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commit 211de93367304ab395357f8cb12568a4d1e20701 upstream.
The transaction is only able to free PERTRANS reservations for a root
once that root has been recorded with the TRANS tag on the roots radix
tree. Therefore, until we are sure that this root will get tagged, it
isn't safe to convert. Generally, this is not an issue as *some*
transaction will likely tag the root before long and this reservation
will get freed in that transaction, but technically it could stick
around until unmount and result in a warning about leaked metadata
reservation space.
This path is most exercised by running the generic/269 fstest with
CONFIG_BTRFS_DEBUG.
Fixes: a6496849671a ("btrfs: fix start transaction qgroup rsv double free")
CC: stable@vger.kernel.org # 6.6+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 71537e35c324ea6fbd68377a4f26bb93a831ae35 upstream.
When running delayed inode updates, we do not record the inode's root in
the transaction, but we do allocate PREALLOC and thus converted PERTRANS
space for it. To be sure we free that PERTRANS meta rsv, we must ensure
that we record the root in the transaction.
Fixes: 4f5427ccce5d ("btrfs: delayed-inode: Use new qgroup meta rsv for delayed inode and item")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 74e97958121aa1f5854da6effba70143f051b0cd upstream.
Create subvolume, create snapshot and delete subvolume all use
btrfs_subvolume_reserve_metadata() to reserve metadata for the changes
done to the parent subvolume's fs tree, which cannot be mediated in the
normal way via start_transaction. When quota groups (squota or qgroups)
are enabled, this reserves qgroup metadata of type PREALLOC. Once the
operation is associated to a transaction, we convert PREALLOC to
PERTRANS, which gets cleared in bulk at the end of the transaction.
However, the error paths of these three operations were not implementing
this lifecycle correctly. They unconditionally converted the PREALLOC to
PERTRANS in a generic cleanup step regardless of errors or whether the
operation was fully associated to a transaction or not. This resulted in
error paths occasionally converting this rsv to PERTRANS without calling
record_root_in_trans successfully, which meant that unless that root got
recorded in the transaction by some other thread, the end of the
transaction would not free that root's PERTRANS, leaking it. Ultimately,
this resulted in hitting a WARN in CONFIG_BTRFS_DEBUG builds at unmount
for the leaked reservation.
The fix is to ensure that every qgroup PREALLOC reservation observes the
following properties:
1. any failure before record_root_in_trans is called successfully
results in freeing the PREALLOC reservation.
2. after record_root_in_trans, we convert to PERTRANS, and now the
transaction owns freeing the reservation.
This patch enforces those properties on the three operations. Without
it, generic/269 with squotas enabled at mkfs time would fail in ~5-10
runs on my system. With this patch, it ran successfully 1000 times in a
row.
Fixes: e85fde5162bf ("btrfs: qgroup: fix qgroup meta rsv leak for subvolume operations")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 141fb8cd206ace23c02cd2791c6da52c1d77d42a upstream.
We use add_root_meta_rsv and sub_root_meta_rsv to track prealloc and
pertrans reservations for subvolumes when quotas are enabled. The
convert function does not properly increment pertrans after decrementing
prealloc, so the count is not accurate.
Note: we check that the fs is not read-only to mirror the logic in
qgroup_convert_meta, which checks that before adding to the pertrans rsv.
Fixes: 8287475a2055 ("btrfs: qgroup: Use root::qgroup_meta_rsv_* to record qgroup meta reserved space")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b2136cc288fce2f24a92f3d656531b2d50ebec5a upstream.
Allocate fs_info and root to have a valid fs_info pointer in case it's
dereferenced by a helper outside of tests, like find_lock_delalloc_range().
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 3c6ee34c6f9cd12802326da26631232a61743501 ]
Change BUG_ON to proper error handling if building the path buffer
fails. The pointers are not printed so we don't accidentally leak kernel
addresses.
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 26b66d1d366a375745755ca7365f67110bbf6bd5 ]
The get_parent handler looks up a parent of a given dentry, this can be
either a subvolume or a directory. The search is set up with offset -1
but it's never expected to find such item, as it would break allowed
range of inode number or a root id. This means it's a corruption (ext4
also returns this error code).
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 7411055db5ce64f836aaffd422396af0075fdc99 ]
The unhandled case in btrfs_relocate_sys_chunks() loop is a corruption,
as it could be caused only by two impossible conditions:
- at first the search key is set up to look for a chunk tree item, with
offset -1, this is an inexact search and the key->offset will contain
the correct offset upon a successful search, a valid chunk tree item
cannot have an offset -1
- after first successful search, the found_key corresponds to a chunk
item, the offset is decremented by 1 before the next loop, it's
impossible to find a chunk item there due to alignment and size
constraints
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 8a565ec04d6c43f330e7401e5af3458431b29bc6 ]
At unpin_extent_cache() if we happen to find an extent map with an
unexpected start offset, we jump to the 'out' label and never release the
reference we added to the extent map through the call to
lookup_extent_mapping(), therefore resulting in a leak. So fix this by
moving the free_extent_map() under the 'out' label.
Fixes: c03c89f821e5 ("btrfs: handle errors returned from unpin_extent_cache()")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 1ec17ef59168a1a6f1105f5dc517f783839a5302 upstream.
Shinichiro reported the following use-after-free triggered by the device
replace operation in fstests btrfs/070.
BTRFS info (device nullb1): scrub: finished on devid 1 with status: 0
==================================================================
BUG: KASAN: slab-use-after-free in do_zone_finish+0x91a/0xb90 [btrfs]
Read of size 8 at addr ffff8881543c8060 by task btrfs-cleaner/3494007
CPU: 0 PID: 3494007 Comm: btrfs-cleaner Tainted: G W 6.8.0-rc5-kts #1
Hardware name: Supermicro Super Server/X11SPi-TF, BIOS 3.3 02/21/2020
Call Trace:
<TASK>
dump_stack_lvl+0x5b/0x90
print_report+0xcf/0x670
? __virt_addr_valid+0x200/0x3e0
kasan_report+0xd8/0x110
? do_zone_finish+0x91a/0xb90 [btrfs]
? do_zone_finish+0x91a/0xb90 [btrfs]
do_zone_finish+0x91a/0xb90 [btrfs]
btrfs_delete_unused_bgs+0x5e1/0x1750 [btrfs]
? __pfx_btrfs_delete_unused_bgs+0x10/0x10 [btrfs]
? btrfs_put_root+0x2d/0x220 [btrfs]
? btrfs_clean_one_deleted_snapshot+0x299/0x430 [btrfs]
cleaner_kthread+0x21e/0x380 [btrfs]
? __pfx_cleaner_kthread+0x10/0x10 [btrfs]
kthread+0x2e3/0x3c0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x31/0x70
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1b/0x30
</TASK>
Allocated by task 3493983:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
__kasan_kmalloc+0xaa/0xb0
btrfs_alloc_device+0xb3/0x4e0 [btrfs]
device_list_add.constprop.0+0x993/0x1630 [btrfs]
btrfs_scan_one_device+0x219/0x3d0 [btrfs]
btrfs_control_ioctl+0x26e/0x310 [btrfs]
__x64_sys_ioctl+0x134/0x1b0
do_syscall_64+0x99/0x190
entry_SYSCALL_64_after_hwframe+0x6e/0x76
Freed by task 3494056:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3f/0x60
poison_slab_object+0x102/0x170
__kasan_slab_free+0x32/0x70
kfree+0x11b/0x320
btrfs_rm_dev_replace_free_srcdev+0xca/0x280 [btrfs]
btrfs_dev_replace_finishing+0xd7e/0x14f0 [btrfs]
btrfs_dev_replace_by_ioctl+0x1286/0x25a0 [btrfs]
btrfs_ioctl+0xb27/0x57d0 [btrfs]
__x64_sys_ioctl+0x134/0x1b0
do_syscall_64+0x99/0x190
entry_SYSCALL_64_after_hwframe+0x6e/0x76
The buggy address belongs to the object at ffff8881543c8000
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 96 bytes inside of
freed 1024-byte region [ffff8881543c8000, ffff8881543c8400)
The buggy address belongs to the physical page:
page:00000000fe2c1285 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1543c8
head:00000000fe2c1285 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x17ffffc0000840(slab|head|node=0|zone=2|lastcpupid=0x1fffff)
page_type: 0xffffffff()
raw: 0017ffffc0000840 ffff888100042dc0 ffffea0019e8f200 dead000000000002
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8881543c7f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881543c7f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881543c8000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881543c8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881543c8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
This UAF happens because we're accessing stale zone information of a
already removed btrfs_device in do_zone_finish().
