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50d281fc43
linux/fs/btrfs
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Anand Jain 50d281fc43 btrfs: scan device in non-exclusive mode 
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>
2023-03-28 00:46:56 +02:00
..
tests btrfs: remove the bdev argument to btrfs_rmap_block 2023-02-15 19:38:55 +01:00
accessors.c btrfs: add eb to btrfs_node_key_ptr_offset 2022-12-05 18:00:58 +01:00
accessors.h btrfs: add stack helpers for a few btrfs items 2022-12-05 18:00:58 +01:00
acl.c for-6.2-tag 2022-12-12 20:47:51 -08:00
acl.h for-6.2-tag 2022-12-12 20:47:51 -08:00
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: skip backref walking during fiemap if we know the leaf is shared 2023-02-15 19:38:50 +01:00
backref.h btrfs: send: skip resolution of our own backref when finding clone source 2022-12-05 18:00:50 +01:00
bio.c btrfs: fix unnecessary increment of read error stat on write error 2023-03-06 19:28:19 +01:00
bio.h btrfs: remove the fs_info argument to btrfs_submit_bio 2023-02-15 19:38:53 +01:00
block-group.c btrfs: zoned: drop space_info->active_total_bytes 2023-03-15 20:51:07 +01:00
block-group.h btrfs: remove the bdev argument to btrfs_rmap_block 2023-02-15 19:38:55 +01:00
block-rsv.c btrfs: simplify percent calculation helpers, rename div_factor 2022-12-05 18:00:48 +01:00
block-rsv.h btrfs: simplify percent calculation helpers, rename div_factor 2022-12-05 18:00:48 +01:00
btrfs_inode.h btrfs: remove now spurious bio submission helpers 2023-02-15 19:38:53 +01:00
check-integrity.c btrfs: use btrfs_dev_name() helper to handle missing devices better 2022-12-05 18:00:57 +01:00
check-integrity.h btrfs: check-integrity: split submit_bio from btrfsic checking 2022-05-16 17:03:12 +02:00
compression.c btrfs: split zone append bios in btrfs_submit_bio 2023-02-15 19:38:53 +01:00
compression.h btrfs: split zone append bios in btrfs_submit_bio 2023-02-15 19:38:53 +01:00
ctree.c btrfs: do unsigned integer division in the extent buffer binary search loop 2023-02-15 19:38:55 +01:00
ctree.h btrfs: do unsigned integer division in the extent buffer binary search loop 2023-02-15 19:38:55 +01:00
defrag.c btrfs: remove the wait argument to btrfs_start_ordered_extent 2023-02-13 17:50:34 +01:00
defrag.h btrfs: move defrag related prototypes to their own header 2022-12-05 18:00:46 +01:00
delalloc-space.c btrfs: update function comments 2022-12-05 18:00:45 +01:00
delalloc-space.h btrfs: move delalloc space related prototypes to delalloc-space.h 2022-12-05 18:00:44 +01:00
delayed-inode.c btrfs: handle btrfs_del_item errors in __btrfs_update_delayed_inode 2023-03-06 19:28:19 +01:00
delayed-inode.h btrfs: extend btrfs_dir_item type to store encryption status 2022-12-05 18:00:43 +01:00
delayed-ref.c btrfs: directly pass in fs_info to btrfs_merge_delayed_refs 2023-02-13 17:50:33 +01:00
delayed-ref.h btrfs: directly pass in fs_info to btrfs_merge_delayed_refs 2023-02-13 17:50:33 +01:00
dev-replace.c btrfs: use btrfs_dev_name() helper to handle missing devices better 2022-12-05 18:00:57 +01:00
dev-replace.h btrfs: move dev-replace prototypes into dev-replace.h 2022-12-05 18:00:47 +01:00
dir-item.c btrfs: move dir-item prototypes into dir-item.h 2022-12-05 18:00:46 +01:00
dir-item.h btrfs: move dir-item prototypes into dir-item.h 2022-12-05 18:00:46 +01:00
discard.c btrfs: hold block group refcount during async discard 2023-02-15 19:38:50 +01:00
discard.h btrfs: cleanup btrfs_discard_update_discardable usage 2020-12-08 15:54:02 +01:00
disk-io.c btrfs: combine btrfs_clear_buffer_dirty and clear_extent_buffer_dirty 2023-02-15 19:38:54 +01:00
disk-io.h btrfs: rename btrfs_clean_tree_block to btrfs_clear_buffer_dirty 2023-02-15 19:38:53 +01:00
export.c btrfs: move super_block specific helpers into super.h 2022-12-05 18:00:47 +01:00
