Currently when doing a write to a file we always reserve metadata space
for inserting data checksums. However we don't need to do it if we have
a nodatacow file (-o nodatacow mount option or chattr +C) or if checksums
are disabled (-o nodatasum mount option), as in that case we are only
adding unnecessary pressure to metadata reservations.
For example on x86_64, with the default node size of 16K, a 4K buffered
write into a nodatacow file is reserving 655360 bytes of metadata space,
as it's accounting for checksums. After this change, which stops reserving
space for checksums if we have a nodatacow file or checksums are disabled,
we only need to reserve 393216 bytes of metadata.
CC: stable@vger.kernel.org # 6.1+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Space reservations for metadata are, most of the time, pessimistic as we
reserve space for worst possible cases - where tree heights are at the
maximum possible height (8), we need to COW every extent buffer in a tree
path, need to split extent buffers, etc.
For data, we generally reserve the exact amount of space we are going to
allocate. The exception here is when using compression, in which case we
reserve space matching the uncompressed size, as the compression only
happens at writeback time and in the worst possible case we need that
amount of space in case the data is not compressible.
This means that when there's not available space in the corresponding
space_info object, we may need to allocate a new block group, and then
that block group might not be used after all. In this case the block
group is never added to the list of unused block groups and ends up
never being deleted - except if we unmount and mount again the fs, as
when reading block groups from disk we add unused ones to the list of
unused block groups (fs_info->unused_bgs). Otherwise a block group is
only added to the list of unused block groups when we deallocate the
last extent from it, so if no extent is ever allocated, the block group
is kept around forever.
This also means that if we have a bunch of tasks reserving space in
parallel we can end up allocating many block groups that end up never
being used or kept around for too long without being used, which has
the potential to result in ENOSPC failures in case for example we over
allocate too many metadata block groups and then end up in a state
without enough unallocated space to allocate a new data block group.
This is more likely to happen with metadata reservations as of kernel
6.7, namely since commit 28270e25c6 ("btrfs: always reserve space for
delayed refs when starting transaction"), because we started to always
reserve space for delayed references when starting a transaction handle
for a non-zero number of items, and also to try to reserve space to fill
the gap between the delayed block reserve's reserved space and its size.
So to avoid this, when finishing the creation a new block group, add the
block group to the list of unused block groups if it's still unused at
that time. This way the next time the cleaner kthread runs, it will delete
the block group if it's still unused and not needed to satisfy existing
space reservations.
Reported-by: Ivan Shapovalov <intelfx@intelfx.name>
Link: https://lore.kernel.org/linux-btrfs/9cdbf0ca9cdda1b4c84e15e548af7d7f9f926382.camel@intelfx.name/
CC: stable@vger.kernel.org # 6.7+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Before deleting a block group that is in the list of unused block groups
(fs_info->unused_bgs), we check if the block group became used before
deleting it, as extents from it may have been allocated after it was added
to the list.
However even if the block group was not yet used, there may be tasks that
have only reserved space and have not yet allocated extents, and they
might be relying on the availability of the unused block group in order
to allocate extents. The reservation works first by increasing the
"bytes_may_use" field of the corresponding space_info object (which may
first require flushing delayed items, allocating a new block group, etc),
and only later a task does the actual allocation of extents.
For metadata we usually don't end up using all reserved space, as we are
pessimistic and typically account for the worst cases (need to COW every
single node in a path of a tree at maximum possible height, etc). For
data we usually reserve the exact amount of space we're going to allocate
later, except when using compression where we always reserve space based
on the uncompressed size, as compression is only triggered when writeback
starts so we don't know in advance how much space we'll actually need, or
if the data is compressible.
So don't delete an unused block group if the total size of its space_info
object minus the block group's size is less then the sum of used space and
space that may be used (space_info->bytes_may_use), as that means we have
tasks that reserved space and may need to allocate extents from the block
group. In this case, besides skipping the deletion, re-add the block group
to the list of unused block groups so that it may be reconsidered later,
in case the tasks that reserved space end up not needing to allocate
extents from it.
Allowing the deletion of the block group while we have reserved space, can
result in tasks failing to allocate metadata extents (-ENOSPC) while under
a transaction handle, resulting in a transaction abort, or failure during
writeback for the case of data extents.
CC: stable@vger.kernel.org # 6.0+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add a helper function to determine if a block group is being used and make
use of it at btrfs_delete_unused_bgs(). This helper will also be used in
future code changes.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While running the CI for an unrelated change I hit the following panic
with generic/648 on btrfs_holes_spacecache.
