#
16cab91a |
| 11-Jan-2022 |
Anand Jain <anand.jain@oracle.com> |
btrfs: match stale devices by dev_t
After the commit "btrfs: harden identification of the stale device", we don't have to match the device path anymore. Instead, we match the dev_t. So pass in the d
btrfs: match stale devices by dev_t
After the commit "btrfs: harden identification of the stale device", we don't have to match the device path anymore. Instead, we match the dev_t. So pass in the dev_t instead of the device path, in the call chain btrfs_forget_devices()->btrfs_free_stale_devices().
Signed-off-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
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#
770c79fb |
| 11-Jan-2022 |
Anand Jain <anand.jain@oracle.com> |
btrfs: harden identification of a stale device
Identifying and removing the stale device from the fs_uuids list is done by btrfs_free_stale_devices(). btrfs_free_stale_devices() in turn depends on
btrfs: harden identification of a stale device
Identifying and removing the stale device from the fs_uuids list is done by btrfs_free_stale_devices(). btrfs_free_stale_devices() in turn depends on device_path_matched() to check if the device appears in more than one btrfs_device structure.
The matching of the device happens by its path, the device path. However, when device mapper is in use, the dm device paths are nothing but a link to the actual block device, which leads to the device_path_matched() failing to match.
Fix this by matching the dev_t as provided by lookup_bdev() instead of plain string compare of the device paths.
Reported-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
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#
ff37c89f |
| 11-Jan-2022 |
Nikolay Borisov <nborisov@suse.com> |
btrfs: move missing device handling in a dedicate function
This simplifies the code flow in read_one_chunk and makes error handling when handling missing devices a bit simpler by reducing it to a si
btrfs: move missing device handling in a dedicate function
This simplifies the code flow in read_one_chunk and makes error handling when handling missing devices a bit simpler by reducing it to a single check if something went wrong. No functional changes.
Reviewed-by: Su Yue <l@damenly.su> 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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#
f26c9238 |
| 14-Dec-2021 |
Qu Wenruo <wqu@suse.com> |
btrfs: remove reada infrastructure
Currently there is only one user for btrfs metadata readahead, and that's scrub.
But even for the single user, it's not providing the correct functionality it nee
btrfs: remove reada infrastructure
Currently there is only one user for btrfs metadata readahead, and that's scrub.
But even for the single user, it's not providing the correct functionality it needs, as scrub needs reada for commit root, which current readahead can't provide. (Although it's pretty easy to add such feature).
Despite this, there are some extra problems related to metadata readahead:
- Duplicated feature with btrfs_path::reada
- Partly duplicated feature of btrfs_fs_info::buffer_radix Btrfs already caches its metadata in buffer_radix, while readahead tries to read the tree block no matter if it's already cached.
- Poor layer separation Metadata readahead works kinda at device level. This is definitely not the correct layer it should be, since metadata is at btrfs logical address space, it should not bother device at all.
This brings extra chance for bugs to sneak in, while brings unnecessary complexity.
- Dead code In the very beginning of scrub.c we have #undef DEBUG, rendering all the debug related code useless and unable to test.
Thus here I purpose to remove the metadata readahead mechanism completely.
[BENCHMARK] There is a full benchmark for the scrub performance difference using the old btrfs_reada_add() and btrfs_path::reada.
For the worst case (no dirty metadata, slow HDD), there could be a 5% performance drop for scrub. For other cases (even SATA SSD), there is no distinguishable performance difference.
The number is reported scrub speed, in MiB/s. The resolution is limited by the reported duration, which only has a resolution of 1 second.
Old New Diff SSD 455.3 466.332 +2.42% HDD 103.927 98.012 -5.69%
Comprehensive test methodology is in the cover letter of the patch.
Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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Revision tags: v5.15.8, v5.15.7 |
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#
554aed7d |
| 07-Dec-2021 |
Johannes Thumshirn <johannes.thumshirn@wdc.com> |
btrfs: zoned: sink zone check into btrfs_repair_one_zone
Sink zone check into btrfs_repair_one_zone() so we don't need to do it in all callers.
Also as btrfs_repair_one_zone() doesn't return a sens
btrfs: zoned: sink zone check into btrfs_repair_one_zone
Sink zone check into btrfs_repair_one_zone() so we don't need to do it in all callers.
Also as btrfs_repair_one_zone() doesn't return a sensible error, make it a boolean function and return false in case it got called on a non-zoned filesystem and true on a zoned filesystem.
Reviewed-by: Josef Bacik <josef@toxicpanda.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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Revision tags: v5.15.6 |
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#
efc0e69c |
| 25-Nov-2021 |
Nikolay Borisov <nborisov@suse.com> |
btrfs: introduce exclusive operation BALANCE_PAUSED state
Current set of exclusive operation states is not sufficient to handle all practical use cases. In particular there is a need to be able to a
btrfs: introduce exclusive operation BALANCE_PAUSED state
Current set of exclusive operation states is not sufficient to handle all practical use cases. In particular there is a need to be able to add a device to a filesystem that have paused balance. Currently there is no way to distinguish between a running and a paused balance. Fix this by introducing BTRFS_EXCLOP_BALANCE_PAUSED which is going to be set in 2 occasions:
1. When a filesystem is mounted with skip_balance and there is an unfinished balance it will now be into BALANCE_PAUSED instead of simply BALANCE state.
2. When a running balance is paused.
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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Revision tags: v5.15.5, v5.15.4, v5.15.3, v5.15.2, v5.15.1 |
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#
fd51eb2f |
| 05-Nov-2021 |
Josef Bacik <josef@toxicpanda.com> |
btrfs: don't use the extent root in btrfs_chunk_alloc_add_chunk_item
We're just using the extent_root to set the chunk owner to root_key->objectid, which is BTRFS_EXTENT_TREE_OBJECTID, so use that d
btrfs: don't use the extent root in btrfs_chunk_alloc_add_chunk_item
We're just using the extent_root to set the chunk owner to root_key->objectid, which is BTRFS_EXTENT_TREE_OBJECTID, so use that directly instead of using the root.
Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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#
bf08387f |
| 19-Nov-2021 |
Qu Wenruo <wqu@suse.com> |
btrfs: don't check stripe length if the profile is not stripe based
[BUG] When debugging calc_bio_boundaries(), I found that even for RAID1 metadata, we're following stripe length to calculate strip
btrfs: don't check stripe length if the profile is not stripe based
[BUG] When debugging calc_bio_boundaries(), I found that even for RAID1 metadata, we're following stripe length to calculate stripe boundary.
