btrfs: move btrfs_dev_replace_update_device_in_mapping_tree to drop declaration

The function is short and simple, we can get rid of the declaration as
it's not necessary for a static function. Move

btrfs: move btrfs_dev_replace_update_device_in_mapping_tree to drop declaration

The function is short and simple, we can get rid of the declaration as
it's not necessary for a static function. Move it before its first
caller. No functional changes.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: remove tmp variable for list traversal in btrfs_init_dev_replace_tgtdev

In the function btrfs_init_dev_replace_tgtdev(), the local variable
devices is used only once, we can remove it.

Revie

btrfs: remove tmp variable for list traversal in btrfs_init_dev_replace_tgtdev

In the function btrfs_init_dev_replace_tgtdev(), the local variable
devices is used only once, we can remove it.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: split and refactor btrfs_sysfs_remove_devices_dir

Similar to btrfs_sysfs_add_devices_dir()'s refactoring, split
btrfs_sysfs_remove_devices_dir() so that we don't have to use the device
argume

btrfs: split and refactor btrfs_sysfs_remove_devices_dir

Similar to btrfs_sysfs_add_devices_dir()'s refactoring, split
btrfs_sysfs_remove_devices_dir() so that we don't have to use the device
argument to indicate whether to free all devices or just one device.

Export btrfs_sysfs_remove_device() as device operations outside of
sysfs.c now calls this instead of btrfs_sysfs_remove_devices_dir().

btrfs_sysfs_remove_devices_dir() is renamed to
btrfs_sysfs_remove_fs_devices() to suite its new role.

Now, no one outside of sysfs.c calls btrfs_sysfs_remove_fs_devices()
so it is redeclared s static. And the same function had to be moved
before its first caller.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: simplify parameters of btrfs_sysfs_add_devices_dir

When we add a device we need to add it to sysfs, so instead of using the
btrfs_sysfs_add_devices_dir() fs_devices argument to specify whethe

btrfs: simplify parameters of btrfs_sysfs_add_devices_dir

When we add a device we need to add it to sysfs, so instead of using the
btrfs_sysfs_add_devices_dir() fs_devices argument to specify whether to
add a device or all of fs_devices, call the helper function directly
btrfs_sysfs_add_device() and thus make it non-static.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: fix replace of seed device

If you replace a seed device in a sprouted fs, it appears to have
successfully replaced the seed device, but if you look closely, it
didn't. Here is an example.

btrfs: fix replace of seed device

If you replace a seed device in a sprouted fs, it appears to have
successfully replaced the seed device, but if you look closely, it
didn't. Here is an example.

$ mkfs.btrfs /dev/sda
$ btrfstune -S1 /dev/sda
$ mount /dev/sda /btrfs
$ btrfs device add /dev/sdb /btrfs
$ umount /btrfs
$ btrfs device scan --forget
$ mount -o device=/dev/sda /dev/sdb /btrfs
$ btrfs replace start -f /dev/sda /dev/sdc /btrfs
$ echo $?
0

BTRFS info (device sdb): dev_replace from /dev/sda (devid 1) to /dev/sdc started
BTRFS info (device sdb): dev_replace from /dev/sda (devid 1) to /dev/sdc finished

$ btrfs fi show
Label: none uuid: ab2c88b7-be81-4a7e-9849-c3666e7f9f4f
Total devices 2 FS bytes used 256.00KiB
devid 1 size 3.00GiB used 520.00MiB path /dev/sdc
devid 2 size 3.00GiB used 896.00MiB path /dev/sdb

Label: none uuid: 10bd3202-0415-43af-96a8-d5409f310a7e
Total devices 1 FS bytes used 128.00KiB
devid 1 size 3.00GiB used 536.00MiB path /dev/sda

So as per the replace start command and kernel log replace was successful.
Now let's try to clean mount.

$ umount /btrfs
$ btrfs device scan --forget

$ mount -o device=/dev/sdc /dev/sdb /btrfs
mount: /btrfs: wrong fs type, bad option, bad superblock on /dev/sdb, missing codepage or helper program, or other error.

[ 636.157517] BTRFS error (device sdc): failed to read chunk tree: -2
[ 636.180177] BTRFS error (device sdc): open_ctree failed

That's because per dev items it is still looking for the original seed
device.

