a comment about the safety of
punching delalloc extents based holding the IOLOCK_EXCL. This
comment is wrong, and punching delalloc extents is not race free.
When we punch out a delalloc extent after a write failure in
xfs_buffered_write_iomap_end(), we punch out the page cache with
truncate_pagecache_range() before we punch out the delalloc extents.
At this point, we only hold the IOLOCK_EXCL, so there is nothing
stopping mmap() write faults racing with this cleanup operation,
reinstantiating a folio over the range we are about to punch and
hence requiring the delalloc extent to be kept.
If this race condition is hit, we can end up with a dirty page in
the page cache that has no delalloc extent or space reservation
backing it. This leads to bad things happening at writeback time.
To avoid this race condition, we need the page cache truncation to
be atomic w.r.t. the extent manipulation. We can do this by holding
the mapping->invalidate_lock exclusively across this operation -
this will prevent new pages from being inserted into the page cache
whilst we are removing the pages and the backing extent and space
reservation.
Taking the mapping->invalidate_lock exclusively in the buffered
write IO path is safe - it naturally nests inside the IOLOCK (see
truncate and fallocate paths). iomap_zero_range() can be called from
under the mapping->invalidate_lock (from the truncate path via
either xfs_zero_eof() or xfs_truncate_page(), but iomap_zero_iter()
will not instantiate new delalloc pages (because it skips holes) and
hence will not ever need to punch out delalloc extents on failure.
Fix the locking issue, and clean up the code logic a little to avoid
unnecessary work if we didn't allocate the delalloc extent or wrote
the entire region we allocated.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
When we reserve a delalloc region in xfs_buffered_write_iomap_begin,
we mark the iomap as IOMAP_F_NEW so that the the write context
understands that it allocated the delalloc region.
If we then fail that buffered write, xfs_buffered_write_iomap_end()
checks for the IOMAP_F_NEW flag and if it is set, it punches out
the unused delalloc region that was allocated for the write.
The assumption this code makes is that all buffered write operations
that can allocate space are run under an exclusive lock (i_rwsem).
This is an invalid assumption: page faults in mmap()d regions call
through this same function pair to map the file range being faulted
and this runs only holding the inode->i_mapping->invalidate_lock in
shared mode.
IOWs, we can have races between page faults and write() calls that
fail the nested page cache write operation that result in data loss.
That is, the failing iomap_end call will punch out the data that
the other racing iomap iteration brought into the page cache. This
can be reproduced with generic/34[46] if we arbitrarily fail page
cache copy-in operations from write() syscalls.
Code analysis tells us that the iomap_page_mkwrite() function holds
the already instantiated and uptodate folio locked across the iomap
mapping iterations. Hence the folio cannot be removed from memory
whilst we are mapping the range it covers, and as such we do not
care if the mapping changes state underneath the iomap iteration
loop:
1. if the folio is not already dirty, there is no writeback races
possible.
2. if we allocated the mapping (delalloc or unwritten), the folio
cannot already be dirty. See #1.
3. If the folio is already dirty, it must be up to date. As we hold
it locked, it cannot be reclaimed from memory. Hence we always
have valid data in the page cache while iterating the mapping.
4. Valid data in the page cache can exist when the underlying
mapping is DELALLOC, UNWRITTEN or WRITTEN. Having the mapping
change from DELALLOC->UNWRITTEN or UNWRITTEN->WRITTEN does not
change the data in the page - it only affects actions if we are
initialising a new page. Hence #3 applies and we don't care
about these extent map transitions racing with
iomap_page_mkwrite().
5. iomap_page_mkwrite() checks for page invalidation races
(truncate, hole punch, etc) after it locks the folio. We also
hold the mapping->invalidation_lock here, and hence the mapping
cannot change due to extent removal operations while we are
iterating the folio.
As such, filesystems that don't use bufferheads will never fail
the iomap_folio_mkwrite_iter() operation on the current mapping,
regardless of whether the iomap should be considered stale.
Further, the range we are asked to iterate is limited to the range
inside EOF that the folio spans. Hence, for XFS, we will only map
the exact range we are asked for, and we will only do speculative
preallocation with delalloc if we are mapping a hole at the EOF
page. The iterator will consume the entire range of the folio that
is within EOF, and anything beyond the EOF block cannot be accessed.
We never need to truncate this post-EOF speculative prealloc away in
the context of the iomap_page_mkwrite() iterator because if it
remains unused we'll remove it when the last reference to the inode
goes away.
Hence we don't actually need an .iomap_end() cleanup/error handling
path at all for iomap_page_mkwrite() for XFS. This means we can
separate the page fault processing from the complexity of the
.iomap_end() processing in the buffered write path. This also means
that the buffered write path will also be able to take the
mapping->invalidate_lock as necessary.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve latency
and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place
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Merge tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Most of the MM queue. A few things are still pending.
Liam's maple tree rework didn't make it. This has resulted in a few
other minor patch series being held over for next time.
