commit ca93e44bfb upstream
Some users recently reported that MariaDB was getting a read corruption
when using io_uring on top of btrfs. This started to happen in 5.16,
after commit 51bd9563b6 ("btrfs: fix deadlock due to page faults
during direct IO reads and writes"). That changed btrfs to use the new
iomap flag IOMAP_DIO_PARTIAL and to disable page faults before calling
iomap_dio_rw(). This was necessary to fix deadlocks when the iovector
corresponds to a memory mapped file region. That type of scenario is
exercised by test case generic/647 from fstests.
For this MariaDB scenario, we attempt to read 16K from file offset X
using IOCB_NOWAIT and io_uring. In that range we have 4 extents, each
with a size of 4K, and what happens is the following:
1) btrfs_direct_read() disables page faults and calls iomap_dio_rw();
2) iomap creates a struct iomap_dio object, its reference count is
initialized to 1 and its ->size field is initialized to 0;
3) iomap calls btrfs_dio_iomap_begin() with file offset X, which finds
the first 4K extent, and setups an iomap for this extent consisting
of a single page;
4) At iomap_dio_bio_iter(), we are able to access the first page of the
buffer (struct iov_iter) with bio_iov_iter_get_pages() without
triggering a page fault;
5) iomap submits a bio for this 4K extent
(iomap_dio_submit_bio() -> btrfs_submit_direct()) and increments
the refcount on the struct iomap_dio object to 2; The ->size field
of the struct iomap_dio object is incremented to 4K;
6) iomap calls btrfs_iomap_begin() again, this time with a file
offset of X + 4K. There we setup an iomap for the next extent
that also has a size of 4K;
7) Then at iomap_dio_bio_iter() we call bio_iov_iter_get_pages(),
which tries to access the next page (2nd page) of the buffer.
This triggers a page fault and returns -EFAULT;
8) At __iomap_dio_rw() we see the -EFAULT, but we reset the error
to 0 because we passed the flag IOMAP_DIO_PARTIAL to iomap and
the struct iomap_dio object has a ->size value of 4K (we submitted
a bio for an extent already). The 'wait_for_completion' variable
is not set to true, because our iocb has IOCB_NOWAIT set;
9) At the bottom of __iomap_dio_rw(), we decrement the reference count
of the struct iomap_dio object from 2 to 1. Because we were not
the only ones holding a reference on it and 'wait_for_completion' is
set to false, -EIOCBQUEUED is returned to btrfs_direct_read(), which
just returns it up the callchain, up to io_uring;
10) The bio submitted for the first extent (step 5) completes and its
bio endio function, iomap_dio_bio_end_io(), decrements the last
reference on the struct iomap_dio object, resulting in calling
iomap_dio_complete_work() -> iomap_dio_complete().
11) At iomap_dio_complete() we adjust the iocb->ki_pos from X to X + 4K
and return 4K (the amount of io done) to iomap_dio_complete_work();
12) iomap_dio_complete_work() calls the iocb completion callback,
iocb->ki_complete() with a second argument value of 4K (total io
done) and the iocb with the adjust ki_pos of X + 4K. This results
in completing the read request for io_uring, leaving it with a
result of 4K bytes read, and only the first page of the buffer
filled in, while the remaining 3 pages, corresponding to the other
3 extents, were not filled;
13) For the application, the result is unexpected because if we ask
to read N bytes, it expects to get N bytes read as long as those
N bytes don't cross the EOF (i_size).
MariaDB reports this as an error, as it's not expecting a short read,
since it knows it's asking for read operations fully within the i_size
boundary. This is typical in many applications, but it may also be
questionable if they should react to such short reads by issuing more
read calls to get the remaining data. Nevertheless, the short read
happened due to a change in btrfs regarding how it deals with page
faults while in the middle of a read operation, and there's no reason
why btrfs can't have the previous behaviour of returning the whole data
that was requested by the application.
The problem can also be triggered with the following simple program:
/* Get O_DIRECT */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <liburing.h>
int main(int argc, char *argv[])
{
char *foo_path;
struct io_uring ring;
struct io_uring_sqe *sqe;
struct io_uring_cqe *cqe;
struct iovec iovec;
int fd;
long pagesize;
void *write_buf;
void *read_buf;
ssize_t ret;
int i;
if (argc != 2) {
fprintf(stderr, "Use: %s <directory>\n", argv[0]);
return 1;
}
foo_path = malloc(strlen(argv[1]) + 5);
if (!foo_path) {
fprintf(stderr, "Failed to allocate memory for file path\n");
return 1;
}
strcpy(foo_path, argv[1]);
strcat(foo_path, "/foo");
/*
* Create file foo with 2 extents, each with a size matching
* the page size. Then allocate a buffer to read both extents
* with io_uring, using O_DIRECT and IOCB_NOWAIT. Before doing
* the read with io_uring, access the first page of the buffer
* to fault it in, so that during the read we only trigger a
* page fault when accessing the second page of the buffer.
*/
fd = open(foo_path, O_CREAT | O_TRUNC | O_WRONLY |
O_DIRECT, 0666);
if (fd == -1) {
fprintf(stderr,
"Failed to create file 'foo': %s (errno %d)",
strerror(errno), errno);
return 1;
}
pagesize = sysconf(_SC_PAGE_SIZE);
ret = posix_memalign(&write_buf, pagesize, 2 * pagesize);
if (ret) {
fprintf(stderr, "Failed to allocate write buffer\n");
return 1;
}
memset(write_buf, 0xab, pagesize);
memset(write_buf + pagesize, 0xcd, pagesize);
/* Create 2 extents, each with a size matching page size. */
for (i = 0; i < 2; i++) {
ret = pwrite(fd, write_buf + i * pagesize, pagesize,
i * pagesize);
if (ret != pagesize) {
fprintf(stderr,
"Failed to write to file, ret = %ld errno %d (%s)\n",
ret, errno, strerror(errno));
return 1;
}
ret = fsync(fd);
if (ret != 0) {
fprintf(stderr, "Failed to fsync file\n");
return 1;
}
}
close(fd);
fd = open(foo_path, O_RDONLY | O_DIRECT);
if (fd == -1) {
fprintf(stderr,
"Failed to open file 'foo': %s (errno %d)",
strerror(errno), errno);
return 1;
}
ret = posix_memalign(&read_buf, pagesize, 2 * pagesize);
if (ret) {
fprintf(stderr, "Failed to allocate read buffer\n");
return 1;
}
/*
* Fault in only the first page of the read buffer.
* We want to trigger a page fault for the 2nd page of the
* read buffer during the read operation with io_uring
* (O_DIRECT and IOCB_NOWAIT).
