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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull kmap conversion updates from David Sterba:
"This contains changes regarding kmap API use and eg conversion from
kmap_atomic to kmap_local_page.
The API belongs to memory management but to save cross-tree
dependency headaches we've agreed to take it through the btrfs tree
because there are some trivial conversions possible, while the rest
will need some time and getting the easy cases out of the way would be
convenient.
The changes can be grouped:
- function exports, new helpers
- new VM_BUG_ON for additional verification; it's been discussed if
it should be VM_BUG_ON or BUG_ON, the former was chosen due to
performance reasons
- code replaced by relevant helpers"
[ This is an updated version of a request that originally came in during
the merge window, but I asked for some updates:
https://lore.kernel.org/lkml/cover.1614090658.git.dsterba@suse.com/
which is why this got merge after the merge window closed. - Linus ]
* 'kmap-conversion-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: use copy_highpage() instead of 2 kmaps()
btrfs: use memcpy_[to|from]_page() and kmap_local_page()
mm/highmem: Add VM_BUG_ON() to mem*_page() calls
mm/highmem: Introduce memcpy_page(), memmove_page(), and memset_page()
mm/highmem: Convert memcpy_[to|from]_page() to kmap_local_page()
mm/highmem: Lift memcpy_[to|from]_page to core
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There are many places where kmap/memove/kunmap patterns occur.
This pattern exists in the core common function copy_highpage().
Use copy_highpage to avoid open coding the use of kmap and leverages the
core functions use of kmap_local_page().
Development of this patch was aided by the following coccinelle script:
// <smpl>
// SPDX-License-Identifier: GPL-2.0-only
// Find kmap/copypage/kunmap pattern and replace with copy_highpage calls
//
// NOTE: The expressions in the copy page version of this kmap pattern are
// overly complex and so these all need individual attention.
//
// Confidence: Low
// Copyright: (C) 2021 Intel Corporation
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options:
//
// Then a copy_page where we have 2 pages involved.
//
@ copy_page_rule @
expression page, page2, To, From, Size;
identifier ptr, ptr2;
type VP, VP2;
@@
/* kmap */
(
-VP ptr = kmap(page);
...
-VP2 ptr2 = kmap(page2);
|
-VP ptr = kmap_atomic(page);
...
-VP2 ptr2 = kmap_atomic(page2);
|
-ptr = kmap(page);
...
-ptr2 = kmap(page2);
|
-ptr = kmap_atomic(page);
...
-ptr2 = kmap_atomic(page2);
)
// 1 or more copy versions of the entire page
<+...
(
-copy_page(To, From);
+copy_highpage(To, From);
|
-memmove(To, From, Size);
+memmoveExtra(To, From, Size);
)
...+>
/* kunmap */
(
-kunmap(page2);
...
-kunmap(page);
|
-kunmap(page);
...
-kunmap(page2);
|
-kmap_atomic(ptr2);
...
-kmap_atomic(ptr);
)
// Remove any pointers left unused
@
depends on copy_page_rule
@
identifier copy_page_rule.ptr;
identifier copy_page_rule.ptr2;
type VP, VP1;
type VP2, VP21;
@@
-VP ptr;
... when != ptr;
? VP1 ptr;
-VP2 ptr2;
... when != ptr2;
? VP21 ptr2;
// </smpl>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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There are many places where the pattern kmap/memcpy/kunmap occurs.
This pattern was lifted to the core common functions
memcpy_[to|from]_page().
Use these new functions to reduce the code, eliminate direct uses of
kmap, and leverage the new core functions use of kmap_local_page().
Also, there is 1 place where a kmap/memcpy is followed by an
optional memset. Here we leave the kmap open coded to avoid remapping
the page but use kmap_local_page() directly.
Development of this patch was aided by the coccinelle script:
// <smpl>
// SPDX-License-Identifier: GPL-2.0-only
// Find kmap/memcpy/kunmap pattern and replace with memcpy*page calls
//
// NOTE: Offsets and other expressions may be more complex than what the script
// will automatically generate. Therefore a catchall rule is provided to find
// the pattern which then must be evaluated by hand.
//
// Confidence: Low
// Copyright: (C) 2021 Intel Corporation
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options:
//
// simple memcpy version
//
@ memcpy_rule1 @
expression page, T, F, B, Off;
identifier ptr;
type VP;
@@
(
-VP ptr = kmap(page);
|
-ptr = kmap(page);
|
-VP ptr = kmap_atomic(page);
|
-ptr = kmap_atomic(page);
)
<+...
(
-memcpy(ptr + Off, F, B);
+memcpy_to_page(page, Off, F, B);
|
-memcpy(ptr, F, B);
+memcpy_to_page(page, 0, F, B);
|
-memcpy(T, ptr + Off, B);
+memcpy_from_page(T, page, Off, B);
|
-memcpy(T, ptr, B);
+memcpy_from_page(T, page, 0, B);
)
...+>
(
-kunmap(page);
|
-kunmap_atomic(ptr);
)
// Remove any pointers left unused
@
depends on memcpy_rule1
@
identifier memcpy_rule1.ptr;
type VP, VP1;
@@
-VP ptr;
... when != ptr;
? VP1 ptr;
//
// Some callers kmap without a temp pointer
//
@ memcpy_rule2 @
expression page, T, Off, F, B;
@@
<+...
