btrfs: return a literal instead of a variable in btrfs_init_dev_replace()

This is just a small clean up, it doesn't change how the code works.
Originally this code had a goto so we needed to set "re

btrfs: return a literal instead of a variable in btrfs_init_dev_replace()

This is just a small clean up, it doesn't change how the code works.
Originally this code had a goto so we needed to set "ret = 0;" but now
it returns directly and so we can simplify it a bit by doing a
"return 0;" and removing the assignment.

Reviewed-by: Anand Jain <[email protected]>
Signed-off-by: Dan Carpenter <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: use BTRFS_PATH_AUTO_FREE in btrfs_run_dev_replace()

This is the trivial pattern for path auto free, initialize at the
beginning and free at the end with simple goto -> return conversions.

Re

btrfs: use BTRFS_PATH_AUTO_FREE in btrfs_run_dev_replace()

This is the trivial pattern for path auto free, initialize at the
beginning and free at the end with simple goto -> return conversions.

Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: use BTRFS_PATH_AUTO_FREE in btrfs_init_dev_replace()

This is the trivial pattern for path auto free, initialize at the
beginning and free at the end with simple goto -> return conversions.

R

btrfs: use BTRFS_PATH_AUTO_FREE in btrfs_init_dev_replace()

This is the trivial pattern for path auto free, initialize at the
beginning and free at the end with simple goto -> return conversions.

Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: dev-replace: remove unnecessary call to btrfs_mark_buffer_dirty()

The call to btrfs_mark_buffer_dirty() at btrfs_run_dev_replace() is not
necessary as we have a path setup for writing with bt

btrfs: dev-replace: remove unnecessary call to btrfs_mark_buffer_dirty()

The call to btrfs_mark_buffer_dirty() at btrfs_run_dev_replace() is not
necessary as we have a path setup for writing with btrfs_search_slot()
having a 'cow' argument set to 1.

This just makes the code more verbose, confusing and add a little extra
overhead and well as increase the module's text size, so remove it.

Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Filipe Manana <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: correct typos in multiple comments across various files

Fix some confusing spelling errors that were currently identified,
the details are as follows:

block-group.c: 2800: uncompressible

btrfs: correct typos in multiple comments across various files

Fix some confusing spelling errors that were currently identified,
the details are as follows:

block-group.c: 2800: uncompressible ==> incompressible
extent-tree.c: 3131: EXTEMT ==> EXTENT
extent_io.c: 3124: utlizing ==> utilizing
extent_map.c: 1323: ealier ==> earlier
extent_map.c: 1325: possiblity ==> possibility
fiemap.c: 189: emmitted ==> emitted
fiemap.c: 197: emmitted ==> emitted
fiemap.c: 203: emmitted ==> emitted
transaction.h: 36: trasaction ==> transaction
volumes.c: 5312: filesysmte ==> filesystem
zoned.c: 1977: trasnsaction ==> transaction

Signed-off-by: Shen Lichuan <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: don't take dev_replace rwsem on task already holding it

Running fstests btrfs/011 with MKFS_OPTIONS="-O rst" to force the usage of
the RAID stripe-tree, we get the following splat from lockde

btrfs: don't take dev_replace rwsem on task already holding it

Running fstests btrfs/011 with MKFS_OPTIONS="-O rst" to force the usage of
the RAID stripe-tree, we get the following splat from lockdep:

BTRFS info (device sdd): dev_replace from /dev/sdd (devid 1) to /dev/sdb started

============================================
WARNING: possible recursive locking detected
6.11.0-rc3-btrfs-for-next #599 Not tainted
--------------------------------------------
btrfs/2326 is trying to acquire lock:
ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250

but task is already holding lock:
ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(&fs_info->dev_replace.rwsem);
lock(&fs_info->dev_replace.rwsem);

*** DEADLOCK ***

May be due to missing lock nesting notation

1 lock held by btrfs/2326:
#0: ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250