*/
memset(read_buf, 0, 1);
ret = io_uring_queue_init(1, &ring, 0);
if (ret != 0) {
fprintf(stderr, "Failed to create io_uring queue\n");
return 1;
}
sqe = io_uring_get_sqe(&ring);
if (!sqe) {
fprintf(stderr, "Failed to get io_uring sqe\n");
return 1;
}
iovec.iov_base = read_buf;
iovec.iov_len = 2 * pagesize;
io_uring_prep_readv(sqe, fd, &iovec, 1, 0);
ret = io_uring_submit_and_wait(&ring, 1);
if (ret != 1) {
fprintf(stderr,
"Failed at io_uring_submit_and_wait()\n");
return 1;
}
ret = io_uring_wait_cqe(&ring, &cqe);
if (ret < 0) {
fprintf(stderr, "Failed at io_uring_wait_cqe()\n");
return 1;
}
printf("io_uring read result for file foo:\n\n");
printf(" cqe->res == %d (expected %d)\n", cqe->res, 2 * pagesize);
printf(" memcmp(read_buf, write_buf) == %d (expected 0)\n",
memcmp(read_buf, write_buf, 2 * pagesize));
io_uring_cqe_seen(&ring, cqe);
io_uring_queue_exit(&ring);
return 0;
}
When running it on an unpatched kernel:
$ gcc io_uring_test.c -luring
$ mkfs.btrfs -f /dev/sda
$ mount /dev/sda /mnt/sda
$ ./a.out /mnt/sda
io_uring read result for file foo:
cqe->res == 4096 (expected 8192)
memcmp(read_buf, write_buf) == -205 (expected 0)
After this patch, the read always returns 8192 bytes, with the buffer
filled with the correct data. Although that reproducer always triggers
the bug in my test vms, it's possible that it will not be so reliable
on other environments, as that can happen if the bio for the first
extent completes and decrements the reference on the struct iomap_dio
object before we do the atomic_dec_and_test() on the reference at
__iomap_dio_rw().
Fix this in btrfs by having btrfs_dio_iomap_begin() return -EAGAIN
whenever we try to satisfy a non blocking IO request (IOMAP_NOWAIT flag
set) over a range that spans multiple extents (or a mix of extents and
holes). This avoids returning success to the caller when we only did
partial IO, which is not optimal for writes and for reads it's actually
incorrect, as the caller doesn't expect to get less bytes read than it has
requested (unless EOF is crossed), as previously mentioned. This is also
the type of behaviour that xfs follows (xfs_direct_write_iomap_begin()),
even though it doesn't use IOMAP_DIO_PARTIAL.
A test case for fstests will follow soon.
Link: https://lore.kernel.org/linux-btrfs/CABVffEM0eEWho+206m470rtM0d9J8ue85TtR-A_oVTuGLWFicA@mail.gmail.com/
Link: https://lore.kernel.org/linux-btrfs/CAHF2GV6U32gmqSjLe=XKgfcZAmLCiH26cJ2OnHGp5x=VAH4OHQ@mail.gmail.com/
CC: stable@vger.kernel.org # 5.16+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit a7d16d9a07 ]
This is a long time leftover from when I originally added the free space
inode, the point was to catch cases where we weren't honoring the NOCOW
flag. However there exists a race with relocation, if we allocate our
free space inode in a block group that is about to be relocated, we
could trigger the COW path before the relocation has the opportunity to
find the extents and delete the free space cache. In production where
we have auto-relocation enabled we're seeing this WARN_ON_ONCE() around
5k times in a 2 week period, so not super common but enough that it's at
the top of our metrics.
We're properly handling the error here, and with us phasing out v1 space
cache anyway just drop the WARN_ON_ONCE.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 6d82ad13c4 upstream.
Running generic/406 causes the following WARNING in btrfs_destroy_inode()
which tells there are outstanding extents left.
In btrfs_get_blocks_direct_write(), we reserve a temporary outstanding
extents with btrfs_delalloc_reserve_metadata() (or indirectly from
btrfs_delalloc_reserve_space(()). We then release the outstanding extents
with btrfs_delalloc_release_extents(). However, the "len" can be modified
in the COW case, which releases fewer outstanding extents than expected.
Fix it by calling btrfs_delalloc_release_extents() for the original length.
To reproduce the warning, the filesystem should be 1 GiB. It's
triggering a short-write, due to not being able to allocate a large
extent and instead allocating a smaller one.
WARNING: CPU: 0 PID: 757 at fs/btrfs/inode.c:8848 btrfs_destroy_inode+0x1e6/0x210 [btrfs]
Modules linked in: btrfs blake2b_generic xor lzo_compress
lzo_decompress raid6_pq zstd zstd_decompress zstd_compress xxhash zram
zsmalloc
CPU: 0 PID: 757 Comm: umount Not tainted 5.17.0-rc8+ #101
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS d55cb5a 04/01/2014
RIP: 0010:btrfs_destroy_inode+0x1e6/0x210 [btrfs]
RSP: 0018:ffffc9000327bda8 EFLAGS: 00010206
RAX: 0000000000000000 RBX: ffff888100548b78 RCX: 0000000000000000
RDX: 0000000000026900 RSI: 0000000000000000 RDI: ffff888100548b78
RBP: ffff888100548940 R08: 0000000000000000 R09: ffff88810b48aba8
R10: 0000000000000001 R11: ffff8881004eb240 R12: ffff88810b48a800
R13: ffff88810b48ec08 R14: ffff88810b48ed00 R15: ffff888100490c68
FS: 00007f8549ea0b80(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f854a09e733 CR3: 000000010a2e9003 CR4: 0000000000370eb0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
destroy_inode+0x33/0x70
dispose_list+0x43/0x60
evict_inodes+0x161/0x1b0
generic_shutdown_super+0x2d/0x110
kill_anon_super+0xf/0x20
btrfs_kill_super+0xd/0x20 [btrfs]
deactivate_locked_super+0x27/0x90
cleanup_mnt+0x12c/0x180
task_work_run+0x54/0x80
exit_to_user_mode_prepare+0x152/0x160
syscall_exit_to_user_mode+0x12/0x30
do_syscall_64+0x42/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f854a000fb7
Fixes: f0bfa76a11 ("btrfs: fix ENOSPC failure when attempting direct IO write into NOCOW range")
CC: stable@vger.kernel.org # 5.17
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 60021bd754 upstream.
A subvolume with an active swapfile must not be deleted otherwise it
would not be possible to deactivate it.
After the subvolume is deleted, we cannot swapoff the swapfile in this
deleted subvolume because the path is unreachable. The swapfile is
still active and holding references, the filesystem cannot be unmounted.
The test looks like this:
mkfs.btrfs -f $dev > /dev/null
mount $dev $mnt
btrfs sub create $mnt/subvol
touch $mnt/subvol/swapfile
chmod 600 $mnt/subvol/swapfile
chattr +C $mnt/subvol/swapfile
dd if=/dev/zero of=$mnt/subvol/swapfile bs=1K count=4096
mkswap $mnt/subvol/swapfile
swapon $mnt/subvol/swapfile
btrfs sub delete $mnt/subvol
swapoff $mnt/subvol/swapfile # failed: No such file or directory
swapoff --all
unmount $mnt # target is busy.
To prevent above issue, we simply check that whether the subvolume
contains any active swapfile, and stop the deleting process. This
behavior is like snapshot ioctl dealing with a swapfile.
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Kaiwen Hu <kevinhu@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f0bfa76a11 upstream.
When doing a direct IO write against a file range that either has
preallocated extents in that range or has regular extents and the file
has the NOCOW attribute set, the write fails with -ENOSPC when all of
the following conditions are met:
1) There are no data blocks groups with enough free space matching
the size of the write;
2) There's not enough unallocated space for allocating a new data block
group;
3) The extents in the target file range are not shared, neither through
snapshots nor through reflinks.
This is wrong because a NOCOW write can be done in such case, and in fact
it's possible to do it using a buffered IO write, since when failing to
allocate data space, the buffered IO path checks if a NOCOW write is
possible.
The failure in direct IO write path comes from the fact that early on,
at btrfs_dio_iomap_begin(), we try to allocate data space for the write
and if it that fails we return the error and stop - we never check if we
can do NOCOW. But later, at btrfs_get_blocks_direct_write(), we check
if we can do a NOCOW write into the range, or a subset of the range, and
then release the previously reserved data space.
Fix this by doing the data reservation only if needed, when we must COW,
at btrfs_get_blocks_direct_write() instead of doing it at
btrfs_dio_iomap_begin(). This also simplifies a bit the logic and removes
the inneficiency of doing unnecessary data reservations.