$ btrfs inspect-internal dump-tree -d /dev/sdb

item 0 key (DEV_ITEMS DEV_ITEM 1) itemoff 16185 itemsize 98
devid 1 total_bytes 3221225472 bytes_used 545259520
io_align 4096 io_width 4096 sector_size 4096 type 0
generation 6 start_offset 0 dev_group 0
seek_speed 0 bandwidth 0
uuid 59368f50-9af2-4b17-91da-8a783cc418d4 <--- seed uuid
fsid 10bd3202-0415-43af-96a8-d5409f310a7e <--- seed fsid
item 1 key (DEV_ITEMS DEV_ITEM 2) itemoff 16087 itemsize 98
devid 2 total_bytes 3221225472 bytes_used 939524096
io_align 4096 io_width 4096 sector_size 4096 type 0
generation 0 start_offset 0 dev_group 0
seek_speed 0 bandwidth 0
uuid 56a0a6bc-4630-4998-8daf-3c3030c4256a <- sprout uuid
fsid ab2c88b7-be81-4a7e-9849-c3666e7f9f4f <- sprout fsid

But the replaced target has the following uuid+fsid in its superblock
which doesn't match with the expected uuid+fsid in its devitem.

$ btrfs in dump-super /dev/sdc | egrep '^generation|dev_item.uuid|dev_item.fsid|devid'
generation 20
dev_item.uuid 59368f50-9af2-4b17-91da-8a783cc418d4
dev_item.fsid ab2c88b7-be81-4a7e-9849-c3666e7f9f4f [match]
dev_item.devid 1

So if you provide the original seed device the mount shall be
successful. Which so long happening in the test case btrfs/163.

$ btrfs device scan --forget
$ mount -o device=/dev/sda /dev/sdb /btrfs

Fix in this patch:
If a seed is not sprouted then there is no replacement of it, because of
its read-only filesystem with a read-only device. Similarly, in the case
of a sprouted filesystem, the seed device is still read only. So, mark
it as you can't replace a seed device, you can only add a new device and
then delete the seed device. If replace is attempted then returns
-EINVAL.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: enumerate the type of exclusive operation in progress

Instead of using a flag bit for exclusive operation, use a variable to
store which exclusive operation is being performed. Introduce an

btrfs: enumerate the type of exclusive operation in progress

Instead of using a flag bit for exclusive operation, use a variable to
store which exclusive operation is being performed. Introduce an API
to start and finish an exclusive operation.

This would enable another way for tools to check which operation is
running on why starting an exclusive operation failed. The followup
patch adds a sysfs_notify() to alert userspace when the state changes, so
userspace can perform select() on it to get notified of the change.

This would enable us to enqueue a command which will wait for current
exclusive operation to complete before issuing the next exclusive
operation. This has been done synchronously as opposed to a background
process, or else error collection (if any) will become difficult.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update comments ]
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: change nr to u64 in btrfs_start_delalloc_roots

We have btrfs_wait_ordered_roots() which takes a u64 for nr, but
btrfs_start_delalloc_roots() that takes an int for nr, which makes using
them i

btrfs: change nr to u64 in btrfs_start_delalloc_roots

We have btrfs_wait_ordered_roots() which takes a u64 for nr, but
btrfs_start_delalloc_roots() that takes an int for nr, which makes using
them in conjunction, especially for something like (u64)-1, annoying and
inconsistent. Fix btrfs_start_delalloc_roots() to take a u64 for nr and
adjust start_delalloc_inodes() and it's callers appropriately.

This means we've adjusted start_delalloc_inodes() to take a pointer of
nr since we want to preserve the ability for start-delalloc_inodes() to
return an error, so simply make it do the nr adjusting as necessary.

Part of adjusting the callers to this means changing
btrfs_writeback_inodes_sb_nr() to take a u64 for items. This may be
confusing because it seems unrelated, but the caller of
btrfs_writeback_inodes_sb_nr() already passes in a u64, it's just the
function variable that needs to be changed.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: fix filesystem corruption after a device replace

We use a device's allocation state tree to track ranges in a device used
for allocated chunks, and we set ranges in this tree when allocating

btrfs: fix filesystem corruption after a device replace

We use a device's allocation state tree to track ranges in a device used
for allocated chunks, and we set ranges in this tree when allocating a new
chunk. However after a device replace operation, we were not setting the
allocated ranges in the new device's allocation state tree, so that tree
is empty after a device replace.