# mkfs.btrfs -m raid1 -d raid1 /dev/test/scratch[12] # mount /dev/test/scratch /mnt/btrfs # xfs_io -f -c "pwrite 0 64K" /mnt/btrfs/file # umount
Above very basic operations will make calc_bio_boundaries() to report the following result:
submit_extent_page: r/i=1/1 file_offset=22036480 len_to_stripe_boundary=49152 submit_extent_page: r/i=1/1 file_offset=30474240 len_to_stripe_boundary=65536 ... submit_extent_page: r/i=1/1 file_offset=30523392 len_to_stripe_boundary=16384 submit_extent_page: r/i=1/1 file_offset=30457856 len_to_stripe_boundary=16384 submit_extent_page: r/i=5/257 file_offset=0 len_to_stripe_boundary=65536 submit_extent_page: r/i=5/257 file_offset=65536 len_to_stripe_boundary=65536 submit_extent_page: r/i=1/1 file_offset=30490624 len_to_stripe_boundary=49152 submit_extent_page: r/i=1/1 file_offset=30507008 len_to_stripe_boundary=32768
Where "r/i" is the rootid and inode, 1/1 means they metadata. The remaining names match the member used in kernel.
Even all data/metadata are using RAID1, we're still following stripe length.
[CAUSE] This behavior is caused by a wrong condition in btrfs_get_io_geometry():
if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) { /* Fill using stripe_len */ len = min_t(u64, em->len - offset, max_len); } else { len = em->len - offset; }
This means, only for SINGLE we will not follow stripe_len.
However for profiles like RAID1*, DUP, they don't need to bother stripe_len.
This can lead to unnecessary bio split for RAID1*/DUP profiles, and can even be a blockage for future zoned RAID support.
[FIX] Introduce one single-use macro, BTRFS_BLOCK_GROUP_STRIPE_MASK, and change the condition to only calculate the length using stripe length for stripe based profiles.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> 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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#
16beac87 |
| 10-Nov-2021 |
Naohiro Aota <naohiro.aota@wdc.com> |
btrfs: zoned: cache reported zone during mount
When mounting a device, we are reporting the zones twice: once for checking the zone attributes in btrfs_get_dev_zone_info and once for loading block g
btrfs: zoned: cache reported zone during mount
When mounting a device, we are reporting the zones twice: once for checking the zone attributes in btrfs_get_dev_zone_info and once for loading block groups' zone info in btrfs_load_block_group_zone_info(). With a lot of block groups, that leads to a lot of REPORT ZONE commands and slows down the mount process.
This patch introduces a zone info cache in struct btrfs_zoned_device_info. The cache is populated while in btrfs_get_dev_zone_info() and used for btrfs_load_block_group_zone_info() to reduce the number of REPORT ZONE commands. The zone cache is then released after loading the block groups, as it will not be much effective during the run time.
Benchmark: Mount an HDD with 57,007 block groups Before patch: 171.368 seconds After patch: 64.064 seconds
While it still takes a minute due to the slowness of loading all the block groups, the patch reduces the mount time by 1/3.
Link: https://lore.kernel.org/linux-btrfs/CAHQ7scUiLtcTqZOMMY5kbWUBOhGRwKo6J6wYPT5WY+C=cD49nQ@mail.gmail.com/ Fixes: 5b316468983d ("btrfs: get zone information of zoned block devices") CC: stable@vger.kernel.org Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
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#
849eae5e |
| 09-Nov-2021 |
Anand Jain <anand.jain@oracle.com> |
btrfs: consolidate device_list_mutex in prepare_sprout to its parent
btrfs_prepare_sprout() splices seed devices into its own struct fs_devices, so that its parent function btrfs_init_new_device() c
btrfs: consolidate device_list_mutex in prepare_sprout to its parent
btrfs_prepare_sprout() splices seed devices into its own struct fs_devices, so that its parent function btrfs_init_new_device() can add the new sprout device to fs_info->fs_devices.
Both btrfs_prepare_sprout() and btrfs_init_new_device() need device_list_mutex. But they are holding it separately, thus create a small race window. Close it and hold device_list_mutex across both functions btrfs_init_new_device() and btrfs_prepare_sprout().
Split btrfs_prepare_sprout() into btrfs_init_sprout() and btrfs_setup_sprout(). This split is essential because device_list_mutex must not be held for allocations in btrfs_init_sprout() but must be held for btrfs_setup_sprout(). So now a common device_list_mutex can be used between btrfs_init_new_device() and btrfs_setup_sprout().
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>
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Revision tags: v5.15, v5.14.14, v5.14.13, v5.14.12, v5.14.11, v5.14.10, v5.14.9, v5.14.8, v5.14.7 |
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#
fd880809 |
| 20-Sep-2021 |
Anand Jain <anand.jain@oracle.com> |
btrfs: switch seeding_dev in init_new_device to bool
Declare int seeding_dev as a bool. Also, move its declaration a line below to adjust packing.
Reviewed-by: Nikolay Borisov <nborisov@suse.com> S
btrfs: switch seeding_dev in init_new_device to bool
Declare int seeding_dev as a bool. Also, move its declaration a line below to adjust packing.
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>
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#
3212fa14 |
| 21-Oct-2021 |
Josef Bacik <josef@toxicpanda.com> |
btrfs: drop the _nr from the item helpers
Now that all call sites are using the slot number to modify item values, rename the SETGET helpers to raw_item_*(), and then rework the _nr() helpers to be
btrfs: drop the _nr from the item helpers
Now that all call sites are using the slot number to modify item values, rename the SETGET helpers to raw_item_*(), and then rework the _nr() helpers to be the btrfs_item_*() btrfs_set_item_*() helpers, and then rename all of the callers to the new helpers.
Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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#
4989d4a0 |
| 15-Dec-2021 |
Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> |
btrfs: fix missing blkdev_put() call in btrfs_scan_one_device()
The function btrfs_scan_one_device() calls blkdev_get_by_path() and blkdev_put() to get and release its target block device. However,
btrfs: fix missing blkdev_put() call in btrfs_scan_one_device()
The function btrfs_scan_one_device() calls blkdev_get_by_path() and blkdev_put() to get and release its target block device. However, when btrfs_sb_log_location_bdev() fails, blkdev_put() is not called and the block device is left without clean up. This triggered failure of fstests generic/085. Fix the failure path of btrfs_sb_log_location_bdev() to call blkdev_put().