(
-memcpy(kmap(page) + Off, F, B);
+memcpy_to_page(page, Off, F, B);
|
-memcpy(kmap(page), F, B);
+memcpy_to_page(page, 0, F, B);
|
-memcpy(T, kmap(page) + Off, B);
+memcpy_from_page(T, page, Off, B);
|
-memcpy(T, kmap(page), B);
+memcpy_from_page(T, page, 0, B);
)
...+>
-kunmap(page);
// No need for the ptr variable removal
//
// Catch all
//
@ memcpy_rule3 @
expression page;
expression GenTo, GenFrom, GenSize;
identifier ptr;
type VP;
@@
(
-VP ptr = kmap(page);
|
-ptr = kmap(page);
|
-VP ptr = kmap_atomic(page);
|
-ptr = kmap_atomic(page);
)
<+...
(
//
// Some call sites have complex expressions within the memcpy
// match a catch all to be evaluated by hand.
//
-memcpy(GenTo, GenFrom, GenSize);
+memcpy_to_pageExtra(page, GenTo, GenFrom, GenSize);
+memcpy_from_pageExtra(GenTo, page, GenFrom, GenSize);
)
...+>
(
-kunmap(page);
|
-kunmap_atomic(ptr);
)
// Remove any pointers left unused
@
depends on memcpy_rule3
@
identifier memcpy_rule3.ptr;
type VP, VP1;
@@
-VP ptr;
... when != ptr;
? VP1 ptr;
// <smpl>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"This is the first batch of fixes that usually arrive during the merge
window code freeze. Regressions and stable material.
Regressions:
- fix deadlock in log sync in zoned mode
- fix bugs in subpage mode still wrongly assuming sectorsize == page
size
Fixes:
- fix missing kunmap of the Q stripe in RAID6
- block group fixes:
- fix race between extent freeing/allocation when using bitmaps
- avoid double put of block group when emptying cluster
- swapfile fixes:
- fix swapfile writes vs running scrub
- fix swapfile activation vs snapshot creation
- fix stale data exposure after cloning a hole with NO_HOLES enabled
- remove tree-checker check that does not work in case information
from other leaves is necessary"
* tag 'for-5.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: zoned: fix deadlock on log sync
btrfs: avoid double put of block group when emptying cluster
btrfs: fix stale data exposure after cloning a hole with NO_HOLES enabled
btrfs: tree-checker: do not error out if extent ref hash doesn't match
btrfs: fix race between swap file activation and snapshot creation
btrfs: fix race between writes to swap files and scrub
btrfs: avoid checking for RO block group twice during nocow writeback
btrfs: fix race between extent freeing/allocation when using bitmaps
btrfs: make check_compressed_csum() to be subpage compatible
btrfs: make btrfs_submit_compressed_read() subpage compatible
btrfs: fix raid6 qstripe kmap
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Lockdep with fstests test case btrfs/041 detected a unsafe locking
scenario when we allocate the log node on a zoned filesystem.
btrfs/041
============================================
WARNING: possible recursive locking detected
5.11.0-rc7+ #939 Not tainted
--------------------------------------------
xfs_io/698 is trying to acquire lock:
ffff88810cd673a0 (&root->log_mutex){+.+.}-{3:3}, at: btrfs_sync_log+0x3d1/0xee0 [btrfs]
but task is already holding lock:
ffff88810b0fc3a0 (&root->log_mutex){+.+.}-{3:3}, at: btrfs_sync_log+0x313/0xee0 [btrfs]
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&root->log_mutex);
lock(&root->log_mutex);
*** DEADLOCK ***
May be due to missing lock nesting notation
2 locks held by xfs_io/698:
#0: ffff88810cd66620 (sb_internal){.+.+}-{0:0}, at: btrfs_sync_file+0x2c3/0x570 [btrfs]
#1: ffff88810b0fc3a0 (&root->log_mutex){+.+.}-{3:3}, at: btrfs_sync_log+0x313/0xee0 [btrfs]
stack backtrace:
CPU: 0 PID: 698 Comm: xfs_io Not tainted 5.11.0-rc7+ #939
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4-rebuilt.opensuse.org 04/01/2014
Call Trace:
dump_stack+0x77/0x97
__lock_acquire.cold+0xb9/0x32a
lock_acquire+0xb5/0x400
? btrfs_sync_log+0x3d1/0xee0 [btrfs]
__mutex_lock+0x7b/0x8d0
? btrfs_sync_log+0x3d1/0xee0 [btrfs]
? btrfs_sync_log+0x3d1/0xee0 [btrfs]
? find_first_extent_bit+0x9f/0x100 [btrfs]
? __mutex_unlock_slowpath+0x35/0x270
btrfs_sync_log+0x3d1/0xee0 [btrfs]
btrfs_sync_file+0x3a8/0x570 [btrfs]
__x64_sys_fsync+0x34/0x60
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
This happens, because we are taking the ->log_mutex albeit it has already
been locked.
Also while at it, fix the bogus unlock of the tree_log_mutex in the error
handling.