The sequence of events is as follows:
btrfs_dev_replace_start
btrfs_scrub_dev
btrfs_dev_replace_finishing
btrfs_dev_replace_update_device_in_mapping_tree <-- devices replaced
btrfs_rm_dev_replace_free_srcdev
btrfs_free_device <-- device freed
cleaner_kthread
btrfs_delete_unused_bgs
btrfs_zone_finish
do_zone_finish <-- refers the freed device
The reason for this is that we're using a cached pointer to the chunk_map
from the block group, but on device replace this cached pointer can
contain stale device entries.
The staleness comes from the fact, that btrfs_block_group::physical_map is
not a pointer to a btrfs_chunk_map but a memory copy of it.
Also take the fs_info::dev_replace::rwsem to prevent
btrfs_dev_replace_update_device_in_mapping_tree() from changing the device
underneath us again.
Note: btrfs_dev_replace_update_device_in_mapping_tree() is holding
fs_info::mapping_tree_lock, but as this is a spinning read/write lock we
cannot take it as the call to blkdev_zone_mgmt() requires a memory
allocation which may not sleep.
But btrfs_dev_replace_update_device_in_mapping_tree() is always called with
the fs_info::dev_replace::rwsem held in write mode.
Many thanks to Shinichiro for analyzing the bug.
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
CC: stable@vger.kernel.org # 6.8
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 74098a989b9c3370f768140b7783a7aaec2759b3 upstream.
At the moment scrub_supers() doesn't grab the super block's location via
the zoned device aware btrfs_sb_log_location() but via btrfs_sb_offset().
This leads to checksum errors on 'scrub' as we're not accessing the
correct location of the super block.
So use btrfs_sb_log_location() for getting the super blocks location on
scrub.
Reported-by: WA AM <waautomata@gmail.com>
Link: http://lore.kernel.org/linux-btrfs/CANU2Z0EvUzfYxczLgGUiREoMndE9WdQnbaawV5Fv5gNXptPUKw@mail.gmail.com
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a8b70c7f8600bc77d03c0b032c0662259b9e615e upstream.
Commit f4a9f219411f ("btrfs: do not delete unused block group if it may be
used soon") changed the behaviour of deleting unused block-groups on zoned
filesystems. Starting with this commit, we're using
btrfs_space_info_used() to calculate the number of used bytes in a
space_info. But btrfs_space_info_used() also accounts
btrfs_space_info::bytes_zone_unusable as used bytes.
So if a block group is 100% zone_unusable it is skipped from the deletion
step.
In order not to skip fully zone_unusable block-groups, also check if the
block-group has bytes left that can be used on a zoned filesystem.
Fixes: f4a9f219411f ("btrfs: do not delete unused block group if it may be used soon")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ef1e68236b9153c27cb7cf29ead0c532870d4215 upstream.
There are reports from tree-checker that detects corrupted nodes,
without any obvious pattern so possibly an overwrite in memory.
After some debugging it turns out there's a race when reading an extent
buffer the uptodate status can be missed.
To prevent concurrent reads for the same extent buffer,
read_extent_buffer_pages() performs these checks:
/* (1) */
if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
return 0;
/* (2) */
if (test_and_set_bit(EXTENT_BUFFER_READING, &eb->bflags))
goto done;
At this point, it seems safe to start the actual read operation. Once
that completes, end_bbio_meta_read() does
/* (3) */
set_extent_buffer_uptodate(eb);
/* (4) */
clear_bit(EXTENT_BUFFER_READING, &eb->bflags);
Normally, this is enough to ensure only one read happens, and all other
callers wait for it to finish before returning. Unfortunately, there is
a racey interleaving:
Thread A | Thread B | Thread C
---------+----------+---------
(1) | |
| (1) |
(2) | |
(3) | |
(4) | |
| (2) |
| | (1)
When this happens, thread B kicks of an unnecessary read. Worse, thread
C will see UPTODATE set and return immediately, while the read from
thread B is still in progress. This race could result in tree-checker
errors like this as the extent buffer is concurrently modified:
BTRFS critical (device dm-0): corrupted node, root=256
block=8550954455682405139 owner mismatch, have 11858205567642294356
expect [256, 18446744073709551360]
Fix it by testing UPTODATE again after setting the READING bit, and if
it's been set, skip the unnecessary read.
Fixes: d7172f52e993 ("btrfs: use per-buffer locking for extent_buffer reading")
Link: https://lore.kernel.org/linux-btrfs/CAHk-=whNdMaN9ntZ47XRKP6DBes2E5w7fi-0U3H2+PS18p+Pzw@mail.gmail.com/
Link: https://lore.kernel.org/linux-btrfs/f51a6d5d7432455a6a858d51b49ecac183e0bbc9.1706312914.git.wqu@suse.com/
Link: https://lore.kernel.org/linux-btrfs/c7241ea4-fcc6-48d2-98c8-b5ea790d6c89@gmx.com/
CC: stable@vger.kernel.org # 6.5+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Tavian Barnes <tavianator@tavianator.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor update of changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9f7eb8405dcbc79c5434821e9e3e92abe187ee8e upstream.
Boris managed to create a device capable of changing its maj:min without
altering its device path.
Only multi-devices can be scanned. A device that gets scanned and remains
in the btrfs kernel cache might end up with an incorrect maj:min.
Despite the temp-fsid feature patch did not introduce this bug, it could
lead to issues if the above multi-device is converted to a single device
with a stale maj:min. Subsequently, attempting to mount the same device
with the correct maj:min might mistake it for another device with the same
fsid, potentially resulting in wrongly auto-enabling the temp-fsid feature.
To address this, this patch validates the device's maj:min at the time of
device open and updates it if it has changed since the last scan.
CC: stable@vger.kernel.org # 6.7+
Fixes: a5b8a5f9f835 ("btrfs: support cloned-device mount capability")
Reported-by: Boris Burkov <boris@bur.io>
Co-developed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Boris Burkov <boris@bur.io>#
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d565fffa68560ac540bf3d62cc79719da50d5e7a upstream.
There are reports that since version 6.7 update-grub fails to find the
device of the root on systems without initrd and on a single device.
This looks like the device name changed in the output of
/proc/self/mountinfo:
6.5-rc5 working
18 1 0:16 / / rw,noatime - btrfs /dev/sda8 ...
6.7 not working:
17 1 0:15 / / rw,noatime - btrfs /dev/root ...
and "update-grub" shows this error:
/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?)
This looks like it's related to the device name, but grub-probe
recognizes the "/dev/root" path and tries to find the underlying device.
However there's a special case for some filesystems, for btrfs in
particular.
The generic root device detection heuristic is not done and it all
relies on reading the device infos by a btrfs specific ioctl. This ioctl
returns the device name as it was saved at the time of device scan (in
this case it's /dev/root).
The change in 6.7 for temp_fsid to allow several single device
filesystem to exist with the same fsid (and transparently generate a new
UUID at mount time) was to skip caching/registering such devices.
This also skipped mounted device. One step of scanning is to check if
the device name hasn't changed, and if yes then update the cached value.
This broke the grub-probe as it always read the device /dev/root and
couldn't find it in the system. A temporary workaround is to create a
symlink but this does not survive reboot.
