Commit Graph

198 Commits

Author SHA1 Message Date
David Sterba
f590040ce2 btrfs: dev-replace: properly validate device names
commit 9845664b9ee47ce7ee7ea93caf47d39a9d4552c4 upstream.

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/000000000000d1a1d1060cc9c5e7@google.com/
Link: https://lore.kernel.org/linux-btrfs/tencent_44CA0665C9836EF9EEC80CB9E7E206DF5206@qq.com/
CC: stable@vger.kernel.org # 4.19+
CC: Edward Adam Davis <eadavis@qq.com>
Reported-and-tested-by: syzbot+33f23b49ac24f986c9e8@syzkaller.appspotmail.com
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-03-06 14:45:10 +00:00
Christoph Hellwig
2bbc72f14f btrfs: don't take a bio_counter reference for cloned bios
Stop grabbing an extra bio_counter reference for each clone bio in a
mirrored write and instead just release the one original reference in
btrfs_end_bioc once all the bios for a single btrfs_bio have completed
instead of at the end of btrfs_submit_bio once all bios have been
submitted.

This means the reference is now carried by the "upper" btrfs_bio only
instead of each lower bio.

Also remove the now unused btrfs_bio_counter_inc_noblocked helper.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-09-26 12:27:58 +02:00
Josef Bacik
9283b9e09a btrfs: remove lock protection for BLOCK_GROUP_FLAG_TO_COPY
We use this during device replace for zoned devices, we were simply
taking the lock because it was in a bit field and we needed the lock to
be safe with other modifications in the bitfield.  With the bit helpers
we no longer require that locking.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-09-26 12:27:54 +02:00
Josef Bacik
3349b57fd4 btrfs: convert block group bit field to use bit helpers
We use a bit field in the btrfs_block_group for different flags, however
this is awkward because we have to hold the block_group->lock for any
modification of any of these fields, and makes the code clunky for a few
of these flags.  Convert these to a properly flags setup so we can
utilize the bit helpers.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-09-26 12:27:54 +02:00
Anand Jain
f2c3bec215 btrfs: add info when mount fails due to stale replace target
If the replace target device reappears after the suspended replace is
cancelled, it blocks the mount operation as it can't find the matching
replace-item in the metadata. As shown below,

   BTRFS error (device sda5): replace devid present without an active replace item

To overcome this situation, the user can run the command

   btrfs device scan --forget <replace target device>

and try the mount command again. And also, to avoid repeating the issue,
superblock on the devid=0 must be wiped.

   wipefs -a device-path-to-devid=0.

This patch adds some info when this situation occurs.

Reported-by: Samuel Greiner <samuel@balkonien.org>
Link: https://lore.kernel.org/linux-btrfs/b4f62b10-b295-26ea-71f9-9a5c9299d42c@balkonien.org/T/
CC: stable@vger.kernel.org # 5.0+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-23 22:15:21 +02:00
Anand Jain
59a3991984 btrfs: replace: drop assert for suspended replace
If the filesystem mounts with the replace-operation in a suspended state
and try to cancel the suspended replace-operation, we hit the assert. The
assert came from the commit fe97e2e173 ("btrfs: dev-replace: replace's
scrub must not be running in suspended state") that was actually not
required. So just remove it.

 $ mount /dev/sda5 /btrfs

    BTRFS info (device sda5): cannot continue dev_replace, tgtdev is missing
    BTRFS info (device sda5): you may cancel the operation after 'mount -o degraded'

 $ mount -o degraded /dev/sda5 /btrfs <-- success.

 $ btrfs replace cancel /btrfs

    kernel: assertion failed: ret != -ENOTCONN, in fs/btrfs/dev-replace.c:1131
    kernel: ------------[ cut here ]------------
    kernel: kernel BUG at fs/btrfs/ctree.h:3750!

After the patch:

 $ btrfs replace cancel /btrfs

    BTRFS info (device sda5): suspended dev_replace from /dev/sda5 (devid 1) to <missing disk> canceled

Fixes: fe97e2e173 ("btrfs: dev-replace: replace's scrub must not be running in suspended state")
CC: stable@vger.kernel.org # 5.0+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-23 22:15:21 +02:00
David Sterba
c1867eb33e btrfs: clean up chained assignments
The chained assignments may be convenient to write, but make readability
a bit worse as it's too easy to overlook that there are several values
set on the same line while this is rather an exception.  Making it
consistent everywhere avoids surprises.