Multi-gen LRU still isn't merged as we were waiting for mapletree to
stabilize. The current plan is to merge MGLRU into -mm soon and to
later reintroduce mapletree, with a view to hopefully getting both
into 6.1-rc1.
Summary:
- The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve
latency and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place"
[ XFS merge from hell as per Darrick Wong in
https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]
* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
tools/testing/selftests/vm/hmm-tests.c: fix build
mm: Kconfig: fix typo
mm: memory-failure: convert to pr_fmt()
mm: use is_zone_movable_page() helper
hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
hugetlbfs: cleanup some comments in inode.c
hugetlbfs: remove unneeded header file
hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
hugetlbfs: use helper macro SZ_1{K,M}
mm: cleanup is_highmem()
mm/hmm: add a test for cross device private faults
selftests: add soft-dirty into run_vmtests.sh
selftests: soft-dirty: add test for mprotect
mm/mprotect: fix soft-dirty check in can_change_pte_writable()
mm: memcontrol: fix potential oom_lock recursion deadlock
mm/gup.c: fix formatting in check_and_migrate_movable_page()
xfs: fail dax mount if reflink is enabled on a partition
mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
userfaultfd: don't fail on unrecognized features
hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
...
- Improve scalability of the XFS log by removing spinlocks and global
synchronization points.
- Add security labels to whiteout inodes to match the other filesystems.
- Clean up per-ag pointer passing to simplify call sites.
- Reduce verifier overhead by precalculating more AG geometry.
- Implement fast-path lockless lookups in the buffer cache to reduce
spinlock hammering.
- Make attr forks a permanent part of the inode structure to fix a UAF
bug and because most files these days tend to have security labels and
soon will have parent pointers too.
- Clean up XFS_IFORK_Q usage and give it a better name.
- Fix more UAF bugs in the xattr code.
- SOB my tags.
- Fix some typos in the timestamp range documentation.
- Fix a few more memory leaks.
- Code cleanups and typo fixes.
- Fix an unlocked inode fork pointer access in getbmap.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Merge tag 'xfs-5.20-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull xfs updates from Darrick Wong:
"The biggest changes for this release are the log scalability
improvements, lockless lookups for the buffer cache, and making the
attr fork a permanent part of the incore inode in preparation for
directory parent pointers.
There's also a bunch of bug fixes that have accumulated since -rc5. I
might send you a second pull request with some more bug fixes that I'm
still working on.
Once the merge window ends, I will hand maintainership back to Dave
Chinner until the 6.1-rc1 release so that I can conduct the design
review for the online fsck feature, and try to get it merged.
Summary:
- Improve scalability of the XFS log by removing spinlocks and global
synchronization points.
- Add security labels to whiteout inodes to match the other
filesystems.
- Clean up per-ag pointer passing to simplify call sites.
- Reduce verifier overhead by precalculating more AG geometry.
- Implement fast-path lockless lookups in the buffer cache to reduce
spinlock hammering.
- Make attr forks a permanent part of the inode structure to fix a
UAF bug and because most files these days tend to have security
labels and soon will have parent pointers too.
- Clean up XFS_IFORK_Q usage and give it a better name.
- Fix more UAF bugs in the xattr code.
- SOB my tags.
- Fix some typos in the timestamp range documentation.
- Fix a few more memory leaks.
- Code cleanups and typo fixes.
- Fix an unlocked inode fork pointer access in getbmap"
* tag 'xfs-5.20-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (61 commits)
xfs: delete extra space and tab in blank line
xfs: fix NULL pointer dereference in xfs_getbmap()
xfs: Fix typo 'the the' in comment
xfs: Fix comment typo
xfs: don't leak memory when attr fork loading fails
xfs: fix for variable set but not used warning
xfs: xfs_buf cache destroy isn't RCU safe
xfs: delete unnecessary NULL checks
xfs: fix comment for start time value of inode with bigtime enabled
xfs: fix use-after-free in xattr node block inactivation
xfs: lockless buffer lookup
xfs: remove a superflous hash lookup when inserting new buffers
xfs: reduce the number of atomic when locking a buffer after lookup
xfs: merge xfs_buf_find() and xfs_buf_get_map()
xfs: break up xfs_buf_find() into individual pieces
xfs: add in-memory iunlink log item
xfs: add log item precommit operation
xfs: combine iunlink inode update functions
xfs: clean up xfs_iunlink_update_inode()
xfs: double link the unlinked inode list
...
This adds the async buffered write support to XFS. For async buffered
write requests, the request will return -EAGAIN if the ilock cannot be
obtained immediately.
Signed-off-by: Stefan Roesch <shr@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20220623175157.1715274-15-shr@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch changes the helper function xfs_ilock_for_iomap such that the
lock mode must be passed in.
Signed-off-by: Stefan Roesch <shr@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20220623175157.1715274-14-shr@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In fsdax mode, WRITE and ZERO on a shared extent need CoW performed.