Fixes: 3ddebf27fcd3 ("btrfs: zoned: reorder log node allocation on zoned filesystem")
Reviewed-by: Filipe Manana <fdmanana@suse.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>
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It's wrong calling btrfs_put_block_group in
__btrfs_return_cluster_to_free_space if the block group passed is
different than the block group the cluster represents. As this means the
cluster doesn't have a reference to the passed block group. This results
in double put and a use-after-free bug.
Fix this by simply bailing if the block group we passed in does not
match the block group on the cluster.
Fixes: fa9c0d795f7b ("Btrfs: rework allocation clustering")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
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When using the NO_HOLES feature, if we clone a file range that spans only
a hole into a range that is at or beyond the current i_size of the
destination file, we end up not setting the full sync runtime flag on the
inode. As a result, if we then fsync the destination file and have a power
failure, after log replay we can end up exposing stale data instead of
having a hole for that range.
The conditions for this to happen are the following:
1) We have a file with a size of, for example, 1280K;
2) There is a written (non-prealloc) extent for the file range from 1024K
to 1280K with a length of 256K;
3) This particular file extent layout is durably persisted, so that the
existing superblock persisted on disk points to a subvolume root where
the file has that exact file extent layout and state;
4) The file is truncated to a smaller size, to an offset lower than the
start offset of its last extent, for example to 800K. The truncate sets
the full sync runtime flag on the inode;
6) Fsync the file to log it and clear the full sync runtime flag;
7) Clone a region that covers only a hole (implicit hole due to NO_HOLES)
into the file with a destination offset that starts at or beyond the
256K file extent item we had - for example to offset 1024K;
8) Since the clone operation does not find extents in the source range,
we end up in the if branch at the bottom of btrfs_clone() where we
punch a hole for the file range starting at offset 1024K by calling
btrfs_replace_file_extents(). There we end up not setting the full
sync flag on the inode, because we don't know we are being called in
a clone context (and not fallocate's punch hole operation), and
neither do we create an extent map to represent a hole because the
requested range is beyond eof;
9) A further fsync to the file will be a fast fsync, since the clone
operation did not set the full sync flag, and therefore it relies on
modified extent maps to correctly log the file layout. But since
it does not find any extent map marking the range from 1024K (the
previous eof) to the new eof, it does not log a file extent item
for that range representing the hole;
10) After a power failure no hole for the range starting at 1024K is
punched and we end up exposing stale data from the old 256K extent.
Turning this into exact steps:
$ mkfs.btrfs -f -O no-holes /dev/sdi
$ mount /dev/sdi /mnt
# Create our test file with 3 extents of 256K and a 256K hole at offset
# 256K. The file has a size of 1280K.
$ xfs_io -f -s \
-c "pwrite -S 0xab -b 256K 0 256K" \
-c "pwrite -S 0xcd -b 256K 512K 256K" \
-c "pwrite -S 0xef -b 256K 768K 256K" \
-c "pwrite -S 0x73 -b 256K 1024K 256K" \
/mnt/sdi/foobar
# Make sure it's durably persisted. We want the last committed super
# block to point to this particular file extent layout.
sync
# Now truncate our file to a smaller size, falling within a position of
# the second extent. This sets the full sync runtime flag on the inode.
# Then fsync the file to log it and clear the full sync flag from the
# inode. The third extent is no longer part of the file and therefore
# it is not logged.
$ xfs_io -c "truncate 800K" -c "fsync" /mnt/foobar
# Now do a clone operation that only clones the hole and sets back the
# file size to match the size it had before the truncate operation
# (1280K).
$ xfs_io \
-c "reflink /mnt/foobar 256K 1024K 256K" \
-c "fsync" \
/mnt/foobar
# File data before power failure:
$ od -A d -t x1 /mnt/foobar
0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
*
0262144 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0524288 cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd
*
0786432 ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef
*
0819200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
1310720
<power fail>
# Mount the fs again to replay the log tree.
$ mount /dev/sdi /mnt
# File data after power failure:
$ od -A d -t x1 /mnt/foobar
0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
*
0262144 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0524288 cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd
*
0786432 ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef
*
0819200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
1048576 73 73 73 73 73 73 73 73 73 73 73 73 73 73 73 73
*
1310720
The range from 1024K to 1280K should correspond to a hole but instead it
points to stale data, to the 256K extent that should not exist after the
truncate operation.
The issue does not exists when not using NO_HOLES, because for that case
we use file extent items to represent holes, these are found and copied
during the loop that iterates over extents at btrfs_clone(), and that
causes btrfs_replace_file_extents() to be called with a non-NULL
extent_info argument and therefore set the full sync runtime flag on the
inode.
So fix this by making the code that deals with a trailing hole during
cloning, at btrfs_clone(), to set the full sync flag on the inode, if the
range starts at or beyond the current i_size.
A test case for fstests will follow soon.
Backporting notes: for kernel 5.4 the change goes to ioctl.c into
btrfs_clone before the last call to btrfs_punch_hole_range.