The pattern where inode times are initialized reuses the first value and
the order is mtime, ctime. In other blocks the assignments are expanded
so the order of variables is similar to the neighboring code.

Signed-off-by: David Sterba <dsterba@suse.com>
2022-07-25 17:45:39 +02:00
Anand Jain
b67d73c1ff btrfs: use a local variable for fs_devices pointer in btrfs_dev_replace_finishing
In the function btrfs_dev_replace_finishing, we dereferenced
fs_info->fs_devices 6 times. Use keep local variable for that.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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>
2022-05-16 17:03:08 +02:00
Gabriel Niebler
9bc5fc0417 btrfs: use btrfs_for_each_slot in mark_block_group_to_copy
This function can be simplified by refactoring to use the new iterator
macro.  No functional changes.

Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: Gabriel Niebler <gniebler@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-05-16 17:03:07 +02:00
Filipe Manana
a692e13d87 btrfs: fix assertion failure during scrub due to block group reallocation
During a scrub, or device replace, we can race with block group removal
and allocation and trigger the following assertion failure:

[7526.385524] assertion failed: cache->start == chunk_offset, in fs/btrfs/scrub.c:3817
[7526.387351] ------------[ cut here ]------------
[7526.387373] kernel BUG at fs/btrfs/ctree.h:3599!
[7526.388001] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
[7526.388970] CPU: 2 PID: 1158150 Comm: btrfs Not tainted 5.17.0-rc8-btrfs-next-114 #4
[7526.390279] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[7526.392430] RIP: 0010:assertfail.constprop.0+0x18/0x1a [btrfs]
[7526.393520] Code: f3 48 c7 c7 20 (...)
[7526.396926] RSP: 0018:ffffb9154176bc40 EFLAGS: 00010246
[7526.397690] RAX: 0000000000000048 RBX: ffffa0db8a910000 RCX: 0000000000000000
[7526.398732] RDX: 0000000000000000 RSI: ffffffff9d7239a2 RDI: 00000000ffffffff
[7526.399766] RBP: ffffa0db8a911e10 R08: ffffffffa71a3ca0 R09: 0000000000000001
[7526.400793] R10: 0000000000000001 R11: 0000000000000000 R12: ffffa0db4b170800
[7526.401839] R13: 00000003494b0000 R14: ffffa0db7c55b488 R15: ffffa0db8b19a000
[7526.402874] FS:  00007f6c99c40640(0000) GS:ffffa0de6d200000(0000) knlGS:0000000000000000
[7526.404038] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[7526.405040] CR2: 00007f31b0882160 CR3: 000000014b38c004 CR4: 0000000000370ee0
[7526.406112] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[7526.407148] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[7526.408169] Call Trace:
[7526.408529]  <TASK>
[7526.408839]  scrub_enumerate_chunks.cold+0x11/0x79 [btrfs]
[7526.409690]  ? do_wait_intr_irq+0xb0/0xb0
[7526.410276]  btrfs_scrub_dev+0x226/0x620 [btrfs]
[7526.410995]  ? preempt_count_add+0x49/0xa0
[7526.411592]  btrfs_ioctl+0x1ab5/0x36d0 [btrfs]
[7526.412278]  ? __fget_files+0xc9/0x1b0
[7526.412825]  ? kvm_sched_clock_read+0x14/0x40
[7526.413459]  ? lock_release+0x155/0x4a0
[7526.414022]  ? __x64_sys_ioctl+0x83/0xb0
[7526.414601]  __x64_sys_ioctl+0x83/0xb0
[7526.415150]  do_syscall_64+0x3b/0xc0
[7526.415675]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[7526.416408] RIP: 0033:0x7f6c99d34397
[7526.416931] Code: 3c 1c e8 1c ff (...)
[7526.419641] RSP: 002b:00007f6c99c3fca8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[7526.420735] RAX: ffffffffffffffda RBX: 00005624e1e007b0 RCX: 00007f6c99d34397
[7526.421779] RDX: 00005624e1e007b0 RSI: 00000000c400941b RDI: 0000000000000003
[7526.422820] RBP: 0000000000000000 R08: 00007f6c99c40640 R09: 0000000000000000
[7526.423906] R10: 00007f6c99c40640 R11: 0000000000000246 R12: 00007fff746755de
[7526.424924] R13: 00007fff746755df R14: 0000000000000000 R15: 00007f6c99c40640
[7526.425950]  </TASK>

That assertion is relatively new, introduced with commit d04fbe19ae
("btrfs: scrub: cleanup the argument list of scrub_chunk()").