This means that a fitrim operation after a device replace will trim the
device ranges that have allocated chunks and extents, as we trim every
range for which there is not a range marked in the device's allocation
state tree. It is also important during chunk allocation, since the
device's allocation state is used to determine if a range is already
allocated when allocating a new chunk.

This is trivial to reproduce and the following script triggers the bug:

$ cat reproducer.sh
#!/bin/bash

DEV1="/dev/sdg"
DEV2="/dev/sdh"
DEV3="/dev/sdi"

wipefs -a $DEV1 $DEV2 $DEV3 &> /dev/null

# Create a raid1 test fs on 2 devices.
mkfs.btrfs -f -m raid1 -d raid1 $DEV1 $DEV2 > /dev/null
mount $DEV1 /mnt/btrfs

xfs_io -f -c "pwrite -S 0xab 0 10M" /mnt/btrfs/foo

echo "Starting to replace $DEV1 with $DEV3"
btrfs replace start -B $DEV1 $DEV3 /mnt/btrfs
echo

echo "Running fstrim"
fstrim /mnt/btrfs
echo

echo "Unmounting filesystem"
umount /mnt/btrfs

echo "Mounting filesystem in degraded mode using $DEV3 only"
wipefs -a $DEV1 $DEV2 &> /dev/null
mount -o degraded $DEV3 /mnt/btrfs
if [ $? -ne 0 ]; then
dmesg | tail
echo
echo "Failed to mount in degraded mode"
exit 1
fi

echo
echo "File foo data (expected all bytes = 0xab):"
od -A d -t x1 /mnt/btrfs/foo

umount /mnt/btrfs

When running the reproducer:

$ ./replace-test.sh
wrote 10485760/10485760 bytes at offset 0
10 MiB, 2560 ops; 0.0901 sec (110.877 MiB/sec and 28384.5216 ops/sec)
Starting to replace /dev/sdg with /dev/sdi

Running fstrim

Unmounting filesystem
Mounting filesystem in degraded mode using /dev/sdi only
mount: /mnt/btrfs: wrong fs type, bad option, bad superblock on /dev/sdi, missing codepage or helper program, or other error.
[19581.748641] BTRFS info (device sdg): dev_replace from /dev/sdg (devid 1) to /dev/sdi started
[19581.803842] BTRFS info (device sdg): dev_replace from /dev/sdg (devid 1) to /dev/sdi finished
[19582.208293] BTRFS info (device sdi): allowing degraded mounts
[19582.208298] BTRFS info (device sdi): disk space caching is enabled
[19582.208301] BTRFS info (device sdi): has skinny extents
[19582.212853] BTRFS warning (device sdi): devid 2 uuid 1f731f47-e1bb-4f00-bfbb-9e5a0cb4ba9f is missing
[19582.213904] btree_readpage_end_io_hook: 25839 callbacks suppressed
[19582.213907] BTRFS error (device sdi): bad tree block start, want 30490624 have 0
[19582.214780] BTRFS warning (device sdi): failed to read root (objectid=7): -5
[19582.231576] BTRFS error (device sdi): open_ctree failed

Failed to mount in degraded mode

So fix by setting all allocated ranges in the replace target device when
the replace operation is finishing, when we are holding the chunk mutex
and we can not race with new chunk allocations.

A test case for fstests follows soon.

Fixes: 1c11b63eff2a67 ("btrfs: replace pending/pinned chunks lists with io tree")
CC: stable@vger.kernel.org # 5.2+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: move btrfs_rm_dev_replace_free_srcdev outside of all locks

When closing and freeing the source device we could end up doing our
final blkdev_put() on the bdev, which will grab the bd_mutex.

btrfs: move btrfs_rm_dev_replace_free_srcdev outside of all locks

When closing and freeing the source device we could end up doing our
final blkdev_put() on the bdev, which will grab the bd_mutex. As such
we want to be holding as few locks as possible, so move this call
outside of the dev_replace->lock_finishing_cancel_unmount lock. Since
we're modifying the fs_devices we need to make sure we're holding the
uuid_mutex here, so take that as well.