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The tree checker checks the extent ref hash at read and write time to
make sure we do not corrupt the file system. Generally extent
references go inline, but if we have enough of them we need to make an
item, which looks like
key.objectid = <bytenr>
key.type = <BTRFS_EXTENT_DATA_REF_KEY|BTRFS_TREE_BLOCK_REF_KEY>
key.offset = hash(tree, owner, offset)
However if key.offset collide with an unrelated extent reference we'll
simply key.offset++ until we get something that doesn't collide.
Obviously this doesn't match at tree checker time, and thus we error
while writing out the transaction. This is relatively easy to
reproduce, simply do something like the following
xfs_io -f -c "pwrite 0 1M" file
offset=2
for i in {0..10000}
do
xfs_io -c "reflink file 0 ${offset}M 1M" file
offset=$(( offset + 2 ))
done
xfs_io -c "reflink file 0 17999258914816 1M" file
xfs_io -c "reflink file 0 35998517829632 1M" file
xfs_io -c "reflink file 0 53752752058368 1M" file
btrfs filesystem sync
And the sync will error out because we'll abort the transaction. The
magic values above are used because they generate hash collisions with
the first file in the main subvol.
The fix for this is to remove the hash value check from tree checker, as
we have no idea which offset ours should belong to.
Reported-by: Tuomas Lähdekorpi <tuomas.lahdekorpi@gmail.com>
Fixes: 0785a9aacf9d ("btrfs: tree-checker: Add EXTENT_DATA_REF check")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment]
Signed-off-by: David Sterba <dsterba@suse.com>
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When creating a snapshot we check if the current number of swap files, in
the root, is non-zero, and if it is, we error out and warn that we can not
create the snapshot because there are active swap files.
However this is racy because when a task started activation of a swap
file, another task might have started already snapshot creation and might
have seen the counter for the number of swap files as zero. This means
that after the swap file is activated we may end up with a snapshot of the
same root successfully created, and therefore when the first write to the
swap file happens it has to fall back into COW mode, which should never
happen for active swap files.
Basically what can happen is:
1) Task A starts snapshot creation and enters ioctl.c:create_snapshot().
There it sees that root->nr_swapfiles has a value of 0 so it continues;
2) Task B enters btrfs_swap_activate(). It is not aware that another task
started snapshot creation but it did not finish yet. It increments
root->nr_swapfiles from 0 to 1;
3) Task B checks that the file meets all requirements to be an active
swap file - it has NOCOW set, there are no snapshots for the inode's
root at the moment, no file holes, no reflinked extents, etc;
4) Task B returns success and now the file is an active swap file;
5) Task A commits the transaction to create the snapshot and finishes.
The swap file's extents are now shared between the original root and
the snapshot;
6) A write into an extent of the swap file is attempted - there is a
snapshot of the file's root, so we fall back to COW mode and therefore
the physical location of the extent changes on disk.
So fix this by taking the snapshot lock during swap file activation before
locking the extent range, as that is the order in which we lock these
during buffered writes.
Fixes: ed46ff3d42378 ("Btrfs: support swap files")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When we active a swap file, at btrfs_swap_activate(), we acquire the
exclusive operation lock to prevent the physical location of the swap
file extents to be changed by operations such as balance and device
replace/resize/remove. We also call there can_nocow_extent() which,
among other things, checks if the block group of a swap file extent is
currently RO, and if it is we can not use the extent, since a write
into it would result in COWing the extent.
However we have no protection against a scrub operation running after we
activate the swap file, which can result in the swap file extents to be
COWed while the scrub is running and operating on the respective block
group, because scrub turns a block group into RO before it processes it
and then back again to RW mode after processing it. That means an attempt
to write into a swap file extent while scrub is processing the respective
block group, will result in COWing the extent, changing its physical
location on disk.
Fix this by making sure that block groups that have extents that are used
by active swap files can not be turned into RO mode, therefore making it
not possible for a scrub to turn them into RO mode. When a scrub finds a
block group that can not be turned to RO due to the existence of extents
used by swap files, it proceeds to the next block group and logs a warning
message that mentions the block group was skipped due to active swap
files - this is the same approach we currently use for balance.
Fixes: ed46ff3d42378 ("Btrfs: support swap files")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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During the nocow writeback path, we currently iterate the rbtree of block
groups twice: once for checking if the target block group is RO with the
call to btrfs_extent_readonly()), and once again for getting a nocow
reference on the block group with a call to btrfs_inc_nocow_writers().