The block group we get at scrub_enumerate_chunks() can actually have a
start address that is smaller then the chunk offset we extracted from a
device extent item we got from the commit root of the device tree.
This is very rare, but it can happen due to a race with block group
removal and allocation. For example, the following steps show how this
can happen:

1) We are at transaction T, and we have the following blocks groups,
   sorted by their logical start address:

   [ bg A, start address A, length 1G (data) ]
   [ bg B, start address B, length 1G (data) ]
   (...)
   [ bg W, start address W, length 1G (data) ]

     --> logical address space hole of 256M,
         there used to be a 256M metadata block group here

   [ bg Y, start address Y, length 256M (metadata) ]

      --> Y matches W's end offset + 256M

   Block group Y is the block group with the highest logical address in
   the whole filesystem;

2) Block group Y is deleted and its extent mapping is removed by the call
   to remove_extent_mapping() made from btrfs_remove_block_group().

   So after this point, the last element of the mapping red black tree,
   its rightmost node, is the mapping for block group W;

3) While still at transaction T, a new data block group is allocated,
   with a length of 1G. When creating the block group we do a call to
   find_next_chunk(), which returns the logical start address for the
   new block group. This calls returns X, which corresponds to the
   end offset of the last block group, the rightmost node in the mapping
   red black tree (fs_info->mapping_tree), plus one.

   So we get a new block group that starts at logical address X and with
   a length of 1G. It spans over the whole logical range of the old block
   group Y, that was previously removed in the same transaction.

   However the device extent allocated to block group X is not the same
   device extent that was used by block group Y, and it also does not
   overlap that extent, which must be always the case because we allocate
   extents by searching through the commit root of the device tree
   (otherwise it could corrupt a filesystem after a power failure or
   an unclean shutdown in general), so the extent allocator is behaving
   as expected;

4) We have a task running scrub, currently at scrub_enumerate_chunks().
   There it searches for device extent items in the device tree, using
   its commit root. It finds a device extent item that was used by
   block group Y, and it extracts the value Y from that item into the
   local variable 'chunk_offset', using btrfs_dev_extent_chunk_offset();

   It then calls btrfs_lookup_block_group() to find block group for
   the logical address Y - since there's currently no block group that
   starts at that logical address, it returns block group X, because
   its range contains Y.

   This results in triggering the assertion:

      ASSERT(cache->start == chunk_offset);

   right before calling scrub_chunk(), as cache->start is X and
   chunk_offset is Y.

This is more likely to happen of filesystems not larger than 50G, because
for these filesystems we use a 256M size for metadata block groups and
a 1G size for data block groups, while for filesystems larger than 50G,
we use a 1G size for both data and metadata block groups (except for
zoned filesystems). It could also happen on any filesystem size due to
the fact that system block groups are always smaller (32M) than both
data and metadata block groups, but these are not frequently deleted, so
much less likely to trigger the race.

So make scrub skip any block group with a start offset that is less than
the value we expect, as that means it's a new block group that was created
in the current transaction. It's pointless to continue and try to scrub
its extents, because scrub searches for extents using the commit root, so
it won't find any. For a device replace, skip it as well for the same
reasons, and we don't need to worry about the possibility of extents of
the new block group not being to the new device, because we have the write
duplication setup done through btrfs_map_block().

Fixes: d04fbe19ae ("btrfs: scrub: cleanup the argument list of scrub_chunk()")
CC: stable@vger.kernel.org # 5.17
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-04-21 16:06:19 +02:00
Anand Jain
4889bc05a9 btrfs: add device major-minor info in the struct btrfs_device
Internally it is common to use the major-minor number to identify a
device and, at a few locations in btrfs, we use the major-minor number
to match the device.