assertion failed: block_start != EXTENT_MAP_HOLE, in fs/btrfs/extent_io.c:1385
------------[ cut here ]------------
kernel BUG at fs/btrfs/extent_io.c:1385!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 PID: 2695096 Comm: fsstress Kdump: loaded Tainted: G W 6.8.0-rc2+ #1
RIP: 0010:__extent_writepage_io.constprop.0+0x4c1/0x5c0
Call Trace:
<TASK>
extent_write_cache_pages+0x2ac/0x8f0
extent_writepages+0x87/0x110
do_writepages+0xd5/0x1f0
filemap_fdatawrite_wbc+0x63/0x90
__filemap_fdatawrite_range+0x5c/0x80
btrfs_fdatawrite_range+0x1f/0x50
btrfs_write_out_cache+0x507/0x560
btrfs_write_dirty_block_groups+0x32a/0x420
commit_cowonly_roots+0x21b/0x290
btrfs_commit_transaction+0x813/0x1360
btrfs_sync_file+0x51a/0x640
__x64_sys_fdatasync+0x52/0x90
do_syscall_64+0x9c/0x190
entry_SYSCALL_64_after_hwframe+0x6e/0x76
This happens because we fail to write out the free space cache in one
instance, come back around and attempt to write it again. However on
the second pass through we go to call btrfs_get_extent() on the inode to
get the extent mapping. Because this is a new block group, and with the
free space inode we always search the commit root to avoid deadlocking
with the tree, we find nothing and return a EXTENT_MAP_HOLE for the
requested range.
This happens because the first time we try to write the space cache out
we hit an error, and on an error we drop the extent mapping. This is
normal for normal files, but the free space cache inode is special. We
always expect the extent map to be correct. Thus the second time
through we end up with a bogus extent map.
Since we're deprecating this feature, the most straightforward way to
fix this is to simply skip dropping the extent map range for this failed
range.
I shortened the test by using error injection to stress the area to make
it easier to reproduce. With this patch in place we no longer panic
with my error injection test.
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
There is a syzbot crash, triggered by the ASSERT() during subvolume
creation:
assertion failed: !anon_dev, in fs/btrfs/disk-io.c:1319
------------[ cut here ]------------
kernel BUG at fs/btrfs/disk-io.c:1319!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
RIP: 0010:btrfs_get_root_ref.part.0+0x9aa/0xa60
<TASK>
btrfs_get_new_fs_root+0xd3/0xf0
create_subvol+0xd02/0x1650
btrfs_mksubvol+0xe95/0x12b0
__btrfs_ioctl_snap_create+0x2f9/0x4f0
btrfs_ioctl_snap_create+0x16b/0x200
btrfs_ioctl+0x35f0/0x5cf0
__x64_sys_ioctl+0x19d/0x210
do_syscall_64+0x3f/0xe0
entry_SYSCALL_64_after_hwframe+0x63/0x6b
---[ end trace 0000000000000000 ]---
[CAUSE]
During create_subvol(), after inserting root item for the newly created
subvolume, we would trigger btrfs_get_new_fs_root() to get the
btrfs_root of that subvolume.
The idea here is, we have preallocated an anonymous device number for
the subvolume, thus we can assign it to the new subvolume.
But there is really nothing preventing things like backref walk to read
the new subvolume.
If that happens before we call btrfs_get_new_fs_root(), the subvolume
would be read out, with a new anonymous device number assigned already.
In that case, we would trigger ASSERT(), as we really expect no one to
read out that subvolume (which is not yet accessible from the fs).
But things like backref walk is still possible to trigger the read on
the subvolume.
Thus our assumption on the ASSERT() is not correct in the first place.
[FIX]
Fix it by removing the ASSERT(), and just free the @anon_dev, reset it
to 0, and continue.
If the subvolume tree is read out by something else, it should have
already get a new anon_dev assigned thus we only need to free the
preallocated one.
Reported-by: Chenyuan Yang <chenyuan0y@gmail.com>
Fixes: 2dfb1e43f5 ("btrfs: preallocate anon block device at first phase of snapshot creation")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Filipe Manana <fdmanana@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>
If a subvolume still exists, forbid deleting its qgroup 0/subvolid.
This behavior generally leads to incorrect behavior in squotas and
doesn't have a legitimate purpose.
Fixes: cecbb533b5 ("btrfs: record simple quota deltas in delayed refs")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Creating a qgroup 0/subvolid leads to various races and it isn't
helpful, because you can't specify a subvol id when creating a subvol,
so you can't be sure it will be the right one. Any requirements on the
automatic subvol can be gratified by using a higher level qgroup and the
inheritance parameters of subvol creation.
Fixes: cecbb533b5 ("btrfs: record simple quota deltas in delayed refs")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When some ioctl flags are checked we return EOPNOTSUPP, like for
BTRFS_SCRUB_SUPPORTED_FLAGS, BTRFS_SUBVOL_CREATE_ARGS_MASK or fallocate
modes. The EINVAL is supposed to be for a supported but invalid
values or combination of options. Fix that when checking send flags so
it's consistent with the rest.
CC: stable@vger.kernel.org # 4.14+
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5rryOLzp3EKq8RTbjMHMHeaJubfpsVLF6H4qJnKCUR1w@mail.gmail.com/
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
If there is an extent beyond chunk boundary, currently RST scrub would
error out.
[CAUSE]
In scrub_submit_extent_sector_read(), we completely rely on
extent_sector_bitmap, which is populated using extent tree.
The extent tree can be corrupted that there is an extent item beyond a
chunk.
In that case, RST scrub would fail and error out.
[FIX]
Despite the extent_sector_bitmap usage, also limit the read to chunk
boundary.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
There is a bug report that, on a ext4-converted btrfs, scrub leads to
various problems, including:
- "unable to find chunk map" errors
BTRFS info (device vdb): scrub: started on devid 1
BTRFS critical (device vdb): unable to find chunk map for logical 2214744064 length 4096
BTRFS critical (device vdb): unable to find chunk map for logical 2214744064 length 45056
This would lead to unrepariable errors.