Fixes: 12659251ca5df ("btrfs: implement log-structured superblock for ZONED mode") CC: stable@vger.kernel.org # 5.15+ Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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#
4d9380e0 |
| 04-Nov-2021 |
Filipe Manana <fdmanana@suse.com> |
btrfs: silence lockdep when reading chunk tree during mount
Often some test cases like btrfs/161 trigger lockdep splats that complain about possible unsafe lock scenario due to the fact that during
btrfs: silence lockdep when reading chunk tree during mount
Often some test cases like btrfs/161 trigger lockdep splats that complain about possible unsafe lock scenario due to the fact that during mount, when reading the chunk tree we end up calling blkdev_get_by_path() while holding a read lock on a leaf of the chunk tree. That produces a lockdep splat like the following:
[ 3653.683975] ====================================================== [ 3653.685148] WARNING: possible circular locking dependency detected [ 3653.686301] 5.15.0-rc7-btrfs-next-103 #1 Not tainted [ 3653.687239] ------------------------------------------------------ [ 3653.688400] mount/447465 is trying to acquire lock: [ 3653.689320] ffff8c6b0c76e528 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev.part.0+0xe7/0x320 [ 3653.691054] but task is already holding lock: [ 3653.692155] ffff8c6b0a9f39e0 (btrfs-chunk-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x24/0x110 [btrfs] [ 3653.693978] which lock already depends on the new lock.
[ 3653.695510] the existing dependency chain (in reverse order) is: [ 3653.696915] -> #3 (btrfs-chunk-00){++++}-{3:3}: [ 3653.698053] down_read_nested+0x4b/0x140 [ 3653.698893] __btrfs_tree_read_lock+0x24/0x110 [btrfs] [ 3653.699988] btrfs_read_lock_root_node+0x31/0x40 [btrfs] [ 3653.701205] btrfs_search_slot+0x537/0xc00 [btrfs] [ 3653.702234] btrfs_insert_empty_items+0x32/0x70 [btrfs] [ 3653.703332] btrfs_init_new_device+0x563/0x15b0 [btrfs] [ 3653.704439] btrfs_ioctl+0x2110/0x3530 [btrfs] [ 3653.705405] __x64_sys_ioctl+0x83/0xb0 [ 3653.706215] do_syscall_64+0x3b/0xc0 [ 3653.706990] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 3653.708040] -> #2 (sb_internal#2){.+.+}-{0:0}: [ 3653.708994] lock_release+0x13d/0x4a0 [ 3653.709533] up_write+0x18/0x160 [ 3653.710017] btrfs_sync_file+0x3f3/0x5b0 [btrfs] [ 3653.710699] __loop_update_dio+0xbd/0x170 [loop] [ 3653.711360] lo_ioctl+0x3b1/0x8a0 [loop] [ 3653.711929] block_ioctl+0x48/0x50 [ 3653.712442] __x64_sys_ioctl+0x83/0xb0 [ 3653.712991] do_syscall_64+0x3b/0xc0 [ 3653.713519] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 3653.714233] -> #1 (&lo->lo_mutex){+.+.}-{3:3}: [ 3653.715026] __mutex_lock+0x92/0x900 [ 3653.715648] lo_open+0x28/0x60 [loop] [ 3653.716275] blkdev_get_whole+0x28/0x90 [ 3653.716867] blkdev_get_by_dev.part.0+0x142/0x320 [ 3653.717537] blkdev_open+0x5e/0xa0 [ 3653.718043] do_dentry_open+0x163/0x390 [ 3653.718604] path_openat+0x3f0/0xa80 [ 3653.719128] do_filp_open+0xa9/0x150 [ 3653.719652] do_sys_openat2+0x97/0x160 [ 3653.720197] __x64_sys_openat+0x54/0x90 [ 3653.720766] do_syscall_64+0x3b/0xc0 [ 3653.721285] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 3653.721986] -> #0 (&disk->open_mutex){+.+.}-{3:3}: [ 3653.722775] __lock_acquire+0x130e/0x2210 [ 3653.723348] lock_acquire+0xd7/0x310 [ 3653.723867] __mutex_lock+0x92/0x900 [ 3653.724394] blkdev_get_by_dev.part.0+0xe7/0x320 [ 3653.725041] blkdev_get_by_path+0xb8/0xd0 [ 3653.725614] btrfs_get_bdev_and_sb+0x1b/0xb0 [btrfs] [ 3653.726332] open_fs_devices+0xd7/0x2c0 [btrfs] [ 3653.726999] btrfs_read_chunk_tree+0x3ad/0x870 [btrfs] [ 3653.727739] open_ctree+0xb8e/0x17bf [btrfs] [ 3653.728384] btrfs_mount_root.cold+0x12/0xde [btrfs] [ 3653.729130] legacy_get_tree+0x30/0x50 [ 3653.729676] vfs_get_tree+0x28/0xc0 [ 3653.730192] vfs_kern_mount.part.0+0x71/0xb0 [ 3653.730800] btrfs_mount+0x11d/0x3a0 [btrfs] [ 3653.731427] legacy_get_tree+0x30/0x50 [ 3653.731970] vfs_get_tree+0x28/0xc0 [ 3653.732486] path_mount+0x2d4/0xbe0 [ 3653.732997] __x64_sys_mount+0x103/0x140 [ 3653.733560] do_syscall_64+0x3b/0xc0 [ 3653.734080] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 3653.734782] other info that might help us debug this:
[ 3653.735784] Chain exists of: &disk->open_mutex --> sb_internal#2 --> btrfs-chunk-00
[ 3653.737123] Possible unsafe locking scenario:
[ 3653.737865] CPU0 CPU1 [ 3653.738435] ---- ---- [ 3653.739007] lock(btrfs-chunk-00); [ 3653.739449] lock(sb_internal#2); [ 3653.740193] lock(btrfs-chunk-00); [ 3653.740955] lock(&disk->open_mutex); [ 3653.741431] *** DEADLOCK ***