There's a report from syzbot probably hitting one of the cases where
the bd_mutex and device_list_mutex are taken in the wrong order, however
it's not with device replace, like this patch fixes. As there's no
reproducer available so far, we can't verify the fix.

https://lore.kernel.org/lkml/000000000000fc04d105afcf86d7@google.com/
dashboard link: https://syzkaller.appspot.com/bug?extid=84a0634dc5d21d488419

WARNING: possible circular locking dependency detected
5.9.0-rc5-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/6878 is trying to acquire lock:
ffff88804c17d780 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_put+0x30/0x520 fs/block_dev.c:1804

but task is already holding lock:
ffff8880908cfce0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: close_fs_devices.part.0+0x2e/0x800 fs/btrfs/volumes.c:1159

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #4 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:956 [inline]
__mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
btrfs_finish_chunk_alloc+0x281/0xf90 fs/btrfs/volumes.c:5255
btrfs_create_pending_block_groups+0x2f3/0x700 fs/btrfs/block-group.c:2109
__btrfs_end_transaction+0xf5/0x690 fs/btrfs/transaction.c:916
find_free_extent_update_loop fs/btrfs/extent-tree.c:3807 [inline]
find_free_extent+0x23b7/0x2e60 fs/btrfs/extent-tree.c:4127
btrfs_reserve_extent+0x166/0x460 fs/btrfs/extent-tree.c:4206
cow_file_range+0x3de/0x9b0 fs/btrfs/inode.c:1063
btrfs_run_delalloc_range+0x2cf/0x1410 fs/btrfs/inode.c:1838
writepage_delalloc+0x150/0x460 fs/btrfs/extent_io.c:3439
__extent_writepage+0x441/0xd00 fs/btrfs/extent_io.c:3653
extent_write_cache_pages.constprop.0+0x69d/0x1040 fs/btrfs/extent_io.c:4249
extent_writepages+0xcd/0x2b0 fs/btrfs/extent_io.c:4370
do_writepages+0xec/0x290 mm/page-writeback.c:2352
__writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461
writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721
wb_writeback+0x2ad/0xd40 fs/fs-writeback.c:1894
wb_do_writeback fs/fs-writeback.c:2039 [inline]
wb_workfn+0x2dc/0x13e0 fs/fs-writeback.c:2080
process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

-> #3 (sb_internal#2){.+.+}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write+0x234/0x470 fs/super.c:1672
sb_start_intwrite include/linux/fs.h:1690 [inline]
start_transaction+0xbe7/0x1170 fs/btrfs/transaction.c:624
find_free_extent_update_loop fs/btrfs/extent-tree.c:3789 [inline]
find_free_extent+0x25e1/0x2e60 fs/btrfs/extent-tree.c:4127
btrfs_reserve_extent+0x166/0x460 fs/btrfs/extent-tree.c:4206
cow_file_range+0x3de/0x9b0 fs/btrfs/inode.c:1063
btrfs_run_delalloc_range+0x2cf/0x1410 fs/btrfs/inode.c:1838
writepage_delalloc+0x150/0x460 fs/btrfs/extent_io.c:3439
__extent_writepage+0x441/0xd00 fs/btrfs/extent_io.c:3653
extent_write_cache_pages.constprop.0+0x69d/0x1040 fs/btrfs/extent_io.c:4249
extent_writepages+0xcd/0x2b0 fs/btrfs/extent_io.c:4370
do_writepages+0xec/0x290 mm/page-writeback.c:2352
__writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461
writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721
wb_writeback+0x2ad/0xd40 fs/fs-writeback.c:1894
wb_do_writeback fs/fs-writeback.c:2039 [inline]
wb_workfn+0x2dc/0x13e0 fs/fs-writeback.c:2080
process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