- Use-after-free KASAN reports:
==================================================================
BUG: KASAN: slab-use-after-free in __blk_rq_map_sg+0x18f/0x7c0
Read of size 8 at addr ffff8881013c9040 by task btrfs/909
CPU: 0 PID: 909 Comm: btrfs Not tainted 6.7.0-x64v3-dbg #11 c50636e9419a8354555555245df535e380563b2b
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 2023.11-2 12/24/2023
Call Trace:
<TASK>
dump_stack_lvl+0x43/0x60
print_report+0xcf/0x640
kasan_report+0xa6/0xd0
__blk_rq_map_sg+0x18f/0x7c0
virtblk_prep_rq.isra.0+0x215/0x6a0 [virtio_blk 19a65eeee9ae6fcf02edfad39bb9ddee07dcdaff]
virtio_queue_rqs+0xc4/0x310 [virtio_blk 19a65eeee9ae6fcf02edfad39bb9ddee07dcdaff]
blk_mq_flush_plug_list.part.0+0x780/0x860
__blk_flush_plug+0x1ba/0x220
blk_finish_plug+0x3b/0x60
submit_initial_group_read+0x10a/0x290 [btrfs e57987a360bed82fe8756dcd3e0de5406ccfe965]
flush_scrub_stripes+0x38e/0x430 [btrfs e57987a360bed82fe8756dcd3e0de5406ccfe965]
scrub_stripe+0x82a/0xae0 [btrfs e57987a360bed82fe8756dcd3e0de5406ccfe965]
scrub_chunk+0x178/0x200 [btrfs e57987a360bed82fe8756dcd3e0de5406ccfe965]
scrub_enumerate_chunks+0x4bc/0xa30 [btrfs e57987a360bed82fe8756dcd3e0de5406ccfe965]
btrfs_scrub_dev+0x398/0x810 [btrfs e57987a360bed82fe8756dcd3e0de5406ccfe965]
btrfs_ioctl+0x4b9/0x3020 [btrfs e57987a360bed82fe8756dcd3e0de5406ccfe965]
__x64_sys_ioctl+0xbd/0x100
do_syscall_64+0x5d/0xe0
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f47e5e0952b
- Crash, mostly due to above use-after-free
[CAUSE]
The converted fs has the following data chunk layout:
item 2 key (FIRST_CHUNK_TREE CHUNK_ITEM 2214658048) itemoff 16025 itemsize 80
length 86016 owner 2 stripe_len 65536 type DATA|single
For above logical bytenr 2214744064, it's at the chunk end
(2214658048 + 86016 = 2214744064).
This means btrfs_submit_bio() would split the bio, and trigger endio
function for both of the two halves.
However scrub_submit_initial_read() would only expect the endio function
to be called once, not any more.
This means the first endio function would already free the bbio::bio,
leaving the bvec freed, thus the 2nd endio call would lead to
use-after-free.
[FIX]
- Make sure scrub_read_endio() only updates bits in its range
Since we may read less than 64K at the end of the chunk, we should not
touch the bits beyond chunk boundary.
- Make sure scrub_submit_initial_read() only to read the chunk range
This is done by calculating the real number of sectors we need to
read, and add sector-by-sector to the bio.
Thankfully the scrub read repair path won't need extra fixes:
- scrub_stripe_submit_repair_read()
With above fixes, we won't update error bit for range beyond chunk,
thus scrub_stripe_submit_repair_read() should never submit any read
beyond the chunk.
Reported-by: Rongrong <i@rong.moe>
Fixes: e02ee89baa ("btrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure")
Tested-by: Rongrong <i@rong.moe>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In the normal case we check if a page is under writeback and skip it
before we attempt to begin writeback.
The exception is subpage metadata writes, where we know we don't have an
eb under writeback and we're doing it one eb at a time. Since
b5612c3686 ("mm: return void from folio_start_writeback() and related
functions") we now will BUG_ON() if we call folio_start_writeback()
on a folio that's already under writeback. Previously
folio_start_writeback() would bail if writeback was already started.
Fix this in the subpage code by checking if we have writeback set and
skipping it if we do. This fixes the panic we were seeing on subpage.
Reviewed-by: Qu Wenruo <wqu@suse.com>
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>
btrfs/330, which tests our old trick to allow
mount -o ro,subvol=/x /dev/sda1 /foo
mount -o rw,subvol=/y /dev/sda1 /bar
fails on the block group tree. This is because we aren't preserving the
mount options for what is essentially a remount, and thus we're ending
up without the FREE_SPACE_TREE mount option, which triggers our free
space tree delete codepath. This isn't possible with the block group
tree and thus it falls over.
Fix this by making sure we copy the existing mount options for the
existing fs mount over in this case.
Fixes: f044b31867 ("btrfs: handle the ro->rw transition for mounting different subvolumes")
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's a warning in btrfs_issue_discard() when the range is not aligned
to 512 bytes, originally added in 4d89d377bb ("btrfs:
btrfs_issue_discard ensure offset/length are aligned to sector
boundaries"). We can't do sub-sector writes anyway so the adjustment is
the only thing that we can do and the warning is unnecessary.