export.h btrfs: simplify generation check in btrfs_get_dentry 2022-12-05 18:00:41 +01:00
extent_io.c btrfs: pass a btrfs_bio to btrfs_use_append 2023-02-15 19:38:55 +01:00
extent_io.h btrfs: combine btrfs_clear_buffer_dirty and clear_extent_buffer_dirty 2023-02-15 19:38:54 +01:00
extent_map.c btrfs: fix extent map logging bit not cleared for split maps after dropping range 2023-03-06 19:28:19 +01:00
extent_map.h btrfs: remove no longer used btrfs_next_extent_map() 2022-12-05 18:00:56 +01:00
extent-io-tree.c btrfs: fix spelling mistakes found using codespell 2023-02-15 19:38:50 +01:00
extent-io-tree.h btrfs: remove the io_failure_record infrastructure 2023-02-15 19:38:51 +01:00
extent-tree.c btrfs: rename btrfs_clean_tree_block to btrfs_clear_buffer_dirty 2023-02-15 19:38:53 +01:00
extent-tree.h btrfs: introduce size class to block group allocator 2023-02-13 17:50:34 +01:00
file-item.c btrfs: simplify the btrfs_csum_one_bio calling convention 2023-02-15 19:38:52 +01:00
file-item.h btrfs: simplify the btrfs_csum_one_bio calling convention 2023-02-15 19:38:52 +01:00
file.c btrfs: remove the wait argument to btrfs_start_ordered_extent 2023-02-13 17:50:34 +01:00
file.h btrfs: use cached state when looking for delalloc ranges with fiemap 2022-12-05 18:00:56 +01:00
free-space-cache.c btrfs: zoned: count fresh BG region as zone unusable 2023-03-15 20:51:07 +01:00
free-space-cache.h btrfs: convert discard stat defs to enum 2022-12-05 18:00:45 +01:00
free-space-tree.c btrfs: rename btrfs_clean_tree_block to btrfs_clear_buffer_dirty 2023-02-15 19:38:53 +01:00
free-space-tree.h
fs.c btrfs: sysfs: update fs features directory asynchronously 2023-02-13 17:50:35 +01:00
fs.h btrfs: rename BTRFS_FS_NO_OVERCOMMIT to BTRFS_FS_ACTIVE_ZONE_TRACKING 2023-03-15 20:51:06 +01:00
inode-item.c btrfs: move file-item prototypes into their own header 2022-12-05 18:00:46 +01:00
inode-item.h btrfs: use struct fscrypt_str instead of struct qstr 2022-12-05 18:00:43 +01:00
inode.c btrfs: fix compiler warning on SPARC/PA-RISC handling fscrypt_setup_filename 2023-03-15 20:51:06 +01:00
ioctl.c btrfs: fix race between quota disable and quota assign ioctls 2023-03-28 00:46:53 +02:00
ioctl.h btrfs: move ioctl prototypes into ioctl.h 2022-12-05 18:00:46 +01:00
Kconfig btrfs: use generic Kconfig option for 256kB page size limit 2022-01-20 08:52:55 +02:00
locking.c btrfs: move accessor helpers into accessors.h 2022-12-05 18:00:42 +01:00
locking.h btrfs: move the lockdep helpers into locking.h 2022-12-05 18:00:44 +01:00
lru_cache.c btrfs: send: cache utimes operations for directories if possible 2023-02-15 19:38:50 +01:00
lru_cache.h btrfs: send: cache utimes operations for directories if possible 2023-02-15 19:38:50 +01:00
lzo.c btrfs: use PAGE_{ALIGN, ALIGNED, ALIGN_DOWN} macro 2023-02-13 17:50:34 +01:00
Makefile btrfs: send: genericize the backref cache to allow it to be reused 2023-02-13 17:50:35 +01:00
messages.c btrfs: move btrfs_abort_transaction to transaction.c 2023-02-13 17:50:33 +01:00
messages.h btrfs: move btrfs_abort_transaction to transaction.c 2023-02-13 17:50:33 +01:00
misc.h btrfs: simplify percent calculation helpers, rename div_factor 2022-12-05 18:00:48 +01:00
ordered-data.c btrfs: remove the wait argument to btrfs_start_ordered_extent 2023-02-13 17:50:34 +01:00
ordered-data.h btrfs: don't rely on unchanging ->bi_bdev for zone append remaps 2023-02-15 19:38:55 +01:00
orphan.c btrfs: move orphan prototypes into orphan.h 2022-12-05 18:00:47 +01:00
orphan.h btrfs: move orphan prototypes into orphan.h 2022-12-05 18:00:47 +01:00
print-tree.c btrfs: move struct btrfs_tree_parent_check out of disk-io.h 2022-12-05 18:00:57 +01:00
print-tree.h btrfs: print the actual offset in btrfs_root_name 2021-01-07 17:25:05 +01:00
props.c btrfs: move super_block specific helpers into super.h 2022-12-05 18:00:47 +01:00
props.h btrfs: make module init/exit match their sequence 2022-12-05 18:00:40 +01:00