stack backtrace:
CPU: 1 UID: 0 PID: 2326 Comm: btrfs Not tainted 6.11.0-rc3-btrfs-for-next #599
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Call Trace:
<TASK>
dump_stack_lvl+0x5b/0x80
__lock_acquire+0x2798/0x69d0
? __pfx___lock_acquire+0x10/0x10
? __pfx___lock_acquire+0x10/0x10
lock_acquire+0x19d/0x4a0
? btrfs_map_block+0x39f/0x2250
? __pfx_lock_acquire+0x10/0x10
? find_held_lock+0x2d/0x110
? lock_is_held_type+0x8f/0x100
down_read+0x8e/0x440
? btrfs_map_block+0x39f/0x2250
? __pfx_down_read+0x10/0x10
? do_raw_read_unlock+0x44/0x70
? _raw_read_unlock+0x23/0x40
btrfs_map_block+0x39f/0x2250
? btrfs_dev_replace_by_ioctl+0xd69/0x1d00
? btrfs_bio_counter_inc_blocked+0xd9/0x2e0
? __kasan_slab_alloc+0x6e/0x70
? __pfx_btrfs_map_block+0x10/0x10
? __pfx_btrfs_bio_counter_inc_blocked+0x10/0x10
? kmem_cache_alloc_noprof+0x1f2/0x300
? mempool_alloc_noprof+0xed/0x2b0
btrfs_submit_chunk+0x28d/0x17e0
? __pfx_btrfs_submit_chunk+0x10/0x10
? bvec_alloc+0xd7/0x1b0
? bio_add_folio+0x171/0x270
? __pfx_bio_add_folio+0x10/0x10
? __kasan_check_read+0x20/0x20
btrfs_submit_bio+0x37/0x80
read_extent_buffer_pages+0x3df/0x6c0
btrfs_read_extent_buffer+0x13e/0x5f0
read_tree_block+0x81/0xe0
read_block_for_search+0x4bd/0x7a0
? __pfx_read_block_for_search+0x10/0x10
btrfs_search_slot+0x78d/0x2720
? __pfx_btrfs_search_slot+0x10/0x10
? lock_is_held_type+0x8f/0x100
? kasan_save_track+0x14/0x30
? __kasan_slab_alloc+0x6e/0x70
? kmem_cache_alloc_noprof+0x1f2/0x300
btrfs_get_raid_extent_offset+0x181/0x820
? __pfx_lock_acquire+0x10/0x10
? __pfx_btrfs_get_raid_extent_offset+0x10/0x10
? down_read+0x194/0x440
? __pfx_down_read+0x10/0x10
? do_raw_read_unlock+0x44/0x70
? _raw_read_unlock+0x23/0x40
btrfs_map_block+0x5b5/0x2250
? __pfx_btrfs_map_block+0x10/0x10
scrub_submit_initial_read+0x8fe/0x11b0
? __pfx_scrub_submit_initial_read+0x10/0x10
submit_initial_group_read+0x161/0x3a0
? lock_release+0x20e/0x710
? __pfx_submit_initial_group_read+0x10/0x10
? __pfx_lock_release+0x10/0x10
scrub_simple_mirror.isra.0+0x3eb/0x580
scrub_stripe+0xe4d/0x1440
? lock_release+0x20e/0x710
? __pfx_scrub_stripe+0x10/0x10
? __pfx_lock_release+0x10/0x10
? do_raw_read_unlock+0x44/0x70
? _raw_read_unlock+0x23/0x40
scrub_chunk+0x257/0x4a0
scrub_enumerate_chunks+0x64c/0xf70
? __mutex_unlock_slowpath+0x147/0x5f0
? __pfx_scrub_enumerate_chunks+0x10/0x10
? bit_wait_timeout+0xb0/0x170
? __up_read+0x189/0x700
? scrub_workers_get+0x231/0x300
? up_write+0x490/0x4f0
btrfs_scrub_dev+0x52e/0xcd0
? create_pending_snapshots+0x230/0x250
? __pfx_btrfs_scrub_dev+0x10/0x10
btrfs_dev_replace_by_ioctl+0xd69/0x1d00
? lock_acquire+0x19d/0x4a0
? __pfx_btrfs_dev_replace_by_ioctl+0x10/0x10
? lock_release+0x20e/0x710
? btrfs_ioctl+0xa09/0x74f0
? __pfx_lock_release+0x10/0x10
? do_raw_spin_lock+0x11e/0x240
? __pfx_do_raw_spin_lock+0x10/0x10
btrfs_ioctl+0xa14/0x74f0
? lock_acquire+0x19d/0x4a0
? find_held_lock+0x2d/0x110
? __pfx_btrfs_ioctl+0x10/0x10
? lock_release+0x20e/0x710
? do_sigaction+0x3f0/0x860
? __pfx_do_vfs_ioctl+0x10/0x10
? do_raw_spin_lock+0x11e/0x240
? lockdep_hardirqs_on_prepare+0x270/0x3e0
? _raw_spin_unlock_irq+0x28/0x50
? do_sigaction+0x3f0/0x860
? __pfx_do_sigaction+0x10/0x10
? __x64_sys_rt_sigaction+0x18e/0x1e0
? __pfx___x64_sys_rt_sigaction+0x10/0x10
? __x64_sys_close+0x7c/0xd0
__x64_sys_ioctl+0x137/0x190
do_syscall_64+0x71/0x140
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f0bd1114f9b
Code: Unable to access opcode bytes at 0x7f0bd1114f71.
RSP: 002b:00007ffc8a8c3130 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f0bd1114f9b
RDX: 00007ffc8a8c35e0 RSI: 00000000ca289435 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000007
R10: 0000000000000008 R11: 0000000000000246 R12: 00007ffc8a8c6c85
R13: 00000000398e72a0 R14: 0000000000004361 R15: 0000000000000004
</TASK>