CC: stable@vger.kernel.org # 4.19+
Reported-by: syzbot+4a4f1eba14eb5c3417d1@syzkaller.appspotmail.com
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The error message should accurately reflect the size rather than the
type.
Fixes: f82d1c7ca8 ("btrfs: tree-checker: Add EXTENT_ITEM and METADATA_ITEM check")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Chung-Chiang Cheng <cccheng@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
If we have a filesystem with 4k sectorsize, and an inlined compressed
extent created like this:
item 4 key (257 INODE_ITEM 0) itemoff 15863 itemsize 160
generation 8 transid 8 size 4096 nbytes 4096
block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x0(none)
item 5 key (257 INODE_REF 256) itemoff 15839 itemsize 24
index 2 namelen 14 name: source_inlined
item 6 key (257 EXTENT_DATA 0) itemoff 15770 itemsize 69
generation 8 type 0 (inline)
inline extent data size 48 ram_bytes 4096 compression 3 (zstd)
Then trying to reflink that extent in an aarch64 system with 64K page
size, the reflink would just fail:
# xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest
XFS_IOC_CLONE_RANGE: Input/output error
[CAUSE]
In zstd_decompress(), we didn't treat @start_byte as just a page offset,
but also use it as an indicator on whether we should error out, without
any proper explanation (this is copied from other decompression code).
In reality, for subpage cases, although @start_byte can be non-zero,
we should never switch input/output buffer nor error out, since the whole
input/output buffer should never exceed one sector, thus we should not
need to do any buffer switch.
Thus the current code using @start_byte as a condition to switch
input/output buffer or finish the decompression is completely incorrect.
[FIX]
The fix involves several modification:
- Rename @start_byte to @dest_pgoff to properly express its meaning
- Use @sectorsize other than PAGE_SIZE to properly initialize the
output buffer size
- Use correct destination offset inside the destination page
- Simplify the main loop
Since the input/output buffer should never switch, we only need one
zstd_decompress_stream() call.
- Consider early end as an error
After the fix, even on 64K page sized aarch64, above reflink now
works as expected:
# xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest
linked 4096/4096 bytes at offset 61440
And results the correct file layout:
item 9 key (258 INODE_ITEM 0) itemoff 15542 itemsize 160
generation 10 transid 10 size 65536 nbytes 4096
block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x0(none)
item 10 key (258 INODE_REF 256) itemoff 15528 itemsize 14
index 3 namelen 4 name: dest
item 11 key (258 XATTR_ITEM 3817753667) itemoff 15445 itemsize 83
location key (0 UNKNOWN.0 0) type XATTR
transid 10 data_len 37 name_len 16
name: security.selinux
data unconfined_u:object_r:unlabeled_t:s0
item 12 key (258 EXTENT_DATA 61440) itemoff 15392 itemsize 53
generation 10 type 1 (regular)
extent data disk byte 13631488 nr 4096
extent data offset 0 nr 4096 ram 4096
extent compression 0 (none)
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
If we have a filesystem with 4k sectorsize, and an inlined compressed
extent created like this:
item 4 key (257 INODE_ITEM 0) itemoff 15863 itemsize 160
generation 8 transid 8 size 4096 nbytes 4096
block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x0(none)
item 5 key (257 INODE_REF 256) itemoff 15839 itemsize 24
index 2 namelen 14 name: source_inlined
item 6 key (257 EXTENT_DATA 0) itemoff 15770 itemsize 69
generation 8 type 0 (inline)
inline extent data size 48 ram_bytes 4096 compression 2 (lzo)
Then trying to reflink that extent in an aarch64 system with 64K page
size, the reflink would just fail:
# xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest
XFS_IOC_CLONE_RANGE: Input/output error
[CAUSE]
In zlib_decompress(), we didn't treat @start_byte as just a page offset,
but also use it as an indicator on whether we should error out, without
any proper explanation (this is from the very beginning of btrfs).
In reality, for subpage cases, although @start_byte can be non-zero,
we should never switch input/output buffer nor error out, since the whole
input/output buffer should never exceed one sector.
Note: The above assumption is only not true if we're going to support
multi-page sectorsize.
Thus the current code using @start_byte as a condition to switch
input/output buffer or finish the decompression is completely incorrect.