Since btrfs_inc_nocow_writers() already returns false when the target
block group is RO, remove the call to btrfs_extent_readonly(). Not only
we avoid searching the blocks group rbtree twice, it also helps reduce
contention on the lock that protects it (specially since it is a spin
lock and not a read-write lock). That may make a noticeable difference
on very large filesystems, with thousands of allocated block groups.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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During allocation the allocator will try to allocate an extent using
cluster policy. Once the current cluster is exhausted it will remove the
entry under btrfs_free_cluster::lock and subsequently acquire
btrfs_free_space_ctl::tree_lock to dispose of the already-deleted entry
and adjust btrfs_free_space_ctl::total_bitmap. This poses a problem
because there exists a race condition between removing the entry under
one lock and doing the necessary accounting holding a different lock
since extent freeing only uses the 2nd lock. This can result in the
following situation:
T1: T2:
btrfs_alloc_from_cluster insert_into_bitmap <holds tree_lock>
if (entry->bytes == 0) if (block_group && !list_empty(&block_group->cluster_list)) {
rb_erase(entry)
spin_unlock(&cluster->lock);
(total_bitmaps is still 4) spin_lock(&cluster->lock);
<doesn't find entry in cluster->root>
spin_lock(&ctl->tree_lock); <goes to new_bitmap label, adds
<blocked since T2 holds tree_lock> <a new entry and calls add_new_bitmap>
recalculate_thresholds <crashes,
due to total_bitmaps
becoming 5 and triggering
an ASSERT>
To fix this ensure that once depleted, the cluster entry is deleted when
both cluster lock and tree locks are held in the allocator (T1), this
ensures that even if there is a race with a concurrent
insert_into_bitmap call it will correctly find the entry in the cluster
and add the new space to it.
CC: <stable@vger.kernel.org> # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently check_compressed_csum() completely relies on sectorsize ==
PAGE_SIZE to do checksum verification for compressed extents.
To make it subpage compatible, this patch will:
- Do extra calculation for the csum range
Since we have multiple sectors inside a page, we need to only hash
the range we want, not the full page anymore.
- Do sector-by-sector hash inside the page
With this patch and previous conversion on
btrfs_submit_compressed_read(), now we can read subpage compressed
extents properly, and do proper csum verification.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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For compressed read, we always submit page read using page size. This
doesn't work well with subpage, as for subpage one page can contain
several sectors. Such submission will read range out of what we want,
and cause problems.
Thankfully to make it subpage compatible, we only need to change how the
last page of the compressed extent is read.
Instead of always adding a full page to the compressed read bio, if we're
at the last page, calculate the size using compressed length, so that we
only add part of the range into the compressed read bio.
Since we are here, also change the PAGE_SIZE used in
lookup_extent_mapping() to sectorsize.
This modification won't cause any functional change, as
lookup_extent_mapping() can handle the case where the search range is
larger than found extent range.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When a qstripe is required an extra page is allocated and mapped. There
were 3 problems:
1) There is no corresponding call of kunmap() for the qstripe page.
2) There is no reason to map the qstripe page more than once if the
number of bits set in rbio->dbitmap is greater than one.
3) There is no reason to map the parity page and unmap it each time
through the loop.
The page memory can continue to be reused with a single mapping on each
iteration by raid6_call.gen_syndrome() without remapping. So map the
page for the duration of the loop.
Similarly, improve the algorithm by mapping the parity page just 1 time.
Fixes: 5a6ac9eacb49 ("Btrfs, raid56: support parity scrub on raid56")
CC: stable@vger.kernel.org # 4.4.x: c17af96554a8: btrfs: raid56: simplify tracking of Q stripe presence
CC: stable@vger.kernel.org # 4.4.x
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Pull more xfs updates from Darrick Wong:
"The most notable fix here prevents premature reuse of freed metadata
blocks, and adding the ability to detect accidental nested
transactions, which are not allowed here.
- Restore a disused sysctl control knob that was inadvertently
dropped during the merge window to avoid fstests regressions.
- Don't speculatively release freed blocks from the busy list until
we're actually allocating them, which fixes a rare log recovery
regression.
- Don't nest transactions when scanning for free space.
- Add an idiot^Wmaintainer light to detect nested transactions. ;)"
* tag 'xfs-5.12-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: use current->journal_info for detecting transaction recursion
xfs: don't nest transactions when scanning for eofblocks
xfs: don't reuse busy extents on extent trim
xfs: restore speculative_cow_prealloc_lifetime sysctl
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Because the iomap code using PF_MEMALLOC_NOFS to detect transaction
recursion in XFS is just wrong. Remove it from the iomap code and
replace it with XFS specific internal checks using
current->journal_info instead.
[djwong: This change also realigns the lifetime of NOFS flag changes to
match the incore transaction, instead of the inconsistent scheme we have
now.]
Fixes: 9070733b4efa ("xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Brian Foster reported a lockdep warning on xfs/167:
============================================
WARNING: possible recursive locking detected
5.11.0-rc4 #35 Tainted: G W I
--------------------------------------------
fsstress/17733 is trying to acquire lock:
ffff8e0fd1d90650 (sb_internal){++++}-{0:0}, at: xfs_free_eofblocks+0x104/0x1d0 [xfs]
but task is already holding lock:
ffff8e0fd1d90650 (sb_internal){++++}-{0:0}, at: xfs_trans_alloc_inode+0x5f/0x160 [xfs]
stack backtrace:
CPU: 38 PID: 17733 Comm: fsstress Tainted: G W I 5.11.0-rc4 #35
Hardware name: Dell Inc. PowerEdge R740/01KPX8, BIOS 1.6.11 11/20/2018
Call Trace:
dump_stack+0x8b/0xb0
__lock_acquire.cold+0x159/0x2ab
lock_acquire+0x116/0x370
xfs_trans_alloc+0x1ad/0x310 [xfs]
xfs_free_eofblocks+0x104/0x1d0 [xfs]
xfs_blockgc_scan_inode+0x24/0x60 [xfs]
xfs_inode_walk_ag+0x202/0x4b0 [xfs]
xfs_inode_walk+0x66/0xc0 [xfs]
xfs_trans_alloc+0x160/0x310 [xfs]
xfs_trans_alloc_inode+0x5f/0x160 [xfs]
xfs_alloc_file_space+0x105/0x300 [xfs]
xfs_file_fallocate+0x270/0x460 [xfs]
vfs_fallocate+0x14d/0x3d0
__x64_sys_fallocate+0x3e/0x70
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The cause of this is the new code that spurs a scan to garbage collect
speculative preallocations if we fail to reserve enough blocks while
allocating a transaction. While the warning itself is a fairly benign
lockdep complaint, it does expose a potential livelock if the rwsem
behavior ever changes with regards to nesting read locks when someone's
waiting for a write lock.
