This implements journal callbacks j_submit|finish_inode_data_buffers()
with different behavior for data=journal: to write-protect pages under
commit, preventing changes to buffers writeably mapped to userspace.
If a buffer's content changes between commit's checksum calculation
and write-out to disk, it can cause journal recovery/mount failures
upon a kernel crash or power loss.
[ 27.334874] EXT4-fs: Warning: mounting with data=journal disables delayed allocation, dioread_nolock, and O_DIRECT support!
[ 27.339492] JBD2: Invalid checksum recovering data block 8705 in log
[ 27.342716] JBD2: recovery failed
[ 27.343316] EXT4-fs (loop0): error loading journal
mount: /ext4: can't read superblock on /dev/loop0.
In j_submit_inode_data_buffers() we write-protect the inode's pages
with write_cache_pages() and redirty w/ writepage callback if needed.
In j_finish_inode_data_buffers() there is nothing do to.
And in order to use the callbacks, inodes are added to the inode list
in transaction in __ext4_journalled_writepage() and ext4_page_mkwrite().
In ext4_page_mkwrite() we must make sure that the buffers are attached
to the transaction as jbddirty with write_end_fn(), as already done in
__ext4_journalled_writepage().
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Reported-by: Dann Frazier <dann.frazier@canonical.com>
Reported-by: kernel test robot <lkp@intel.com> # wbc.nr_to_write
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201006004841.600488-5-mfo@canonical.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
These are two fixes for data journalling required by
the next patch, discovered while testing it.
First, the optimization to return early if all buffers
are mapped is not appropriate for the next patch:
The inode _must_ be added to the transaction's list in
data=journal mode (so to write-protect pages on commit)
thus we cannot return early there.
Second, once that optimization to reduce transactions
was disabled for data=journal mode, more transactions
happened, and occasionally hit this warning message:
'JBD2: Spotted dirty metadata buffer'.
Reason is, block_page_mkwrite() will set_buffer_dirty()
before do_journal_get_write_access() that is there to
prevent it. This issue was masked by the optimization.
So, on data=journal use __block_write_begin() instead.
This also requires page locking and len recalculation.
(see block_page_mkwrite() for implementation details.)
Finally, as Jan noted there is little sharing between
data=journal and other modes in ext4_page_mkwrite().
However, a prototype of ext4_journalled_page_mkwrite()
showed there still would be lots of duplicated lines
(tens of) that didn't seem worth it.
Thus this patch ends up with an ugly goto to skip all
non-data journalling code (to avoid long indentations,
but that can be changed..) in the beginning, and just
a conditional in the transaction section.
Well, we skip a common part to data journalling which
is the page truncated check, but we do it again after
ext4_journal_start() when we re-acquire the page lock
(so not to acquire the page lock twice needlessly for
data journalling.)
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20201006004841.600488-4-mfo@canonical.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Introduce journal callbacks to allow different behaviors
for an inode in journal_submit|finish_inode_data_buffers().
The existing users of the current behavior (ext4, ocfs2)
are adapted to use the previously exported functions
that implement the current behavior.
Users are callers of jbd2_journal_inode_ranged_write|wait(),
which adds the inode to the transaction's inode list with
the JI_WRITE|WAIT_DATA flags. Only ext4 and ocfs2 in-tree.
Both CONFIG_EXT4_FS and CONFIG_OCSFS2_FS select CONFIG_JBD2,
which builds fs/jbd2/commit.c and journal.c that define and
export the functions, so we can call directly in ext4/ocfs2.
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20201006004841.600488-3-mfo@canonical.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Export functions that implement the current behavior done
for an inode in journal_submit|finish_inode_data_buffers().
No functional change.
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20201006004841.600488-2-mfo@canonical.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Now we only use sb_bread_unmovable() to read superblock and descriptor
block at mount time, so there is no opportunity that we need to clear
buffer verified bit and also handle buffer write_io error bit. But for
the sake of unification, let's introduce ext4_sb_bread_unmovable() to
replace all sb_bread_unmovable(). After this patch, we stop using read
helpers in fs/buffer.c.