[FIX]
The fix involves several modifications:
- Rename @start_byte to @dest_pgoff to properly express its meaning
- Use @sectorsize other than PAGE_SIZE to properly initialize the
output buffer size
- Use correct destination offset inside the destination page
- Use memcpy_to_page() to copy the contents to the destination page
- Use memzero_page() to zero out the tailing part
- Consider early end as an error
After the fix, even on 64K page sized aarch64, above reflink now
works as expected:
# xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest
linked 4096/4096 bytes at offset 61440
And results the correct file layout:
item 9 key (258 INODE_ITEM 0) itemoff 15542 itemsize 160
generation 10 transid 10 size 65536 nbytes 4096
block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x0(none)
item 10 key (258 INODE_REF 256) itemoff 15528 itemsize 14
index 3 namelen 4 name: dest
item 11 key (258 XATTR_ITEM 3817753667) itemoff 15445 itemsize 83
location key (0 UNKNOWN.0 0) type XATTR
transid 10 data_len 37 name_len 16
name: security.selinux
data unconfined_u:object_r:unlabeled_t:s0
item 12 key (258 EXTENT_DATA 61440) itemoff 15392 itemsize 53
generation 10 type 1 (regular)
extent data disk byte 13631488 nr 4096
extent data offset 0 nr 4096 ram 4096
extent compression 0 (none)
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
If we have a filesystem with 4k sectorsize, and an inlined compressed
extent created like this:
item 4 key (257 INODE_ITEM 0) itemoff 15863 itemsize 160
generation 8 transid 8 size 4096 nbytes 4096
block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x0(none)
item 5 key (257 INODE_REF 256) itemoff 15839 itemsize 24
index 2 namelen 14 name: source_inlined
item 6 key (257 EXTENT_DATA 0) itemoff 15770 itemsize 69
generation 8 type 0 (inline)
inline extent data size 48 ram_bytes 4096 compression 1 (zlib)
Which has an inline compressed extent at file offset 0, and its
decompressed size is 4K, allowing us to reflink that 4K range to another
location (which will not be compressed).
If we do such reflink on a subpage system, it would fail like this:
# xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest
XFS_IOC_CLONE_RANGE: Input/output error
[CAUSE]
In zlib_decompress(), we didn't treat @start_byte as just a page offset,
but also use it as an indicator on whether we should switch our output
buffer.
In reality, for subpage cases, although @start_byte can be non-zero,
we should never switch input/output buffer, since the whole input/output
buffer should never exceed one sector.
Note: The above assumption is only not true if we're going to support
multi-page sectorsize.
Thus the current code using @start_byte as a condition to switch
input/output buffer or finish the decompression is completely incorrect.
[FIX]
The fix involves several modifications:
- Rename @start_byte to @dest_pgoff to properly express its meaning
- Add an extra ASSERT() inside btrfs_decompress() to make sure the
input/output size never exceeds one sector.
- Use Z_FINISH flag to make sure the decompression happens in one go
- Remove the loop needed to switch input/output buffers
- Use correct destination offset inside the destination page
- Consider early end as an error
After the fix, even on 64K page sized aarch64, above reflink now
works as expected:
# xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest
linked 4096/4096 bytes at offset 61440
And resulted a correct file layout:
item 9 key (258 INODE_ITEM 0) itemoff 15542 itemsize 160
generation 10 transid 10 size 65536 nbytes 4096
block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x0(none)
item 10 key (258 INODE_REF 256) itemoff 15528 itemsize 14
index 3 namelen 4 name: dest
item 11 key (258 XATTR_ITEM 3817753667) itemoff 15445 itemsize 83
location key (0 UNKNOWN.0 0) type XATTR
transid 10 data_len 37 name_len 16
name: security.selinux
data unconfined_u:object_r:unlabeled_t:s0
item 12 key (258 EXTENT_DATA 61440) itemoff 15392 itemsize 53
generation 10 type 1 (regular)
extent data disk byte 13631488 nr 4096
extent data offset 0 nr 4096 ram 4096
extent compression 0 (none)
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add extra sanity check for btrfs_ioctl_defrag_range_args::flags.
This is not really to enhance fuzzing tests, but as a preparation for
future expansion on btrfs_ioctl_defrag_range_args.
In the future we're going to add new members, allowing more fine tuning
for btrfs defrag. Without the -ENONOTSUPP error, there would be no way
to detect if the kernel supports those new defrag features.
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Filipe Manana <fdmanana@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>
Sweet Tea spotted a race between subvolume deletion and snapshotting
that can result in the root item for the snapshot having the
BTRFS_ROOT_SUBVOL_DEAD flag set. The race is:
Thread 1 | Thread 2
----------------------------------------------|----------
btrfs_delete_subvolume |
btrfs_set_root_flags(BTRFS_ROOT_SUBVOL_DEAD)|
|btrfs_mksubvol
| down_read(subvol_sem)
| create_snapshot
| ...
| create_pending_snapshot
| copy root item from source
down_write(subvol_sem) |
This flag is only checked in send and swap activate, which this would
cause to fail mysteriously.
create_snapshot() now checks the root refs to reject a deleted
subvolume, so we can fix this by locking subvol_sem earlier so that the
BTRFS_ROOT_SUBVOL_DEAD flag and the root refs are updated atomically.
CC: stable@vger.kernel.org # 4.14+
Reported-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The btrfs CI reported a lockdep warning as follows by running generic
generic/129.
WARNING: possible circular locking dependency detected
6.7.0-rc5+ #1 Not tainted
------------------------------------------------------
kworker/u5:5/793427 is trying to acquire lock:
ffff88813256d028 (&cache->lock){+.+.}-{2:2}, at: btrfs_zone_finish_one_bg+0x5e/0x130
but task is already holding lock:
ffff88810a23a318 (&fs_info->zone_active_bgs_lock){+.+.}-{2:2}, at: btrfs_zone_finish_one_bg+0x34/0x130
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&fs_info->zone_active_bgs_lock){+.+.}-{2:2}:
...