After that, new allocated extents needs to be remapped to the file. So,
add a CoW identification in ->iomap_begin(), and implement ->iomap_end()
to do the remapping work.
[akpm@linux-foundation.org: make xfs_dax_fault() static]
Link: https://lkml.kernel.org/r/20220603053738.1218681-14-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.wiliams@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace this shouty macro with a real C function that has a more
descriptive name.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Syzkaller reported a UAF bug a while back:
==================================================================
BUG: KASAN: use-after-free in xfs_ilock_attr_map_shared+0xe3/0xf6 fs/xfs/xfs_inode.c:127
Read of size 4 at addr ffff88802cec919c by task syz-executor262/2958
CPU: 2 PID: 2958 Comm: syz-executor262 Not tainted
5.15.0-0.30.3-20220406_1406 #3
Hardware name: Red Hat KVM, BIOS 1.13.0-2.module+el8.3.0+7860+a7792d29
04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x82/0xa9 lib/dump_stack.c:106
print_address_description.constprop.9+0x21/0x2d5 mm/kasan/report.c:256
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold.14+0x7f/0x11b mm/kasan/report.c:459
xfs_ilock_attr_map_shared+0xe3/0xf6 fs/xfs/xfs_inode.c:127
xfs_attr_get+0x378/0x4c2 fs/xfs/libxfs/xfs_attr.c:159
xfs_xattr_get+0xe3/0x150 fs/xfs/xfs_xattr.c:36
__vfs_getxattr+0xdf/0x13d fs/xattr.c:399
cap_inode_need_killpriv+0x41/0x5d security/commoncap.c:300
security_inode_need_killpriv+0x4c/0x97 security/security.c:1408
dentry_needs_remove_privs.part.28+0x21/0x63 fs/inode.c:1912
dentry_needs_remove_privs+0x80/0x9e fs/inode.c:1908
do_truncate+0xc3/0x1e0 fs/open.c:56
handle_truncate fs/namei.c:3084 [inline]
do_open fs/namei.c:3432 [inline]
path_openat+0x30ab/0x396d fs/namei.c:3561
do_filp_open+0x1c4/0x290 fs/namei.c:3588
do_sys_openat2+0x60d/0x98c fs/open.c:1212
do_sys_open+0xcf/0x13c fs/open.c:1228
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0x0
RIP: 0033:0x7f7ef4bb753d
Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48
89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73
01 c3 48 8b 0d 1b 79 2c 00 f7 d8 64 89 01 48
RSP: 002b:00007f7ef52c2ed8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 0000000000404148 RCX: 00007f7ef4bb753d
RDX: 00007f7ef4bb753d RSI: 0000000000000000 RDI: 0000000020004fc0
RBP: 0000000000404140 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e
R13: 00007ffd794db37f R14: 00007ffd794db470 R15: 00007f7ef52c2fc0
</TASK>
Allocated by task 2953:
kasan_save_stack+0x19/0x38 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
__kasan_slab_alloc+0x68/0x7c mm/kasan/common.c:467
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook mm/slab.h:519 [inline]
slab_alloc_node mm/slub.c:3213 [inline]
slab_alloc mm/slub.c:3221 [inline]
kmem_cache_alloc+0x11b/0x3eb mm/slub.c:3226
kmem_cache_zalloc include/linux/slab.h:711 [inline]
xfs_ifork_alloc+0x25/0xa2 fs/xfs/libxfs/xfs_inode_fork.c:287
xfs_bmap_add_attrfork+0x3f2/0x9b1 fs/xfs/libxfs/xfs_bmap.c:1098
xfs_attr_set+0xe38/0x12a7 fs/xfs/libxfs/xfs_attr.c:746
xfs_xattr_set+0xeb/0x1a9 fs/xfs/xfs_xattr.c:59
__vfs_setxattr+0x11b/0x177 fs/xattr.c:180
__vfs_setxattr_noperm+0x128/0x5e0 fs/xattr.c:214
__vfs_setxattr_locked+0x1d4/0x258 fs/xattr.c:275
vfs_setxattr+0x154/0x33d fs/xattr.c:301
setxattr+0x216/0x29f fs/xattr.c:575
__do_sys_fsetxattr fs/xattr.c:632 [inline]
__se_sys_fsetxattr fs/xattr.c:621 [inline]
__x64_sys_fsetxattr+0x243/0x2fe fs/xattr.c:621
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0x0
Freed by task 2949:
kasan_save_stack+0x19/0x38 mm/kasan/common.c:38
kasan_set_track+0x1c/0x21 mm/kasan/common.c:46
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free mm/kasan/common.c:328 [inline]
__kasan_slab_free+0xe2/0x10e mm/kasan/common.c:374
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1700 [inline]
slab_free_freelist_hook mm/slub.c:1726 [inline]
slab_free mm/slub.c:3492 [inline]
kmem_cache_free+0xdc/0x3ce mm/slub.c:3508
xfs_attr_fork_remove+0x8d/0x132 fs/xfs/libxfs/xfs_attr_leaf.c:773
xfs_attr_sf_removename+0x5dd/0x6cb fs/xfs/libxfs/xfs_attr_leaf.c:822