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20200924073337.861472-8-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
We have already remove open codes that invoke helpers provide by
fs/buffer.c in all places reading metadata buffers. This patch switch to
use ext4_sb_bread() to replace all sb_bread() helpers, which is
ext4_read_bh() helper back end.
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20200924073337.861472-7-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
If we readahead inode tables in __ext4_get_inode_loc(), it may bypass
buffer_write_io_error() check, so introduce ext4_sb_breadahead_unmovable()
to handle this special case.
This patch also replace sb_breadahead_unmovable() in ext4_fill_super()
for the sake of unification.
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20200924073337.861472-6-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
We have already introduced ext4_buffer_uptodate() to re-set the uptodate
bit on buffer which has been failed to write out to disk. Just remove
the redundant codes and switch to use ext4_buffer_uptodate() in
__ext4_get_inode_loc().
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20200924073337.861472-5-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Revome all open codes that read metadata buffers, switch to use
ext4_read_bh_*() common helpers.
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Suggested-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200924073337.861472-4-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The previous patch add clear_buffer_verified() before we read metadata
block from disk again, but it's rather easy to miss clearing of this bit
because currently we read metadata buffer through different open codes
(e.g. ll_rw_block(), bh_submit_read() and invoke submit_bh() directly).
So, it's time to add common helpers to unify in all the places reading
metadata buffers instead. This patch add 3 helpers:
- ext4_read_bh_nowait(): async read metadata buffer if it's actually
not uptodate, clear buffer_verified bit before read from disk.
- ext4_read_bh(): sync version of read metadata buffer, it will wait
until the read operation return and check the return status.
- ext4_read_bh_lock(): try to lock the buffer before read buffer, it
will skip reading if the buffer is already locked.
After this patch, we need to use these helpers in all the places reading
metadata buffer instead of different open codes.
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Suggested-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200924073337.861472-3-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The metadata buffer is no longer trusted after we read it from disk
again because it is not uptodate for some reasons (e.g. failed to write
back). Otherwise we may get below memory corruption problem in
ext4_ext_split()->memset() if we read stale data from the newly
allocated extent block on disk which has been failed to async write
out but miss verify again since the verified bit has already been set
on the buffer.
[ 29.774674] BUG: unable to handle kernel paging request at ffff88841949d000
...
[ 29.783317] Oops: 0002 [#2] SMP
[ 29.784219] R10: 00000000000f4240 R11: 0000000000002e28 R12: ffff88842fa1c800
[ 29.784627] CPU: 1 PID: 126 Comm: kworker/u4:3 Tainted: G D W
[ 29.785546] R13: ffffffff9cddcc20 R14: ffffffff9cddd420 R15: ffff88842fa1c2f8
[ 29.786679] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),BIOS ?-20190727_0738364
[ 29.787588] FS: 0000000000000000(0000) GS:ffff88842fa00000(0000) knlGS:0000000000000000
[ 29.789288] Workqueue: writeback wb_workfn
[ 29.790319] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 29.790321] (flush-8:0)
[ 29.790844] CR2: 0000000000000008 CR3: 00000004234f2000 CR4: 00000000000006f0
[ 29.791924] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 29.792839] RIP: 0010:__memset+0x24/0x30
[ 29.793739] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 29.794256] Code: 90 90 90 90 90 90 0f 1f 44 00 00 49 89 f9 48 89 d1 83 e2 07 48 c1 e9 033
[ 29.795161] Kernel panic - not syncing: Fatal exception in interrupt
...