-> #0 (&cache->lock){+.+.}-{2:2}:
...
This is because we take fs_info->zone_active_bgs_lock after a block_group's
lock in btrfs_zone_activate() while doing the opposite in other places.
Fix the issue by expanding the fs_info->zone_active_bgs_lock's critical
section and taking it before a block_group's lock.
Fixes: a7e1ac7bdc ("btrfs: zoned: reserve zones for an active metadata/system block group")
CC: stable@vger.kernel.org # 6.6
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The error path of btrfs_get_chunk_map() releases
fs_info->mapping_tree_lock. But, it is taken and released in
btrfs_find_chunk_map(). So, there is no need to do so.
Fixes: 7dc66abb5a ("btrfs: use a dedicated data structure for chunk maps")
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When compiling with gcc version 14.0.0 20231220 (experimental)
and W=1, I've noticed the following warning:
fs/btrfs/send.c: In function 'btrfs_ioctl_send':
fs/btrfs/send.c:8208:44: warning: 'kvcalloc' sizes specified with 'sizeof'
in the earlier argument and not in the later argument [-Wcalloc-transposed-args]
8208 | sctx->clone_roots = kvcalloc(sizeof(*sctx->clone_roots),
| ^
Since 'n' and 'size' arguments of 'kvcalloc()' are multiplied to
calculate the final size, their actual order doesn't affect the result
and so this is not a bug. But it's still worth to fix it.
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Writing sequentially to a huge file on btrfs on a SMR HDD revealed a
decline of the performance (220 MiB/s to 30 MiB/s after 500 minutes).
The performance goes down because of increased latency of the extent
allocation, which is induced by a traversing of a lot of full block groups.
So, this patch optimizes the ffe_ctl->hint_byte by choosing a block group
with sufficient size from the active block group list, which does not
contain full block groups.
After applying the patch, the performance is maintained well.
Fixes: 2eda57089e ("btrfs: zoned: implement sequential extent allocation")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out prepare_allocation_zoned() for further extension. While at
it, optimize the if-branch a bit.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@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>
Instead of passing three individual members of 'struct btrfs_io_geometry'
into btrfs_max_io_len(), pass a pointer to btrfs_io_geometry.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of passing three members of 'struct btrfs_io_geometry' into
set_io_stripe() pass a pointer to the whole structure and then get the needed
members out of btrfs_io_geometry.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Open code set_io_stripe() for RAID56, as it
a) uses a different method to calculate the stripe_index
b) doesn't need to go through raid-stripe-tree mapping code.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that all the per-profile if/else statement blocks have been
converted to calls to helper the conversion to switch/case is
straightforward.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have a container for the I/O geometry that has all the needed
information for the block mappings of SINGLE profiles, factor out a helper
calculating this information.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have a container for the I/O geometry that has all the needed
information for the block mappings of RAID5 and RAID6, factor out a helper
calculating this information.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Reduce the scope of 'data_stripes' in btrfs_map_block(). While the
change alone may not make too much sense, it helps us factoring out a
helper function for the block mapping of RAID56 I/O.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have a container for the I/O geometry that has all the needed
information for the block mappings of RAID10, factor out a helper calculating
this information.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have a container for the I/O geometry that has all the needed
information for the block mappings of DUP, factor out a helper calculating
this information.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have a container for the I/O geometry that has all the needed
information for the block mappings of RAID1, factor out a helper calculating
this information.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have a container for the I/O geometry that has all the needed
information for the block mappings of RAID0, factor out a helper calculating
this information.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Re-introduce struct btrfs_io_geometry, holding the necessary bits and
pieces needed in btrfs_map_block() to decide the I/O geometry of a specific
block mapping.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The check in btrfs_map_block() deciding if a particular I/O is targeting a
single device is getting more and more convoluted.
Factor out the check conditions into a helper function, with no functional
change otherwise.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
Test case btrfs/124 failed if larger metadata folio is enabled, the
dying message looks like this:
BTRFS error (device dm-2): bad tree block start, mirror 2 want 31686656 have 0
BTRFS info (device dm-2): read error corrected: ino 0 off 31686656 (dev /dev/mapper/test-scratch2 sector 20928)
BUG: kernel NULL pointer dereference, address: 0000000000000020
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
CPU: 6 PID: 350881 Comm: btrfs Tainted: G OE 6.7.0-rc3-custom+ #128
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 2/2/2022
RIP: 0010:btrfs_read_extent_buffer+0x106/0x180 [btrfs]
PKRU: 55555554
Call Trace:
<TASK>
read_tree_block+0x33/0xb0 [btrfs]
read_block_for_search+0x23e/0x340 [btrfs]
btrfs_search_slot+0x2f9/0xe60 [btrfs]
btrfs_lookup_csum+0x75/0x160 [btrfs]
btrfs_lookup_bio_sums+0x21a/0x560 [btrfs]
btrfs_submit_chunk+0x152/0x680 [btrfs]
btrfs_submit_bio+0x1c/0x50 [btrfs]
submit_one_bio+0x40/0x80 [btrfs]
submit_extent_page+0x158/0x390 [btrfs]
btrfs_do_readpage+0x330/0x740 [btrfs]
extent_readahead+0x38d/0x6c0 [btrfs]
read_pages+0x94/0x2c0
page_cache_ra_unbounded+0x12d/0x190
relocate_file_extent_cluster+0x7c1/0x9d0 [btrfs]
relocate_block_group+0x2d3/0x560 [btrfs]
btrfs_relocate_block_group+0x2c7/0x4b0 [btrfs]
btrfs_relocate_chunk+0x4c/0x1a0 [btrfs]
btrfs_balance+0x925/0x13c0 [btrfs]
btrfs_ioctl+0x19f1/0x25d0 [btrfs]
__x64_sys_ioctl+0x90/0xd0
do_syscall_64+0x3f/0xf0
entry_SYSCALL_64_after_hwframe+0x6e/0x76
[CAUSE]
The dying line is at btrfs_repair_io_failure() call inside
btrfs_repair_eb_io_failure().