qgroup.c btrfs: fix race between quota disable and quota assign ioctls 2023-03-28 00:46:53 +02:00
qgroup.h btrfs: sink gfp_t parameter to btrfs_qgroup_trace_extent 2022-12-05 18:00:43 +01:00
raid56.c btrfs: raid56: handle endio in scrub_rbio 2023-02-15 19:38:55 +01:00
raid56.h btrfs: fix spelling mistakes found using codespell 2023-02-15 19:38:50 +01:00
rcu-string.h btrfs: replace strncpy() with strscpy() 2022-12-05 18:00:59 +01:00
ref-verify.c btrfs: move accessor helpers into accessors.h 2022-12-05 18:00:42 +01:00
ref-verify.h
reflink.c btrfs: pass btrfs_inode to btrfs_inode_unlock 2022-12-05 18:00:53 +01:00
reflink.h
relocation.c btrfs: use PAGE_{ALIGN, ALIGNED, ALIGN_DOWN} macro 2023-02-13 17:50:34 +01:00
relocation.h btrfs: move relocation prototypes into relocation.h 2022-12-05 18:00:47 +01:00
root-tree.c btrfs: move orphan prototypes into orphan.h 2022-12-05 18:00:47 +01:00
root-tree.h btrfs: move root tree prototypes to their own header 2022-12-05 18:00:44 +01:00
scrub.c btrfs: fix spelling mistakes found using codespell 2023-02-15 19:38:50 +01:00
scrub.h btrfs: move scrub prototypes into scrub.h 2022-12-05 18:00:47 +01:00
send.c btrfs: send: cache utimes operations for directories if possible 2023-02-15 19:38:50 +01:00
send.h btrfs: send add define for v2 buffer size 2022-12-05 18:00:41 +01:00
space-info.c btrfs: zoned: drop space_info->active_total_bytes 2023-03-15 20:51:07 +01:00
space-info.h btrfs: zoned: drop space_info->active_total_bytes 2023-03-15 20:51:07 +01:00
subpage.c btrfs: move the printk helpers out of ctree.h 2022-12-05 18:00:41 +01:00
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 spelling mistakes found using codespell 2023-02-15 19:38:50 +01:00
super.h btrfs: move super_block specific helpers into super.h 2022-12-05 18:00:47 +01:00
sysfs.c btrfs: sysfs: add size class stats 2023-03-01 19:27:20 +01:00
sysfs.h btrfs: sysfs: update fs features directory asynchronously 2023-02-13 17:50:35 +01:00
transaction.c btrfs: sysfs: update fs features directory asynchronously 2023-02-13 17:50:35 +01:00
transaction.h btrfs: move btrfs_abort_transaction to transaction.c 2023-02-13 17:50:33 +01:00
tree-checker.c btrfs: pass the extent buffer for the btrfs_item_nr helpers 2022-12-05 18:00:58 +01:00
tree-checker.h btrfs: move struct btrfs_tree_parent_check out of disk-io.h 2022-12-05 18:00:57 +01:00
tree-log.c btrfs: replace btrfs_wait_tree_block_writeback by wait_on_extent_buffer_writeback 2023-02-15 19:38:54 +01:00
tree-log.h btrfs: use a negative value for BTRFS_LOG_FORCE_COMMIT 2023-02-13 17:50:34 +01:00
tree-mod-log.c btrfs: add eb to btrfs_node_key_ptr_offset 2022-12-05 18:00:58 +01:00
tree-mod-log.h btrfs: fix SPDX comment in tree-mod-log.h 2022-12-05 18:00:48 +01:00
ulist.c btrfs: constify ulist parameter of ulist_next() 2022-12-05 18:00:50 +01:00
ulist.h btrfs: constify ulist parameter of ulist_next() 2022-12-05 18:00:50 +01:00
uuid-tree.c btrfs: move uuid tree prototypes to uuid-tree.h 2022-12-05 18:00:46 +01:00
uuid-tree.h btrfs: move uuid tree prototypes to uuid-tree.h 2022-12-05 18:00:46 +01:00
verity.c btrfs: move orphan prototypes into orphan.h 2022-12-05 18:00:47 +01:00
verity.h btrfs: move verity prototypes into verity.h 2022-12-05 18:00:47 +01:00
volumes.c btrfs: scan device in non-exclusive mode 2023-03-28 00:46:56 +02:00
volumes.h btrfs: remove struct btrfs_io_geometry 2023-02-15 19:38:52 +01:00
xattr.c btrfs: move dir-item prototypes into dir-item.h 2022-12-05 18:00:46 +01:00
xattr.h
zlib.c btrfs: zlib: zero-initialize zlib workspace 2023-01-25 20:11:08 +01:00
zoned.c btrfs: zoned: drop space_info->active_total_bytes 2023-03-15 20:51:07 +01:00
zoned.h btrfs: pass a btrfs_bio to btrfs_use_append 2023-02-15 19:38:55 +01:00
zstd.c btrfs: constify input buffer parameter in compression code 2022-12-05 18:00:55 +01:00