This happens because on RAID stripe-tree filesystems we recurse back into
btrfs_map_block() on scrub to perform the logical to device physical
mapping.

But as the device replace task is already holding the dev_replace::rwsem
we deadlock.

So don't take the dev_replace::rwsem in case our task is the task performing
the device replace.

Suggested-by: Filipe Manana <[email protected]>
Signed-off-by: Johannes Thumshirn <[email protected]>
Reviewed-by: Filipe Manana <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: more efficient chunk map iteration when device replace finishes

When iterating the chunk maps when a device replace finishes we are doing
a full rbtree search for each chunk map, which is not

btrfs: more efficient chunk map iteration when device replace finishes

When iterating the chunk maps when a device replace finishes we are doing
a full rbtree search for each chunk map, which is not the most efficient
thing to do, wasting CPU time. As we are holding a write lock on the tree
during the whole iteration, we can simply start from the first node in the
tree and then move to the next chunk map by doing a rb_next() call - the
only exception is when we need to reschedule, in which case we have to do
a full rbtree search since we dropped the write lock and the tree may have
changed (chunk maps may have been removed and the tree got rebalanced).
So just do that.

Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: reschedule when updating chunk maps at the end of a device replace

At the end of a device replace we must go over all the chunk maps and
update their stripes to point to the target device ins

btrfs: reschedule when updating chunk maps at the end of a device replace

At the end of a device replace we must go over all the chunk maps and
update their stripes to point to the target device instead of the source
device. We iterate over the chunk maps while holding a write lock and
we never reschedule, which can result in monopolizing a CPU for too long
and blocking readers for too long (it's a rw lock, non-blocking).

So improve on this by rescheduling if necessary. This is safe because at
this point we are holding the chunk mutex, which means no new chunks can
be allocated and therefore we don't risk missing a new chunk map that
covers a range behind the last one we processed before rescheduling.

Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: simplify range parameters of btrfs_wait_ordered_roots()

The range is specified only in two ways, we can simplify the case for
the whole filesystem range as a NULL block group parameter.

Sign

btrfs: simplify range parameters of btrfs_wait_ordered_roots()

The range is specified only in two ways, we can simplify the case for
the whole filesystem range as a NULL block group parameter.

Signed-off-by: David Sterba <[email protected]>

show more ...

set_blocksize(): switch to passing struct file *

Signed-off-by: Al Viro <[email protected]>

btrfs: pass btrfs_device to btrfs_scratch_superblocks()

Replace the two parameters bdev and name by one that can be used to get
them both.

Reviewed-by: Josef Bacik <[email protected]>
Reviewed-b

btrfs: pass btrfs_device to btrfs_scratch_superblocks()

Replace the two parameters bdev and name by one that can be used to get
them both.

Reviewed-by: Josef Bacik <[email protected]>
Reviewed-by: Qu Wenruo <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: remove unused included headers

With help of neovim, LSP and clangd we can identify header files that
are not actually needed to be included in the .c files. This is focused
only on removal (w

btrfs: remove unused included headers

With help of neovim, LSP and clangd we can identify header files that
are not actually needed to be included in the .c files. This is focused
only on removal (with minor fixups), further cleanups are possible but
will require doing the header files properly with forward declarations,
minimized includes and include-what-you-use care.

Reviewed-by: Josef Bacik <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: port device access to file

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Christian Brauner <brauner@

btrfs: port device access to file

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

show more ...

btrfs: dev-replace: properly validate device names

There's a syzbot report that device name buffers passed to device
replace are not properly checked for string termination which could lead
to a rea

btrfs: dev-replace: properly validate device names

There's a syzbot report that device name buffers passed to device
replace are not properly checked for string termination which could lead
to a read out of bounds in getname_kernel().