[ 3653.742176] 3 locks held by mount/447465: [ 3653.742739] #0: ffff8c6acf85c0e8 (&type->s_umount_key#44/1){+.+.}-{3:3}, at: alloc_super+0xd5/0x3b0 [ 3653.744114] #1: ffffffffc0b28f70 (uuid_mutex){+.+.}-{3:3}, at: btrfs_read_chunk_tree+0x59/0x870 [btrfs] [ 3653.745563] #2: ffff8c6b0a9f39e0 (btrfs-chunk-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x24/0x110 [btrfs] [ 3653.747066] stack backtrace: [ 3653.747723] CPU: 4 PID: 447465 Comm: mount Not tainted 5.15.0-rc7-btrfs-next-103 #1 [ 3653.748873] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 3653.750592] Call Trace: [ 3653.750967] dump_stack_lvl+0x57/0x72 [ 3653.751526] check_noncircular+0xf3/0x110 [ 3653.752136] ? stack_trace_save+0x4b/0x70 [ 3653.752748] __lock_acquire+0x130e/0x2210 [ 3653.753356] lock_acquire+0xd7/0x310 [ 3653.753898] ? blkdev_get_by_dev.part.0+0xe7/0x320 [ 3653.754596] ? lock_is_held_type+0xe8/0x140 [ 3653.755125] ? blkdev_get_by_dev.part.0+0xe7/0x320 [ 3653.755729] ? blkdev_get_by_dev.part.0+0xe7/0x320 [ 3653.756338] __mutex_lock+0x92/0x900 [ 3653.756794] ? blkdev_get_by_dev.part.0+0xe7/0x320 [ 3653.757400] ? do_raw_spin_unlock+0x4b/0xa0 [ 3653.757930] ? _raw_spin_unlock+0x29/0x40 [ 3653.758437] ? bd_prepare_to_claim+0x129/0x150 [ 3653.758999] ? trace_module_get+0x2b/0xd0 [ 3653.759508] ? try_module_get.part.0+0x50/0x80 [ 3653.760072] blkdev_get_by_dev.part.0+0xe7/0x320 [ 3653.760661] ? devcgroup_check_permission+0xc1/0x1f0 [ 3653.761288] blkdev_get_by_path+0xb8/0xd0 [ 3653.761797] btrfs_get_bdev_and_sb+0x1b/0xb0 [btrfs] [ 3653.762454] open_fs_devices+0xd7/0x2c0 [btrfs] [ 3653.763055] ? clone_fs_devices+0x8f/0x170 [btrfs] [ 3653.763689] btrfs_read_chunk_tree+0x3ad/0x870 [btrfs] [ 3653.764370] ? kvm_sched_clock_read+0x14/0x40 [ 3653.764922] open_ctree+0xb8e/0x17bf [btrfs] [ 3653.765493] ? super_setup_bdi_name+0x79/0xd0 [ 3653.766043] btrfs_mount_root.cold+0x12/0xde [btrfs] [ 3653.766780] ? rcu_read_lock_sched_held+0x3f/0x80 [ 3653.767488] ? kfree+0x1f2/0x3c0 [ 3653.767979] legacy_get_tree+0x30/0x50 [ 3653.768548] vfs_get_tree+0x28/0xc0 [ 3653.769076] vfs_kern_mount.part.0+0x71/0xb0 [ 3653.769718] btrfs_mount+0x11d/0x3a0 [btrfs] [ 3653.770381] ? rcu_read_lock_sched_held+0x3f/0x80 [ 3653.771086] ? kfree+0x1f2/0x3c0 [ 3653.771574] legacy_get_tree+0x30/0x50 [ 3653.772136] vfs_get_tree+0x28/0xc0 [ 3653.772673] path_mount+0x2d4/0xbe0 [ 3653.773201] __x64_sys_mount+0x103/0x140 [ 3653.773793] do_syscall_64+0x3b/0xc0 [ 3653.774333] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 3653.775094] RIP: 0033:0x7f648bc45aaa
This happens because through btrfs_read_chunk_tree(), which is called only during mount, ends up acquiring the mutex open_mutex of a block device while holding a read lock on a leaf of the chunk tree while other paths need to acquire other locks before locking extent buffers of the chunk tree.
Since at mount time when we call btrfs_read_chunk_tree() we know that we don't have other tasks running in parallel and modifying the chunk tree, we can simply skip locking of chunk tree extent buffers. So do that and move the assertion that checks the fs is not yet mounted to the top block of btrfs_read_chunk_tree(), with a comment before doing it.
Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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#
5d03dbeb |
| 04-Oct-2021 |
Li Zhang <zhanglikernel@gmail.com> |
btrfs: clear MISSING device status bit in btrfs_close_one_device
Reported bug: https://github.com/kdave/btrfs-progs/issues/389
There's a problem with scrub reporting aborted status but returning er
btrfs: clear MISSING device status bit in btrfs_close_one_device
Reported bug: https://github.com/kdave/btrfs-progs/issues/389
There's a problem with scrub reporting aborted status but returning error code 0, on a filesystem with missing and readded device.
Roughly these steps:
- mkfs -d raid1 dev1 dev2 - fill with data - unmount - make dev1 disappear - mount -o degraded - copy more data - make dev1 appear again
Running scrub afterwards reports that the command was aborted, but the system log message says the exit code was 0.
It seems that the cause of the error is decrementing fs_devices->missing_devices but not clearing device->dev_state. Every time we umount filesystem, it would call close_ctree, And it would eventually involve btrfs_close_one_device to close the device, but it only decrements fs_devices->missing_devices but does not clear the device BTRFS_DEV_STATE_MISSING bit. Worse, this bug will cause Integer Overflow, because every time umount, fs_devices->missing_devices will decrease. If fs_devices->missing_devices value hit 0, it would overflow.