The right fix is to allow updating the device path of a mounted
filesystem even if this is a single device one.
In the fix, check if the device's major:minor number matches with the
cached device. If they do, then we can allow the scan to happen so that
device_list_add() can take care of updating the device path. The file
descriptor remains unchanged.
This does not affect the temp_fsid feature, the UUID of the mounted
filesystem remains the same and the matching is based on device major:minor
which is unique per mounted filesystem.
This covers the path when the device (that exists for all mounted
devices) name changes, updating /dev/root to /dev/sdx. Any other single
device with filesystem and is not mounted is still skipped.
Note that if a system is booted and initial mount is done on the
/dev/root device, this will be the cached name of the device. Only after
the command "btrfs device scan" it will change as it triggers the
rename.
The fix was verified by users whose systems were affected.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=218353
Link: https://lore.kernel.org/lkml/CAKLYgeJ1tUuqLcsquwuFqjDXPSJpEiokrWK2gisPKDZLs8Y2TQ@mail.gmail.com/
Fixes: bc27d6f0aa0e ("btrfs: scan but don't register device on single device filesystem")
CC: stable@vger.kernel.org # 6.7+
Tested-by: Alex Romosan <aromosan@gmail.com>
Tested-by: CHECK_1234543212345@protonmail.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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 4dc1d69c2b101eee0bf071187794ffed2f9c2596 ]
At unpin_extent_range() we print warning messages that are supposed to
print an interval in the form "[X, Y)", with the first element being an
inclusive start offset and the second element being the exclusive end
offset of a range. However we end up printing the range's length instead
of the range's exclusive end offset, so fix that to avoid having confusing
and non-sense messages in case we hit one of these unexpected scenarios.
Fixes: 00deaf04df35 ("btrfs: log messages at unpin_extent_range() during unexpected cases")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit c03c89f821e51325d0e592cf625cf5e0a26fa3a7 ]
We've had numerous attempts to let function unpin_extent_cache() return
void as it only returns 0. There are still error cases to handle so do
that, in addition to the verbose messages. The only caller
btrfs_finish_one_ordered() will now abort the transaction, previously it
let it continue which could lead to further problems.
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 4dc1d69c2b10 ("btrfs: fix warning messages not printing interval at unpin_extent_range()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 86211eea8ae1676cc819d2b4fdc8d995394be07d ]
[BUG]
Currently btrfs can create subvolume with an invalid qgroup inherit
without triggering any error:
# mkfs.btrfs -O quota -f $dev
# mount $dev $mnt
# btrfs subvolume create -i 2/0 $mnt/subv1
# btrfs qgroup show -prce --sync $mnt
Qgroupid Referenced Exclusive Path
-------- ---------- --------- ----
0/5 16.00KiB 16.00KiB <toplevel>
0/256 16.00KiB 16.00KiB subv1
[CAUSE]
We only do a very basic size check for btrfs_qgroup_inherit structure,
but never really verify if the values are correct.
Thus in btrfs_qgroup_inherit() function, we have to skip non-existing
qgroups, and never return any error.
[FIX]
Fix the behavior and introduce extra checks:
- Introduce early check for btrfs_qgroup_inherit structure
Not only the size, but also all the qgroup ids would be verified.
And the timing is very early, so we can return error early.
This early check is very important for snapshot creation, as snapshot
is delayed to transaction commit.
- Drop support for btrfs_qgroup_inherit::num_ref_copies and
num_excl_copies
Those two members are used to specify to copy refr/excl numbers from
other qgroups.
This would definitely mark qgroup inconsistent, and btrfs-progs has
dropped the support for them for a long time.
It's time to drop the support for kernel.
- Verify the supported btrfs_qgroup_inherit::flags
Just in case we want to add extra flags for btrfs_qgroup_inherit.
Now above subvolume creation would fail with -ENOENT other than silently
ignore the non-existing qgroup.
CC: stable@vger.kernel.org # 6.7+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 41044b41ad2c8c8165a42ec6e9a4096826dcf153 ]
Add a convenience helper to get a fs_info from a VFS inode pointer
instead of open coding the chain or using btrfs_sb() that in some cases
does one more pointer hop. This is implemented as a macro (still with
type checking) so we don't need full definitions of struct btrfs_inode,
btrfs_root or btrfs_fs_info.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 86211eea8ae1 ("btrfs: qgroup: validate btrfs_qgroup_inherit parameter")
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit b33d2e535f9b2a1c4210cfc4843ac0dbacbeebcc ]
Add convenience helpers to get a fs_info from a page or folio pointer
instead of open coding the chain or using btrfs_sb() that in some cases
does one more pointer hop. This is implemented as a macro (still with
type checking) so we don't need full definitions of struct page, folio,
btrfs_root and btrfs_fs_info. The latter can't be static inlines as this
would create loop between ctree.h <-> fs.h, or the headers would have to
be restructured.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 86211eea8ae1 ("btrfs: qgroup: validate btrfs_qgroup_inherit parameter")
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit c8293894afa718653688b2fa98ab68317c875a00 ]
Add convenience helpers to get a struct btrfs_inode from a page or folio
pointer instead of open coding the chain or intermediate BTRFS_I. This
is implemented as a macro (still with type checking) so we don't need
full definitions of struct page or address_space.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 86211eea8ae1 ("btrfs: qgroup: validate btrfs_qgroup_inherit parameter")
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 4e00422ee62663e31e611d7de4d2c4aa3f8555f2 ]
The block size stored in the super block is used by subsystems outside
of btrfs and it's a copy of fs_info::sectorsize. Unify that to always
use our sectorsize, with the exception of mount where we first need to
use fixed values (4K) until we read the super block and can set the
sectorsize.
Replace all uses, in most cases it's fewer pointer indirections.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 86211eea8ae1 ("btrfs: qgroup: validate btrfs_qgroup_inherit parameter")
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit dfba9f47730604a46c284f6099a11c5686b6289d ]
Turn set_page_extent_mapped() into a wrapper around this version.
Saves a call to compound_head() for callers who already have a folio
and removes a couple of users of page->mapping.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 86211eea8ae1 ("btrfs: qgroup: validate btrfs_qgroup_inherit parameter")
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit ae6bd7f9b46a29af52ebfac25d395757e2031d0d ]
At contains_pending_extent() the value of the end offset of a chunk we
found in the device's allocation state io tree is inclusive, so when
we calculate the length we pass to the in_range() macro, we must sum
1 to the expression "physical_end - physical_offset".
In practice the wrong calculation should be harmless as chunks sizes
are never 1 byte and we should never have 1 byte ranges of unallocated
space. Nevertheless fix the wrong calculation.
Reported-by: Alex Lyakas <alex.lyakas@zadara.com>
Link: https://lore.kernel.org/linux-btrfs/CAOcd+r30e-f4R-5x-S7sV22RJPe7+pgwherA6xqN2_qe7o4XTg@mail.gmail.com/
Fixes: 1c11b63eff2a ("btrfs: replace pending/pinned chunks lists with io tree")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit d139ded8b9cdb897bb9539eb33311daf9a177fd2 ]
[BUG]
If qgroup is marked inconsistent (e.g. caused by operations needing full
subtree rescan, like creating a snapshot and assign to a higher level
qgroup), btrfs would immediately start leaking its data reserved space.