xfs_attr_remove_iter+0x68c/0x805 fs/xfs/libxfs/xfs_attr.c:1413
xfs_attr_remove_args+0xb1/0x10d fs/xfs/libxfs/xfs_attr.c:684
xfs_attr_set+0xf1e/0x12a7 fs/xfs/libxfs/xfs_attr.c:802
xfs_xattr_set+0xeb/0x1a9 fs/xfs/xfs_xattr.c:59
__vfs_removexattr+0x106/0x16a fs/xattr.c:468
cap_inode_killpriv+0x24/0x47 security/commoncap.c:324
security_inode_killpriv+0x54/0xa1 security/security.c:1414
setattr_prepare+0x1a6/0x897 fs/attr.c:146
xfs_vn_change_ok+0x111/0x15e fs/xfs/xfs_iops.c:682
xfs_vn_setattr_size+0x5f/0x15a fs/xfs/xfs_iops.c:1065
xfs_vn_setattr+0x125/0x2ad fs/xfs/xfs_iops.c:1093
notify_change+0xae5/0x10a1 fs/attr.c:410
do_truncate+0x134/0x1e0 fs/open.c:64
handle_truncate fs/namei.c:3084 [inline]
do_open fs/namei.c:3432 [inline]
path_openat+0x30ab/0x396d fs/namei.c:3561
do_filp_open+0x1c4/0x290 fs/namei.c:3588
do_sys_openat2+0x60d/0x98c fs/open.c:1212
do_sys_open+0xcf/0x13c fs/open.c:1228
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0x0
The buggy address belongs to the object at ffff88802cec9188
which belongs to the cache xfs_ifork of size 40
The buggy address is located 20 bytes inside of
40-byte region [ffff88802cec9188, ffff88802cec91b0)
The buggy address belongs to the page:
page:00000000c3af36a1 refcount:1 mapcount:0 mapping:0000000000000000
index:0x0 pfn:0x2cec9
flags: 0xfffffc0000200(slab|node=0|zone=1|lastcpupid=0x1fffff)
raw: 000fffffc0000200 ffffea00009d2580 0000000600000006 ffff88801a9ffc80
raw: 0000000000000000 0000000080490049 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88802cec9080: fb fb fb fc fc fa fb fb fb fb fc fc fb fb fb fb
ffff88802cec9100: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc
>ffff88802cec9180: fc fa fb fb fb fb fc fc fa fb fb fb fb fc fc fb
^
ffff88802cec9200: fb fb fb fb fc fc fb fb fb fb fb fc fc fb fb fb
ffff88802cec9280: fb fb fc fc fa fb fb fb fb fc fc fa fb fb fb fb
==================================================================
The root cause of this bug is the unlocked access to xfs_inode.i_afp
from the getxattr code paths while trying to determine which ILOCK mode
to use to stabilize the xattr data. Unfortunately, the VFS does not
acquire i_rwsem when vfs_getxattr (or listxattr) call into the
filesystem, which means that getxattr can race with a removexattr that's
tearing down the attr fork and crash:
xfs_attr_set: xfs_attr_get:
xfs_attr_fork_remove: xfs_ilock_attr_map_shared:
xfs_idestroy_fork(ip->i_afp);
kmem_cache_free(xfs_ifork_cache, ip->i_afp);
if (ip->i_afp &&
ip->i_afp = NULL;
xfs_need_iread_extents(ip->i_afp))
<KABOOM>
ip->i_forkoff = 0;
Regrettably, the VFS is much more lax about i_rwsem and getxattr than
is immediately obvious -- not only does it not guarantee that we hold
i_rwsem, it actually doesn't guarantee that we *don't* hold it either.
The getxattr system call won't acquire the lock before calling XFS, but
the file capabilities code calls getxattr with and without i_rwsem held
to determine if the "security.capabilities" xattr is set on the file.
Fixing the VFS locking requires a treewide investigation into every code
path that could touch an xattr and what i_rwsem state it expects or sets
up. That could take years or even prove impossible; fortunately, we
can fix this UAF problem inside XFS.
An earlier version of this patch used smp_wmb in xfs_attr_fork_remove to
ensure that i_forkoff is always zeroed before i_afp is set to null and
changed the read paths to use smp_rmb before accessing i_forkoff and
i_afp, which avoided these UAF problems. However, the patch author was
too busy dealing with other problems in the meantime, and by the time he
came back to this issue, the situation had changed a bit.
On a modern system with selinux, each inode will always have at least
one xattr for the selinux label, so it doesn't make much sense to keep
incurring the extra pointer dereference. Furthermore, Allison's
upcoming parent pointer patchset will also cause nearly every inode in
the filesystem to have extended attributes. Therefore, make the inode
attribute fork structure part of struct xfs_inode, at a cost of 40 more
bytes.