-> #2 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}:
__flush_work+0x60e/0xac0 kernel/workqueue.c:3041
wb_shutdown+0x180/0x220 mm/backing-dev.c:355
bdi_unregister+0x174/0x590 mm/backing-dev.c:872
del_gendisk+0x820/0xa10 block/genhd.c:933
loop_remove drivers/block/loop.c:2192 [inline]
loop_control_ioctl drivers/block/loop.c:2291 [inline]
loop_control_ioctl+0x3b1/0x480 drivers/block/loop.c:2257
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl fs/ioctl.c:739 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #1 (loop_ctl_mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:956 [inline]
__mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
lo_open+0x19/0xd0 drivers/block/loop.c:1893
__blkdev_get+0x759/0x1aa0 fs/block_dev.c:1507
blkdev_get fs/block_dev.c:1639 [inline]
blkdev_open+0x227/0x300 fs/block_dev.c:1753
do_dentry_open+0x4b9/0x11b0 fs/open.c:817
do_open fs/namei.c:3251 [inline]
path_openat+0x1b9a/0x2730 fs/namei.c:3368
do_filp_open+0x17e/0x3c0 fs/namei.c:3395
do_sys_openat2+0x16d/0x420 fs/open.c:1168
do_sys_open fs/open.c:1184 [inline]
__do_sys_open fs/open.c:1192 [inline]
__se_sys_open fs/open.c:1188 [inline]
__x64_sys_open+0x119/0x1c0 fs/open.c:1188
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #0 (&bdev->bd_mutex){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:2496 [inline]
check_prevs_add kernel/locking/lockdep.c:2601 [inline]
validate_chain kernel/locking/lockdep.c:3218 [inline]
__lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4426
lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
__mutex_lock_common kernel/locking/mutex.c:956 [inline]
__mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
blkdev_put+0x30/0x520 fs/block_dev.c:1804
btrfs_close_bdev fs/btrfs/volumes.c:1117 [inline]
btrfs_close_bdev fs/btrfs/volumes.c:1107 [inline]
btrfs_close_one_device fs/btrfs/volumes.c:1133 [inline]
close_fs_devices.part.0+0x1a4/0x800 fs/btrfs/volumes.c:1161
close_fs_devices fs/btrfs/volumes.c:1193 [inline]
btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179
close_ctree+0x688/0x6cb fs/btrfs/disk-io.c:4149
generic_shutdown_super+0x144/0x370 fs/super.c:464
kill_anon_super+0x36/0x60 fs/super.c:1108
btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2265
deactivate_locked_super+0x94/0x160 fs/super.c:335
deactivate_super+0xad/0xd0 fs/super.c:366
cleanup_mnt+0x3a3/0x530 fs/namespace.c:1118
task_work_run+0xdd/0x190 kernel/task_work.c:141
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop kernel/entry/common.c:163 [inline]
exit_to_user_mode_prepare+0x1e1/0x200 kernel/entry/common.c:190
syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265
entry_SYSCALL_64_after_hwframe+0x44/0xa9

other info that might help us debug this:

Chain exists of:
&bdev->bd_mutex --> sb_internal#2 --> &fs_devs->device_list_mutex

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&fs_devs->device_list_mutex);
lock(sb_internal#2);
lock(&fs_devs->device_list_mutex);
lock(&bdev->bd_mutex);

*** DEADLOCK ***

3 locks held by syz-executor.0/6878:
#0: ffff88809070c0e0 (&type->s_umount_key#70){++++}-{3:3}, at: deactivate_super+0xa5/0xd0 fs/super.c:365
#1: ffffffff8a5b37a8 (uuid_mutex){+.+.}-{3:3}, at: btrfs_close_devices+0x23/0x1f0 fs/btrfs/volumes.c:1178
#2: ffff8880908cfce0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: close_fs_devices.part.0+0x2e/0x800 fs/btrfs/volumes.c:1159

stack backtrace:
CPU: 0 PID: 6878 Comm: syz-executor.0 Not tainted 5.9.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x198/0x1fd lib/dump_stack.c:118
check_noncircular+0x324/0x3e0 kernel/locking/lockdep.c:1827
check_prev_add kernel/locking/lockdep.c:2496 [inline]
check_prevs_add kernel/locking/lockdep.c:2601 [inline]
validate_chain kernel/locking/lockdep.c:3218 [inline]
__lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4426
lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
__mutex_lock_common kernel/locking/mutex.c:956 [inline]
__mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
blkdev_put+0x30/0x520 fs/block_dev.c:1804
btrfs_close_bdev fs/btrfs/volumes.c:1117 [inline]
btrfs_close_bdev fs/btrfs/volumes.c:1107 [inline]
btrfs_close_one_device fs/btrfs/volumes.c:1133 [inline]
close_fs_devices.part.0+0x1a4/0x800 fs/btrfs/volumes.c:1161
close_fs_devices fs/btrfs/volumes.c:1193 [inline]
btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179
close_ctree+0x688/0x6cb fs/btrfs/disk-io.c:4149
generic_shutdown_super+0x144/0x370 fs/super.c:464
kill_anon_super+0x36/0x60 fs/super.c:1108
btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2265
deactivate_locked_super+0x94/0x160 fs/super.c:335
deactivate_super+0xad/0xd0 fs/super.c:366
cleanup_mnt+0x3a3/0x530 fs/namespace.c:1118
task_work_run+0xdd/0x190 kernel/task_work.c:141
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop kernel/entry/common.c:163 [inline]
exit_to_user_mode_prepare+0x1e1/0x200 kernel/entry/common.c:190
syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x460027
RSP: 002b:00007fff59216328 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000076035 RCX: 0000000000460027
RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007fff592163d0
RBP: 0000000000000333 R08: 0000000000000000 R09: 000000000000000b
R10: 0000000000000005 R11: 0000000000000246 R12: 00007fff59217460
R13: 0000000002df2a60 R14: 0000000000000000 R15: 00007fff59217460

