linux-stable/fs/btrfs
Anand Jain 8a6539ea36 btrfs: scan device in non-exclusive mode
commit 50d281fc43 upstream.

This fixes mkfs/mount/check failures due to race with systemd-udevd
scan.

During the device scan initiated by systemd-udevd, other user space
EXCL operations such as mkfs, mount, or check may get blocked and result
in a "Device or resource busy" error. This is because the device
scan process opens the device with the EXCL flag in the kernel.

Two reports were received:

 - btrfs/179 test case, where the fsck command failed with the -EBUSY
   error

 - LTP pwritev03 test case, where mkfs.vfs failed with
   the -EBUSY error, when mkfs.vfs tried to overwrite old btrfs filesystem
   on the device.

In both cases, fsck and mkfs (respectively) were racing with a
systemd-udevd device scan, and systemd-udevd won, resulting in the
-EBUSY error for fsck and mkfs.

Reproducing the problem has been difficult because there is a very
small window during which these userspace threads can race to
acquire the exclusive device open. Even on the system where the problem
was observed, the problem occurrences were anywhere between 10 to 400
iterations and chances of reproducing decreases with debug printk()s.

However, an exclusive device open is unnecessary for the scan process,
as there are no write operations on the device during scan. Furthermore,
during the mount process, the superblock is re-read in the below
function call chain:

  btrfs_mount_root
   btrfs_open_devices
    open_fs_devices
     btrfs_open_one_device
       btrfs_get_bdev_and_sb

So, to fix this issue, removes the FMODE_EXCL flag from the scan
operation, and add a comment.

The case where mkfs may still write to the device and a scan is running,
the btrfs signature is not written at that time so scan will not
recognize such device.