The following example test script reproduces the problem:
$ cat dio-nocow-enospc.sh
#!/bin/bash
DEV=/dev/sdj
MNT=/mnt/sdj
# Use a small fixed size (1G) filesystem so that it's quick to fill
# it up.
# Make sure the mixed block groups feature is not enabled because we
# later want to not have more space available for allocating data
# extents but still have enough metadata space free for the file writes.
mkfs.btrfs -f -b $((1024 * 1024 * 1024)) -O ^mixed-bg $DEV
mount $DEV $MNT
# Create our test file with the NOCOW attribute set.
touch $MNT/foobar
chattr +C $MNT/foobar
# Now fill in all unallocated space with data for our test file.
# This will allocate a data block group that will be full and leave
# no (or a very small amount of) unallocated space in the device, so
# that it will not be possible to allocate a new block group later.
echo
echo "Creating test file with initial data..."
xfs_io -c "pwrite -S 0xab -b 1M 0 900M" $MNT/foobar
# Now try a direct IO write against file range [0, 10M[.
# This should succeed since this is a NOCOW file and an extent for the
# range was previously allocated.
echo
echo "Trying direct IO write over allocated space..."
xfs_io -d -c "pwrite -S 0xcd -b 10M 0 10M" $MNT/foobar
umount $MNT
When running the test:
$ ./dio-nocow-enospc.sh
(...)
Creating test file with initial data...
wrote 943718400/943718400 bytes at offset 0
900 MiB, 900 ops; 0:00:01.43 (625.526 MiB/sec and 625.5265 ops/sec)
Trying direct IO write over allocated space...
pwrite: No space left on device
A test case for fstests will follow, testing both this direct IO write
scenario as well as the buffered IO write scenario to make it less likely
to get future regressions on the buffered IO case.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c2f822635d upstream.
If we extended the size of a swapfile after its header was created (by the
mkswap utility) and then try to activate it, we will map the entire file
when activating the swap file, instead of limiting to the max size defined
in the swap file's header.
Currently test case generic/643 from fstests fails because we do not
respect that size limit defined in the swap file's header.
So fix this by not mapping file ranges beyond the max size defined in the
swap header.
This is the same type of bug that iomap used to have, and was fixed in
commit 36ca7943ac ("mm/swap: consider max pages in
iomap_swapfile_add_extent").
Fixes: ed46ff3d42 ("Btrfs: support swap files")
CC: stable@vger.kernel.org # 5.4+
Reviewed-and-tested-by: Josef Bacik <josef@toxicpanda.com
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit d24fa5c1da upstream.
In preparation to fix a bug in btrfs_show_devname().
Convert fs_devices::latest_bdev type from struct block_device to struct
btrfs_device and, rename the member to fs_devices::latest_dev.
So that btrfs_show_devname() can use fs_devices::latest_dev::name.
Tested-by: Su Yue <l@damenly.su>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 37f00a6d2e upstream
There are several places in our codebase where we check if a root is the
root of the data reloc tree and subsequent patches will introduce more.
Factor out the check into a small helper function instead of open coding
it multiple times.
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'for-5.15-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"Last minute fixes for crash on 32bit architectures when compression is
in use. It's a regression introduced in 5.15-rc and I'd really like
not let this into the final release, fixes via stable trees would add
unnecessary delay.
The problem is on 32bit architectures with highmem enabled, the pages
for compression may need to be kmapped, while the patches removed that
as we don't use GFP_HIGHMEM allocations anymore. The pages that don't
come from local allocation still may be from highmem. Despite being on
32bit there's enough such ARM machines in use so it's not a marginal
issue.
I did full reverts of the patches one by one instead of a huge one.
There's one exception for the "lzo" revert as there was an
intermediate patch touching the same code to make it compatible with
subpage. I can't revert that one too, so the revert in lzo.c is
manual. Qu Wenruo has worked on that with me and verified the changes"
* tag 'for-5.15-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Revert "btrfs: compression: drop kmap/kunmap from lzo"
Revert "btrfs: compression: drop kmap/kunmap from zlib"
Revert "btrfs: compression: drop kmap/kunmap from zstd"
Revert "btrfs: compression: drop kmap/kunmap from generic helpers"
- Simplify the bio_end_page usage in the buffered IO code.
- Support reading inline data at nonzero offsets for erofs.
- Fix some typos and bad grammar.
- Convert kmap_atomic usage in the inline data read path.
- Add some extra inline data input checking.
- Fix a memory corruption bug stemming from iomap_swapfile_activate
trying to activate more pages than mm was expecting.
- Pass errnos through the page writeback code so that writeback errors
are reported correctly instead of being munged to EIO.
- Replace iomap_apply with a open-coded iterator loops to reduce the
number of indirect calls by a third to a half.
- Refactor the fsdax code to use iomap iterators instead of the
open-coded iomap_apply code that it had before.
- Format file range iomap tracepoint data in hexadecimal and
standardize the names used in the pretty-print string.
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Merge tag 'iomap-5.15-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull iomap updates from Darrick Wong:
"The most notable externally visible change for this cycle is the
addition of support for reads to inline tail fragments of files, which
was requested by the erofs developers; and a correction for a kernel
memory corruption bug if the sysadmin tries to activate a swapfile
with more pages than the swapfile header suggests.
We also now report writeback completion errors to the file mapping
correctly, instead of munging all errors into EIO.
Internally, the bulk of the changes are Christoph's patchset to reduce
the indirect function call count by a third to a half by converting
iomap iteration from a loop pattern to a generator/consumer pattern.
As an added bonus, fsdax no longer open-codes iomap apply loops.
Summary:
- Simplify the bio_end_page usage in the buffered IO code.
- Support reading inline data at nonzero offsets for erofs.
- Fix some typos and bad grammar.
- Convert kmap_atomic usage in the inline data read path.
- Add some extra inline data input checking.
- Fix a memory corruption bug stemming from iomap_swapfile_activate
trying to activate more pages than mm was expecting.
- Pass errnos through the page writeback code so that writeback
errors are reported correctly instead of being munged to EIO.
- Replace iomap_apply with a open-coded iterator loops to reduce the
number of indirect calls by a third to a half.
- Refactor the fsdax code to use iomap iterators instead of the
open-coded iomap_apply code that it had before.
- Format file range iomap tracepoint data in hexadecimal and
standardize the names used in the pretty-print string"
* tag 'iomap-5.15-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (41 commits)
iomap: standardize tracepoint formatting and storage
mm/swap: consider max pages in iomap_swapfile_add_extent
iomap: move loop control code to iter.c
iomap: constify iomap_iter_srcmap
fsdax: switch the fault handlers to use iomap_iter
fsdax: factor out a dax_fault_actor() helper
fsdax: factor out helpers to simplify the dax fault code
iomap: rework unshare flag
iomap: pass an iomap_iter to various buffered I/O helpers
iomap: remove iomap_apply
fsdax: switch dax_iomap_rw to use iomap_iter
iomap: switch iomap_swapfile_activate to use iomap_iter
iomap: switch iomap_seek_data to use iomap_iter
iomap: switch iomap_seek_hole to use iomap_iter
iomap: switch iomap_bmap to use iomap_iter
iomap: switch iomap_fiemap to use iomap_iter
iomap: switch __iomap_dio_rw to use iomap_iter
iomap: switch iomap_page_mkwrite to use iomap_iter
iomap: switch iomap_zero_range to use iomap_iter
iomap: switch iomap_file_unshare to use iomap_iter
...
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Merge tag 'for-5.15-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"The highlights of this round are integrations with fs-verity and
idmapped mounts, the rest is usual mix of minor improvements, speedups
and cleanups.
There are some patches outside of btrfs, namely updating some VFS
interfaces, all straightforward and acked.