Fix this by freeing the transaction and jumping back to xfs_trans_alloc
like this patch in the V4 submission[1].
[1] https://lore.kernel.org/linux-xfs/161142798066.2171939.9311024588681972086.stgit@magnolia/
Fixes: a1a7d05a0576 ("xfs: flush speculative space allocations when we run out of space")
Reported-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Freed extents are marked busy from the point the freeing transaction
commits until the associated CIL context is checkpointed to the log.
This prevents reuse and overwrite of recently freed blocks before
the changes are committed to disk, which can lead to corruption
after a crash. The exception to this rule is that metadata
allocation is allowed to reuse busy extents because metadata changes
are also logged.
As of commit 97d3ac75e5e0 ("xfs: exact busy extent tracking"), XFS
has allowed modification or complete invalidation of outstanding
busy extents for metadata allocations. This implementation assumes
that use of the associated extent is imminent, which is not always
the case. For example, the trimmed extent might not satisfy the
minimum length of the allocation request, or the allocation
algorithm might be involved in a search for the optimal result based
on locality.
generic/019 reproduces a corruption caused by this scenario. First,
a metadata block (usually a bmbt or symlink block) is freed from an
inode. A subsequent bmbt split on an unrelated inode attempts a near
mode allocation request that invalidates the busy block during the
search, but does not ultimately allocate it. Due to the busy state
invalidation, the block is no longer considered busy to subsequent
allocation. A direct I/O write request immediately allocates the
block and writes to it. Finally, the filesystem crashes while in a
state where the initial metadata block free had not committed to the
on-disk log. After recovery, the original metadata block is in its
original location as expected, but has been corrupted by the
aforementioned dio.
This demonstrates that it is fundamentally unsafe to modify busy
extent state for extents that are not guaranteed to be allocated.
This applies to pretty much all of the code paths that currently
trim busy extents for one reason or another. Therefore to address
this problem, drop the reuse mechanism from the busy extent trim
path. This code already knows how to return partial non-busy ranges
of the targeted free extent and higher level code tracks the busy
state of the allocation attempt. If a block allocation fails where
one or more candidate extents is busy, we force the log and retry
the allocation.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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In commit 9669f51de5c0 I tried to get rid of the undocumented cow gc
lifetime knob. The knob's function was never documented and it now
doesn't really have a function since eof and cow gc have been
consolidated.
Regrettably, xfs/231 relies on it and regresses on for-next. I did not
succeed at getting far enough through fstests patch review for the fixup
to land in time.
Restore the sysctl knob, document what it did (does?), put it on the
deprecation schedule, and rip out a redundant function.
Fixes: 9669f51de5c0 ("xfs: consolidate the eofblocks and cowblocks workers")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Pull more block updates from Jens Axboe:
"A few stragglers (and one due to me missing it originally), and fixes
for changes in this merge window mostly. In particular:
- blktrace cleanups (Chaitanya, Greg)
- Kill dead blk_pm_* functions (Bart)
- Fixes for the bio alloc changes (Christoph)
- Fix for the partition changes (Christoph, Ming)
- Fix for turning off iopoll with polled IO inflight (Jeffle)
- nbd disconnect fix (Josef)
- loop fsync error fix (Mauricio)
- kyber update depth fix (Yang)
- max_sectors alignment fix (Mikulas)
- Add bio_max_segs helper (Matthew)"
* tag 'block-5.12-2021-02-27' of git://git.kernel.dk/linux-block: (21 commits)
block: Add bio_max_segs
blktrace: fix documentation for blk_fill_rw()
block: memory allocations in bounce_clone_bio must not fail
block: remove the gfp_mask argument to bounce_clone_bio
block: fix bounce_clone_bio for passthrough bios
block-crypto-fallback: use a bio_set for splitting bios
block: fix logging on capacity change
blk-settings: align max_sectors on "logical_block_size" boundary
block: reopen the device in blkdev_reread_part
block: don't skip empty device in in disk_uevent
blktrace: remove debugfs file dentries from struct blk_trace
nbd: handle device refs for DESTROY_ON_DISCONNECT properly
kyber: introduce kyber_depth_updated()
loop: fix I/O error on fsync() in detached loop devices
block: fix potential IO hang when turning off io_poll
block: get rid of the trace rq insert wrapper
blktrace: fix blk_rq_merge documentation
blktrace: fix blk_rq_issue documentation
blktrace: add blk_fill_rwbs documentation comment
block: remove superfluous param in blk_fill_rwbs()
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It's often inconvenient to use BIO_MAX_PAGES due to min() requiring the
sign to be the same. Introduce bio_max_segs() and change BIO_MAX_PAGES to
be unsigned to make it easier for the users.