This patch adds a clunky if_present field where necessary to maintain
the existing logic of xattr fork null pointer testing in the existing
codebase. The next patch switches the logic over to XFS_IFORK_Q and it
all goes away.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
We're about to make this logic do a bit more, so convert the macro to a
static inline function for better typechecking and fewer shouty macros.
No functional changes here.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
This commit enables upgrading existing inodes to use large extent counters
provided that underlying filesystem's superblock has large extent counter
feature enabled.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
The maximum extent length depends on maximum block count that can be stored in
a BMBT record. Hence this commit defines MAXEXTLEN based on
BMBT_BLOCKCOUNT_BITLEN.
While at it, the commit also renames MAXEXTLEN to XFS_MAX_BMBT_EXTLEN.
Suggested-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Remove the last user of ->bdev in dax.c by requiring the file system to
pass in an address that already includes the DAX offset. As part of the
only set ->bdev or ->daxdev when actually required in the ->iomap_begin
methods.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> [erofs]
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-27-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Add a flag so that the file system can easily detect DAX operations
based just on the iomap operation requested instead of looking at
inode state using IS_DAX. This will be needed to apply the to be
added partition offset only for operations that actually use DAX,
but not things like fiemap that are based on the block device.
In the long run it should also allow turning the bdev, dax_dev
and inline_data into a union.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-25-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
To prepare for looking at the IOMAP_DAX flag in xfs_bmbt_to_iomap pass in
the input mapping flags to xfs_bmbt_to_iomap.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-24-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
While the buffered write iomap ops do work due to the fact that zeroing
never allocates blocks, the DAX zeroing should use the direct ops just
like actual DAX I/O.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-23-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Unshare the DAX and iomap buffered I/O page zeroing code. This code
previously did a IS_DAX check deep inside the iomap code, which in
fact was the only DAX check in the code. Instead move these checks
into the callers. Most callers already have DAX special casing anyway
and XFS will need it for reflink support as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-19-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Add helpers to prepare for using different DAX operations.
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
[hch: split from a larger patch + slight cleanups]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-16-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
While prototyping a free space defragmentation tool, I observed an
unexpected IO error while running a sequence of commands that can be
recreated by the following sequence of commands:
# xfs_io -f -c "pwrite -S 0x58 -b 10m 0 10m" file1
# cp --reflink=always file1 file2
# punch-alternating -o 1 file2
# xfs_io -c "funshare 0 10m" file2
fallocate: Input/output error
I then scraped this (abbreviated) stack trace from dmesg:
WARNING: CPU: 0 PID: 30788 at fs/iomap/buffered-io.c:577 iomap_write_begin+0x376/0x450
CPU: 0 PID: 30788 Comm: xfs_io Not tainted 5.14.0-rc6-xfsx #rc6 5ef57b62a900814b3e4d885c755e9014541c8732
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:iomap_write_begin+0x376/0x450
RSP: 0018:ffffc90000c0fc20 EFLAGS: 00010297
RAX: 0000000000000001 RBX: ffffc90000c0fd10 RCX: 0000000000001000
RDX: ffffc90000c0fc54 RSI: 000000000000000c RDI: 000000000000000c
RBP: ffff888005d5dbd8 R08: 0000000000102000 R09: ffffc90000c0fc50
R10: 0000000000b00000 R11: 0000000000101000 R12: ffffea0000336c40
R13: 0000000000001000 R14: ffffc90000c0fd10 R15: 0000000000101000
FS: 00007f4b8f62fe40(0000) GS:ffff88803ec00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056361c554108 CR3: 000000000524e004 CR4: 00000000001706f0
Call Trace:
iomap_unshare_actor+0x95/0x140
iomap_apply+0xfa/0x300
iomap_file_unshare+0x44/0x60
xfs_reflink_unshare+0x50/0x140 [xfs 61947ea9b3a73e79d747dbc1b90205e7987e4195]
xfs_file_fallocate+0x27c/0x610 [xfs 61947ea9b3a73e79d747dbc1b90205e7987e4195]
vfs_fallocate+0x133/0x330
__x64_sys_fallocate+0x3e/0x70
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f4b8f79140a
Looking at the iomap tracepoints, I saw this:
iomap_iter: dev 8:64 ino 0x100 pos 0 length 0 flags WRITE|0x80 (0x81) ops xfs_buffered_write_iomap_ops caller iomap_file_unshare
iomap_iter_dstmap: dev 8:64 ino 0x100 bdev 8:64 addr -1 offset 0 length 131072 type DELALLOC flags SHARED
iomap_iter_srcmap: dev 8:64 ino 0x100 bdev 8:64 addr 147456 offset 0 length 4096 type MAPPED flags
iomap_iter: dev 8:64 ino 0x100 pos 0 length 4096 flags WRITE|0x80 (0x81) ops xfs_buffered_write_iomap_ops caller iomap_file_unshare
iomap_iter_dstmap: dev 8:64 ino 0x100 bdev 8:64 addr -1 offset 4096 length 4096 type DELALLOC flags SHARED
console: WARNING: CPU: 0 PID: 30788 at fs/iomap/buffered-io.c:577 iomap_write_begin+0x376/0x450
The first time funshare calls ->iomap_begin, xfs sees that the first
block is shared and creates a 128k delalloc reservation in the COW fork.