Features:
- fs-verity support, using standard ioctls, backward compatible with
read-only limitation on inodes with previously enabled fs-verity
- idmapped mount support
- make mount with rescue=ibadroots more tolerant to partially damaged
trees
- allow raid0 on a single device and raid10 on two devices,
degenerate cases but might be useful as an intermediate step during
conversion to other profiles
- zoned mode block group auto reclaim can be disabled via sysfs knob
Performance improvements:
- continue readahead of node siblings even if target node is in
memory, could speed up full send (on sample test +11%)
- batching of delayed items can speed up creating many files
- fsync/tree-log speedups
- avoid unnecessary work (gains +2% throughput, -2% run time on
sample load)
- reduced lock contention on renames (on dbench +4% throughput,
up to -30% latency)
Fixes:
- various zoned mode fixes
- preemptive flushing threshold tuning, avoid excessive work on
almost full filesystems
Core:
- continued subpage support, preparation for implementing remaining
features like compression and defragmentation; with some
limitations, write is now enabled on 64K page systems with 4K
sectors, still considered experimental
- no readahead on compressed reads
- inline extents disabled
- disabled raid56 profile conversion and mount
- improved flushing logic, fixing early ENOSPC on some workloads
- inode flags have been internally split to read-only and read-write
incompat bit parts, used by fs-verity
- new tree items for fs-verity
- descriptor item
- Merkle tree item
- inode operations extended to be namespace-aware
- cleanups and refactoring
Generic code changes:
- fs: new export filemap_fdatawrite_wbc
- fs: removed sync_inode
- block: bio_trim argument type fixups
- vfs: add namespace-aware lookup"
* tag 'for-5.15-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (114 commits)
btrfs: reset replace target device to allocation state on close
btrfs: zoned: fix ordered extent boundary calculation
btrfs: do not do preemptive flushing if the majority is global rsv
btrfs: reduce the preemptive flushing threshold to 90%
btrfs: tree-log: check btrfs_lookup_data_extent return value
btrfs: avoid unnecessarily logging directories that had no changes
btrfs: allow idmapped mount
btrfs: handle ACLs on idmapped mounts
btrfs: allow idmapped INO_LOOKUP_USER ioctl
btrfs: allow idmapped SUBVOL_SETFLAGS ioctl
btrfs: allow idmapped SET_RECEIVED_SUBVOL ioctls
btrfs: relax restrictions for SNAP_DESTROY_V2 with subvolids
btrfs: allow idmapped SNAP_DESTROY ioctls
btrfs: allow idmapped SNAP_CREATE/SUBVOL_CREATE ioctls
btrfs: check whether fsgid/fsuid are mapped during subvolume creation
btrfs: allow idmapped permission inode op
btrfs: allow idmapped setattr inode op
btrfs: allow idmapped tmpfile inode op
btrfs: allow idmapped symlink inode op
btrfs: allow idmapped mkdir inode op
...
This reverts commit f216562731.
[BUG]
It's no longer possible to create compressed inline extent after commit
f216562731 ("btrfs: compression: don't try to compress if we don't
have enough pages").
[CAUSE]
For compression code, there are several possible reasons we have a range
that needs to be compressed while it's no more than one page.
- Compressed inline write
The data is always smaller than one sector and the test lacks the
condition to properly recognize a non-inline extent.
- Compressed subpage write
For the incoming subpage compressed write support, we require page
alignment of the delalloc range.
And for 64K page size, we can compress just one page into smaller
sectors.
For those reasons, the requirement for the data to be more than one page
is not correct, and is already causing regression for compressed inline
data writeback. The idea of skipping one page to avoid wasting CPU time
could be revisited in the future.
[FIX]
Fix it by reverting the offending commit.
Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Link: https://lore.kernel.org/linux-btrfs/afa2742.c084f5d6.17b6b08dffc@tnonline.net
Fixes: f216562731 ("btrfs: compression: don't try to compress if we don't have enough pages")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Creating subvolumes and snapshots is one of the core features of btrfs
and is even available to unprivileged users. Make it possible to use
subvolume and snapshot creation on idmapped mounts. This is a fairly
straightforward operation since all the permission checking helpers are
already capable of handling idmapped mounts. So we just need to pass
down the mount's userns.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enable btrfs_permission() to handle idmapped mounts. This is just a
matter of passing down the mount's userns.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enable btrfs_setattr() to handle idmapped mounts. This is just a matter
of passing down the mount's userns.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enable btrfs_tmpfile() to handle idmapped mounts. This is just a matter
of passing down the mount's userns.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enable btrfs_symlink() to handle idmapped mounts. This is just a matter
of passing down the mount's userns.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enable btrfs_mkdir() to handle idmapped mounts. This is just a matter of
passing down the mount's userns.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enable btrfs_create() to handle idmapped mounts. This is just a matter
of passing down the mount's userns.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enable btrfs_mknod() to handle idmapped mounts. This is just a matter of
passing down the mount's userns.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enable btrfs_getattr() to handle idmapped mounts. This is just a matter
of passing down the mount's userns.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enable btrfs_rename() to handle idmapped mounts. This is just a matter
of passing down the mount's userns.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Extend btrfs_new_inode() to take the idmapped mount into account when
initializing a new inode. This is just a matter of passing down the
mount's userns. The rest is taken care of in inode_init_owner(). This is
a preliminary patch to make the individual btrfs inode operations
idmapped mount aware.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We call split_zoned_em() on an extent_map on submitting a bio for it. Thus,
we can assume the extent_map is PINNED, not LOGGING, and in the modified
list. Add ASSERT()s to ensure the extent_maps after the split also has the
proper flags set and are in the modified list.
Suggested-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At the very end of btrfs_rename_exchange(), in case an error happened, we
are checking if 'new_inode' is NULL, but that is not needed since during a
rename exchange, unlike regular renames, 'new_inode' can never be NULL,
and if it were, we would have a crashed much earlier when we dereference it
multiple times.
So remove the check because it is not necessary and because it is causing
static checkers to emit a warning. I probably introduced the check by
copy-pasting similar code from btrfs_rename(), where 'new_inode' can be
NULL, in commit 86e8aa0e77 ("Btrfs: unpin logs if rename exchange
operation fails").
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Writing out the verity data is too large of an operation to do in a
single transaction. If we are interrupted before we finish creating
fsverity metadata for a file, or fail to clean up already created
metadata after a failure, we could leak the verity items that we already
committed.
To address this issue, we use the orphan mechanism. When we start
enabling verity on a file, we also add an orphan item for that inode.
When we are finished, we delete the orphan. However, if we are
interrupted midway, the orphan will be present at mount and we can
cleanup the half-formed verity state.
There is a possible race with a normal unlink operation: if unlink and
verity run on the same file in parallel, it is possible for verity to
succeed and delete the still legitimate orphan added by unlink. Then, if
we are interrupted and mount in that state, we will never clean up the
inode properly. This is also possible for a file created with O_TMPFILE.
Check nlink==0 before deleting to avoid this race.
A final thing to note is that this is a resurrection of using orphans to
signal an operation besides "delete this inode". The old case was to
signal the need to do a truncate. That case still technically applies
for mounting very old file systems, so we need to take some care to not
clobber it. To that end, we just have to be careful that verity orphan
cleanup is a no-op for non-verity files.
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add support for fsverity in btrfs. To support the generic interface in
fs/verity, we add two new item types in the fs tree for inodes with
verity enabled. One stores the per-file verity descriptor and btrfs
verity item and the other stores the Merkle tree data itself.
Verity checking is done in end_page_read just before a page is marked
uptodate. This naturally handles a variety of edge cases like holes,
preallocated extents, and inline extents. Some care needs to be taken to
not try to verity pages past the end of the file, which are accessed by
the generic buffered file reading code under some circumstances like
reading to the end of the last page and trying to read again. Direct IO
on a verity file falls back to buffered reads.