The following script can easily reproduce it:
mkfs.btrfs -O quota -f $dev
mount $dev $mnt
btrfs subvolume create $mnt/subv1
btrfs qgroup create 1/0 $mnt
# This snapshot creation would mark qgroup inconsistent,
# as the ownership involves different higher level qgroup, thus
# we have to rescan both source and snapshot, which can be very
# time consuming, thus here btrfs just choose to mark qgroup
# inconsistent, and let users to determine when to do the rescan.
btrfs subv snapshot -i 1/0 $mnt/subv1 $mnt/snap1
# Now this write would lead to qgroup rsv leak.
xfs_io -f -c "pwrite 0 64k" $mnt/file1
# And at unmount time, btrfs would report 64K DATA rsv space leaked.
umount $mnt
And we would have the following dmesg output for the unmount:
BTRFS info (device dm-1): last unmount of filesystem 14a3d84e-f47b-4f72-b053-a8a36eef74d3
BTRFS warning (device dm-1): qgroup 0/5 has unreleased space, type 0 rsv 65536
[CAUSE]
Since commit e15e9f43c7ca ("btrfs: introduce
BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING to skip qgroup accounting"),
we introduce a mode for btrfs qgroup to skip the timing consuming
backref walk, if the qgroup is already inconsistent.
But this skip also covered the data reserved freeing, thus the qgroup
reserved space for each newly created data extent would not be freed,
thus cause the leakage.
[FIX]
Make the data extent reserved space freeing mandatory.
The qgroup reserved space handling is way cheaper compared to the
backref walking part, and we always have the super sensitive leak
detector, thus it's definitely worth to always free the qgroup
reserved data space.
Reported-by: Fabian Vogt <fvogt@suse.com>
Fixes: e15e9f43c7ca ("btrfs: introduce BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING to skip qgroup accounting")
CC: stable@vger.kernel.org # 6.1+
Link: https://bugzilla.suse.com/show_bug.cgi?id=1216196
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 978b63f7464abcfd364a6c95f734282c50f3decf ]
For fiemap we recently stopped locking the target extent range for the
whole duration of the fiemap call, in order to avoid a deadlock in a
scenario where the fiemap buffer happens to be a memory mapped range of
the same file. This use case is very unlikely to be useful in practice but
it may be triggered by fuzz testing (syzbot, etc).
This however introduced a race that makes us miss delalloc ranges for
file regions that are currently holes, so the caller of fiemap will not
be aware that there's data for some file regions. This can be quite
serious for some use cases - for example in coreutils versions before 9.0,
the cp program used fiemap to detect holes and data in the source file,
copying only regions with data (extents or delalloc) from the source file
to the destination file in order to preserve holes (see the documentation
for its --sparse command line option). This means that if cp was used
with a source file that had delalloc in a hole, the destination file could
end up without that data, which is effectively a data loss issue, if it
happened to hit the race described below.
The race happens like this:
1) Fiemap is called, without the FIEMAP_FLAG_SYNC flag, for a file that
has delalloc in the file range [64M, 65M[, which is currently a hole;
2) Fiemap locks the inode in shared mode, then starts iterating the
inode's subvolume tree searching for file extent items, without having
the whole fiemap target range locked in the inode's io tree - the
change introduced recently by commit b0ad381fa769 ("btrfs: fix
deadlock with fiemap and extent locking"). It only locks ranges in
the io tree when it finds a hole or prealloc extent since that
commit;
3) Note that fiemap clones each leaf before using it, and this is to
avoid deadlocks when locking a file range in the inode's io tree and
the fiemap buffer is memory mapped to some file, because writing
to the page with btrfs_page_mkwrite() will wait on any ordered extent
for the page's range and the ordered extent needs to lock the range
and may need to modify the same leaf, therefore leading to a deadlock
on the leaf;
4) While iterating the file extent items in the cloned leaf before
finding the hole in the range [64M, 65M[, the delalloc in that range
is flushed and its ordered extent completes - meaning the corresponding
file extent item is in the inode's subvolume tree, but not present in
the cloned leaf that fiemap is iterating over;
5) When fiemap finds the hole in the [64M, 65M[ range by seeing the gap in
the cloned leaf (or a file extent item with disk_bytenr == 0 in case
the NO_HOLES feature is not enabled), it will lock that file range in
the inode's io tree and then search for delalloc by checking for the
EXTENT_DELALLOC bit in the io tree for that range and ordered extents
(with btrfs_find_delalloc_in_range()). But it finds nothing since the
delalloc in that range was already flushed and the ordered extent
completed and is gone - as a result fiemap will not report that there's
delalloc or an extent for the range [64M, 65M[, so user space will be
mislead into thinking that there's a hole in that range.
This could actually be sporadically triggered with test case generic/094
from fstests, which reports a missing extent/delalloc range like this:
# generic/094 2s ... - output mismatch (see /home/fdmanana/git/hub/xfstests/results//generic/094.out.bad)
# --- tests/generic/094.out 2020-06-10 19:29:03.830519425 +0100
# +++ /home/fdmanana/git/hub/xfstests/results//generic/094.out.bad 2024-02-28 11:00:00.381071525 +0000
# @@ -1,3 +1,9 @@
# QA output created by 094
# fiemap run with sync
# fiemap run without sync
# +ERROR: couldn't find extent at 7
# +map is 'HHDDHPPDPHPH'
# +logical: [ 5.. 6] phys: 301517.. 301518 flags: 0x800 tot: 2
# +logical: [ 8.. 8] phys: 301520.. 301520 flags: 0x800 tot: 1
# ...
# (Run 'diff -u /home/fdmanana/git/hub/xfstests/tests/generic/094.out /home/fdmanana/git/hub/xfstests/results//generic/094.out.bad' to see the entire diff)
So in order to fix this, while still avoiding deadlocks in the case where
the fiemap buffer is memory mapped to the same file, change fiemap to work
like the following:
1) Always lock the whole range in the inode's io tree before starting to
iterate the inode's subvolume tree searching for file extent items,
just like we did before commit b0ad381fa769 ("btrfs: fix deadlock with
fiemap and extent locking");
2) Now instead of writing to the fiemap buffer every time we have an extent
to report, write instead to a temporary buffer (1 page), and when that
buffer becomes full, stop iterating the file extent items, unlock the
range in the io tree, release the search path, submit all the entries
kept in that buffer to the fiemap buffer, and then resume the search
for file extent items after locking again the remainder of the range in
the io tree.
The buffer having a size of a page, allows for 146 entries in a system
with 4K pages. This is a large enough value to have a good performance
by avoiding too many restarts of the search for file extent items.
In other words this preserves the huge performance gains made in the
last two years to fiemap, while avoiding the deadlocks in case the
fiemap buffer is memory mapped to the same file (useless in practice,
but possible and exercised by fuzz testing and syzbot).
Fixes: b0ad381fa769 ("btrfs: fix deadlock with fiemap and extent locking")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- fix freeing allocated id for anon dev when snapshot creation fails
- fiemap fixes:
- followup for a recent deadlock fix, ranges that fiemap can access
can still race with ordered extent completion
- make sure fiemap with SYNC flag does not race with writes
* tag 'for-6.8-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix double free of anonymous device after snapshot creation failure
btrfs: ensure fiemap doesn't race with writes when FIEMAP_FLAG_SYNC is given
btrfs: fix race between ordered extent completion and fiemap
|
|
When creating a snapshot we may do a double free of an anonymous device
in case there's an error committing the transaction. The second free may
result in freeing an anonymous device number that was allocated by some
other subsystem in the kernel or another btrfs filesystem.
The steps that lead to this:
1) At ioctl.c:create_snapshot() we allocate an anonymous device number
and assign it to pending_snapshot->anon_dev;
2) Then we call btrfs_commit_transaction() and end up at
transaction.c:create_pending_snapshot();
3) There we call btrfs_get_new_fs_root() and pass it the anonymous device
number stored in pending_snapshot->anon_dev;
4) btrfs_get_new_fs_root() frees that anonymous device number because
btrfs_lookup_fs_root() returned a root - someone else did a lookup
of the new root already, which could some task doing backref walking;
5) After that some error happens in the transaction commit path, and at
ioctl.c:create_snapshot() we jump to the 'fail' label, and after
that we free again the same anonymous device number, which in the
meanwhile may have been reallocated somewhere else, because
pending_snapshot->anon_dev still has the same value as in step 1.