The delalloc reservation is returned as dstmap, and the shared block is
returned as srcmap. So far so good.
funshare calls ->iomap_begin to try the second block. This time there's
no srcmap (punch-alternating punched it out!) but we still have the
delalloc reservation in the COW fork. Therefore, we again return the
reservation as dstmap and the hole as srcmap. iomap_unshare_iter
incorrectly tries to unshare the hole, which __iomap_write_begin rejects
because shared regions must be fully written and therefore cannot
require zeroing.
Therefore, change the buffered write iomap_begin function not to set
IOMAP_F_SHARED when there isn't a source mapping to read from for the
unsharing.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Remove the shouty macro and instead use the inline function that
matches other state/feature check wrapper naming. This conversion
was done with sed.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Replace m_flags feature checks with xfs_has_<feature>() calls and
rework the setup code to set flags in m_features.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
In preparation to enable -Wimplicit-fallthrough for Clang, fix
the following warnings by replacing /* fall through */ comments,
and its variants, with the new pseudo-keyword macro fallthrough:
fs/xfs/libxfs/xfs_alloc.c:3167:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_da_btree.c:286:3: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_ag_resv.c:346:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_ag_resv.c:388:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_bmap_util.c:246:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_export.c:88:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_export.c:96:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_file.c:867:3: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_ioctl.c:562:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_ioctl.c:1548:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_iomap.c:1040:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_inode.c:852:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_log.c:2627:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/xfs_trans_buf.c:298:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/bmap.c:275:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/btree.c:48:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/common.c:85:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/common.c:138:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/common.c:698:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/dabtree.c:51:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/repair.c:951:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/scrub/agheader.c:89:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
Notice that Clang doesn't recognize /* fall through */ comments as
implicit fall-through markings, so in order to globally enable
-Wimplicit-fallthrough for Clang, these comments need to be
replaced with fallthrough; in the whole codebase.
Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
The in-memory XFS_IFEXTENTS is now only used to check if an inode with
extents still needs the extents to be read into memory before doing
operations that need the extent map. Add a new xfs_need_iread_extents
helper that returns true for btree format forks that do not have any
entries in the in-memory extent btree, and use that instead of checking
the XFS_IFEXTENTS flag.
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>
Move the XFS_IFEXTENTS check from the callers into xfs_iread_extents to
simplify the code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
In preparation of removing the historic icinode struct, move the on-disk
size field into the containing xfs_inode structure.
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>
With dax enabled filesystems, a direct write operation into an existing
unwritten extent results in xfs_iomap_write_direct() zero-ing and converting
the extent into a normal extent before the actual data is copied from the
userspace buffer.
The inode extent count can increase by 2 if the extent range being written to
maps to the middle of the existing unwritten extent range. Hence this commit
uses XFS_IEXT_WRITE_UNWRITTEN_CNT as the extent count delta when such a write
operation is being performed.
Fixes: 727e1acd29 ("xfs: Check for extent overflow when trivally adding a new extent")
Reported-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
- Fix an ABBA deadlock when renaming files on overlayfs.
- Make sure that we can't overflow the inode extent counters when adding
to or removing extents from a file.
- Make directory sgid inheritance work the same way as all the other
filesystems.
- Don't drain the buffer cache on freeze and ro remount, which should
reduce the amount of time if read-only workloads are continuing
during the freeze.
- Fix a bug where symlink size isn't reported to the vfs in ecryptfs.
- Disentangle log cleaning from log covering. This refactoring sets us
up for future changes to the log, though for now it simply means that
we can use covering for freezes, and cleaning becomes something we
only do at unmount.
- Speed up file fsyncs by reducing iolock cycling.
- Fix delalloc blocks leaking when changing the project id fails because
of input validation errors in FSSETXATTR.
- Fix oversized quota reservation when converting unwritten extents
during a DAX write.
- Create a transaction allocation helper function to standardize the
idiom of allocating a transaction, reserving blocks, locking inodes,
and reserving quota. Replace all the open-coded logic for file
creation, file ownership changes, and file modifications to use them.
- Actually shut down the fs if the incore quota reservations get
corrupted.
- Fix background block garbage collection scans to not block and to
actually clean out CoW staging extents properly.
- Run block gc scans when we run low on project quota.
- Use the standardized transaction allocation helpers to make it so that
ENOSPC and EDQUOT errors during reservation will back out, invoke the
block gc scanner, and try again. This is preparation for introducing
background inode garbage collection in the next cycle.