Verity relies on PageChecked for the Merkle tree data itself to avoid
re-walking up shared paths in the tree. For this reason, we need to
cache the Merkle tree data. Since the file is immutable after verity is
turned on, we can cache it at an index past EOF.
Use the new inode ro_flags to store verity on the inode item, so that we
can enable verity on a file, then rollback to an older kernel and still
mount the file system and read the file. Since we can't safely write the
file anymore without ruining the invariants of the Merkle tree, we mark
a ro_compat flag on the file system when a file has verity enabled.
Acked-by: Eric Biggers <ebiggers@google.com>
Co-developed-by: Chris Mason <clm@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently, inode flags are fully backwards incompatible in btrfs. If we
introduce a new inode flag, then tree-checker will detect it and fail.
This can even cause us to fail to mount entirely. To make it possible to
introduce new flags which can be read-only compatible, like VERITY, we
add new ro flags to btrfs without treating them quite so harshly in
tree-checker. A read-only file system can survive an unexpected flag,
and can be mounted.
As for the implementation, it unfortunately gets a little complicated.
The on-disk representation of the inode, btrfs_inode_item, has an __le64
for flags but the in-memory representation, btrfs_inode, uses a u32.
David Sterba had the nice idea that we could reclaim those wasted 32 bits
on disk and use them for the new ro_compat flags.
It turns out that the tree-checker code which checks for unknown flags
is broken, and ignores the upper 32 bits we are hoping to use. The issue
is that the flags use the literal 1 rather than 1ULL, so the flags are
signed ints, and one of them is specifically (1 << 31). As a result, the
mask which ORs the flags is a negative integer on machines where int is
32 bit twos complement. When tree-checker evaluates the expression:
btrfs_inode_flags(leaf, iitem) & ~BTRFS_INODE_FLAG_MASK)
The mask is something like 0x80000abc, which gets promoted to u64 with
sign extension to 0xffffffff80000abc. Negating that 64 bit mask leaves
all the upper bits zeroed, and we can't detect unexpected flags.
This suggests that we can't use those bits after all. Luckily, we have
good reason to believe that they are zero anyway. Inode flags are
metadata, which is always checksummed, so any bit flips that would
introduce 1s would cause a checksum failure anyway (excluding the
improbable case of the checksum getting corrupted exactly badly).
Further, unless the 1 << 31 flag is used, the cast to u64 of the 32 bit
inode flag should preserve its value and not add leading zeroes
(at least for twos complement). The only place that flag
(BTRFS_INODE_ROOT_ITEM_INIT) is used is in a special inode embedded in
the root item, and indeed for that inode we see 0xffffffff80000000 as
the flags on disk. However, that inode is never seen by tree checker,
nor is it used in a context where verity might be meaningful.
Theoretically, a future ro flag might cause trouble on that inode, so we
should proactively clean up that mess before it does.
With the introduction of the new ro flags, keep two separate unsigned
masks and check them against the appropriate u32. Since we no longer run
afoul of sign extension, this also stops writing out 0xffffffff80000000
in root_item inodes going forward.
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When btrfs_run_delalloc_range() failed, we will error out.
But there is a strange comment mentioning that
btrfs_run_delalloc_range() could have returned value >0 to indicate the
IO has already started.
Commit 40f765805f ("Btrfs: split up __extent_writepage to lower stack
usage") introduced the comment, but unfortunately at that time, we were
already using @page_started to indicate that case, and still return 0.
Furthermore, even if that comment was right (which is not), we would
return -EIO if the IO had already started.
By all means the comment is incorrect, just remove the comment along
with the dead check.
Just to be extra safe, add an ASSERT() in btrfs_run_delalloc_range() to
make sure we either return 0 or error, no positive return value.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During renames we pin the logs of the roots a bit too early, before the
calls to btrfs_insert_inode_ref(). We can pin the logs after those calls,
since those will not change anything in a log tree.
In a scenario where we have multiple and diverse filesystem operations
running in parallel, those calls can take a significant amount of time,
due to lock contention on extent buffers, and delay log commits from other
tasks for longer than necessary.
So just pin logs after calls to btrfs_insert_inode_ref() and right before
the first operation that can update a log tree.
The following script that uses dbench was used for testing:
$ cat dbench-test.sh
#!/bin/bash
DEV=/dev/nvme0n1
MNT=/mnt/nvme0n1
MOUNT_OPTIONS="-o ssd"
MKFS_OPTIONS="-m single -d single"
echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
umount $DEV &> /dev/null
mkfs.btrfs -f $MKFS_OPTIONS $DEV
mount $MOUNT_OPTIONS $DEV $MNT
dbench -D $MNT -t 120 16
umount $MNT
The tests were run on a machine with 12 cores, 64G of RAN, a NVMe device
and using a non-debug kernel config (Debian's default config).
The results compare a branch without this patch and without the previous
patch in the series, that has the subject:
"btrfs: eliminate some false positives when checking if inode was logged"
Versus the same branch with these two patches applied.
dbench with 8 clients, results before:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 4391359 0.009 249.745
Close 3225882 0.001 3.243
Rename 185953 0.065 240.643
Unlink 886669 0.049 249.906
Deltree 112 2.455 217.433
Mkdir 56 0.002 0.004
Qpathinfo 3980281 0.004 3.109
Qfileinfo 697579 0.001 0.187
Qfsinfo 729780 0.002 2.424
Sfileinfo 357764 0.004 1.415
Find 1538861 0.016 4.863
WriteX 2189666 0.010 3.327
ReadX 6883443 0.002 0.729
LockX 14298 0.002 0.073
UnlockX 14298 0.001 0.042
Flush 307777 2.447 303.663
Throughput 1149.6 MB/sec 8 clients 8 procs max_latency=303.666 ms
dbench with 8 clients, results after:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 4269920 0.009 213.532
Close 3136653 0.001 0.690
Rename 180805 0.082 213.858
Unlink 862189 0.050 172.893
Deltree 112 2.998 218.328
Mkdir 56 0.002 0.003
Qpathinfo 3870158 0.004 5.072
Qfileinfo 678375 0.001 0.194
Qfsinfo 709604 0.002 0.485
Sfileinfo 347850 0.004 1.304
Find 1496310 0.017 5.504
WriteX 2129613 0.010 2.882
ReadX 6693066 0.002 1.517
LockX 13902 0.002 0.075
UnlockX 13902 0.001 0.055
Flush 299276 2.511 220.189
Throughput 1187.33 MB/sec 8 clients 8 procs max_latency=220.194 ms
+3.2% throughput, -31.8% max latency
dbench with 16 clients, results before:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 5978334 0.028 156.507
Close 4391598 0.001 1.345
Rename 253136 0.241 155.057
Unlink 1207220 0.182 257.344
Deltree 160 6.123 36.277
Mkdir 80 0.003 0.005
Qpathinfo 5418817 0.012 6.867
Qfileinfo 949929 0.001 0.941
Qfsinfo 993560 0.002 1.386
Sfileinfo 486904 0.004 2.829
Find 2095088 0.059 8.164
WriteX 2982319 0.017 9.029
ReadX 9371484 0.002 4.052
LockX 19470 0.002 0.461
UnlockX 19470 0.001 0.990
Flush 418936 2.740 347.902
Throughput 1495.31 MB/sec 16 clients 16 procs max_latency=347.909 ms
dbench with 16 clients, results after:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 5711833 0.029 131.240
Close 4195897 0.001 1.732
Rename 241849 0.204 147.831
Unlink 1153341 0.184 231.322
Deltree 160 6.086 30.198
Mkdir 80 0.003 0.021
Qpathinfo 5177011 0.012 7.150
Qfileinfo 907768 0.001 0.793
Qfsinfo 949205 0.002 1.431
Sfileinfo 465317 0.004 2.454
Find 2001541 0.058 7.819
WriteX 2850661 0.017 9.110
ReadX 8952289 0.002 3.991
LockX 18596 0.002 0.655
UnlockX 18596 0.001 0.179
Flush 400342 2.879 293.607
Throughput 1565.73 MB/sec 16 clients 16 procs max_latency=293.611 ms
+4.6% throughput, -16.9% max latency
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When on SINGLE block group, btrfs_get_io_geometry() will return "the
size of the block group - the offset of the logical address within the
block group" as geom.len. Since we allow up to 8 GiB zone size on zoned
filesystem, we can have up to 8 GiB block group, so can have up to 8 GiB
geom.len as well. With this setup, we easily hit the "ASSERT(geom.len <=
INT_MAX);".