With added debugging:
loop1: detected capacity change from 0 to 20971520 BTRFS: device fsid 56ad51f1-5523-463b-8547-c19486c51ebb devid 1 transid 21 /dev/loop1 scanned by systemd-udevd (2311) loop2: detected capacity change from 0 to 20971520 BTRFS: device fsid 56ad51f1-5523-463b-8547-c19486c51ebb devid 2 transid 17 /dev/loop2 scanned by systemd-udevd (2313) BTRFS info (device loop1): flagging fs with big metadata feature BTRFS info (device loop1): allowing degraded mounts BTRFS info (device loop1): using free space tree BTRFS info (device loop1): has skinny extents BTRFS info (device loop1): before clear_missing.00000000f706684d /dev/loop1 0 BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1 BTRFS info (device loop1): flagging fs with big metadata feature BTRFS info (device loop1): allowing degraded mounts BTRFS info (device loop1): using free space tree BTRFS info (device loop1): has skinny extents BTRFS info (device loop1): before clear_missing.00000000f706684d /dev/loop1 0 BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 0 BTRFS info (device loop1): flagging fs with big metadata feature BTRFS info (device loop1): allowing degraded mounts BTRFS info (device loop1): using free space tree BTRFS info (device loop1): has skinny extents BTRFS info (device loop1): before clear_missing.00000000f706684d /dev/loop1 18446744073709551615 BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 18446744073709551615
If fs_devices->missing_devices is 0, next time it would be 18446744073709551615
After apply this patch, the fs_devices->missing_devices seems to be right:
$ truncate -s 10g test1 $ truncate -s 10g test2 $ losetup /dev/loop1 test1 $ losetup /dev/loop2 test2 $ mkfs.btrfs -draid1 -mraid1 /dev/loop1 /dev/loop2 -f $ losetup -d /dev/loop2 $ mount -o degraded /dev/loop1 /mnt/1 $ umount /mnt/1 $ mount -o degraded /dev/loop1 /mnt/1 $ umount /mnt/1 $ mount -o degraded /dev/loop1 /mnt/1 $ umount /mnt/1 $ dmesg
loop1: detected capacity change from 0 to 20971520 loop2: detected capacity change from 0 to 20971520 BTRFS: device fsid 15aa1203-98d3-4a66-bcae-ca82f629c2cd devid 1 transid 5 /dev/loop1 scanned by mkfs.btrfs (1863) BTRFS: device fsid 15aa1203-98d3-4a66-bcae-ca82f629c2cd devid 2 transid 5 /dev/loop2 scanned by mkfs.btrfs (1863) BTRFS info (device loop1): flagging fs with big metadata feature BTRFS info (device loop1): allowing degraded mounts BTRFS info (device loop1): disk space caching is enabled BTRFS info (device loop1): has skinny extents BTRFS info (device loop1): before clear_missing.00000000975bd577 /dev/loop1 0 BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1 BTRFS info (device loop1): checking UUID tree BTRFS info (device loop1): flagging fs with big metadata feature BTRFS info (device loop1): allowing degraded mounts BTRFS info (device loop1): disk space caching is enabled BTRFS info (device loop1): has skinny extents BTRFS info (device loop1): before clear_missing.00000000975bd577 /dev/loop1 0 BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1 BTRFS info (device loop1): flagging fs with big metadata feature BTRFS info (device loop1): allowing degraded mounts BTRFS info (device loop1): disk space caching is enabled BTRFS info (device loop1): has skinny extents BTRFS info (device loop1): before clear_missing.00000000975bd577 /dev/loop1 0 BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing BTRFS info (device loop1): before clear_missing.0000000000000000 /dev/loop2 1
CC: stable@vger.kernel.org # 4.19+ Signed-off-by: Li Zhang <zhanglikernel@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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#
54fde91f |
| 14-Oct-2021 |
Josef Bacik <josef@toxicpanda.com> |
btrfs: update device path inode time instead of bd_inode
Christoph pointed out that I'm updating bdev->bd_inode for the device time when we remove block devices from a btrfs file system, however thi
btrfs: update device path inode time instead of bd_inode
Christoph pointed out that I'm updating bdev->bd_inode for the device time when we remove block devices from a btrfs file system, however this isn't actually exposed to anything. The inode we want to update is the one that's associated with the path to the device, usually on devtmpfs, so that blkid notices the difference.
We still don't want to do the blkdev_open, so use kern_path() to get the path to the given device and do the update time on that inode.
Fixes: 8f96a5bfa150 ("btrfs: update the bdev time directly when closing") Reported-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
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#
2bb2e00e |
| 13-Oct-2021 |
Filipe Manana <fdmanana@suse.com> |
btrfs: fix deadlock between chunk allocation and chunk btree modifications
When a task is doing some modification to the chunk btree and it is not in the context of a chunk allocation or a chunk rem
btrfs: fix deadlock between chunk allocation and chunk btree modifications
When a task is doing some modification to the chunk btree and it is not in the context of a chunk allocation or a chunk removal, it can deadlock with another task that is currently allocating a new data or metadata chunk.
These contexts are the following:
* When relocating a system chunk, when we need to COW the extent buffers that belong to the chunk btree;
* When adding a new device (ioctl), where we need to add a new device item to the chunk btree;
* When removing a device (ioctl), where we need to remove a device item from the chunk btree;
* When resizing a device (ioctl), where we need to update a device item in the chunk btree and may need to relocate a system chunk that lies beyond the new device size when shrinking a device.
The problem happens due to a sequence of steps like the following:
1) Task A starts a data or metadata chunk allocation and it locks the chunk mutex;
2) Task B is relocating a system chunk, and when it needs to COW an extent buffer of the chunk btree, it has locked both that extent buffer as well as its parent extent buffer;
3) Since there is not enough available system space, either because none of the existing system block groups have enough free space or because the only one with enough free space is in RO mode due to the relocation, task B triggers a new system chunk allocation. It blocks when trying to acquire the chunk mutex, currently held by task A;
4) Task A enters btrfs_chunk_alloc_add_chunk_item(), in order to insert the new chunk item into the chunk btree and update the existing device items there. But in order to do that, it has to lock the extent buffer that task B locked at step 2, or its parent extent buffer, but task B is waiting on the chunk mutex, which is currently locked by task A, therefore resulting in a deadlock.