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pull io_uring thread rewrite from Jens Axboe:
"This converts the io-wq workers to be forked off the tasks in question
instead of being kernel threads that assume various bits of the
original task identity.
This kills > 400 lines of code from io_uring/io-wq, and it's the worst
part of the code. We've had several bugs in this area, and the worry
is always that we could be missing some pieces for file types doing
unusual things (recent /dev/tty example comes to mind, userfaultfd
reads installing file descriptors is another fun one... - both of
which need special handling, and I bet it's not the last weird oddity
we'll find).
With these identical workers, we can have full confidence that we're
never missing anything. That, in itself, is a huge win. Outside of
that, it's also more efficient since we're not wasting space and code
on tracking state, or switching between different states.
I'm sure we're going to find little things to patch up after this
series, but testing has been pretty thorough, from the usual
regression suite to production. Any issue that may crop up should be
manageable.
There's also a nice series of further reductions we can do on top of
this, but I wanted to get the meat of it out sooner rather than later.
The general worry here isn't that it's fundamentally broken. Most of
the little issues we've found over the last week have been related to
just changes in how thread startup/exit is done, since that's the main
difference between using kthreads and these kinds of threads. In fact,
if all goes according to plan, I want to get this into the 5.10 and
5.11 stable branches as well.
That said, the changes outside of io_uring/io-wq are:
- arch setup, simple one-liner to each arch copy_thread()
implementation.
- Removal of net and proc restrictions for io_uring, they are no
longer needed or useful"
* tag 'io_uring-worker.v3-2021-02-25' of git://git.kernel.dk/linux-block: (30 commits)
io-wq: remove now unused IO_WQ_BIT_ERROR
io_uring: fix SQPOLL thread handling over exec
io-wq: improve manager/worker handling over exec
io_uring: ensure SQPOLL startup is triggered before error shutdown
io-wq: make buffered file write hashed work map per-ctx
io-wq: fix race around io_worker grabbing
io-wq: fix races around manager/worker creation and task exit
io_uring: ensure io-wq context is always destroyed for tasks
arch: ensure parisc/powerpc handle PF_IO_WORKER in copy_thread()
io_uring: cleanup ->user usage
io-wq: remove nr_process accounting
io_uring: flag new native workers with IORING_FEAT_NATIVE_WORKERS
net: remove cmsg restriction from io_uring based send/recvmsg calls
Revert "proc: don't allow async path resolution of /proc/self components"
Revert "proc: don't allow async path resolution of /proc/thread-self components"
io_uring: move SQPOLL thread io-wq forked worker
io-wq: make io_wq_fork_thread() available to other users
io-wq: only remove worker from free_list, if it was there
io_uring: remove io_identity
io_uring: remove any grabbing of context
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This flag is now dead, remove it.
Fixes: 1cbd9c2bcf02 ("io-wq: don't create any IO workers upfront")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Just like the changes for io-wq, ensure that we re-fork the SQPOLL
thread if the owner execs. Mark the ctx sq thread as sqo_exec if
it dies, and the ring as needing a wakeup which will force the task
to enter the kernel. When it does, setup the new thread and proceed
as usual.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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exec will cancel any threads, including the ones that io-wq is using. This
isn't a problem, in fact we'd prefer it to be that way since it means we
know that any async work cancels naturally without having to handle it
proactively.
But it does mean that we need to setup a new manager, as the manager and
workers are gone. Handle this at queue time, and cancel work if we fail.
Since the manager can go away without us noticing, ensure that the manager
itself holds a reference to the 'wq' as well. Rename io_wq_destroy() to
io_wq_put() to reflect that.
In the future we can now simplify exec cancelation handling, for now just
leave it the same.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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syzbot reports the following hang:
INFO: task syz-executor.0:12538 can't die for more than 143 seconds.
task:syz-executor.0 state:D stack:28352 pid:12538 ppid: 8423 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4324 [inline]
__schedule+0x90c/0x21a0 kernel/sched/core.c:5075
schedule+0xcf/0x270 kernel/sched/core.c:5154
schedule_timeout+0x1db/0x250 kernel/time/timer.c:1868
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x168/0x270 kernel/sched/completion.c:138
io_sq_thread_finish+0x96/0x580 fs/io_uring.c:7152
io_sq_offload_create fs/io_uring.c:7929 [inline]
io_uring_create fs/io_uring.c:9465 [inline]
io_uring_setup+0x1fb2/0x2c20 fs/io_uring.c:9550
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
which is due to exiting after the SQPOLL thread has been created, but
hasn't been started yet. Ensure that we always complete the startup
side when waiting for it to exit.
Reported-by: syzbot+c927c937cba8ef66dd4a@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Before the io-wq thread change, we maintained a hash work map and lock
per-node per-ring. That wasn't ideal, as we really wanted it to be per
ring. But now that we have per-task workers, the hash map ends up being
just per-task. That'll work just fine for the normal case of having
one task use a ring, but if you share the ring between tasks, then it's
considerably worse than it was before.