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ add syzbot reference ]
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: move btrfs_scratch_superblocks into btrfs_dev_replace_finishing

We need to move the closing of the src_device out of all the device
replace locking, but we definitely want to zero out the sup

btrfs: move btrfs_scratch_superblocks into btrfs_dev_replace_finishing

We need to move the closing of the src_device out of all the device
replace locking, but we definitely want to zero out the superblock
before we commit the last time to make sure the device is properly
removed. Handle this by pushing btrfs_scratch_superblocks into
btrfs_dev_replace_finishing, and then later on we'll move the src_device
closing and freeing stuff where we need it to be.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: sysfs, rename device_link add/remove functions

Since commit 668e48af7a94 ("btrfs: sysfs, add devid/dev_state kobject and
device attributes"), the functions btrfs_sysfs_add_device_link() and
b

btrfs: sysfs, rename device_link add/remove functions

Since commit 668e48af7a94 ("btrfs: sysfs, add devid/dev_state kobject and
device attributes"), the functions btrfs_sysfs_add_device_link() and
btrfs_sysfs_rm_device_link() do more than just adding and removing the
device link as its name indicated. Rename them to be more specific
that's about the directory with the attirbutes

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: Add overview of device replace

The overview of btrfs dev-replace. It mentions some corner cases caused
by the write duplication and scrub based data copy.

Reviewed-by: Anand Jain <anand.jai

btrfs: Add overview of device replace

The overview of btrfs dev-replace. It mentions some corner cases caused
by the write duplication and scrub based data copy.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ adjust wording ]
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: dev-replace: remove warning for unknown return codes when finished

The fstests btrfs/011 triggered a warning at the end of device replace,

[ 1891.998975] BTRFS warning (device vdd): failed

btrfs: dev-replace: remove warning for unknown return codes when finished

The fstests btrfs/011 triggered a warning at the end of device replace,

[ 1891.998975] BTRFS warning (device vdd): failed setting block group ro: -28
[ 1892.038338] BTRFS error (device vdd): btrfs_scrub_dev(/dev/vdd, 1, /dev/vdb) failed -28
[ 1892.059993] ------------[ cut here ]------------
[ 1892.063032] WARNING: CPU: 2 PID: 2244 at fs/btrfs/dev-replace.c:506 btrfs_dev_replace_start.cold+0xf9/0x140 [btrfs]
[ 1892.074346] CPU: 2 PID: 2244 Comm: btrfs Not tainted 5.5.0-rc7-default+ #942
[ 1892.079956] RIP: 0010:btrfs_dev_replace_start.cold+0xf9/0x140 [btrfs]

[ 1892.096576] RSP: 0018:ffffbb58c7b3fd10 EFLAGS: 00010286
[ 1892.098311] RAX: 00000000ffffffe4 RBX: 0000000000000001 RCX: 8888888888888889
[ 1892.100342] RDX: 0000000000000001 RSI: ffff9e889645f5d8 RDI: ffffffff92821080
[ 1892.102291] RBP: ffff9e889645c000 R08: 000001b8878fe1f6 R09: 0000000000000000
[ 1892.104239] R10: ffffbb58c7b3fd08 R11: 0000000000000000 R12: ffff9e88a0017000
[ 1892.106434] R13: ffff9e889645f608 R14: ffff9e88794e1000 R15: ffff9e88a07b5200
[ 1892.108642] FS: 00007fcaed3f18c0(0000) GS:ffff9e88bda00000(0000) knlGS:0000000000000000
[ 1892.111558] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1892.113492] CR2: 00007f52509ff420 CR3: 00000000603dd002 CR4: 0000000000160ee0

[ 1892.115814] Call Trace:
[ 1892.116896] btrfs_dev_replace_by_ioctl+0x35/0x60 [btrfs]
[ 1892.118962] btrfs_ioctl+0x1d62/0x2550 [btrfs]

caused by the previous patch ("btrfs: scrub: Require mandatory block
group RO for dev-replace"). Hitting ENOSPC is possible and could happen
when the block group is set read-only, preventing NOCOW writes to the
area that's being accessed by dev-replace.