Add a helper that validates both source and target device name buffers.
For devid as the source initialize the buffer to empty string in case
something tries to read it later.

This was originally analyzed and fixed in a different way by Edward Adam
Davis (see links).

Link: https://lore.kernel.org/linux-btrfs/[email protected]/
Link: https://lore.kernel.org/linux-btrfs/[email protected]/
CC: [email protected] # 4.19+
CC: Edward Adam Davis <[email protected]>
Reported-and-tested-by: [email protected]
Reviewed-by: Boris Burkov <[email protected]>
Signed-off-by: David Sterba <[email protected]>

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btrfs: use a dedicated data structure for chunk maps

Currently we abuse the extent_map structure for two purposes:

1) To actually represent extents for inodes;
2) To represent chunk mappings.

This

btrfs: use a dedicated data structure for chunk maps

Currently we abuse the extent_map structure for two purposes:

1) To actually represent extents for inodes;
2) To represent chunk mappings.

This is odd and has several disadvantages:

1) To create a chunk map, we need to do two memory allocations: one for
an extent_map structure and another one for a map_lookup structure, so
more potential for an allocation failure and more complicated code to
manage and link two structures;

2) For a chunk map we actually only use 3 fields (24 bytes) of the
respective extent map structure: the 'start' field to have the logical
start address of the chunk, the 'len' field to have the chunk's size,
and the 'orig_block_len' field to contain the chunk's stripe size.

Besides wasting a memory, it's also odd and not intuitive at all to
have the stripe size in a field named 'orig_block_len'.

We are also using 'block_len' of the extent_map structure to contain
the chunk size, so we have 2 fields for the same value, 'len' and
'block_len', which is pointless;

3) When an extent map is associated to a chunk mapping, we set the bit
EXTENT_FLAG_FS_MAPPING on its flags and then make its member named
'map_lookup' point to the associated map_lookup structure. This means
that for an extent map associated to an inode extent, we are not using
this 'map_lookup' pointer, so wasting 8 bytes (on a 64 bits platform);

4) Extent maps associated to a chunk mapping are never merged or split so
it's pointless to use the existing extent map infrastructure.

So add a dedicated data structure named 'btrfs_chunk_map' to represent
chunk mappings, this is basically the existing map_lookup structure with
some extra fields:

1) 'start' to contain the chunk logical address;
2) 'chunk_len' to contain the chunk's length;
3) 'stripe_size' for the stripe size;
4) 'rb_node' for insertion into a rb tree;
5) 'refs' for reference counting.

This way we do a single memory allocation for chunk mappings and we don't
waste memory for them with unused/unnecessary fields from an extent_map.

We also save 8 bytes from the extent_map structure by removing the
'map_lookup' pointer, so the size of struct extent_map is reduced from
144 bytes down to 136 bytes, and we can now have 30 extents map per 4K
page instead of 28.

Reviewed-by: Josef Bacik <[email protected]>
Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: Convert to bdev_open_by_path()

Convert btrfs to use bdev_open_by_path() and pass the handle around. We
also drop the holder from struct btrfs_device as it is now not needed
anymore.

CC: Dav

btrfs: Convert to bdev_open_by_path()

Convert btrfs to use bdev_open_by_path() and pass the handle around. We
also drop the holder from struct btrfs_device as it is now not needed
anymore.

CC: David Sterba <[email protected]>
CC: [email protected]
Acked-by: Christoph Hellwig <[email protected]>
Reviewed-by: Christian Brauner <[email protected]>
Signed-off-by: Jan Kara <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Christian Brauner <[email protected]>

show more ...

btrfs: abort transaction on generation mismatch when marking eb as dirty

When marking an extent buffer as dirty, at btrfs_mark_buffer_dirty(),
we check if its generation matches the running transact

btrfs: abort transaction on generation mismatch when marking eb as dirty

When marking an extent buffer as dirty, at btrfs_mark_buffer_dirty(),
we check if its generation matches the running transaction and if not we
just print a warning. Such mismatch is an indicator that something really
went wrong and only printing a warning message (and stack trace) is not
enough to prevent a corruption. Allowing a transaction to commit with such
an extent buffer will trigger an error if we ever try to read it from disk
due to a generation mismatch with its parent generation.

So abort the current transaction with -EUCLEAN if we notice a generation
mismatch. For this we need to pass a transaction handle to
btrfs_mark_buffer_dirty() which is always available except in test code,
in which case we can pass NULL since it operates on dummy extent buffers
and all test roots have a single node/leaf (root node at level 0).

Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: check-integrity: remove btrfsic_unmount() function

The function btrfsic_mount() is part of the deprecated check-integrity
functionality.

Now let's remove the main entry point of check-integr

btrfs: check-integrity: remove btrfsic_unmount() function

The function btrfsic_mount() is part of the deprecated check-integrity
functionality.

Now let's remove the main entry point of check-integrity, and thankfully
most of the check-integrity code is self-contained inside
check-integrity.c, we can safely remove the function without huge
changes to btrfs code base.

Signed-off-by: Qu Wenruo <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: make find_first_extent_bit() return a boolean

Currently find_first_extent_bit() returns a 0 if it found a range in the
given io tree and 1 if it didn't find any. There's no need to return any

btrfs: make find_first_extent_bit() return a boolean

Currently find_first_extent_bit() returns a 0 if it found a range in the
given io tree and 1 if it didn't find any. There's no need to return any
errors, so make the return value a boolean and invert the logic to make
more sense: return true if it found a range and false if it didn't find
any range.

Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: rename __btrfs_map_block to btrfs_map_block

Now that the old btrfs_map_block is gone, drop the leading underscores
from __btrfs_map_block.

Reviewed-by: Qu Wenruo <[email protected]>
Reviewed-by:

btrfs: rename __btrfs_map_block to btrfs_map_block

Now that the old btrfs_map_block is gone, drop the leading underscores
from __btrfs_map_block.

Reviewed-by: Qu Wenruo <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: drop gfp from parameter extent state helpers

Now that all extent state bit helpers effectively take the GFP_NOFS mask
(and GFP_NOWAIT is encoded in the bits) we can remove the parameter.
This

btrfs: drop gfp from parameter extent state helpers

Now that all extent state bit helpers effectively take the GFP_NOFS mask
(and GFP_NOWAIT is encoded in the bits) we can remove the parameter.
This reduces stack consumption in many functions and simplifies a lot of
code.

Net effect on module on a release build:

text data bss dec hex filename
1250432 20985 16088 1287505 13a551 pre/btrfs.ko
1247074 20985 16088 1284147 139833 post/btrfs.ko

DELTA: -3358

Signed-off-by: David Sterba <[email protected]>

show more ...

btrfs: open code set_extent_bits

This helper calls set_extent_bit with two more parameters set to default
values, but otherwise it's purpose is not clear.

Reviewed-by: Christoph Hellwig <[email protected]

btrfs: open code set_extent_bits

This helper calls set_extent_bit with two more parameters set to default
values, but otherwise it's purpose is not clear.

Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Qu Wenruo <[email protected]>
Signed-off-by: David Sterba <[email protected]>

show more ...

block: replace fmode_t with a block-specific type for block open flags

The only overlap between the block open flags mapped into the fmode_t and
other uses of fmode_t are FMODE_READ and FMODE_WRITE.

block: replace fmode_t with a block-specific type for block open flags

The only overlap between the block open flags mapped into the fmode_t and
other uses of fmode_t are FMODE_READ and FMODE_WRITE. Define a new
blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and
->ioctl and stop abusing fmode_t.

Signed-off-by: Christoph Hellwig <[email protected]>
Acked-by: Jack Wang <[email protected]> [rnbd]
Reviewed-by: Hannes Reinecke <[email protected]>
Reviewed-by: Christian Brauner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

show more ...

block: use the holder as indication for exclusive opens

The current interface for exclusive opens is rather confusing as it
requires both the FMODE_EXCL flag and a holder. Remove the need to pass
F

block: use the holder as indication for exclusive opens

The current interface for exclusive opens is rather confusing as it
requires both the FMODE_EXCL flag and a holder. Remove the need to pass
FMODE_EXCL and just key off the exclusive open off a non-NULL holder.

For blkdev_put this requires adding the holder argument, which provides
better debug checking that only the holder actually releases the hold,
but at the same time allows removing the now superfluous mode argument.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Acked-by: David Sterba <[email protected]> [btrfs]
Acked-by: Jack Wang <[email protected]> [rnbd]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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block: introduce holder ops

Add a new blk_holder_ops structure, which is passed to blkdev_get_by_* and
installed in the block_device for exclusive claims. It will be used to
allow the block layer t

block: introduce holder ops

Add a new blk_holder_ops structure, which is passed to blkdev_get_by_* and
installed in the block_device for exclusive claims. It will be used to
allow the block layer to call back into the user of the block device for
thing like notification of a removed device or a device resize.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Acked-by: Dave Chinner <[email protected]>
Reviewed-by: Dave Chinner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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