Recently syzbot ran into this and reported the following trace:
------------[ cut here ]------------
ida_free called for id=51 which is not allocated.
WARNING: CPU: 1 PID: 31038 at lib/idr.c:525 ida_free+0x370/0x420 lib/idr.c:525
Modules linked in:
CPU: 1 PID: 31038 Comm: syz-executor.2 Not tainted 6.8.0-rc4-syzkaller-00410-gc02197fc9076 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:ida_free+0x370/0x420 lib/idr.c:525
Code: 10 42 80 3c 28 (...)
RSP: 0018:ffffc90015a67300 EFLAGS: 00010246
RAX: be5130472f5dd000 RBX: 0000000000000033 RCX: 0000000000040000
RDX: ffffc90009a7a000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc90015a673f0 R08: ffffffff81577992 R09: 1ffff92002b4cdb4
R10: dffffc0000000000 R11: fffff52002b4cdb5 R12: 0000000000000246
R13: dffffc0000000000 R14: ffffffff8e256b80 R15: 0000000000000246
FS: 00007fca3f4b46c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f167a17b978 CR3: 000000001ed26000 CR4: 0000000000350ef0
Call Trace:
<TASK>
btrfs_get_root_ref+0xa48/0xaf0 fs/btrfs/disk-io.c:1346
create_pending_snapshot+0xff2/0x2bc0 fs/btrfs/transaction.c:1837
create_pending_snapshots+0x195/0x1d0 fs/btrfs/transaction.c:1931
btrfs_commit_transaction+0xf1c/0x3740 fs/btrfs/transaction.c:2404
create_snapshot+0x507/0x880 fs/btrfs/ioctl.c:848
btrfs_mksubvol+0x5d0/0x750 fs/btrfs/ioctl.c:998
btrfs_mksnapshot+0xb5/0xf0 fs/btrfs/ioctl.c:1044
__btrfs_ioctl_snap_create+0x387/0x4b0 fs/btrfs/ioctl.c:1306
btrfs_ioctl_snap_create_v2+0x1ca/0x400 fs/btrfs/ioctl.c:1393
btrfs_ioctl+0xa74/0xd40
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfe/0x170 fs/ioctl.c:857
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7fca3e67dda9
Code: 28 00 00 00 (...)
RSP: 002b:00007fca3f4b40c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fca3e7abf80 RCX: 00007fca3e67dda9
RDX: 00000000200005c0 RSI: 0000000050009417 RDI: 0000000000000003
RBP: 00007fca3e6ca47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fca3e7abf80 R15: 00007fff6bf95658
</TASK>
Where we get an explicit message where we attempt to free an anonymous
device number that is not currently allocated. It happens in a different
code path from the example below, at btrfs_get_root_ref(), so this change
may not fix the case triggered by syzbot.
To fix at least the code path from the example above, change
btrfs_get_root_ref() and its callers to receive a dev_t pointer argument
for the anonymous device number, so that in case it frees the number, it
also resets it to 0, so that up in the call chain we don't attempt to do
the double free.
CC: stable@vger.kernel.org # 5.10+
Link: https://lore.kernel.org/linux-btrfs/000000000000f673a1061202f630@google.com/
Fixes: e03ee2fe873e ("btrfs: do not ASSERT() if the newly created subvolume already got read")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
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When FIEMAP_FLAG_SYNC is given to fiemap the expectation is that that
are no concurrent writes and we get a stable view of the inode's extent
layout.
When the flag is given we flush all IO (and wait for ordered extents to
complete) and then lock the inode in shared mode, however that leaves open
the possibility that a write might happen right after the flushing and
before locking the inode. So fix this by flushing again after locking the
inode - we leave the initial flushing before locking the inode to avoid
holding the lock and blocking other RO operations while waiting for IO
and ordered extents to complete. The second flushing while holding the
inode's lock will most of the time do nothing or very little since the
time window for new writes to have happened is small.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
For fiemap we recently stopped locking the target extent range for the
whole duration of the fiemap call, in order to avoid a deadlock in a
scenario where the fiemap buffer happens to be a memory mapped range of
the same file. This use case is very unlikely to be useful in practice but
it may be triggered by fuzz testing (syzbot, etc).
However by not locking the target extent range for the whole duration of
the fiemap call we can race with an ordered extent. This happens like
this:
1) The fiemap task finishes processing a file extent item that covers
the file range [512K, 1M[, and that file extent item is the last item
in the leaf currently being processed;
2) And ordered extent for the file range [768K, 2M[, in COW mode,
completes (btrfs_finish_one_ordered()) and the file extent item
covering the range [512K, 1M[ is trimmed to cover the range
[512K, 768K[ and then a new file extent item for the range [768K, 2M[
is inserted in the inode's subvolume tree;
3) The fiemap task calls fiemap_next_leaf_item(), which then calls
btrfs_next_leaf() to find the next leaf / item. This finds that the
the next key following the one we previously processed (its type is
BTRFS_EXTENT_DATA_KEY and its offset is 512K), is the key corresponding
to the new file extent item inserted by the ordered extent, which has
a type of BTRFS_EXTENT_DATA_KEY and an offset of 768K;
4) Later the fiemap code ends up at emit_fiemap_extent() and triggers
the warning:
if (cache->offset + cache->len > offset) {
WARN_ON(1);
return -EINVAL;
}
Since we get 1M > 768K, because the previously emitted entry for the
old extent covering the file range [512K, 1M[ ends at an offset that
is greater than the new extent's start offset (768K). This makes fiemap
fail with -EINVAL besides triggering the warning that produces a stack
trace like the following:
[1621.677651] ------------[ cut here ]------------
[1621.677656] WARNING: CPU: 1 PID: 204366 at fs/btrfs/extent_io.c:2492 emit_fiemap_extent+0x84/0x90 [btrfs]
[1621.677899] Modules linked in: btrfs blake2b_generic (...)
[1621.677951] CPU: 1 PID: 204366 Comm: pool Not tainted 6.8.0-rc5-btrfs-next-151+ #1
[1621.677954] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[1621.677956] RIP: 0010:emit_fiemap_extent+0x84/0x90 [btrfs]
[1621.678033] Code: 2b 4c 89 63 (...)
[1621.678035] RSP: 0018:ffffab16089ffd20 EFLAGS: 00010206
[1621.678037] RAX: 00000000004fa000 RBX: ffffab16089ffe08 RCX: 0000000000009000
[1621.678039] RDX: 00000000004f9000 RSI: 00000000004f1000 RDI: ffffab16089ffe90
[1621.678040] RBP: 00000000004f9000 R08: 0000000000001000 R09: 0000000000000000
[1621.678041] R10: 0000000000000000 R11: 0000000000001000 R12: 0000000041d78000
[1621.678043] R13: 0000000000001000 R14: 0000000000000000 R15: ffff9434f0b17850
[1621.678044] FS: 00007fa6e20006c0(0000) GS:ffff943bdfa40000(0000) knlGS:0000000000000000
[1621.678046] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[1621.678048] CR2: 00007fa6b0801000 CR3: 000000012d404002 CR4: 0000000000370ef0
[1621.678053] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[1621.678055] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[1621.678056] Call Trace:
[1621.678074] <TASK>
[1621.678076] ? __warn+0x80/0x130
[1621.678082] ? emit_fiemap_extent+0x84/0x90 [btrfs]
[1621.678159] ? report_bug+0x1f4/0x200
[1621.678164] ? handle_bug+0x42/0x70
[1621.678167] ? exc_invalid_op+0x14/0x70
[1621.678170] ? asm_exc_invalid_op+0x16/0x20
[1621.678178] ? emit_fiemap_extent+0x84/0x90 [btrfs]
[1621.678253] extent_fiemap+0x766/0xa30 [btrfs]
[1621.678339] btrfs_fiemap+0x45/0x80 [btrfs]
[1621.678420] do_vfs_ioctl+0x1e4/0x870
[1621.678431] __x64_sys_ioctl+0x6a/0xc0
[1621.678434] do_syscall_64+0x52/0x120
[1621.678445] entry_SYSCALL_64_after_hwframe+0x6e/0x76
There's also another case where before calling btrfs_next_leaf() we are
processing a hole or a prealloc extent and we had several delalloc ranges
within that hole or prealloc extent. In that case if the ordered extents
complete before we find the next key, we may end up finding an extent item
with an offset smaller than (or equals to) the offset in cache->offset.