The function is still relying on the extent buffer using page sized
folios.
When the extent buffer is using larger folio, we go into the 2nd slot of
folios[], and triggered the NULL pointer dereference.
[FIX]
Migrate btrfs_repair_io_failure() to folio interfaces.
So that when we hit a larger folio, we just submit the whole folio in
one go.
This also affects data repair path through btrfs_end_repair_bio(),
thankfully data is still fully page based, we can just add an
ASSERT(), and use page_folio() to convert the page to folio.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
Test case btrfs/002 would fail if larger folios are enabled for
metadata:
assertion failed: folio, in fs/btrfs/extent_io.c:4358
------------[ cut here ]------------
kernel BUG at fs/btrfs/extent_io.c:4358!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 PID: 30916 Comm: fsstress Tainted: G OE 6.7.0-rc3-custom+ #128
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 2/2/2022
RIP: 0010:assert_eb_folio_uptodate+0x98/0xe0 [btrfs]
Call Trace:
<TASK>
extent_buffer_test_bit+0x3c/0x70 [btrfs]
free_space_test_bit+0xcd/0x140 [btrfs]
modify_free_space_bitmap+0x27a/0x430 [btrfs]
add_to_free_space_tree+0x8d/0x160 [btrfs]
__btrfs_free_extent.isra.0+0xef1/0x13c0 [btrfs]
__btrfs_run_delayed_refs+0x786/0x13c0 [btrfs]
btrfs_run_delayed_refs+0x33/0x120 [btrfs]
btrfs_commit_transaction+0xa2/0x1350 [btrfs]
iterate_supers+0x77/0xe0
ksys_sync+0x60/0xa0
__do_sys_sync+0xa/0x20
do_syscall_64+0x3f/0xf0
entry_SYSCALL_64_after_hwframe+0x6e/0x76
</TASK>
[CAUSE]
The function extent_buffer_test_bit() is not folio compatible.
It still assumes the old fixed page size, when an extent buffer with
large folio passed in, only eb->folios[0] is populated.
Then if the target bit range falls in the 2nd page of the folio, then we
would check eb->folios[1], and trigger the ASSERT().
[FIX]
Just migrate eb_bitmap_offset() to folio interfaces, using the
folio_size() to replace PAGE_SIZE.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we still go the old page based iterator functions, like
bio_for_each_segment_all(), we can hit middle pages of a folio (compound
page).
In that case if we set any page flag on those middle pages, we can
easily trigger VM_BUG_ON(), as for compound page flags, they should
follow their flag policies (normally only set on leading or tail pages).
To avoid such problem in the future full folio migration, here we do:
- Change from bio_for_each_segment_all() to bio_for_each_folio_all()
This completely removes the ability to access the middle page.
- Add extra ASSERT()s for data read/write paths
To ensure we only get single paged folio for data now.
- Rename those end io functions to follow a certain schema
* end_bbio_compressed_read()
* end_bbio_compressed_write()
These two endio functions don't set any page flags, as they use pages
not mapped to any address space.
They can be very good candidates for higher order folio testing.
And they are shared between compression and encoded IO.
* end_bbio_data_read()
* end_bbio_data_write()
* end_bbio_meta_read()
* end_bbio_meta_write()
The old function names are not unified:
- end_bio_extent_writepage()
- end_bio_extent_readpage()
- extent_buffer_write_end_io()
- extent_buffer_read_end_io()
They share no schema on where the "end_*io" string should be, nor can
be confusing just using "extent_buffer" and "extent" to distinguish
data and metadata paths.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Although subpage itself is conflicting with higher folio, since subpage
(sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE) means we will never
need higher order folio, there is a hidden pitfall:
- btrfs_page_*() helpers
Those helpers are an abstraction to handle both subpage and non-subpage
cases, which means we're going to pass pages pointers to those helpers.
And since those helpers are shared between data and metadata paths, it's
unavoidable to let them to handle folios, including higher order
folios).
Meanwhile for true subpage case, we should only have a single page
backed folios anyway, thus add a new ASSERT() for btrfs_subpage_assert()
to ensure that.
Also since those helpers are shared between both data and metadata, add
some extra ASSERT()s for data path to make sure we only get single page
backed folio for now.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These two functions are still using the old page based code, which is
not going to handle larger folios at all.