So when we identify a new btrfs device through device add or device
replace or device-scan/ready save the device's major-minor (dev_t) in the
struct btrfs_device so that we don't have to call lookup_bdev() again.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-03-14 13:13:47 +01:00
Anand Jain
bef16b5298 btrfs: simplify fs_devices member access in btrfs_init_dev_replace_tgtdev
In btrfs_init_dev_replace_tgtdev() we dereference fs_info to get
fs_devices many times, instead save a point to the fs_devices.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-03-14 13:13:46 +01:00
Qu Wenruo
f26c923860 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>
2022-01-07 14:18:26 +01:00
Naohiro Aota
16beac87e9 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: 5b31646898 ("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>
2022-01-03 15:09:44 +01:00
Josef Bacik
3212fa14e7 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>
2022-01-03 15:09:43 +01:00
Linus Torvalds
037c50bfbe Merge tag 'for-5.16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
 "The updates this time are more under the hood and enhancing existing
  features (subpage with compression and zoned namespaces).

  Performance related:

   - misc small inode logging improvements (+3% throughput, -11% latency
     on sample dbench workload)

   - more efficient directory logging: bulk item insertion, less tree
     searches and locking

   - speed up bulk insertion of items into a b-tree, which is used when
     logging directories, when running delayed items for directories
     (fsync and transaction commits) and when running the slow path
     (full sync) of an fsync (bulk creation run time -4%, deletion -12%)

  Core:

   - continued subpage support
      - make defragmentation work
      - make compression write work

   - zoned mode
      - support ZNS (zoned namespaces), zone capacity is number of
        usable blocks in each zone
      - add dedicated block group (zoned) for relocation, to prevent
        out of order writes in some cases
      - greedy block group reclaim, pick the ones with least usable
        space first

   - preparatory work for send protocol updates

   - error handling improvements

   - cleanups and refactoring

  Fixes:

   - lockdep warnings
      - in show_devname callback, on seeding device
      - device delete on loop device due to conversions to workqueues

   - fix deadlock between chunk allocation and chunk btree modifications

   - fix tracking of missing device count and status"

* tag 'for-5.16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (140 commits)
  btrfs: remove root argument from check_item_in_log()
  btrfs: remove root argument from add_link()
  btrfs: remove root argument from btrfs_unlink_inode()
  btrfs: remove root argument from drop_one_dir_item()
  btrfs: clear MISSING device status bit in btrfs_close_one_device
  btrfs: call btrfs_check_rw_degradable only if there is a missing device
  btrfs: send: prepare for v2 protocol
  btrfs: fix comment about sector sizes supported in 64K systems
  btrfs: update device path inode time instead of bd_inode
  fs: export an inode_update_time helper
  btrfs: fix deadlock when defragging transparent huge pages
  btrfs: sysfs: convert scnprintf and snprintf to sysfs_emit
  btrfs: make btrfs_super_block size match BTRFS_SUPER_INFO_SIZE
  btrfs: update comments for chunk allocation -ENOSPC cases
  btrfs: fix deadlock between chunk allocation and chunk btree modifications
  btrfs: zoned: use greedy gc for auto reclaim
  btrfs: check-integrity: stop storing the block device name in btrfsic_dev_state
  btrfs: use btrfs_get_dev_args_from_path in dev removal ioctls
  btrfs: add a btrfs_get_dev_args_from_path helper
  btrfs: handle device lookup with btrfs_dev_lookup_args
  ...
2021-11-01 12:48:25 -07:00
Josef Bacik
562d7b1512 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>
2021-10-26 19:08:07 +02:00
Christoph Hellwig
cda00eba02 btrfs: use bdev_nr_bytes instead of open coding it
Use the proper helper to read the block device size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Acked-by: David Sterba <dsterba@suse.com>
Link: https://lore.kernel.org/r/20211018101130.1838532-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:43:22 -06:00
David Sterba
1a9fd4172d btrfs: fix typos in comments
Fix typos that have snuck in since the last round. Found by codespell.