The ASSERT looks like to guard btrfs_bio_clone_partial() and bio_trim()
which both take "int" (now u64 due to the previous patch). So to be
precise the ASSERT should check if clone_len <= UINT_MAX. But actually,
clone_len is already capped by bio.bi_iter.bi_size which is unsigned
int. So the ASSERT is not necessary.
Drop the ASSERT and properly compare submit_len and geom.len in u64.
Then, let the implicit casting to convert it to u64.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
sync_inode() has some holes that can cause problems if we're under heavy
ENOSPC pressure. If there's writeback running on a separate thread
sync_inode() will skip writing the inode altogether. What we really
want is to make sure writeback has been started on all the pages to make
sure we can see the ordered extents and wait on them if appropriate.
Switch to this new helper which will allow us to accomplish this and
avoid ENOSPC'ing early.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I've been debugging an early ENOSPC problem in production and finally
root caused it to this problem. When we switched to the per-inode in
38d715f494 ("btrfs: use btrfs_start_delalloc_roots in
shrink_delalloc") I pulled out the async extent handling, because we
were doing the correct thing by calling filemap_flush() if we had async
extents set. This would properly wait on any async extents by locking
the page in the second flush, thus making sure our ordered extents were
properly set up.
However when I switched us back to page based flushing, I used
sync_inode(), which allows us to pass in our own wbc. The problem here
is that sync_inode() is smarter than the filemap_* helpers, it tries to
avoid calling writepages at all. This means that our second call could
skip calling do_writepages altogether, and thus not wait on the pagelock
for the async helpers. This means we could come back before any ordered
extents were created and then simply continue on in our flushing
mechanisms and ENOSPC out when we have plenty of space to use.
Fix this by putting back the async pages logic in shrink_delalloc. This
allows us to bulk write out everything that we need to, and then we can
wait in one place for the async helpers to catch up, and then wait on
any ordered extents that are created.
Fixes: e076ab2a2c ("btrfs: shrink delalloc pages instead of full inodes")
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We use the async_delalloc_pages mechanism to make sure that we've
completed our async work before trying to continue our delalloc
flushing. The reason for this is we need to see any ordered extents
that were created by our delalloc flushing. However we're waking up
before we do the submit work, which is before we create the ordered
extents. This is a pretty wide race window where we could potentially
think there are no ordered extents and thus exit shrink_delalloc
prematurely. Fix this by waking us up after we've done the work to
create ordered extents.
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since now we support data and metadata read-write for subpage, remove
the RO requirement for subpage mount.
There are some extra limitations though:
- For now, subpage RW mount is still considered experimental
Thus that mount warning will still be there.
- No compression support
There are still quite some PAGE_SIZE hard coded and quite some call
sites use extent_clear_unlock_delalloc() to unlock locked_page.
This will screw up subpage helpers.
Now for subpage RW mount, no matter what mount option or inode attr is
set, all writes will not be compressed. Although reading compressed
data has no problem.
- No defrag for subpage case
The defrag support for subpage case will come in later patches, which
will also rework the defrag workflow.
- No inline extent will be created
This is mostly due to the fact that filemap_fdatawrite_range() will
trigger more write than the range specified.
In fallocate calls, this behavior can make us to writeback which can
be inlined, before we enlarge the i_size.
This is a very special corner case, and even current btrfs check won't
report error on such inline extent + regular extent.
But considering how much effort has been put to prevent such inline +
regular, I'd prefer to cut off inline extent completely until we have
a good solution.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When relocating partial preallocated data extents (part of the
preallocated extent is written) for subpage, it can cause the following
false alert and make the relocation to fail:
BTRFS info (device dm-3): balance: start -d
BTRFS info (device dm-3): relocating block group 13631488 flags data
BTRFS warning (device dm-3): csum failed root -9 ino 257 off 4096 csum 0x98757625 expected csum 0x00000000 mirror 1
BTRFS error (device dm-3): bdev /dev/mapper/arm_nvme-test errs: wr 0, rd 0, flush 0, corrupt 1, gen 0
BTRFS warning (device dm-3): csum failed root -9 ino 257 off 4096 csum 0x98757625 expected csum 0x00000000 mirror 1
BTRFS error (device dm-3): bdev /dev/mapper/arm_nvme-test errs: wr 0, rd 0, flush 0, corrupt 2, gen 0
BTRFS info (device dm-3): balance: ended with status: -5
The minimal script to reproduce looks like this:
mkfs.btrfs -f -s 4k $dev
mount $dev -o nospace_cache $mnt
xfs_io -f -c "falloc 0 8k" $mnt/file
xfs_io -f -c "pwrite 0 4k" $mnt/file
btrfs balance start -d $mnt
[CAUSE]
Function btrfs_verify_data_csum() checks if the full range has
EXTENT_NODATASUM bit for data reloc inode, if *all* bytes of the range
have EXTENT_NODATASUM bit, then it skip the range.
This works pretty well for regular sectorsize, as in that case
btrfs_verify_data_csum() is called for each sector, thus no problem at
all.
But for subpage case, btrfs_verify_data_csum() is called on each bvec,
which can contain several sectors, and since it checks *all* bytes for
EXTENT_NODATASUM bit, if we have some range with csum, then we will
continue checking all the sectors.
For the preallocated sectors, it doesn't have any csum, thus obviously
the csum won't match and cause the false alert.
[FIX]
Move the EXTENT_NODATASUM check into the main loop, so that we can check
each sector for EXTENT_NODATASUM bit for subpage case.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
There is a possible use-after-free bug when running generic/095.
BUG: Unable to handle kernel data access on write at 0x6b6b6b6b6b6b725b
Faulting instruction address: 0xc000000000283654
c000000000283078 do_raw_spin_unlock+0x88/0x230
c0000000012b1e14 _raw_spin_unlock_irqrestore+0x44/0x90
c000000000a918dc btrfs_subpage_clear_writeback+0xac/0xe0
c0000000009e0458 end_bio_extent_writepage+0x158/0x270
c000000000b6fd14 bio_endio+0x254/0x270
c0000000009fc0f0 btrfs_end_bio+0x1a0/0x200
c000000000b6fd14 bio_endio+0x254/0x270
c000000000b781fc blk_update_request+0x46c/0x670
c000000000b8b394 blk_mq_end_request+0x34/0x1d0
c000000000d82d1c lo_complete_rq+0x11c/0x140
c000000000b880a4 blk_complete_reqs+0x84/0xb0
c0000000012b2ca4 __do_softirq+0x334/0x680
c0000000001dd878 irq_exit+0x148/0x1d0
c000000000016f4c do_IRQ+0x20c/0x240
c000000000009240 hardware_interrupt_common_virt+0x1b0/0x1c0
[CAUSE]
There is very small race window like the following in generic/095.
Thread 1 | Thread 2
--------------------------------+------------------------------------
end_bio_extent_writepage() | btrfs_releasepage()
|- spin_lock_irqsave() | |
|- end_page_writeback() | |
| | |- if (PageWriteback() ||...)
| | |- clear_page_extent_mapped()
| | |- kfree(subpage);
|- spin_unlock_irqrestore().