Reported-by: Sherry Yang <sherry.yang@oracle.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202303170839.fdf23068-oliver.sang@intel.com
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-06 12:10:51 +02:00
..
tests for-6.1-rc4-tag 2022-11-10 08:58:29 -08:00
acl.c btrfs: reserve correct number of items for inode creation 2022-05-16 17:03:08 +02:00
async-thread.c btrfs: simplify WQ_HIGHPRI handling in struct btrfs_workqueue 2022-05-16 17:03:15 +02:00
async-thread.h btrfs: remove unused typedefs get_extent_t and btrfs_work_func_t 2022-07-25 17:45:36 +02:00
backref.c btrfs: fix resolving backrefs for inline extent followed by prealloc 2023-01-07 11:11:38 +01:00
backref.h btrfs: ignore fiemap path cache if we have multiple leaves for a data extent 2022-10-11 14:48:07 +02:00
block-group.c btrfs: use temporary variable for space_info in btrfs_update_block_group 2023-04-06 12:10:42 +02:00
block-group.h btrfs: move btrfs_full_stripe_locks_tree into block-group.h 2022-09-26 12:28:06 +02:00
block-rsv.c btrfs: add KCSAN annotations for unlocked access to block_rsv->full 2022-09-26 12:28:02 +02:00
block-rsv.h btrfs: add KCSAN annotations for unlocked access to block_rsv->full 2022-09-26 12:28:02 +02:00
btrfs_inode.h btrfs: use a runtime flag to indicate an inode is a free space inode 2022-09-26 12:28:07 +02:00
check-integrity.c fs/btrfs: Use the enum req_op and blk_opf_t types 2022-07-14 12:14:32 -06:00
check-integrity.h btrfs: check-integrity: split submit_bio from btrfsic checking 2022-05-16 17:03:12 +02:00
compression.c fs: fix leaked psi pressure state 2022-11-08 15:57:25 -08:00
compression.h for-5.20-tag 2022-08-03 14:54:52 -07:00
ctree.c btrfs: fix assertion failure and blocking during nowait buffered write 2022-11-15 15:01:01 +01:00
ctree.h btrfs: rename BTRFS_FS_NO_OVERCOMMIT to BTRFS_FS_ACTIVE_ZONE_TRACKING 2023-04-06 12:10:35 +02:00
delalloc-space.c btrfs: add the ability to use NO_FLUSH for data reservations 2022-09-29 17:08:28 +02:00
delalloc-space.h btrfs: add the ability to use NO_FLUSH for data reservations 2022-09-29 17:08:28 +02:00
delayed-inode.c btrfs: use delayed items when logging a directory 2022-09-26 12:27:57 +02:00
delayed-inode.h btrfs: use delayed items when logging a directory 2022-09-26 12:27:57 +02:00
delayed-ref.c btrfs: switch btrfs_block_rsv::full to bool 2022-07-25 17:45:40 +02:00
delayed-ref.h btrfs: remove btrfs_delayed_extent_op::is_data 2022-05-16 17:17:31 +02:00
dev-replace.c btrfs: don't take a bio_counter reference for cloned bios 2022-09-26 12:27:58 +02:00
dev-replace.h btrfs: add struct declarations in dev-replace.h 2022-09-26 12:28:07 +02:00
dir-item.c btrfs: use btrfs_for_each_slot in btrfs_search_dir_index_item 2022-05-16 17:03:07 +02:00
discard.c btrfs: hold block group refcount during async discard 2023-03-10 09:34:06 +01:00
discard.h
disk-io.c btrfs: do not abort transaction on failure to write log tree when syncing log 2023-01-24 07:24:36 +01:00
disk-io.h btrfs: fix compat_ro checks against remount 2023-01-12 12:01:56 +01:00
export.c btrfs: fix type of parameter generation in btrfs_get_dentry 2022-10-24 15:28:58 +02:00
export.h btrfs: fix type of parameter generation in btrfs_get_dentry 2022-10-24 15:28:58 +02:00
extent-io-tree.c btrfs: fix off-by-one in delalloc search during lseek 2023-01-12 12:01:56 +01:00
extent-io-tree.h btrfs: stop tracking failed reads in the I/O tree 2022-09-26 12:28:05 +02:00
extent-tree.c btrfs: always report error in run_one_delayed_ref() 2023-01-24 07:24:31 +01:00
extent_io.c btrfs: lock the inode in shared mode before starting fiemap 2023-02-22 12:59:40 +01:00
extent_io.h btrfs: move extent io tree unrelated prototypes to their appropriate header 2022-09-26 12:28:04 +02:00
extent_map.c btrfs: fix extent map logging bit not cleared for split maps after dropping range 2023-03-17 08:50:26 +01:00
extent_map.h btrfs: add helper to replace extent map range with a new extent map 2022-09-29 17:08:30 +02:00
file-item.c btrfs: make can_nocow_extent nowait compatible 2022-09-29 17:08:26 +02:00
file.c btrfs: move the auto defrag code to defrag.c 2023-02-22 12:59:40 +01:00
free-space-cache.c btrfs: zoned: count fresh BG region as zone unusable 2023-04-06 12:10:35 +02:00
free-space-cache.h btrfs: remove use btrfs_remove_free_space_cache instead of variant 2022-09-26 12:27:58 +02:00
free-space-tree.c btrfs: get rid of block group caching progress logic 2022-09-26 12:27:58 +02:00
free-space-tree.h
inode-item.c btrfs: make should_throttle loop local in btrfs_truncate_inode_items 2022-01-07 14:18:25 +01:00
inode-item.h btrfs: add inode to truncate control 2022-01-07 14:18:24 +01:00