- Combine speculative post-EOF block garbage collection with speculative
copy on write block garbage collection.
- Enable multithreaded quotacheck.
- Allow sysadmins to tweak the CPU affinities and maximum concurrency
levels of quotacheck and background blockgc worker pools.
- Expose the inode btree counter feature in the fs geometry ioctl.
- Cleanups of the growfs code in preparation for starting work on
filesystem shrinking.
- Fix all the bloody gcc warnings that the maintainer knows about. :P
- Fix a RST syntax error.
- Don't trigger bmbt corruption assertions after the fs shuts down.
- Restore behavior of forcing SIGBUS on a shut down filesystem when
someone triggers a mmap write fault (or really, any buffered write).
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Merge tag 'xfs-5.12-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull xfs updates from Darrick Wong:
"There's a lot going on this time, which seems about right for this
drama-filled year.
Community developers added some code to speed up freezing when
read-only workloads are still running, refactored the logging code,
added checks to prevent file extent counter overflow, reduced iolock
cycling to speed up fsync and gc scans, and started the slow march
towards supporting filesystem shrinking.
There's a huge refactoring of the internal speculative preallocation
garbage collection code which fixes a bunch of bugs, makes the gc
scheduling per-AG and hence multithreaded, and standardizes the retry
logic when we try to reserve space or quota, can't, and want to
trigger a gc scan. We also enable multithreaded quotacheck to reduce
mount times further. This is also preparation for background file gc,
which may or may not land for 5.13.
We also fixed some deadlocks in the rename code, fixed a quota
accounting leak when FSSETXATTR fails, restored the behavior that
write faults to an mmap'd region actually cause a SIGBUS, fixed a bug
where sgid directory inheritance wasn't quite working properly, and
fixed a bug where symlinks weren't working properly in ecryptfs. We
also now advertise the inode btree counters feature that was
introduced two cycles ago.
Summary:
- Fix an ABBA deadlock when renaming files on overlayfs.
- Make sure that we can't overflow the inode extent counters when
adding to or removing extents from a file.
- Make directory sgid inheritance work the same way as all the other
filesystems.
- Don't drain the buffer cache on freeze and ro remount, which should
reduce the amount of time if read-only workloads are continuing
during the freeze.
- Fix a bug where symlink size isn't reported to the vfs in ecryptfs.
- Disentangle log cleaning from log covering. This refactoring sets
us up for future changes to the log, though for now it simply means
that we can use covering for freezes, and cleaning becomes
something we only do at unmount.
- Speed up file fsyncs by reducing iolock cycling.
- Fix delalloc blocks leaking when changing the project id fails
because of input validation errors in FSSETXATTR.
- Fix oversized quota reservation when converting unwritten extents
during a DAX write.
- Create a transaction allocation helper function to standardize the
idiom of allocating a transaction, reserving blocks, locking
inodes, and reserving quota. Replace all the open-coded logic for
file creation, file ownership changes, and file modifications to
use them.
- Actually shut down the fs if the incore quota reservations get
corrupted.
- Fix background block garbage collection scans to not block and to
actually clean out CoW staging extents properly.
- Run block gc scans when we run low on project quota.
- Use the standardized transaction allocation helpers to make it so
that ENOSPC and EDQUOT errors during reservation will back out,
invoke the block gc scanner, and try again. This is preparation for
introducing background inode garbage collection in the next cycle.
- Combine speculative post-EOF block garbage collection with
speculative copy on write block garbage collection.
- Enable multithreaded quotacheck.
- Allow sysadmins to tweak the CPU affinities and maximum concurrency
levels of quotacheck and background blockgc worker pools.
- Expose the inode btree counter feature in the fs geometry ioctl.
- Cleanups of the growfs code in preparation for starting work on
filesystem shrinking.
- Fix all the bloody gcc warnings that the maintainer knows about. :P
- Fix a RST syntax error.
- Don't trigger bmbt corruption assertions after the fs shuts down.
- Restore behavior of forcing SIGBUS on a shut down filesystem when
someone triggers a mmap write fault (or really, any buffered
write)"
* tag 'xfs-5.12-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (85 commits)
xfs: consider shutdown in bmapbt cursor delete assert
xfs: fix boolreturn.cocci warnings
xfs: restore shutdown check in mapped write fault path
xfs: fix rst syntax error in admin guide
xfs: fix incorrect root dquot corruption error when switching group/project quota types
xfs: get rid of xfs_growfs_{data,log}_t
xfs: rename `new' to `delta' in xfs_growfs_data_private()
libxfs: expose inobtcount in xfs geometry
xfs: don't bounce the iolock between free_{eof,cow}blocks
xfs: expose the blockgc workqueue knobs publicly
xfs: parallelize block preallocation garbage collection
xfs: rename block gc start and stop functions
xfs: only walk the incore inode tree once per blockgc scan
xfs: consolidate the eofblocks and cowblocks workers
xfs: consolidate incore inode radix tree posteof/cowblocks tags
xfs: remove trivial eof/cowblocks functions
xfs: hide xfs_icache_free_cowblocks
xfs: hide xfs_icache_free_eofblocks
xfs: relocate the eofb/cowb workqueue functions
xfs: set WQ_SYSFS on all workqueues in debug mode
...