The race can also happen between writeback and btrfs_invalidatepage(),
although that would be much harder as btrfs_invalidatepage() has much
more work to do before the clear_page_extent_mapped() call.
[FIX]
Here we "wait" for the subapge spinlock to be released before we detach
subpage structure.
So this patch will introduce a new function, wait_subpage_spinlock(), to
do the "wait" by acquiring the spinlock and release it.
Since the caller has ensured the page is not dirty nor writeback, and
page is already locked, the only way to hold the subpage spinlock is
from endio function.
Thus we only need to acquire the spinlock to wait for any existing
holder.
Reported-by: Ritesh Harjani <riteshh@linux.ibm.com>
Tested-by: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When running the following fsx command (extracted from generic/127) on
subpage filesystem, it can create inline extent with regular extents:
fsx -q -l 262144 -o 65536 -S 191110531 -N 9057 -R -W $mnt/file > /tmp/fsx
The offending extent would look like:
item 9 key (257 INODE_REF 256) itemoff 15703 itemsize 14
index 2 namelen 4 name: file
item 10 key (257 EXTENT_DATA 0) itemoff 14975 itemsize 728
generation 7 type 0 (inline)
inline extent data size 707 ram_bytes 707 compression 0 (none)
item 11 key (257 EXTENT_DATA 4096) itemoff 14922 itemsize 53
generation 7 type 2 (prealloc)
prealloc data disk byte 102346752 nr 4096
prealloc data offset 0 nr 4096
[CAUSE]
For subpage filesystem, the writeback is triggered in page units, which
means, even if we just want to writeback range [16K, 20K) for 64K page
system, we will still try to writeback any dirty sector of range [0, 64K).
This is never a problem if sectorsize == PAGE_SIZE, but for subpage,
this can cause unexpected problems.
For above test case, the last several operations from fsx are:
9055 trunc from 0x40000 to 0x2c3
9057 falloc from 0x164c to 0x19d2 (0x386 bytes)
In operation 9055, we dirtied sector [0, 4096), then in falloc, we call
btrfs_wait_ordered_range(inode, start=4096, len=4096), only expecting to
writeback any dirty data in [4096, 8192), but nothing else.
Unfortunately, in subpage case, above btrfs_wait_ordered_range() will
trigger writeback of the range [0, 64K), which includes the data at
[0, 4096).
And since at the call site, we haven't yet increased i_size, which is
still 707, this means cow_file_range() can insert an inline extent.
Resulting above inline + regular extent.
[WORKAROUND]
I don't really have any good short-term solution yet, as this means all
operations that would trigger writeback need to be reviewed for any
i_size change.
So here I choose to disable inline extent creation for subpage case as a
workaround. We have done tons of work just to avoid such extent, so I
don't to create an exception just for subpage.
This only affects inline extent creation, subpage has no problem reading
existing inline extents at all.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When testing experimental subpage compressed write support, it hits a
NULL pointer dereference inside read path:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018
pc : __pi_memcmp+0x28/0x1ec
lr : check_data_csum+0xd0/0x274 [btrfs]
Call trace:
__pi_memcmp+0x28/0x1ec
btrfs_verify_data_csum+0xf4/0x244 [btrfs]
end_bio_extent_readpage+0x1d0/0x6b0 [btrfs]
bio_endio+0x15c/0x1dc
end_workqueue_fn+0x44/0x64 [btrfs]
btrfs_work_helper+0x74/0x250 [btrfs]
process_one_work+0x1d4/0x47c
worker_thread+0x180/0x400
kthread+0x11c/0x120
ret_from_fork+0x10/0x30
Code: 54000261 d100044c d343fd8c f8408403 (f8408424)
---[ end trace 9e2c59f33ea40866 ]---
[CAUSE]
When reading two compressed extents inside the same page, like the
following layout, we trigger above crash:
0 32K 64K
|-------|\\\\\\\|
| \- Compressed extent (A)
\--------- Compressed extent (B)
For compressed read, we don't need to populate its io_bio->csum, as we
rely on compressed_bio->csum to verify the compressed data, and then
copy the decompressed to inode pages.
Normally btrfs_verify_data_csum() skip such page by checking and
clearing its PageChecked flag
But since that flag is still for the full page, when endio for inode
page range [0, 32K) gets executed, it clears PageChecked flag for the
full page.
Then when endio for inode page range [32K, 64K) gets executed, since the
page no longer has PageChecked flag, it just continues checking, even
though io_bio->csum is NULL.
[FIX]
Thankfully there are only two users of PageChecked bit:
- Cow fixup
Since subpage has its own way to trace page dirty (dirty_bitmap) and
ordered bit (ordered_bitmap), it should never trigger cow fixup.
- Compressed read
We can distinguish such read by just checking io_bio->csum.
So just check io_bio->csum before doing the verification to avoid such
NULL pointer dereference.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In commit e65f152e43 ("btrfs: refactor how we finish ordered extent io
for endio functions") there was last caller not using 1 for the uptodate
parameter. Now there's only one, passing 1, so we can remove it and
simplify the code.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit d75855b451 ("btrfs: Remove
extent_io_ops::writepage_start_hook") removes the writepage_start_hook()
and adds btrfs_writepage_cow_fixup() function, there is no need to
follow the old hook parameters.
Remove the @start and @end hook, since currently the fixup check is full
page check, it doesn't need @start and @end hook.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When using the NO_HOLES feature and expanding the size of an inode, we
update the inode's last_trans, last_sub_trans and last_log_commit fields
at maybe_insert_hole() so that a fsync does know that the inode needs to
be logged (by making sure that btrfs_inode_in_log() returns false). This
happens for expanding truncate operations, buffered writes, direct IO
writes and when cloning extents to an offset greater than the inode's
i_size.
However the way we do it is racy, because in between setting the inode's
last_sub_trans and last_log_commit fields, the log transaction ID that was
assigned to last_sub_trans might be committed before we read the root's
last_log_commit and assign that value to last_log_commit. If that happens
it would make a future call to btrfs_inode_in_log() return true. This is
a race that should be extremely unlikely to be hit in practice, and it is
the same that was described by commit bc0939fcfa ("btrfs: fix race
between marking inode needs to be logged and log syncing").
The fix would simply be to set last_log_commit to the value we assigned
to last_sub_trans minus 1, like it was done in that commit. However
updating these two fields plus the last_trans field is pointless here
because all the callers of btrfs_cont_expand() (which is the only
caller of maybe_insert_hole()) always call btrfs_set_inode_last_trans()
or btrfs_update_inode() after calling btrfs_cont_expand(). Calling either
btrfs_set_inode_last_trans() or btrfs_update_inode() guarantees that the
next fsync will log the inode, as it makes btrfs_inode_in_log() return
false.
So just remove the code that explicitly sets the inode's last_trans,
last_sub_trans and last_log_commit fields.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The pages in compressed_pages are not from highmem anymore so we can
drop the mapping for checksum calculation and inline extent.
Signed-off-by: David Sterba <dsterba@suse.com>
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>
Cross-rename lacks a check when that would prevent exchanging a
directory and subvolume from different parent subvolume. This causes
data inconsistencies and is caught before commit by tree-checker,
turning the filesystem to read-only.