One example report when the deadlock happens with system chunk relocation:
INFO: task kworker/u9:5:546 blocked for more than 143 seconds. Not tainted 5.15.0-rc3+ #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u9:5 state:D stack:25936 pid: 546 ppid: 2 flags:0x00004000 Workqueue: events_unbound btrfs_async_reclaim_metadata_space Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 rwsem_down_read_slowpath+0x4ee/0x9d0 kernel/locking/rwsem.c:993 __down_read_common kernel/locking/rwsem.c:1214 [inline] __down_read kernel/locking/rwsem.c:1223 [inline] down_read_nested+0xe6/0x440 kernel/locking/rwsem.c:1590 __btrfs_tree_read_lock+0x31/0x350 fs/btrfs/locking.c:47 btrfs_tree_read_lock fs/btrfs/locking.c:54 [inline] btrfs_read_lock_root_node+0x8a/0x320 fs/btrfs/locking.c:191 btrfs_search_slot_get_root fs/btrfs/ctree.c:1623 [inline] btrfs_search_slot+0x13b4/0x2140 fs/btrfs/ctree.c:1728 btrfs_update_device+0x11f/0x500 fs/btrfs/volumes.c:2794 btrfs_chunk_alloc_add_chunk_item+0x34d/0xea0 fs/btrfs/volumes.c:5504 do_chunk_alloc fs/btrfs/block-group.c:3408 [inline] btrfs_chunk_alloc+0x84d/0xf50 fs/btrfs/block-group.c:3653 flush_space+0x54e/0xd80 fs/btrfs/space-info.c:670 btrfs_async_reclaim_metadata_space+0x396/0xa90 fs/btrfs/space-info.c:953 process_one_work+0x9df/0x16d0 kernel/workqueue.c:2297 worker_thread+0x90/0xed0 kernel/workqueue.c:2444 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 INFO: task syz-executor:9107 blocked for more than 143 seconds. Not tainted 5.15.0-rc3+ #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:23200 pid: 9107 ppid: 7792 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729 btrfs_chunk_alloc+0x31a/0xf50 fs/btrfs/block-group.c:3631 find_free_extent_update_loop fs/btrfs/extent-tree.c:3986 [inline] find_free_extent+0x25cb/0x3a30 fs/btrfs/extent-tree.c:4335 btrfs_reserve_extent+0x1f1/0x500 fs/btrfs/extent-tree.c:4415 btrfs_alloc_tree_block+0x203/0x1120 fs/btrfs/extent-tree.c:4813 __btrfs_cow_block+0x412/0x1620 fs/btrfs/ctree.c:415 btrfs_cow_block+0x2f6/0x8c0 fs/btrfs/ctree.c:570 btrfs_search_slot+0x1094/0x2140 fs/btrfs/ctree.c:1768 relocate_tree_block fs/btrfs/relocation.c:2694 [inline] relocate_tree_blocks+0xf73/0x1770 fs/btrfs/relocation.c:2757 relocate_block_group+0x47e/0xc70 fs/btrfs/relocation.c:3673 btrfs_relocate_block_group+0x48a/0xc60 fs/btrfs/relocation.c:4070 btrfs_relocate_chunk+0x96/0x280 fs/btrfs/volumes.c:3181 __btrfs_balance fs/btrfs/volumes.c:3911 [inline] btrfs_balance+0x1f03/0x3cd0 fs/btrfs/volumes.c:4301 btrfs_ioctl_balance+0x61e/0x800 fs/btrfs/ioctl.c:4137 btrfs_ioctl+0x39ea/0x7b70 fs/btrfs/ioctl.c:4949 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae
So fix this by making sure that whenever we try to modify the chunk btree and we are neither in a chunk allocation context nor in a chunk remove context, we reserve system space before modifying the chunk btree.
Reported-by: Hao Sun <sunhao.th@gmail.com> Link: https://lore.kernel.org/linux-btrfs/CACkBjsax51i4mu6C0C3vJqQN3NR_iVuucoeG3U1HXjrgzn5FFQ@mail.gmail.com/ Fixes: 79bd37120b1495 ("btrfs: rework chunk allocation to avoid exhaustion of the system chunk array") CC: stable@vger.kernel.org # 5.14+ 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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#
1a15eb72 |
| 05-Oct-2021 |
Josef Bacik <josef@toxicpanda.com> |
btrfs: use btrfs_get_dev_args_from_path in dev removal ioctls
For device removal and replace we call btrfs_find_device_by_devspec, which if we give it a device path and nothing else will call btrfs_
btrfs: use btrfs_get_dev_args_from_path in dev removal ioctls
For device removal and replace we call btrfs_find_device_by_devspec, which if we give it a device path and nothing else will call btrfs_get_dev_args_from_path, which opens the block device and reads the super block and then looks up our device based on that.
However at this point we're holding the sb write "lock", so reading the block device pulls in the dependency of ->open_mutex, which produces the following lockdep splat
====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc2+ #405 Not tainted ------------------------------------------------------ losetup/11576 is trying to acquire lock: ffff9bbe8cded938 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x67/0x5e0
but task is already holding lock: ffff9bbe88e4fc68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (&lo->lo_mutex){+.+.}-{3:3}: __mutex_lock+0x7d/0x750 lo_open+0x28/0x60 [loop] blkdev_get_whole+0x25/0xf0 blkdev_get_by_dev.part.0+0x168/0x3c0 blkdev_open+0xd2/0xe0 do_dentry_open+0x161/0x390 path_openat+0x3cc/0xa20 do_filp_open+0x96/0x120 do_sys_openat2+0x7b/0x130 __x64_sys_openat+0x46/0x70 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #3 (&disk->open_mutex){+.+.}-{3:3}: __mutex_lock+0x7d/0x750 blkdev_get_by_dev.part.0+0x56/0x3c0 blkdev_get_by_path+0x98/0xa0 btrfs_get_bdev_and_sb+0x1b/0xb0 btrfs_find_device_by_devspec+0x12b/0x1c0 btrfs_rm_device+0x127/0x610 btrfs_ioctl+0x2a31/0x2e70 __x64_sys_ioctl+0x80/0xb0 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #2 (sb_writers#12){.+.+}-{0:0}: lo_write_bvec+0xc2/0x240 [loop] loop_process_work+0x238/0xd00 [loop] process_one_work+0x26b/0x560 worker_thread+0x55/0x3c0 kthread+0x140/0x160 ret_from_fork+0x1f/0x30
-> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}: process_one_work+0x245/0x560 worker_thread+0x55/0x3c0 kthread+0x140/0x160 ret_from_fork+0x1f/0x30
-> #0 ((wq_completion)loop0){+.+.}-{0:0}: __lock_acquire+0x10ea/0x1d90 lock_acquire+0xb5/0x2b0 flush_workqueue+0x91/0x5e0 drain_workqueue+0xa0/0x110 destroy_workqueue+0x36/0x250 __loop_clr_fd+0x9a/0x660 [loop] block_ioctl+0x3f/0x50 __x64_sys_ioctl+0x80/0xb0 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae
other info that might help us debug this:
Chain exists of: (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex
Possible unsafe locking scenario:
CPU0 CPU1 ---- ---- lock(&lo->lo_mutex); lock(&disk->open_mutex); lock(&lo->lo_mutex); lock((wq_completion)loop0);
*** DEADLOCK ***
1 lock held by losetup/11576: #0: ffff9bbe88e4fc68 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x660 [loop]
stack backtrace: CPU: 0 PID: 11576 Comm: losetup Not tainted 5.14.0-rc2+ #405 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack_lvl+0x57/0x72 check_noncircular+0xcf/0xf0 ? stack_trace_save+0x3b/0x50 __lock_acquire+0x10ea/0x1d90 lock_acquire+0xb5/0x2b0 ? flush_workqueue+0x67/0x5e0 ? lockdep_init_map_type+0x47/0x220 flush_workqueue+0x91/0x5e0 ? flush_workqueue+0x67/0x5e0 ? verify_cpu+0xf0/0x100 drain_workqueue+0xa0/0x110 destroy_workqueue+0x36/0x250 __loop_clr_fd+0x9a/0x660 [loop] ? blkdev_ioctl+0x8d/0x2a0 block_ioctl+0x3f/0x50 __x64_sys_ioctl+0x80/0xb0 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f31b02404cb
Instead what we want to do is populate our device lookup args before we grab any locks, and then pass these args into btrfs_rm_device(). From there we can find the device and do the appropriate removal.