Signed-off-by: David Sterba <dsterba@suse.com>
2021-06-22 14:11:57 +02:00
Josef Bacik
3cb894972f btrfs: do not initialize dev replace for bad dev root
While helping Neal fix his broken file system I added a debug patch to
catch if we were calling btrfs_search_slot with a NULL root, and this
stack trace popped:

  we tried to search with a NULL root
  CPU: 0 PID: 1760 Comm: mount Not tainted 5.11.0-155.nealbtrfstest.1.fc34.x86_64 #1
  Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/22/2020
  Call Trace:
   dump_stack+0x6b/0x83
   btrfs_search_slot.cold+0x11/0x1b
   ? btrfs_init_dev_replace+0x36/0x450
   btrfs_init_dev_replace+0x71/0x450
   open_ctree+0x1054/0x1610
   btrfs_mount_root.cold+0x13/0xfa
   legacy_get_tree+0x27/0x40
   vfs_get_tree+0x25/0xb0
   vfs_kern_mount.part.0+0x71/0xb0
   btrfs_mount+0x131/0x3d0
   ? legacy_get_tree+0x27/0x40
   ? btrfs_show_options+0x640/0x640
   legacy_get_tree+0x27/0x40
   vfs_get_tree+0x25/0xb0
   path_mount+0x441/0xa80
   __x64_sys_mount+0xf4/0x130
   do_syscall_64+0x33/0x40
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x7f644730352e

Fix this by not starting the device replace stuff if we do not have a
NULL dev root.

Reported-by: Neal Gompa <ngompa13@gmail.com>
CC: stable@vger.kernel.org # 5.11+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-17 19:42:14 +01:00
Naohiro Aota
78ce9fc269 btrfs: zoned: mark block groups to copy for device-replace
This is the 1/4 patch to support device-replace on zoned filesystems.

We have two types of IOs during the device replace process. One is an IO
to "copy" (by the scrub functions) all the device extents from the source
device to the destination device. The other one is an IO to "clone" (by
handle_ops_on_dev_replace()) new incoming write IOs from users to the
source device into the target device.

Cloning incoming IOs can break the sequential write rule in on target
device. When a write is mapped in the middle of a block group, the IO is
directed to the middle of a target device zone, which breaks the
sequential write requirement.

However, the cloning function cannot be disabled since incoming IOs
targeting already copied device extents must be cloned so that the IO is
executed on the target device.

We cannot use dev_replace->cursor_{left,right} to determine whether a bio
is going to a not yet copied region. Since we have a time gap between
finishing btrfs_scrub_dev() and rewriting the mapping tree in
btrfs_dev_replace_finishing(), we can have a newly allocated device extent
which is never cloned nor copied.

So the point is to copy only already existing device extents. This patch
introduces mark_block_group_to_copy() to mark existing block groups as a
target of copying. Then, handle_ops_on_dev_replace() and dev-replace can
check the flag to do their job.

Also, btrfs_finish_block_group_to_copy() will check if the copied stripe
is the last stripe in the block group. With the last stripe copied,
the to_copy flag is finally disabled. Afterwards we can safely clone
incoming IOs on this block group.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09 02:46:07 +01:00
Nikolay Borisov
9db4dc241e btrfs: make btrfs_start_delalloc_root's nr argument a long
It's currently u64 which gets instantly translated either to LONG_MAX
(if U64_MAX is passed) or cast to an unsigned long (which is in fact,
wrong because writeback_control::nr_to_write is a signed, long type).

Just convert the function's argument to be long time which obviates the
need to manually convert u64 value to a long. Adjust all call sites
which pass U64_MAX to pass LONG_MAX. Finally ensure that in
shrink_delalloc the u64 is converted to a long without overflowing,
resulting in a negative number.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-08 22:58:51 +01:00
Filipe Manana
3d45f221ce btrfs: fix deadlock when cloning inline extent and low on free metadata space
When cloning an inline extent there are cases where we can not just copy
the inline extent from the source range to the target range (e.g. when the
target range starts at an offset greater than zero). In such cases we copy
the inline extent's data into a page of the destination inode and then
dirty that page. However, after that we will need to start a transaction
for each processed extent and, if we are ever low on available metadata
space, we may need to flush existing delalloc for all dirty inodes in an
attempt to release metadata space - if that happens we may deadlock:

* the async reclaim task queued a delalloc work to flush delalloc for
  the destination inode of the clone operation;

* the task executing that delalloc work gets blocked waiting for the
  range with the dirty page to be unlocked, which is currently locked
  by the task doing the clone operation;

* the async reclaim task blocks waiting for the delalloc work to complete;

* the cloning task is waiting on the waitqueue of its reservation ticket
  while holding the range with the dirty page locked in the inode's
  io_tree;

* if metadata space is not released by some other task (like delalloc for
  some other inode completing for example), the clone task waits forever
  and as a consequence the delalloc work and async reclaim tasks will hang
  forever as well. Releasing more space on the other hand may require
  starting a transaction, which will hang as well when trying to reserve
  metadata space, resulting in a deadlock between all these tasks.