XFS triggers an iomap warning in the write fault path due to a
!PageUptodate() page if a write fault happens to occur on a page
that recently failed writeback. The iomap writeback error handling
code can clear the Uptodate flag if no portion of the page is
submitted for I/O. This is reproduced by fstest generic/019, which
combines various forms of I/O with simulated disk failures that
inevitably lead to filesystem shutdown (which then unconditionally
fails page writeback).
This is a regression introduced by commit f150b42343 ("xfs: split
the iomap ops for buffered vs direct writes") due to the removal of
a shutdown check and explicit error return in the ->iomap_begin()
path used by the write fault path. The explicit error return
historically translated to a SIGBUS, but now carries on with iomap
processing where it complains about the unexpected state. Restore
the shutdown check to xfs_buffered_write_iomap_begin() to restore
historical behavior.
Fixes: f150b42343 ("xfs: split the iomap ops for buffered vs direct writes")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
The two remaining callers of xfs_trans_reserve_quota_nblks are in the
reflink code. These conversions aren't as uniform as the previous
conversions, so call that out in a separate patch.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Make it so that we can reserve rt blocks with the xfs_trans_alloc_inode
wrapper function, then convert a few more callsites.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Create a new helper xfs_trans_alloc_inode that allocates a transaction,
locks and joins an inode to it, and then reserves the appropriate amount
of quota against that transction. Then replace all the open-coded
idioms with a single call to this helper.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Modify xfs_trans_reserve_quota_nblks so that we can reserve data and
realtime blocks from the dquot at the same time. This change has the
theoretical side effect that for allocations to realtime files we will
reserve from the dquot both the number of rtblocks being allocated and
the number of bmbt blocks that might be needed to add the mapping.
However, since the mount code disables quota if it finds a realtime
device, this should not result in any behavior changes.
Now that we've moved the inode creation callers away from using the
_nblks function, we can repurpose the (now unused) ninos argument for
realtime blocks, so make that change. This also replaces the flags
argument with a boolean parameter to force the reservation since we
don't need to distinguish between data and rt quota reservations any
more, and the only flag being passed in was FORCE_RES.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
xfs_trans_cancel will release all the quota resources that were reserved
on behalf of the transaction, so get rid of the explicit unreserve step.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
In commit 3b0fe47805, we reduced the free space requirement to
perform a pre-write unwritten extent conversion on an S_DAX file. Since
we're not actually allocating any space, the logic goes, we only need
enough reservation to handle shape changes in the bmbt.
The same logic should have been applied to quota -- we're not allocating
any space, so we only need to reserve enough quota to handle the bmbt
shape changes.
Fixes: 3b0fe47805 ("xfs: Don't use reserved blocks for data blocks with DAX")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Attempt shared locking for unaligned DIO, but only if the the
underlying extent is already allocated and in written state. On
failure, retry with the existing exclusive locking.
Test case is fio randrw of 512 byte IOs using AIO and an iodepth of
32 IOs.
Vanilla:
READ: bw=4560KiB/s (4670kB/s), 4560KiB/s-4560KiB/s (4670kB/s-4670kB/s), io=134MiB (140MB), run=30001-30001msec
WRITE: bw=4567KiB/s (4676kB/s), 4567KiB/s-4567KiB/s (4676kB/s-4676kB/s), io=134MiB (140MB), run=30001-30001msec
Patched:
READ: bw=37.6MiB/s (39.4MB/s), 37.6MiB/s-37.6MiB/s (39.4MB/s-39.4MB/s), io=1127MiB (1182MB), run=30002-30002msec
WRITE: bw=37.6MiB/s (39.4MB/s), 37.6MiB/s-37.6MiB/s (39.4MB/s-39.4MB/s), io=1128MiB (1183MB), run=30002-30002msec
That's an improvement from ~18k IOPS to a ~150k IOPS, which is
about the IOPS limit of the VM block device setup I'm testing on.
4kB block IO comparison:
READ: bw=296MiB/s (310MB/s), 296MiB/s-296MiB/s (310MB/s-310MB/s), io=8868MiB (9299MB), run=30002-30002msec
WRITE: bw=296MiB/s (310MB/s), 296MiB/s-296MiB/s (310MB/s-310MB/s), io=8878MiB (9309MB), run=30002-30002msec
Which is ~150k IOPS, same as what the test gets for sub-block
AIO+DIO writes with this patch.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
[hch: rebased, split unaligned from nowait]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
A write to a sub-interval of an existing unwritten extent causes
the original extent to be split into 3 extents
i.e. | Unwritten | Real | Unwritten |
Hence extent count can increase by 2.
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