This has happend with scratch devices of size 12G but not with 5G and
20G, so this is depends on timing and other activity on the filesystem.
The whole replace operation is restartable, the space state should be
examined by the user in any case.

The error code is propagated back to the ioctl caller so the kernel
warning is causing false alerts.

Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: sysfs, add devid/dev_state kobject and device attributes

New sysfs attributes that track the filesystem status of devices, stored
in the per-filesystem directory in /sys/fs/btrfs/FSID/devinfo

btrfs: sysfs, add devid/dev_state kobject and device attributes

New sysfs attributes that track the filesystem status of devices, stored
in the per-filesystem directory in /sys/fs/btrfs/FSID/devinfo . There's
a directory for each device, with name corresponding to the numerical
device id.

in_fs_metadata - device is in the list of fs metadata
missing - device is missing (no device node or block device)
replace_target - device is target of replace
writeable - writes from fs are allowed

These attributes reflect the state of the device::dev_state and created
at mount time.

Sample output:
$ pwd
/sys/fs/btrfs/6e1961f1-5918-4ecc-a22f-948897b409f7/devinfo/1/
$ ls
in_fs_metadata missing replace_target writeable
$ cat missing
0

The output from these attributes are 0 or 1. 0 indicates unset and 1
indicates set. These attributes are readonly.

It is observed that the device delete thread and sysfs read thread will
not race because the delete thread calls sysfs kobject_put() which in
turn waits for existing sysfs read to complete.

Note for device replace devid swap:

During the replace the target device temporarily assumes devid 0 before
assigning the devid of the soruce device.

In btrfs_dev_replace_finishing() we remove source sysfs devid using the
function btrfs_sysfs_remove_devices_attr(), so after that call
kobject_rename() to update the devid in the sysfs. This adds and calls
btrfs_sysfs_update_devid() helper function to update the device id.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: add __pure attribute to functions

The attribute is more relaxed than const and the functions could
dereference pointers, as long as the observable state is not changed. We
do have such functi

btrfs: add __pure attribute to functions

The attribute is more relaxed than const and the functions could
dereference pointers, as long as the observable state is not changed. We
do have such functions, based on -Wsuggest-attribute=pure .

The visible effects of this patch are negligible, there are differences
in the assembly but hard to summarize.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: move cond_wake_up functions out of ctree

The file ctree.h serves as a header for everything and has become quite
bloated. Split some helpers that are generic and create a new file that
should

btrfs: move cond_wake_up functions out of ctree

The file ctree.h serves as a header for everything and has become quite
bloated. Split some helpers that are generic and create a new file that
should be the catch-all for code that's not btrfs-specific.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: replace: BTRFS_DEV_REPLACE_ITEM_STATE_x defines should go

The BTRFS_DEV_REPLACE_ITEM_STATE_x defines, as shown in [1], are
unused in both kernel and btrfs-progs (except for one instance of
BT

btrfs: replace: BTRFS_DEV_REPLACE_ITEM_STATE_x defines should go

The BTRFS_DEV_REPLACE_ITEM_STATE_x defines, as shown in [1], are
unused in both kernel and btrfs-progs (except for one instance of
BTRFS_DEV_REPLACE_ITEM_STATE_NEVER_STARTED in kernel).

[1]
btrfs.h:#define BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED 2
btrfs.h:#define BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED 3
btrfs.h:#define BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED 4

Further these define-values are different form its counterpart
BTRFS_IOCTL_DEV_REPLACE_STATE_x series as shown in [2].