So fix this by changing emit_fiemap_extent() to address these three
scenarios like this:
1) For the first case, steps listed above, adjust the length of the
previously cached extent so that it does not overlap with the current
extent, emit the previous one and cache the current file extent item;
2) For the second case where he had a hole or prealloc extent with
multiple delalloc ranges inside the hole or prealloc extent's range,
and the current file extent item has an offset that matches the offset
in the fiemap cache, just discard what we have in the fiemap cache and
assign the current file extent item to the cache, since it's more up
to date;
3) For the third case where he had a hole or prealloc extent with
multiple delalloc ranges inside the hole or prealloc extent's range
and the offset of the file extent item we just found is smaller than
what we have in the cache, just skip the current file extent item
if its range end at or behind the cached extent's end, because we may
have emitted (to the fiemap user space buffer) delalloc ranges that
overlap with the current file extent item's range. If the file extent
item's range goes beyond the end offset of the cached extent, just
emit the cached extent and cache a subrange of the file extent item,
that goes from the end offset of the cached extent to the end offset
of the file extent item.
Dealing with those cases in those ways makes everything consistent by
reflecting the current state of file extent items in the btree and
without emitting extents that have overlapping ranges (which would be
confusing and violating expectations).
This issue could be triggered often with test case generic/561, and was
also hit and reported by Wang Yugui.
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20240223104619.701F.409509F4@e16-tech.com/
Fixes: b0ad381fa769 ("btrfs: fix deadlock with fiemap and extent locking")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A more fixes for recently reported or discovered problems:
- fix corner case of send that would generate potentially large
stream of zeros if there's a hole at the end of the file
- fix chunk validation in zoned mode on conventional zones, it was
possible to create chunks that would not be allowed on sequential
zones
- fix validation of dev-replace ioctl filenames
- fix KCSAN warnings about access to block reserve struct members"
* tag 'for-6.8-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve
btrfs: fix data races when accessing the reserved amount of block reserves
btrfs: send: don't issue unnecessary zero writes for trailing hole
btrfs: dev-replace: properly validate device names
btrfs: zoned: don't skip block group profile checks on conventional zones
|
|
At btrfs_use_block_rsv() we read the size of a block reserve without
locking its spinlock, which makes KCSAN complain because the size of a
block reserve is always updated while holding its spinlock. The report
from KCSAN is the following:
[653.313148] BUG: KCSAN: data-race in btrfs_update_delayed_refs_rsv [btrfs] / btrfs_use_block_rsv [btrfs]
[653.314755] read to 0x000000017f5871b8 of 8 bytes by task 7519 on cpu 0:
[653.314779] btrfs_use_block_rsv+0xe4/0x2f8 [btrfs]
[653.315606] btrfs_alloc_tree_block+0xdc/0x998 [btrfs]
[653.316421] btrfs_force_cow_block+0x220/0xe38 [btrfs]
[653.317242] btrfs_cow_block+0x1ac/0x568 [btrfs]
[653.318060] btrfs_search_slot+0xda2/0x19b8 [btrfs]
[653.318879] btrfs_del_csums+0x1dc/0x798 [btrfs]
[653.319702] __btrfs_free_extent.isra.0+0xc24/0x2028 [btrfs]
[653.320538] __btrfs_run_delayed_refs+0xd3c/0x2390 [btrfs]
[653.321340] btrfs_run_delayed_refs+0xae/0x290 [btrfs]
[653.322140] flush_space+0x5e4/0x718 [btrfs]
[653.322958] btrfs_preempt_reclaim_metadata_space+0x102/0x2f8 [btrfs]
[653.323781] process_one_work+0x3b6/0x838
[653.323800] worker_thread+0x75e/0xb10
[653.323817] kthread+0x21a/0x230
[653.323836] __ret_from_fork+0x6c/0xb8
[653.323855] ret_from_fork+0xa/0x30
[653.323887] write to 0x000000017f5871b8 of 8 bytes by task 576 on cpu 3:
[653.323906] btrfs_update_delayed_refs_rsv+0x1a4/0x250 [btrfs]
[653.324699] btrfs_add_delayed_data_ref+0x468/0x6d8 [btrfs]
[653.325494] btrfs_free_extent+0x76/0x120 [btrfs]
[653.326280] __btrfs_mod_ref+0x6a8/0x6b8 [btrfs]
[653.327064] btrfs_dec_ref+0x50/0x70 [btrfs]
[653.327849] walk_up_proc+0x236/0xa50 [btrfs]
[653.328633] walk_up_tree+0x21c/0x448 [btrfs]
[653.329418] btrfs_drop_snapshot+0x802/0x1328 [btrfs]
[653.330205] btrfs_clean_one_deleted_snapshot+0x184/0x238 [btrfs]
[653.330995] cleaner_kthread+0x2b0/0x2f0 [btrfs]
[653.331781] kthread+0x21a/0x230
[653.331800] __ret_from_fork+0x6c/0xb8
[653.331818] ret_from_fork+0xa/0x30
So add a helper to get the size of a block reserve while holding the lock.
Reading the field while holding the lock instead of using the data_race()
annotation is used in order to prevent load tearing.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
At space_info.c we have several places where we access the ->reserved
field of a block reserve without taking the block reserve's spinlock
first, which makes KCSAN warn about a data race since that field is
always updated while holding the spinlock.
The reports from KCSAN are like the following:
[117.193526] BUG: KCSAN: data-race in btrfs_block_rsv_release [btrfs] / need_preemptive_reclaim [btrfs]
[117.195148] read to 0x000000017f587190 of 8 bytes by task 6303 on cpu 3:
[117.195172] need_preemptive_reclaim+0x222/0x2f0 [btrfs]
[117.195992] __reserve_bytes+0xbb0/0xdc8 [btrfs]
[117.196807] btrfs_reserve_metadata_bytes+0x4c/0x120 [btrfs]
[117.197620] btrfs_block_rsv_add+0x78/0xa8 [btrfs]
[117.198434] btrfs_delayed_update_inode+0x154/0x368 [btrfs]
[117.199300] btrfs_update_inode+0x108/0x1c8 [btrfs]
[117.200122] btrfs_dirty_inode+0xb4/0x140 [btrfs]
[117.200937] btrfs_update_time+0x8c/0xb0 [btrfs]
[117.201754] touch_atime+0x16c/0x1e0
[117.201789] filemap_read+0x674/0x728
[117.201823] btrfs_file_read_iter+0xf8/0x410 [btrfs]
[117.202653] vfs_read+0x2b6/0x498
[117.203454] ksys_read+0xa2/0x150
[117.203473] __s390x_sys_read+0x68/0x88
[117.203495] do_syscall+0x1c6/0x210
[117.203517] __do_syscall+0xc8/0xf0
[117.203539] system_call+0x70/0x98
[117.203579] write to 0x000000017f587190 of 8 bytes by task 11 on cpu 0:
[117.203604] btrfs_block_rsv_release+0x2e8/0x578 [btrfs]
[117.204432] btrfs_delayed_inode_release_metadata+0x7c/0x1d0 [btrfs]
[117.205259] __btrfs_update_delayed_inode+0x37c/0x5e0 [btrfs]
[117.206093] btrfs_async_run_delayed_root+0x356/0x498 [btrfs]
[117.206917] btrfs_work_helper+0x160/0x7a0 [btrfs]
[117.207738] process_one_work+0x3b6/0x838
[117.207768] worker_thread+0x75e/0xb10
[117.207797] kthread+0x21a/0x230
[117.207830] __ret_from_fork+0x6c/0xb8
[117.207861] ret_from_fork+0xa/0x30
So add a helper to get the reserved amount of a block reserve while
holding the lock. The value may be not be up to date anymore when used by
need_preemptive_reclaim() and btrfs_preempt_reclaim_metadata_space(), but
that's ok since the worst it can do is cause more reclaim work do be done
sooner rather than later. Reading the field while holding the lock instead
of using the data_race() annotation is used in order to prevent load
tearing.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
If we have a sparse file with a trailing hole (from the last extent's end
to i_size) and then create an extent in the file that ends before the
file's i_size, then when doing an incremental send we will issue a write
full of zeroes for the range that starts immediately after the new extent
ends up to i_size. While this isn't incorrect because the file ends up
with exactly the same data, it unnecessarily results in using extra space
at the destination with one or more extents full of zeroes instead of
having a hole. In same cases this results in using megabytes or even
gigabytes of unnecessary space.