When this happens, traces like the following show up in dmesg/syslog:

  [87452.323003] INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds.
  [87452.323644]       Tainted: G    B   W         5.10.0-rc4-btrfs-next-73 #1
  [87452.324248] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [87452.324852] task:kworker/u16:11  state:D stack:    0 pid:1810830 ppid:     2 flags:0x00004000
  [87452.325520] Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs]
  [87452.326136] Call Trace:
  [87452.326737]  __schedule+0x5d1/0xcf0
  [87452.327390]  schedule+0x45/0xe0
  [87452.328174]  lock_extent_bits+0x1e6/0x2d0 [btrfs]
  [87452.328894]  ? finish_wait+0x90/0x90
  [87452.329474]  btrfs_invalidatepage+0x32c/0x390 [btrfs]
  [87452.330133]  ? __mod_memcg_state+0x8e/0x160
  [87452.330738]  __extent_writepage+0x2d4/0x400 [btrfs]
  [87452.331405]  extent_write_cache_pages+0x2b2/0x500 [btrfs]
  [87452.332007]  ? lock_release+0x20e/0x4c0
  [87452.332557]  ? trace_hardirqs_on+0x1b/0xf0
  [87452.333127]  extent_writepages+0x43/0x90 [btrfs]
  [87452.333653]  ? lock_acquire+0x1a3/0x490
  [87452.334177]  do_writepages+0x43/0xe0
  [87452.334699]  ? __filemap_fdatawrite_range+0xa4/0x100
  [87452.335720]  __filemap_fdatawrite_range+0xc5/0x100
  [87452.336500]  btrfs_run_delalloc_work+0x17/0x40 [btrfs]
  [87452.337216]  btrfs_work_helper+0xf1/0x600 [btrfs]
  [87452.337838]  process_one_work+0x24e/0x5e0
  [87452.338437]  worker_thread+0x50/0x3b0
  [87452.339137]  ? process_one_work+0x5e0/0x5e0
  [87452.339884]  kthread+0x153/0x170
  [87452.340507]  ? kthread_mod_delayed_work+0xc0/0xc0
  [87452.341153]  ret_from_fork+0x22/0x30
  [87452.341806] INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds.
  [87452.342487]       Tainted: G    B   W         5.10.0-rc4-btrfs-next-73 #1
  [87452.343274] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [87452.344049] task:kworker/u16:1   state:D stack:    0 pid:2426217 ppid:     2 flags:0x00004000
  [87452.344974] Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs]
  [87452.345655] Call Trace:
  [87452.346305]  __schedule+0x5d1/0xcf0
  [87452.346947]  ? kvm_clock_read+0x14/0x30
  [87452.347676]  ? wait_for_completion+0x81/0x110
  [87452.348389]  schedule+0x45/0xe0
  [87452.349077]  schedule_timeout+0x30c/0x580
  [87452.349718]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [87452.350340]  ? lock_acquire+0x1a3/0x490
  [87452.351006]  ? try_to_wake_up+0x7a/0xa20
  [87452.351541]  ? lock_release+0x20e/0x4c0
  [87452.352040]  ? lock_acquired+0x199/0x490
  [87452.352517]  ? wait_for_completion+0x81/0x110
  [87452.353000]  wait_for_completion+0xab/0x110
  [87452.353490]  start_delalloc_inodes+0x2af/0x390 [btrfs]
  [87452.353973]  btrfs_start_delalloc_roots+0x12d/0x250 [btrfs]
  [87452.354455]  flush_space+0x24f/0x660 [btrfs]
  [87452.355063]  btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs]
  [87452.355565]  process_one_work+0x24e/0x5e0
  [87452.356024]  worker_thread+0x20f/0x3b0
  [87452.356487]  ? process_one_work+0x5e0/0x5e0
  [87452.356973]  kthread+0x153/0x170
  [87452.357434]  ? kthread_mod_delayed_work+0xc0/0xc0
  [87452.357880]  ret_from_fork+0x22/0x30
  (...)
  < stack traces of several tasks waiting for the locks of the inodes of the
    clone operation >
  (...)
  [92867.444138] RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
  [92867.444624] RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73f97
  [92867.445116] RDX: 0000000000000000 RSI: 0000560fbd5d7a40 RDI: 0000560fbd5d8960
  [92867.445595] RBP: 00007ffc3371beb0 R08: 0000000000000001 R09: 0000000000000003
  [92867.446070] R10: 00007ffc3371b996 R11: 0000000000000246 R12: 0000000000000000
  [92867.446820] R13: 000000000000001f R14: 00007ffc3371bea0 R15: 00007ffc3371beb0
  [92867.447361] task:fsstress        state:D stack:    0 pid:2508238 ppid:2508153 flags:0x00004000
  [92867.447920] Call Trace:
  [92867.448435]  __schedule+0x5d1/0xcf0
  [92867.448934]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [92867.449423]  schedule+0x45/0xe0
  [92867.449916]  __reserve_bytes+0x4a4/0xb10 [btrfs]
  [92867.450576]  ? finish_wait+0x90/0x90
  [92867.451202]  btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs]
  [92867.451815]  btrfs_block_rsv_add+0x1f/0x50 [btrfs]
  [92867.452412]  start_transaction+0x2d1/0x760 [btrfs]
  [92867.453216]  clone_copy_inline_extent+0x333/0x490 [btrfs]
  [92867.453848]  ? lock_release+0x20e/0x4c0
  [92867.454539]  ? btrfs_search_slot+0x9a7/0xc30 [btrfs]
  [92867.455218]  btrfs_clone+0x569/0x7e0 [btrfs]
  [92867.455952]  btrfs_clone_files+0xf6/0x150 [btrfs]
  [92867.456588]  btrfs_remap_file_range+0x324/0x3d0 [btrfs]
  [92867.457213]  do_clone_file_range+0xd4/0x1f0
  [92867.457828]  vfs_clone_file_range+0x4d/0x230
  [92867.458355]  ? lock_release+0x20e/0x4c0
  [92867.458890]  ioctl_file_clone+0x8f/0xc0
  [92867.459377]  do_vfs_ioctl+0x342/0x750
  [92867.459913]  __x64_sys_ioctl+0x62/0xb0
  [92867.460377]  do_syscall_64+0x33/0x80
  [92867.460842]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  (...)
  < stack traces of more tasks blocked on metadata reservation like the clone
    task above, because the async reclaim task has deadlocked >
  (...)