Suggested-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
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#
faa775c4 |
| 05-Oct-2021 |
Josef Bacik <josef@toxicpanda.com> |
btrfs: add a btrfs_get_dev_args_from_path helper
We are going to want to populate our device lookup args outside of any locks and then do the actual device lookup later, so add a helper to do this w
btrfs: add a btrfs_get_dev_args_from_path helper
We are going to want to populate our device lookup args outside of any locks and then do the actual device lookup later, so add a helper to do this work and make btrfs_find_device_by_devspec() use this helper for now.
Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
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562d7b15 |
| 05-Oct-2021 |
Josef Bacik <josef@toxicpanda.com> |
btrfs: handle device lookup with btrfs_dev_lookup_args
We have a lot of device lookup functions that all do something slightly different. Clean this up by adding a struct to hold the different look
btrfs: handle device lookup with btrfs_dev_lookup_args
We have a lot of device lookup functions that all do something slightly different. Clean this up by adding a struct to hold the different lookup criteria, and then pass this around to btrfs_find_device() so it can do the proper matching based on the lookup criteria.
Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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8b41393f |
| 05-Oct-2021 |
Josef Bacik <josef@toxicpanda.com> |
btrfs: do not call close_fs_devices in btrfs_rm_device
There's a subtle case where if we're removing the seed device from a file system we need to free its private copy of the fs_devices. However w
btrfs: do not call close_fs_devices in btrfs_rm_device
There's a subtle case where if we're removing the seed device from a file system we need to free its private copy of the fs_devices. However we do not need to call close_fs_devices(), because at this point there are no devices left to close as we've closed the last one. The only thing that close_fs_devices() does is decrement ->opened, which should be 1. We want to avoid calling close_fs_devices() here because it has a lockdep_assert_held(&uuid_mutex), and we are going to stop holding the uuid_mutex in this path.
So simply decrement the ->opened counter like we should, and then clean up like normal. Also add a comment explaining what we're doing here as I initially removed this code erroneously.
Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
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8e906945 |
| 05-Oct-2021 |
Anand Jain <anand.jain@oracle.com> |
btrfs: use num_device to check for the last surviving seed device
For both sprout and seed fsids, btrfs_fs_devices::num_devices provides device count including missing btrfs_fs_devices::open_devic
btrfs: use num_device to check for the last surviving seed device
For both sprout and seed fsids, btrfs_fs_devices::num_devices provides device count including missing btrfs_fs_devices::open_devices provides device count excluding missing
We create a dummy struct btrfs_device for the missing device, so num_devices != open_devices when there is a missing device.
In btrfs_rm_devices() we wrongly check for %cur_devices->open_devices before freeing the seed fs_devices. Instead we should check for %cur_devices->num_devices.
Signed-off-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
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6a258d72 |
| 23-Sep-2021 |
Qu Wenruo <wqu@suse.com> |
btrfs: remove btrfs_raid_bio::fs_info member
We can grab fs_info reliably from btrfs_raid_bio::bioc, as the bioc is always passed into alloc_rbio(), and only get released when the raid bio is releas
btrfs: remove btrfs_raid_bio::fs_info member
We can grab fs_info reliably from btrfs_raid_bio::bioc, as the bioc is always passed into alloc_rbio(), and only get released when the raid bio is released.
Remove btrfs_raid_bio::fs_info member, and cleanup all the @fs_info parameters for alloc_rbio() callers.
Reviewed-by: Nikolay Borisov <nborisov@suse.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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731ccf15 |
| 23-Sep-2021 |
Qu Wenruo <wqu@suse.com> |
btrfs: make sure btrfs_io_context::fs_info is always initialized
Currently btrfs_io_context::fs_info is only initialized in btrfs_map_bio, but there are call sites like btrfs_map_sblock() which call
btrfs: make sure btrfs_io_context::fs_info is always initialized
Currently btrfs_io_context::fs_info is only initialized in btrfs_map_bio, but there are call sites like btrfs_map_sblock() which calls __btrfs_map_block() directly, leaving bioc::fs_info uninitialized (NULL).
Currently this is fine, but later cleanup will rely on bioc::fs_info to grab fs_info, and this can be a hidden problem for such usage.
This patch will remove such hidden uninitialized member by always assigning bioc::fs_info at alloc_btrfs_io_context().