Example, reproducer:
$ cat test.sh
#!/bin/bash
DEV=/dev/sdh
MNT=/mnt/sdh
mkfs.btrfs -f $DEV
mount $DEV $MNT
# Create 1G sparse file.
xfs_io -f -c "truncate 1G" $MNT/foobar
# Create base snapshot.
btrfs subvolume snapshot -r $MNT $MNT/mysnap1
# Create send stream (full send) for the base snapshot.
btrfs send -f /tmp/1.snap $MNT/mysnap1
# Now write one extent at the beginning of the file and one somewhere
# in the middle, leaving a gap between the end of this second extent
# and the file's size.
xfs_io -c "pwrite -S 0xab 0 128K" \
-c "pwrite -S 0xcd 512M 128K" \
$MNT/foobar
# Now create a second snapshot which is going to be used for an
# incremental send operation.
btrfs subvolume snapshot -r $MNT $MNT/mysnap2
# Create send stream (incremental send) for the second snapshot.
btrfs send -p $MNT/mysnap1 -f /tmp/2.snap $MNT/mysnap2
# Now recreate the filesystem by receiving both send streams and
# verify we get the same content that the original filesystem had
# and file foobar has only two extents with a size of 128K each.
umount $MNT
mkfs.btrfs -f $DEV
mount $DEV $MNT
btrfs receive -f /tmp/1.snap $MNT
btrfs receive -f /tmp/2.snap $MNT
echo -e "\nFile fiemap in the second snapshot:"
# Should have:
#
# 128K extent at file range [0, 128K[
# hole at file range [128K, 512M[
# 128K extent file range [512M, 512M + 128K[
# hole at file range [512M + 128K, 1G[
xfs_io -r -c "fiemap -v" $MNT/mysnap2/foobar
# File should be using 256K of data (two 128K extents).
echo -e "\nSpace used by the file: $(du -h $MNT/mysnap2/foobar | cut -f 1)"
umount $MNT
Running the test, we can see with fiemap that we get an extent for the
range [512M, 1G[, while in the source filesystem we have an extent for
the range [512M, 512M + 128K[ and a hole for the rest of the file (the
range [512M + 128K, 1G[):
$ ./test.sh
(...)
File fiemap in the second snapshot:
/mnt/sdh/mysnap2/foobar:
EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS
0: [0..255]: 26624..26879 256 0x0
1: [256..1048575]: hole 1048320
2: [1048576..2097151]: 2156544..3205119 1048576 0x1
Space used by the file: 513M
This happens because once we finish processing an inode, at
finish_inode_if_needed(), we always issue a hole (write operations full
of zeros) if there's a gap between the end of the last processed extent
and the file's size, even if that range is already a hole in the parent
snapshot. Fix this by issuing the hole only if the range is not already
a hole.
After this change, running the test above, we get the expected layout:
$ ./test.sh
(...)
File fiemap in the second snapshot:
/mnt/sdh/mysnap2/foobar:
EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS
0: [0..255]: 26624..26879 256 0x0
1: [256..1048575]: hole 1048320
2: [1048576..1048831]: 26880..27135 256 0x1
3: [1048832..2097151]: hole 1048320
Space used by the file: 256K
A test case for fstests will follow soon.
CC: stable@vger.kernel.org # 6.1+
Reported-by: Dorai Ashok S A <dash.btrfs@inix.me>
Link: https://lore.kernel.org/linux-btrfs/c0bf7818-9c45-46a8-b3d3-513230d0c86e@inix.me/
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
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>
|
|
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>
|
|
On a zoned filesystem with conventional zones, we're skipping the block
group profile checks for the conventional zones.
This allows converting a zoned filesystem's data block groups to RAID when
all of the zones backing the chunk are on conventional zones. But this
will lead to problems, once we're trying to allocate chunks backed by
sequential zones.
So also check for conventional zones when loading a block group's profile
on them.
Reported-by: HAN Yuwei <hrx@bupt.moe>
Link: https://lore.kernel.org/all/1ACD2E3643008A17+da260584-2c7f-432a-9e22-9d390aae84cc@bupt.moe/#t
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- Fix a deadlock in fiemap.
There was a big lock around the whole operation that can interfere
with a page fault and mkwrite.
Reducing the lock scope can also speed up fiemap
- Fix range condition for extent defragmentation which could lead to
worse layout in some cases
* tag 'for-6.8-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix deadlock with fiemap and extent locking
btrfs: defrag: avoid unnecessary defrag caused by incorrect extent size
|
|
While working on the patchset to remove extent locking I got a lockdep
splat with fiemap and pagefaulting with my new extent lock replacement
lock.
This deadlock exists with our normal code, we just don't have lockdep
annotations with the extent locking so we've never noticed it.
Since we're copying the fiemap extent to user space on every iteration
we have the chance of pagefaulting. Because we hold the extent lock for
the entire range we could mkwrite into a range in the file that we have
mmap'ed. This would deadlock with the following stack trace
[<0>] lock_extent+0x28d/0x2f0
[<0>] btrfs_page_mkwrite+0x273/0x8a0
[<0>] do_page_mkwrite+0x50/0xb0
[<0>] do_fault+0xc1/0x7b0
[<0>] __handle_mm_fault+0x2fa/0x460
[<0>] handle_mm_fault+0xa4/0x330
[<0>] do_user_addr_fault+0x1f4/0x800
[<0>] exc_page_fault+0x7c/0x1e0
[<0>] asm_exc_page_fault+0x26/0x30
[<0>] rep_movs_alternative+0x33/0x70
[<0>] _copy_to_user+0x49/0x70
[<0>] fiemap_fill_next_extent+0xc8/0x120
[<0>] emit_fiemap_extent+0x4d/0xa0
[<0>] extent_fiemap+0x7f8/0xad0
[<0>] btrfs_fiemap+0x49/0x80
[<0>] __x64_sys_ioctl+0x3e1/0xb50
[<0>] do_syscall_64+0x94/0x1a0
[<0>] entry_SYSCALL_64_after_hwframe+0x6e/0x76
I wrote an fstest to reproduce this deadlock without my replacement lock
and verified that the deadlock exists with our existing locking.
To fix this simply don't take the extent lock for the entire duration of
the fiemap. This is safe in general because we keep track of where we
are when we're searching the tree, so if an ordered extent updates in
the middle of our fiemap call we'll still emit the correct extents
because we know what offset we were on before.
The only place we maintain the lock is searching delalloc. Since the
delalloc stuff can change during writeback we want to lock the extent
range so we have a consistent view of delalloc at the time we're
checking to see if we need to set the delalloc flag.
With this patch applied we no longer deadlock with my testcase.
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
[BUG]
With the following file extent layout, defrag would do unnecessary IO
and result more on-disk space usage.