Another thing to notice is that the worker task that is deadlocked when
trying to flush the destination inode of the clone operation is at
btrfs_invalidatepage(). This is simply because the clone operation has a
destination offset greater than the i_size and we only update the i_size
of the destination file after cloning an extent (just like we do in the
buffered write path).

Since the async reclaim path uses btrfs_start_delalloc_roots() to trigger
the flushing of delalloc for all inodes that have delalloc, add a runtime
flag to an inode to signal it should not be flushed, and for inodes with
that flag set, start_delalloc_inodes() will simply skip them. When the
cloning code needs to dirty a page to copy an inline extent, set that flag
on the inode and then clear it when the clone operation finishes.

This could be sporadically triggered with test case generic/269 from
fstests, which exercises many fsstress processes running in parallel with
several dd processes filling up the entire filesystem.

CC: stable@vger.kernel.org # 5.9+
Fixes: 05a5a7621c ("Btrfs: implement full reflink support for inline extents")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-18 14:49:50 +01:00
Naohiro Aota
b70f509774 btrfs: check and enable ZONED mode
Introduce function btrfs_check_zoned_mode() to check if ZONED flag is
enabled on the file system and if the file system consists of zoned
devices with equal zone size.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09 19:16:03 +01:00
Naohiro Aota
5b31646898 btrfs: get zone information of zoned block devices
If a zoned block device is found, get its zone information (number of
zones and zone size).  To avoid costly run-time zone report
commands to test the device zones type during block allocation, attach
the seq_zones bitmap to the device structure to indicate if a zone is
sequential or accept random writes. Also it attaches the empty_zones
bitmap to indicate if a zone is empty or not.

This patch also introduces the helper function btrfs_dev_is_sequential()
to test if the zone storing a block is a sequential write required zone
and btrfs_dev_is_empty_zone() to test if the zone is a empty zone.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09 19:15:57 +01:00