Make the hash map per ctx instead, which provides full per-ctx buffered
write serialization on hashed writes.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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There's a small window between lookup dropping the reference to the
worker and calling wake_up_process() on the worker task, where the worker
itself could have exited. We ensure that the worker struct itself is
valid, but worker->task may very well be gone by the time we issue the
wakeup.
Fix the race by using a completion triggered by the reference going to
zero, and having exit wait for that completion before proceeding.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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These races have always been there, they are just more apparent now that
we do early cancel of io-wq when the task exits.
Ensure that the io-wq manager sets task state correctly to not miss
wakeups for task creation. This is important if we get a wakeup after
having marked ourselves as TASK_INTERRUPTIBLE. If we do end up creating
workers, then we flip the state back to running, making the subsequent
schedule() a no-op. Also increment the wq ref count before forking the
thread, to avoid a use-after-free.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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If the task ends up doing no IO, the context list is empty and we don't
call into __io_uring_files_cancel() when the task exits. This can cause
a leak of the io-wq structures.
Ensure we always call __io_uring_files_cancel(), even if the task
context list is empty.
Fixes: 5aa75ed5b93f ("io_uring: tie async worker side to the task context")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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At this point we're only using it for memory accounting, so there's no
need to have an extra ->limit_mem - we can just set ->user if we do
the accounting, or leave it at NULL if we don't.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We're now just using fork like we would from userspace, so there's no
need to try and impose extra restrictions or accounting on the user
side of things. That's already being done for us. That also means we
don't have to pass in the user_struct anymore, that's correctly inherited
through ->creds on fork.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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A few reasons to do this:
- The naming of the manager and worker have changed. That's a user visible
change, so makes sense to flag it.
- Opening certain files that use ->signal (like /proc/self or /dev/tty)
now works, and the flag tells the application upfront that this is the
case.
- Related to the above, using signalfd will now work as well.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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This reverts commit 8d4c3e76e3be11a64df95ddee52e99092d42fc19.
No longer needed, as the io-wq worker threads have the right identity.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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This reverts commit 0d4370cfe36b7f1719123b621a4ec4d9c7a25f89.
No longer needed, as the io-wq worker threads have the right identity.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Don't use a kthread for SQPOLL, use a forked worker just like the io-wq
workers. With that done, we can drop the various context grabbing we do
for SQPOLL, it already has everything it needs.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We want to use this in io_uring proper as well, for the SQPOLL thread.
Rename it from fork_thread() to io_wq_fork_thread(), and make it
available through the io-wq.h header.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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If the worker isn't on the free_list, don't attempt to delete it.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We are no longer grabbing state, so no need to maintain an IO identity
that we COW if there are changes.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The async workers are siblings of the task itself, so by definition we
have all the state that we need. Remove any of the state grabbing that
we have, and requests flagging what they need.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Remove the bool return, and the checking for it in the caller.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Instead of using regular kthread kernel threads, create kernel threads
that are like a real thread that the task would create. This ensures that
we get all the context that we need, without having to carry that state
around. This greatly reduces the code complexity, and the risk of missing
state for a given request type.
With the move away from kthread, we can also dump everything related to
assigned state to the new threads.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Just grab it from the worker itself, which we're already passing in.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Move it outside of the io_ring_ctx, and tie it to the io_uring task
context.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We don't support attach anymore, so doesn't make sense to carry the
use_refs reference count. Get rid of it.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Moving towards making the io_wq per ring per task, so we can't really
share it between rings. Which is fine, since we've now dropped some
of that fat from it.
Retain compatibility with how attaching works, so that any attempt to
attach to an fd that doesn't exist, or isn't an io_uring fd, will fail
like it did before.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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When the manager thread starts up, it creates a worker per node for
the given context. Just let these get created dynamically, like we do
for adding further workers.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We hit this case when the task is exiting, and we need somewhere to
do background cleanup of requests. Instead of relying on the io-wq
task manager to do this work for us, just stuff it somewhere where
we can safely run it ourselves directly.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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* for-5.12/io_uring: (21 commits)
io_uring: run task_work on io_uring_register()
io_uring: fix leaving invalid req->flags
io_uring: wait potential ->release() on resurrect
io_uring: keep generic rsrc infra generic
io_uring: zero ref_node after killing it
io_uring: make the !CONFIG_NET helpers a bit more robust
io_uring: don't hold uring_lock when calling io_run_task_work*
io_uring: fail io-wq submission from a task_work
io_uring: don't take uring_lock during iowq cancel
io_uring: fail links more in io_submit_sqe()
io_uring: don't do async setup for links' heads
io_uring: do io_*_prep() early in io_submit_sqe()
io_uring: split sqe-prep and async setup
io_uring: don't submit link on error
io_uring: move req link into submit_state
io_uring: move io_init_req() into io_submit_sqe()
io_uring: move io_init_req()'s definition
io_uring: don't duplicate ->file check in sfr
io_uring: keep io_*_prep() naming consistent
io_uring: kill fictitious submit iteration index
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