Reviewed-by: Nikolay Borisov <nborisov@suse.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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Revision tags: v5.14.6, v5.10.67, v5.10.66, v5.14.5, v5.14.4, v5.10.65, v5.14.3, v5.10.64, v5.14.2, v5.10.63, v5.14.1, v5.10.62, v5.14, v5.10.61, v5.10.60 |
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8ef9dc0f |
| 27-Jul-2021 |
Josef Bacik <josef@toxicpanda.com> |
btrfs: do not take the uuid_mutex in btrfs_rm_device
We got the following lockdep splat while running fstests (specifically btrfs/003 and btrfs/020 in a row) with the new rc. This was uncovered by
btrfs: do not take the uuid_mutex in btrfs_rm_device
We got the following lockdep splat while running fstests (specifically btrfs/003 and btrfs/020 in a row) with the new rc. This was uncovered by 87579e9b7d8d ("loop: use worker per cgroup instead of kworker") which converted loop to using workqueues, which comes with lockdep annotations that don't exist with kworkers. The lockdep splat is as follows:
WARNING: possible circular locking dependency detected 5.14.0-rc2-custom+ #34 Not tainted ------------------------------------------------------ losetup/156417 is trying to acquire lock: ffff9c7645b02d38 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x84/0x600
but task is already holding lock: ffff9c7647395468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x650 [loop]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&lo->lo_mutex){+.+.}-{3:3}: __mutex_lock+0xba/0x7c0 lo_open+0x28/0x60 [loop] blkdev_get_whole+0x28/0xf0 blkdev_get_by_dev.part.0+0x168/0x3c0 blkdev_open+0xd2/0xe0 do_dentry_open+0x163/0x3a0 path_openat+0x74d/0xa40 do_filp_open+0x9c/0x140 do_sys_openat2+0xb1/0x170 __x64_sys_openat+0x54/0x90 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #4 (&disk->open_mutex){+.+.}-{3:3}: __mutex_lock+0xba/0x7c0 blkdev_get_by_dev.part.0+0xd1/0x3c0 blkdev_get_by_path+0xc0/0xd0 btrfs_scan_one_device+0x52/0x1f0 [btrfs] btrfs_control_ioctl+0xac/0x170 [btrfs] __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #3 (uuid_mutex){+.+.}-{3:3}: __mutex_lock+0xba/0x7c0 btrfs_rm_device+0x48/0x6a0 [btrfs] btrfs_ioctl+0x2d1c/0x3110 [btrfs] __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae
-> #2 (sb_writers#11){.+.+}-{0:0}: lo_write_bvec+0x112/0x290 [loop] loop_process_work+0x25f/0xcb0 [loop] process_one_work+0x28f/0x5d0 worker_thread+0x55/0x3c0 kthread+0x140/0x170 ret_from_fork+0x22/0x30
-> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}: process_one_work+0x266/0x5d0 worker_thread+0x55/0x3c0 kthread+0x140/0x170 ret_from_fork+0x22/0x30
-> #0 ((wq_completion)loop0){+.+.}-{0:0}: __lock_acquire+0x1130/0x1dc0 lock_acquire+0xf5/0x320 flush_workqueue+0xae/0x600 drain_workqueue+0xa0/0x110 destroy_workqueue+0x36/0x250 __loop_clr_fd+0x9a/0x650 [loop] lo_ioctl+0x29d/0x780 [loop] block_ioctl+0x3f/0x50 __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae
other info that might help us debug this: Chain exists of: (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&lo->lo_mutex); lock(&disk->open_mutex); lock(&lo->lo_mutex); lock((wq_completion)loop0);
*** DEADLOCK *** 1 lock held by losetup/156417: #0: ffff9c7647395468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x41/0x650 [loop]
stack backtrace: CPU: 8 PID: 156417 Comm: losetup Not tainted 5.14.0-rc2-custom+ #34 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: dump_stack_lvl+0x57/0x72 check_noncircular+0x10a/0x120 __lock_acquire+0x1130/0x1dc0 lock_acquire+0xf5/0x320 ? flush_workqueue+0x84/0x600 flush_workqueue+0xae/0x600 ? flush_workqueue+0x84/0x600 drain_workqueue+0xa0/0x110 destroy_workqueue+0x36/0x250 __loop_clr_fd+0x9a/0x650 [loop] lo_ioctl+0x29d/0x780 [loop] ? __lock_acquire+0x3a0/0x1dc0 ? update_dl_rq_load_avg+0x152/0x360 ? lock_is_held_type+0xa5/0x120 ? find_held_lock.constprop.0+0x2b/0x80 block_ioctl+0x3f/0x50 __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f645884de6b
Usually the uuid_mutex exists to protect the fs_devices that map together all of the devices that match a specific uuid. In rm_device we're messing with the uuid of a device, so it makes sense to protect that here.
However in doing that it pulls in a whole host of lockdep dependencies, as we call mnt_may_write() on the sb before we grab the uuid_mutex, thus we end up with the dependency chain under the uuid_mutex being added under the normal sb write dependency chain, which causes problems with loop devices.
We don't need the uuid mutex here however. If we call btrfs_scan_one_device() before we scratch the super block we will find the fs_devices and not find the device itself and return EBUSY because the fs_devices is open. If we call it after the scratch happens it will not appear to be a valid btrfs file system.
We do not need to worry about other fs_devices modifying operations here because we're protected by the exclusive operations locking.
So drop the uuid_mutex here in order to fix the lockdep splat.
A more detailed explanation from the discussion:
We are worried about rm and scan racing with each other, before this change we'll zero the device out under the UUID mutex so when scan does run it'll make sure that it can go through the whole device scan thing without rm messing with us.
We aren't worried if the scratch happens first, because the result is we don't think this is a btrfs device and we bail out.
The only case we are concerned with is we scratch _after_ scan is able to read the superblock and gets a seemingly valid super block, so lets consider this case.
Scan will call device_list_add() with the device we're removing. We'll call find_fsid_with_metadata_uuid() and get our fs_devices for this UUID. At this point we lock the fs_devices->device_list_mutex. This is what protects us in this case, but we have two cases here.
1. We aren't to the device removal part of the RM. We found our device, and device name matches our path, we go down and we set total_devices to our super number of devices, which doesn't affect anything because we haven't done the remove yet.
2. We are past the device removal part, which is protected by the device_list_mutex. Scan doesn't find the device, it goes down and does the
if (fs_devices->opened) return -EBUSY;
check and we bail out.
Nothing about this situation is ideal, but the lockdep splat is real, and the fix is safe, tho admittedly a bit scary looking.
Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ copy more from the discussion ] Signed-off-by: David Sterba <dsterba@suse.com>
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