[2]
btrfs_tree.h:#define BTRFS_DEV_REPLACE_ITEM_STATE_SUSPENDED 2
btrfs_tree.h:#define BTRFS_DEV_REPLACE_ITEM_STATE_FINISHED 3
btrfs_tree.h:#define BTRFS_DEV_REPLACE_ITEM_STATE_CANCELED 4

So this patch deletes the BTRFS_DEV_REPLACE_ITEM_STATE_x altogether, and
one instance of BTRFS_DEV_REPLACE_ITEM_STATE_NEVER_STARTED is replaced
with BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED in the kernel.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: remove mapping tree structures indirection

fs_info::mapping_tree is the physical<->logical mapping tree and uses
the same underlying structure as extents, but is embedded to another
structure

btrfs: remove mapping tree structures indirection

fs_info::mapping_tree is the physical<->logical mapping tree and uses
the same underlying structure as extents, but is embedded to another
structure. There are no other members and this indirection is useless.
No functional change.

Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: Remove redundant assignment of tgt_device->commit_total_bytes

This is already done in btrfs_init_dev_replace_tgtdev which is the first
phase of device replace, called before doing scrub. Duri

btrfs: Remove redundant assignment of tgt_device->commit_total_bytes

This is already done in btrfs_init_dev_replace_tgtdev which is the first
phase of device replace, called before doing scrub. During that time
exclusive lock is held. Additionally btrfs_fs_device::commit_total_bytes
is always set based on the size of the underlying block device which
shouldn't change once set. This makes the 2nd assignment of the variable
in the finishing phase redundant.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: Explicitly reserve space for devreplace item

Part of device replace involves writing an item to the device root
containing information about pending replace operations. Currently space
for th

btrfs: Explicitly reserve space for devreplace item

Part of device replace involves writing an item to the device root
containing information about pending replace operations. Currently space
for this item is not being explicitly reserved so this works thanks to
presence of global reserve. While not fatal it's not a good practice.
Let's be explicit about space requirement of device replace and reserve
space when starting the transaction.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: Streamline replace sem unlock in btrfs_dev_replace_start

There are only 2 branches which goto leave label with need_unlock set
to true. Essentially need_unlock is used as a substitute for dir

btrfs: Streamline replace sem unlock in btrfs_dev_replace_start

There are only 2 branches which goto leave label with need_unlock set
to true. Essentially need_unlock is used as a substitute for directly
calling up_write. Since the branches needing this are only 2 and their
context is not that big it's more clear to just call up_write where
required. No functional changes.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: Ensure btrfs_init_dev_replace_tgtdev sees up to date values

btrfs_init_dev_replace_tgtdev reads certain values from the source
device (such as commit_total_bytes) which are updated during tra

btrfs: Ensure btrfs_init_dev_replace_tgtdev sees up to date values

btrfs_init_dev_replace_tgtdev reads certain values from the source
device (such as commit_total_bytes) which are updated during transaction
commit. Currently this function is called before committing any pending
transaction, leading to possibly reading outdated values.

Fix this by moving the function below the transaction commit, at this
point the EXCL_OP bit it set hence once transaction is complete the
total size of the device cannot be changed (it's usually changed by
resize/remove ops which are blocked).

Fixes: 9e271ae27e44 ("Btrfs: kernel operation should come after user input has been verified")
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: dev-replace: Remove impossible WARN_ON

This WARN_ON can never trigger because src_device cannot be null.
btrfs_find_device_by_devspec always returns either an error or a valid
pointer to the

btrfs: dev-replace: Remove impossible WARN_ON

This WARN_ON can never trigger because src_device cannot be null.
btrfs_find_device_by_devspec always returns either an error or a valid
pointer to the device. Just remove it.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: Reduce critical section in btrfs_init_dev_replace_tgtdev

There is no point in holding btrfs_fs_devices::device_list_mutex
while initialising fields of the not-yet-published device. Instead,
h

btrfs: Reduce critical section in btrfs_init_dev_replace_tgtdev

There is no point in holding btrfs_fs_devices::device_list_mutex
while initialising fields of the not-yet-published device. Instead,
hold the mutex only when the newly initialised device is being
published. I think holding device_list_mutex here is redundant
altogether, because at this point BTRFS_FS_EXCL_OP is set which
prevents device removal/addition/balance/resize to occur.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: Don't opencode sync_blockdev in btrfs_init_dev_replace_tgtdev

Using sync_blockdev makes it plain obvious what's happening. No
functional changes.

Reviewed-by: Johannes Thumshirn <jthumshirn@

btrfs: Don't opencode sync_blockdev in btrfs_init_dev_replace_tgtdev

Using sync_blockdev makes it plain obvious what's happening. No
functional changes.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...