[ 29.808149] Call Trace:
[ 29.808475] ext4_ext_insert_extent+0x102e/0x1be0
[ 29.809085] ext4_ext_map_blocks+0xa89/0x1bb0
[ 29.809652] ext4_map_blocks+0x290/0x8a0
[ 29.809085] ext4_ext_map_blocks+0xa89/0x1bb0
[ 29.809652] ext4_map_blocks+0x290/0x8a0
[ 29.810161] ext4_writepages+0xc85/0x17c0
...
Fix this by clearing buffer's verified bit if we read meta block from
disk again.
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200924073337.861472-2-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
If userspace asked fsmap to try to count the number of entries, we cannot
return more than UINT_MAX entries because fmh_entries is u32.
Therefore, stop counting if we hit this limit or else we will waste time
to return truncated results.
Fixes: 0c9ec4beec ("ext4: support GETFSMAP ioctls")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Link: https://lore.kernel.org/r/20201001222148.GA49520@magnolia
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Consider a situation when a filesystem was uncleanly shutdown and the
orphan list is not empty and a read-only mount is attempted. The orphan
list cleanup during mount will fail with:
ext4_check_bdev_write_error:193: comm mount: Error while async write back metadata
This happens because sbi->s_bdev_wb_err is not initialized when mounting
the filesystem in read only mode and so ext4_check_bdev_write_error()
falsely triggers.
Initialize sbi->s_bdev_wb_err unconditionally to avoid this problem.
Fixes: bc71726c72 ("ext4: abort the filesystem if failed to async write metadata buffer")
Cc: stable@kernel.org
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200928020556.710971-1-zhangxiaoxu5@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Rename system_blks to s_system_blks inside ext4_sb_info, keep
the naming rules consistent with other variables, which is
convenient for code reading and writing.
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/1600916623-544-2-git-send-email-brookxu@tencent.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Rename journal_dev to s_journal_dev inside ext4_sb_info, keep
the naming rules consistent with other variables, which is
convenient for code reading and writing.
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/1600916623-544-1-git-send-email-brookxu@tencent.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
In case if the file already has underlying blocks/extents allocated
then we don't need to start a journal txn and can directly return
the underlying mapping. Currently ext4_iomap_begin() is used by
both DAX & DIO path. We can check if the write request is an
overwrite & then directly return the mapping information.
This could give a significant perf boost for multi-threaded writes
specially random overwrites.
On PPC64 VM with simulated pmem(DAX) device, ~10x perf improvement
could be seen in random writes (overwrite). Also bcoz this optimizes
away the spinlock contention during jbd2 slab cache allocation
(jbd2_journal_handle). On x86 VM, ~2x perf improvement was observed.
Reported-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/88e795d8a4d5cd22165c7ebe857ba91d68d8813e.1600401668.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The race condition could cause the persisted superblock checksum
to not match the contents of the superblock, causing the
superblock to be considered corrupt.
An example of the race follows. A first thread is interrupted in the
middle of a checksum calculation. Then, another thread changes the
superblock, calculates a new checksum, and sets it. Then, the first
thread resumes and sets the checksum based on the older superblock.
To fix, serialize the superblock checksum calculation using the buffer
header lock. While a spinlock is sufficient, the buffer header is
already there and there is precedent for locking it (e.g. in
ext4_commit_super).
Tested the patch by booting up a kernel with the patch, creating
a filesystem and some files (including some orphans), and then
unmounting and remounting the file system.
Cc: stable@kernel.org
Signed-off-by: Constantine Sapuntzakis <costa@purestorage.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Suggested-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200914161014.22275-1-costa@purestorage.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When ext4_journal_get_write_access() fails, we should
terminate the execution flow and release n_group_desc,
iloc.bh, dind and gdb_bh.
Cc: stable@kernel.org
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20200829025403.3139-1-dinghao.liu@zju.edu.cn
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The 'handle' argument is not used for anything so simply remove it.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/20200826133116.11592-1-nborisov@suse.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Fields s_free_blocks_count_hi, s_r_blocks_count_hi and s_blocks_count_hi
are not valid if EXT4_FEATURE_INCOMPAT_64BIT is not enabled and should be
treated as zeroes.