The migration itself is going to involve the following changes:
- PAGE_SIZE -> folio_size()
- PAGE_SHIFT -> folio_shift()
- get_eb_page_index() -> get_eb_folio_index()
- get_eb_offset_in_page() -> get_eb_offset_in_folio()
And since we're going to support larger folios, although above straight
conversion is good enough, this patch would add extra comments in the
involved functions to explain why the same single line code can now
cover 3 cases:
- folio_size == PAGE_SIZE, sectorsize == PAGE_SIZE, nodesize >= PAGE_SIZE
The common, non-subpage case with per-page folio.
- folio_size > PAGE_SIZE, sectorsize == PAGE_SIZE, nodesize >= PAGE_SIZE
The incoming larger folio, non-subpage case.
- folio_size == PAGE_SIZE, sectorsize < PAGE_SIZE, nodesize < PAGE_SIZE
The existing subpage case, we won't larger folio anyway.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This fixes as case in "btrfs: refactor alloc_extent_buffer() to
allocate-then-attach method".
We have been seeing panics in the CI for the subpage stuff recently, it
happens on btrfs/187 but could potentially happen anywhere.
In the subpage case, if we race with somebody else inserting the same
extent buffer, the error case will end up calling
detach_extent_buffer_page() on the page twice.
This is done first in the bit
for (int i = 0; i < attached; i++)
detach_extent_buffer_page(eb, eb->pages[i];
and then again in btrfs_release_extent_buffer().
This works fine for !subpage because we're the only person who ever has
ourselves on the private, and so when we do the initial
detach_extent_buffer_page() we know we've completely removed it.
However for subpage we could be using this page private elsewhere, so
this results in a double put on the subpage, which can result in an
early freeing.
The fix here is to clear eb->pages[i] for everything we detach. Then
anything still attached to the eb is freed in
btrfs_release_extent_buffer().
Because of this change we must update
btrfs_release_extent_buffer_pages() to not use num_extent_folios,
because it assumes eb->folio[0] is set properly. Since this is only
interested in freeing any pages we have on the extent buffer we can
simply use INLINE_EXTENT_BUFFER_PAGES.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Although we have migrated extent_buffer::pages[] to folios[], we're
still mostly using the folio_page() help to grab the page.
This patch would do the following cleanups for metadata:
- Introduce num_extent_folios() helper
This is to replace most num_extent_pages() callers.
- Use num_extent_folios() to iterate future large folios
This allows us to use things like
bio_add_folio()/bio_add_folio_nofail(), and only set the needed flags
for the folio (aka the leading/tailing page), which reduces the loop
iteration to 1 for large folios.
- Change metadata related functions to use folio pointers
Including their function name, involving:
* attach_extent_buffer_page()
* detach_extent_buffer_page()
* page_range_has_eb()
* btrfs_release_extent_buffer_pages()
* btree_clear_page_dirty()
* btrfs_page_inc_eb_refs()
* btrfs_page_dec_eb_refs()
- Change btrfs_is_subpage() to accept an address_space pointer
This is to allow both page->mapping and folio->mapping to be utilized.
As data is still using the old per-page code, and may keep so for a
while.
- Special corner case place holder for future order mismatches between
extent buffer and inode filemap
For now it's just a block of comments and a dead ASSERT(), no real
handling yet.
The subpage code would still go page, just because subpage and large
folio are conflicting conditions, thus we don't need to bother subpage
with higher order folios at all. Just folio_page(folio, 0) would be
enough.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor styling tweaks ]
Signed-off-by: David Sterba <dsterba@suse.com>
For now extent_buffer::pages[] are still only accepting single page
pointer, thus we can migrate to folios pretty easily.
As for single page, page and folio are 1:1 mapped, including their page
flags.
This patch would just do the conversion from struct page to struct
folio, providing the first step to higher order folio in the future.
This conversion is pretty simple:
- extent_buffer::pages[] -> extent_buffer::folios[]
- page_address(eb->pages[i]) -> folio_address(eb->pages[i])
- eb->pages[i] -> folio_page(eb->folios[i], 0)
There would be more specific cleanups preparing for the incoming higher
order folio support.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently alloc_extent_buffer() utilizes find_or_create_page() to
allocate one page a time for an extent buffer.
This method has the following disadvantages:
- find_or_create_page() is the legacy way of allocating new pages
With the new folio infrastructure, find_or_create_page() is just
redirected to filemap_get_folio().
- Lacks the way to support higher order (order >= 1) folios
As we can not yet let filemap give us a higher order folio.
This patch would change the workflow by the following way:
Old | new
-----------------------------------+-------------------------------------
| ret = btrfs_alloc_page_array();
for (i = 0; i < num_pages; i++) { | for (i = 0; i < num_pages; i++) {
p = find_or_create_page(); | ret = filemap_add_folio();
/* Attach page private */ | /* Reuse page cache if needed */
/* Reused eb if needed */ |
| /* Attach page private and
| reuse eb if needed */
| }
By this we split the page allocation and private attaching into two
parts, allowing future updates to each part more easily, and migrate to
folio interfaces (especially for possible higher order folios).
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The value set as scrub_speed_max accepts size with suffixes
(k/m/g/t/p/e) but we should still validate it for trailing characters,
similar to what we do with chunk_size_store.
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