inode.c for-6.1-rc3-tag 2022-11-03 11:12:48 -07:00
ioctl.c btrfs: fix race between quota disable and quota assign ioctls 2023-04-06 12:10:51 +02:00
Kconfig btrfs: use generic Kconfig option for 256kB page size limit 2022-01-20 08:52:55 +02:00
locking.c btrfs: implement a nowait option for tree searches 2022-09-26 12:46:42 +02:00
locking.h btrfs: implement a nowait option for tree searches 2022-09-26 12:46:42 +02:00
lzo.c btrfs: replace kmap() with kmap_local_page() in lzo.c 2022-07-25 17:45:33 +02:00
Makefile btrfs: move extent state init and alloc functions to their own file 2022-09-26 12:28:03 +02:00
misc.h btrfs: convert the io_failure_tree to a plain rb_tree 2022-09-26 12:28:02 +02:00
ordered-data.c btrfs: add btrfs_try_lock_ordered_range 2022-09-29 17:08:28 +02:00
ordered-data.h btrfs: add btrfs_try_lock_ordered_range 2022-09-29 17:08:28 +02:00
orphan.c
print-tree.c btrfs: unify the error handling pattern for read_tree_block() 2022-03-14 13:13:53 +01:00
print-tree.h
props.c btrfs: remove the unnecessary result variables 2022-09-26 12:28:00 +02:00
props.h btrfs: move common inode creation code into btrfs_create_new_inode() 2022-05-16 17:03:08 +02:00
qgroup.c btrfs: fix race between quota disable and quota assign ioctls 2023-04-06 12:10:51 +02:00
qgroup.h btrfs: introduce BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING to skip qgroup accounting 2022-09-26 12:28:01 +02:00
raid56.c btrfs: raid56: avoid double freeing for rbio if full_stripe_write() failed 2022-10-24 15:26:56 +02:00
raid56.h btrfs: properly abstract the parity raid bio handling 2022-09-26 12:27:59 +02:00
rcu-string.h btrfs: replace strncpy() with strscpy() 2023-01-12 12:01:55 +01:00
ref-verify.c btrfs: stop accessing ->extent_root directly 2022-01-03 15:09:49 +01:00
ref-verify.h
reflink.c btrfs: replace delete argument with EXTENT_CLEAR_ALL_BITS 2022-09-26 12:28:05 +02:00
reflink.h
relocation.c btrfs: add helper to replace extent map range with a new extent map 2022-09-29 17:08:30 +02:00
root-tree.c btrfs: simplify error handling at btrfs_del_root_ref() 2022-09-26 12:27:58 +02:00
scrub.c btrfs: scrub: improve tree block error reporting 2023-03-10 09:33:46 +01:00
send.c btrfs: send: limit number of clones and allocated memory size 2023-03-03 11:52:21 +01:00
send.h btrfs: send: allow protocol version 3 with CONFIG_BTRFS_DEBUG 2022-10-11 14:46:55 +02:00
space-info.c btrfs: rename BTRFS_FS_NO_OVERCOMMIT to BTRFS_FS_ACTIVE_ZONE_TRACKING 2023-04-06 12:10:35 +02:00
space-info.h btrfs: move btrfs_init_async_reclaim_work prototype to space-info.h 2022-09-26 12:28:06 +02:00
struct-funcs.c btrfs: remove redundant check in up check_setget_bounds 2022-07-25 17:45:33 +02:00
subpage.c btrfs: convert process_page_range() to use filemap_get_folios_contig() 2022-09-11 20:26:03 -07:00
subpage.h btrfs: make nodesize >= PAGE_SIZE case to reuse the non-subpage routine 2022-05-16 17:03:11 +02:00
super.c btrfs: fix compat_ro checks against remount 2023-01-12 12:01:56 +01:00
sysfs.c btrfs: sysfs: normalize the error handling branch in btrfs_init_sysfs() 2022-11-23 16:52:22 +01:00
sysfs.h
transaction.c btrfs: fix deadlock when aborting transaction during relocation with scrub 2023-04-06 12:10:51 +02:00
transaction.h btrfs: pass btrfs_fs_info for deleting snapshots and cleaner 2022-03-14 13:13:52 +01:00
tree-checker.c btrfs: tree-checker: check for overlapping extent items 2022-08-17 16:20:25 +02:00
tree-checker.h btrfs: tree-checker: check extent buffer owner against owner rootid 2022-05-16 17:03:09 +02:00
tree-defrag.c btrfs: move the auto defrag code to defrag.c 2023-02-22 12:59:40 +01:00
tree-log.c btrfs: simplify update of last_dir_index_offset when logging a directory 2023-02-14 19:11:52 +01:00
tree-log.h btrfs: simplify update of last_dir_index_offset when logging a directory 2023-02-14 19:11:52 +01:00
tree-mod-log.c
tree-mod-log.h
ulist.c
ulist.h
uuid-tree.c
verity.c btrfs: send: add support for fs-verity 2022-09-26 12:27:55 +02:00
volumes.c btrfs: scan device in non-exclusive mode 2023-04-06 12:10:51 +02:00
volumes.h btrfs: zoned: initialize device's zone info for seeding 2022-11-07 14:35:24 +01:00
xattr.c btrfs: check if root is readonly while setting security xattr 2022-08-22 18:06:30 +02:00
xattr.h
zlib.c btrfs: zlib: zero-initialize zlib workspace 2023-02-14 19:11:40 +01:00
zoned.c btrfs: zoned: count fresh BG region as zone unusable 2023-04-06 12:10:35 +02:00
zoned.h btrfs: zoned: clone zoned device info when cloning a device 2022-11-07 14:35:21 +01:00
zstd.c btrfs: zstd: replace kmap() with kmap_local_page() 2022-07-25 17:45:40 +02:00