Signed-off-by: Petr Malat <oss@malat.biz>
Link: https://lore.kernel.org/r/20200825150016.3363-1-oss@malat.biz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Delete repeated words in fs/ext4/.
{the, this, of, we, after}
Also change spelling of "xttr" in inline.c to "xattr" in 2 places.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200805024850.12129-1-rdunlap@infradead.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4_mb_discard_group_preallocations() can be releasing group lock with
preallocations accumulated on its local list. Thus although
discard_pa_seq was incremented and concurrent allocating processes will
be retrying allocations, it can happen that premature ENOSPC error is
returned because blocks used for preallocations are not available for
reuse yet. Make sure we always free locally accumulated preallocations
before releasing group lock.
Fixes: 07b5b8e1ac ("ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200924150959.4335-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
As we test disk offline/online with running fsstress, we find fsstress
process is keeping running state.
kworker/u32:3-262 [004] ...1 140.787471: ext4_mb_discard_preallocations: dev 8,32 needed 114
....
kworker/u32:3-262 [004] ...1 140.787471: ext4_mb_discard_preallocations: dev 8,32 needed 114
ext4_mb_new_blocks
repeat:
ext4_mb_discard_preallocations_should_retry(sb, ac, &seq)
freed = ext4_mb_discard_preallocations
ext4_mb_discard_group_preallocations
this_cpu_inc(discard_pa_seq);
---> freed == 0
seq_retry = ext4_get_discard_pa_seq_sum
for_each_possible_cpu(__cpu)
__seq += per_cpu(discard_pa_seq, __cpu);
if (seq_retry != *seq) {
*seq = seq_retry;
ret = true;
}
As we see seq_retry is sum of discard_pa_seq every cpu, if
ext4_mb_discard_group_preallocations return zero discard_pa_seq in this
cpu maybe increase one, so condition "seq_retry != *seq" have always
been met.
Ritesh Harjani suggest to in ext4_mb_discard_group_preallocations function we
only increase discard_pa_seq when there is some PA to free.
Fixes: 07b5b8e1ac ("ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/20200916113859.1556397-3-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
After moving ext4's bmap to iomap interface, swapon functionality
on files created using fallocate (which creates unwritten extents) are
failing. This is since iomap_bmap interface returns 0 for unwritten
extents and thus generic_swapfile_activate considers this as holes
and hence bail out with below kernel msg :-
[340.915835] swapon: swapfile has holes
To fix this we need to implement ->swap_activate aops in ext4
which will use ext4_iomap_report_ops. Since we only need to return
the list of extents so ext4_iomap_report_ops should be enough.
Cc: stable@kernel.org
Reported-by: Yuxuan Shui <yshuiv7@gmail.com>
Fixes: ac58e4fb03 ("ext4: move ext4 bmap to use iomap infrastructure")
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/20200904091653.1014334-1-riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
A previous commit changed the notification mode from true/false to an
int, allowing notify-no, notify-yes, or signal-notify. This was
backwards compatible in the sense that any existing true/false user
would translate to either 0 (on notification sent) or 1, the latter
which mapped to TWA_RESUME. TWA_SIGNAL was assigned a value of 2.
Clean this up properly, and define a proper enum for the notification
mode. Now we have:
- TWA_NONE. This is 0, same as before the original change, meaning no
notification requested.
- TWA_RESUME. This is 1, same as before the original change, meaning
that we use TIF_NOTIFY_RESUME.
- TWA_SIGNAL. This uses TIF_SIGPENDING/JOBCTL_TASK_WORK for the
notification.
Clean up all the callers, switching their 0/1/false/true to using the
appropriate TWA_* mode for notifications.