Calling the renameat2 with RENAME_EXCHANGE flags like
renameat2(AT_FDCWD, namesrc, AT_FDCWD, namedest, (1 << 1))
on two paths:
namesrc = dir1/subvol1/dir2
namedest = subvol2/subvol3
will cause key order problem with following write time tree-checker
report:
[1194842.307890] BTRFS critical (device loop1): corrupt leaf: root=5 block=27574272 slot=10 ino=258, invalid previous key objectid, have 257 expect 258
[1194842.322221] BTRFS info (device loop1): leaf 27574272 gen 8 total ptrs 11 free space 15444 owner 5
[1194842.331562] BTRFS info (device loop1): refs 2 lock_owner 0 current 26561
[1194842.338772] item 0 key (256 1 0) itemoff 16123 itemsize 160
[1194842.338793] inode generation 3 size 16 mode 40755
[1194842.338801] item 1 key (256 12 256) itemoff 16111 itemsize 12
[1194842.338809] item 2 key (256 84 2248503653) itemoff 16077 itemsize 34
[1194842.338817] dir oid 258 type 2
[1194842.338823] item 3 key (256 84 2363071922) itemoff 16043 itemsize 34
[1194842.338830] dir oid 257 type 2
[1194842.338836] item 4 key (256 96 2) itemoff 16009 itemsize 34
[1194842.338843] item 5 key (256 96 3) itemoff 15975 itemsize 34
[1194842.338852] item 6 key (257 1 0) itemoff 15815 itemsize 160
[1194842.338863] inode generation 6 size 8 mode 40755
[1194842.338869] item 7 key (257 12 256) itemoff 15801 itemsize 14
[1194842.338876] item 8 key (257 84 2505409169) itemoff 15767 itemsize 34
[1194842.338883] dir oid 256 type 2
[1194842.338888] item 9 key (257 96 2) itemoff 15733 itemsize 34
[1194842.338895] item 10 key (258 12 256) itemoff 15719 itemsize 14
[1194842.339163] BTRFS error (device loop1): block=27574272 write time tree block corruption detected
[1194842.339245] ------------[ cut here ]------------
[1194842.443422] WARNING: CPU: 6 PID: 26561 at fs/btrfs/disk-io.c:449 csum_one_extent_buffer+0xed/0x100 [btrfs]
[1194842.511863] CPU: 6 PID: 26561 Comm: kworker/u17:2 Not tainted 5.14.0-rc3-git+ #793
[1194842.511870] Hardware name: empty empty/S3993, BIOS PAQEX0-3 02/24/2008
[1194842.511876] Workqueue: btrfs-worker-high btrfs_work_helper [btrfs]
[1194842.511976] RIP: 0010:csum_one_extent_buffer+0xed/0x100 [btrfs]
[1194842.512068] RSP: 0018:ffffa2c284d77da0 EFLAGS: 00010282
[1194842.512074] RAX: 0000000000000000 RBX: 0000000000001000 RCX: ffff928867bd9978
[1194842.512078] RDX: 0000000000000000 RSI: 0000000000000027 RDI: ffff928867bd9970
[1194842.512081] RBP: ffff92876b958000 R08: 0000000000000001 R09: 00000000000c0003
[1194842.512085] R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
[1194842.512088] R13: ffff92875f989f98 R14: 0000000000000000 R15: 0000000000000000
[1194842.512092] FS: 0000000000000000(0000) GS:ffff928867a00000(0000) knlGS:0000000000000000
[1194842.512095] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[1194842.512099] CR2: 000055f5384da1f0 CR3: 0000000102fe4000 CR4: 00000000000006e0
[1194842.512103] Call Trace:
[1194842.512128] ? run_one_async_free+0x10/0x10 [btrfs]
[1194842.631729] btree_csum_one_bio+0x1ac/0x1d0 [btrfs]
[1194842.631837] run_one_async_start+0x18/0x30 [btrfs]
[1194842.631938] btrfs_work_helper+0xd5/0x1d0 [btrfs]
[1194842.647482] process_one_work+0x262/0x5e0
[1194842.647520] worker_thread+0x4c/0x320
[1194842.655935] ? process_one_work+0x5e0/0x5e0
[1194842.655946] kthread+0x135/0x160
[1194842.655953] ? set_kthread_struct+0x40/0x40
[1194842.655965] ret_from_fork+0x1f/0x30
[1194842.672465] irq event stamp: 1729
[1194842.672469] hardirqs last enabled at (1735): [<ffffffffbd1104f5>] console_trylock_spinning+0x185/0x1a0
[1194842.672477] hardirqs last disabled at (1740): [<ffffffffbd1104cc>] console_trylock_spinning+0x15c/0x1a0
[1194842.672482] softirqs last enabled at (1666): [<ffffffffbdc002e1>] __do_softirq+0x2e1/0x50a
[1194842.672491] softirqs last disabled at (1651): [<ffffffffbd08aab7>] __irq_exit_rcu+0xa7/0xd0
The corrupted data will not be written, and filesystem can be unmounted
and mounted again (all changes since the last commit will be lost).
Add the missing check for new_ino so that all non-subvolumes must reside
under the same parent subvolume. There's an exception allowing to
exchange two subvolumes from any parents as the directory representing a
subvolume is only a logical link and does not have any other structures
related to the parent subvolume, unlike files, directories etc, that
are always in the inode namespace of the parent subvolume.
Fixes: cdd1fedf82 ("btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT")
CC: stable@vger.kernel.org # 4.7+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Store the block device instead of the gendisk in the btrfs_ordered_extent
structure instead of acquiring a reference to it later.
Note: this is from series removing bdgrab/bdput, btrfs is one of the
last users.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Damien reported a test failure with btrfs/209. The test itself ran fine,
but the fsck ran afterwards reported a corrupted filesystem.
The filesystem corruption happens because we're splitting an extent and
then writing the extent twice. We have to split the extent though, because
we're creating too large extents for a REQ_OP_ZONE_APPEND operation.
When dumping the extent tree, we can see two EXTENT_ITEMs at the same
start address but different lengths.
$ btrfs inspect dump-tree /dev/nullb1 -t extent
...
item 19 key (269484032 EXTENT_ITEM 126976) itemoff 15470 itemsize 53
refs 1 gen 7 flags DATA
extent data backref root FS_TREE objectid 257 offset 786432 count 1
item 20 key (269484032 EXTENT_ITEM 262144) itemoff 15417 itemsize 53
refs 1 gen 7 flags DATA
extent data backref root FS_TREE objectid 257 offset 786432 count 1
The duplicated EXTENT_ITEMs originally come from wrongly split extent_map in
extract_ordered_extent(). Since extract_ordered_extent() uses
create_io_em() to split an existing extent_map, we will have
split->orig_start != split->start. Then, it will be logged with non-zero
"extent data offset". Finally, the logged entries are replayed into
a duplicated EXTENT_ITEM.
Introduce and use proper splitting function for extent_map. The function is
intended to be simple and specific usage for extract_ordered_extent() e.g.
not supporting compression case (we do not allow splitting compressed
extent_map anyway).
There was a question raised by Qu, in summary why we want to split the
extent map (and not the bio):
The problem is not the limit on the zone end, which as you mention is
the same as the block group end. The problem is that data write use zone
append (ZA) operations. ZA BIOs cannot be split so a large extent may
need to be processed with multiple ZA BIOs, While that is also true for
regular writes, the major difference is that ZA are "nameless" write
operation giving back the written sectors on completion. And ZA
operations may be reordered by the block layer (not intentionally
though). Combine both of these characteristics and you can see that the
data for a large extent may end up being shuffled when written resulting
in data corruption and the impossibility to map the extent to some start
sector.
To avoid this problem, zoned btrfs uses the principle "one data extent
== one ZA BIO". So large extents need to be split. This is unfortunate,
but we can revisit this later and optimize, e.g. merge back together the
fragments of an extent once written if they actually were written
sequentially in the zone.
Reported-by: Damien Le Moal <damien.lemoal@wdc.com>
Fixes: d22002fd37 ("btrfs: zoned: split ordered extent when bio is sent")
CC: stable@vger.kernel.org # 5.12+
CC: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