Fixes: e91b481623 ("task_work: teach task_work_add() to do signal_wake_up()")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__io_queue_proc() is used by both, poll reqs and apoll. Don't use
req->poll.events to copy poll mask because for apoll it aliases with
private data of the request.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make sure the async io-wq workers inherit the loginuid and sessionid from
the original task, and restore them to unset once we're done with the
async work item.
While at it, disable the ability for kernel threads to write to their own
loginuid.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Even though we place the req_issued and req_complete in separate
cachelines, there's considerable overhead in doing the atomics
particularly on the completion side.
Get rid of having the two counters, and just use a percpu_counter for
this. That's what it was made for, after all. This considerably
reduces the overhead in __io_free_req().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This avoids doing a copy for each new async IO, if some parts of the
io_identity has changed. We avoid reference counting for the normal
fast path of nothing ever changing.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is, by definition, a per-task structure. So store it in the
task context, instead of doing carrying it in each io_kiocb. We're being
a bit inefficient if members have changed, as that requires an alloc and
copy of a new io_identity struct. The next patch will fix that up.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If the io_identity doesn't completely match the task, then create a
copy of it and use that. The existing copy remains valid until the last
user of it has gone away.
This also changes the personality lookup to be indexed by io_identity,
instead of creds directly.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io-wq contains a pointer to the identity, which we just hold in io_kiocb
for now. This is in preparation for putting this outside io_kiocb. The
only exception is struct files_struct, which we'll need different rules
for to avoid a circular dependency.
No functional changes in this patch.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We solely rely on work->work_flags now, so use that for proper checking
and clearing/dropping of various identity items.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have a number of bits that decide what context to inherit. Set up
io-wq flags for these instead. This is in preparation for always having
the various members set, but not always needing them for all requests.
No intended functional changes in this patch.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There was an assumption that kthread_create_on_node() would properly set
NUMA affinities in terms of CPUs allowed, but it doesn't. Make sure we
do this when creating an io-wq context on NUMA.
Cc: stable@vger.kernel.org
Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This reverts commit 738277adc8.
This change didn't make a lot of sense, and as Linus reports, it actually
fails on clang:
/tmp/io_uring-dd40c4.s:26476: Warning: ignoring changed section
attributes for .data..read_mostly
The arrays are already marked const so, by definition, they are not
just read-mostly, they are read-only.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
REQ_F_COMP_LOCKED is used and implemented in a buggy way. The problem is
that the flag is set before io_put_req() but not cleared after, and if
that wasn't the final reference, the request will be freed with the flag
set from some other context, which may not hold a spinlock. That means
possible races with removing linked timeouts and unsynchronised
completion (e.g. access to CQ).
Instead of fixing REQ_F_COMP_LOCKED, kill the flag and use
task_work_add() to move such requests to a fresh context to free from
it, as was done with __io_free_req_finish().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_req_clean_work() checks REQ_F_COMP_LOCK to pass this two layers up.
Move the check up into __io_free_req(), so at least it doesn't looks so
ugly and would facilitate further changes.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move io_put_req() in io_poll_task_handler() from under spinlock. This
eliminates the need to use REQ_F_COMP_LOCKED, at the expense of
potentially having to grab the lock again. That's still a better trade
off than relying on the locked flag.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If a request had REQ_F_LINK_TIMEOUT it would've been cleared in
__io_kill_linked_timeout() by the time of __io_fail_links(), so no need
to care about it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__io_kill_linked_timeout() sets REQ_F_COMP_LOCKED for a linked timeout
even if it can't cancel it, e.g. it's already running. It not only races
with io_link_timeout_fn() for ->flags field, but also leaves the flag
set and so io_link_timeout_fn() may find it and decide that it holds the
lock. Hopefully, the second problem is potential.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
An incorrect sizeof() is being used, sizeof(file_data->table) is not
correct, it should be sizeof(*file_data->table).
Fixes: 5398ae6985 ("io_uring: clean file_data access in files_register")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Addresses-Coverity: ("Sizeof not portable (SIZEOF_MISMATCH)")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