# mkfs.btrfs -f $dev
# mount $dev $mnt
# xfs_io -f -c "pwrite 0 40m" $mnt/foobar
# sync
# xfs_io -f -c "pwrite 40m 16k" $mnt/foobar
# sync
Above command would lead to the following file extent layout:
item 6 key (257 EXTENT_DATA 0) itemoff 15816 itemsize 53
generation 7 type 1 (regular)
extent data disk byte 298844160 nr 41943040
extent data offset 0 nr 41943040 ram 41943040
extent compression 0 (none)
item 7 key (257 EXTENT_DATA 41943040) itemoff 15763 itemsize 53
generation 8 type 1 (regular)
extent data disk byte 13631488 nr 16384
extent data offset 0 nr 16384 ram 16384
extent compression 0 (none)
Which is mostly fine. We can allow the final 16K to be merged with the
previous 40M, but it's upon the end users' preference.
But if we defrag the file using the default parameters, it would result
worse file layout:
# btrfs filesystem defrag $mnt/foobar
# sync
item 6 key (257 EXTENT_DATA 0) itemoff 15816 itemsize 53
generation 7 type 1 (regular)
extent data disk byte 298844160 nr 41943040
extent data offset 0 nr 8650752 ram 41943040
extent compression 0 (none)
item 7 key (257 EXTENT_DATA 8650752) itemoff 15763 itemsize 53
generation 9 type 1 (regular)
extent data disk byte 340787200 nr 33292288
extent data offset 0 nr 33292288 ram 33292288
extent compression 0 (none)
item 8 key (257 EXTENT_DATA 41943040) itemoff 15710 itemsize 53
generation 8 type 1 (regular)
extent data disk byte 13631488 nr 16384
extent data offset 0 nr 16384 ram 16384
extent compression 0 (none)
Note the original 40M extent is still there, but a new 32M extent is
created for no benefit at all.
[CAUSE]
There is an existing check to make sure we won't defrag a large enough
extent (the threshold is by default 32M).
But the check is using the length to the end of the extent:
range_len = em->len - (cur - em->start);
/* Skip too large extent */
if (range_len >= extent_thresh)
goto next;
This means, for the first 8MiB of the extent, the range_len is always
smaller than the default threshold, and would not be defragged.
But after the first 8MiB, the remaining part would fit the requirement,
and be defragged.
Such different behavior inside the same extent caused the above problem,
and we should avoid different defrag decision inside the same extent.
[FIX]
Instead of using @range_len, just use @em->len, so that we have a
consistent decision among the same file extent.
Now with this fix, we won't touch the extent, thus not making it any
worse.
Reported-by: Filipe Manana <fdmanana@suse.com>
Fixes: 0cb5950f3f3b ("btrfs: fix deadlock when reserving space during defrag")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A few regular fixes and one fix for space reservation regression since
6.7 that users have been reporting:
- fix over-reservation of metadata chunks due to not keeping proper
balance between global block reserve and delayed refs reserve; in
practice this leaves behind empty metadata block groups, the
workaround is to reclaim them by using the '-musage=1' balance
filter
- other space reservation fixes:
- do not delete unused block group if it may be used soon
- do not reserve space for checksums for NOCOW files
- fix extent map assertion failure when writing out free space inode
- reject encoded write if inode has nodatasum flag set
- fix chunk map leak when loading block group zone info"
* tag 'for-6.8-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: don't refill whole delayed refs block reserve when starting transaction
btrfs: zoned: fix chunk map leak when loading block group zone info
btrfs: reject encoded write if inode has nodatasum flag set
btrfs: don't reserve space for checksums when writing to nocow files
btrfs: add new unused block groups to the list of unused block groups
btrfs: do not delete unused block group if it may be used soon
btrfs: add and use helper to check if block group is used
btrfs: don't drop extent_map for free space inode on write error
|
|
Since commit 28270e25c69a ("btrfs: always reserve space for delayed refs
when starting transaction") we started not only to reserve metadata space
for the delayed refs a caller of btrfs_start_transaction() might generate
but also to try to fully refill the delayed refs block reserve, because
there are several case where we generate delayed refs and haven't reserved
space for them, relying on the global block reserve. Relying too much on
the global block reserve is not always safe, and can result in hitting
-ENOSPC during transaction commits or worst, in rare cases, being unable
to mount a filesystem that needs to do orphan cleanup or anything that
requires modifying the filesystem during mount, and has no more
unallocated space and the metadata space is nearly full. This was
explained in detail in that commit's change log.
However the gap between the reserved amount and the size of the delayed
refs block reserve can be huge, so attempting to reserve space for such
a gap can result in allocating many metadata block groups that end up
not being used. After a recent patch, with the subject:
"btrfs: add new unused block groups to the list of unused block groups"
We started to add new block groups that are unused to the list of unused
block groups, to avoid having them around for a very long time in case
they are never used, because a block group is only added to the list of
unused block groups when we deallocate the last extent or when mounting
the filesystem and the block group has 0 bytes used. This is not a problem
introduced by the commit mentioned earlier, it always existed as our
metadata space reservations are, most of the time, pessimistic and end up
not using all the space they reserved, so we can occasionally end up with
one or two unused metadata block groups for a long period. However after
that commit mentioned earlier, we are just more pessimistic in the
metadata space reservations when starting a transaction and therefore the
issue is more likely to happen.
This however is not always enough because we might create unused metadata
block groups when reserving metadata space at a high rate if there's
always a gap in the delayed refs block reserve and the cleaner kthread
isn't triggered often enough or is busy with other work (running delayed
iputs, cleaning deleted roots, etc), not to mention the block group's
allocated space is only usable for a new block group after the transaction
used to remove it is committed.
A user reported that he's getting a lot of allocated metadata block groups
but the usage percentage of metadata space was very low compared to the
total allocated space, specially after running a series of block group
relocations.
So for now stop trying to refill the gap in the delayed refs block reserve
and reserve space only for the delayed refs we are expected to generate
when starting a transaction.
CC: stable@vger.kernel.org # 6.7+
Reported-by: Ivan Shapovalov <intelfx@intelfx.name>
Link: https://lore.kernel.org/linux-btrfs/9cdbf0ca9cdda1b4c84e15e548af7d7f9f926382.camel@intelfx.name/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H6802ayLHUJFztzZAVzBLJAGdFx=6FHNNy87+obZXXZpQ@mail.gmail.com/
Tested-by: Ivan Shapovalov <intelfx@intelfx.name>
Reported-by: Heddxh <g311571057@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CAE93xANEby6RezOD=zcofENYZOT-wpYygJyauyUAZkLv6XVFOA@mail.gmail.com/
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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At btrfs_load_block_group_zone_info() we never drop a reference on the
chunk map we have looked up, therefore leaking a reference on it. So
add the missing btrfs_free_chunk_map() at the end of the function.
Fixes: 7dc66abb5a47 ("btrfs: use a dedicated data structure for chunk maps")
Reported-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently we allow an encoded write against inodes that have the NODATASUM
flag set, either because they are NOCOW files or they were created while
the filesystem was mounted with "-o nodatasum". This results in having
compressed extents without corresponding checksums, which is a filesystem
inconsistency reported by 'btrfs check'.
For example, running btrfs/281 with MOUNT_OPTIONS="-o nodatacow" triggers
this and 'btrfs check' errors out with:
[1/7] checking root items
[2/7] checking extents
[3/7] checking free space tree
[4/7] checking fs roots
root 256 inode 257 errors 1040, bad file extent, some csum missing
root 256 inode 258 errors 1040, bad file extent, some csum missing
ERROR: errors found in fs roots
(...)
So reject encoded writes if the target inode has NODATASUM set.
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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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>
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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 28270e25c69a ("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>
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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>
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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>
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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>
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|
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- two fixes preventing deletion and manual creation of subvolume qgroup
- unify error code returned for unknown send flags
- fix assertion during subvolume creation when anonymous device could
be allocated by other thread (e.g. due to backref walk)
* tag 'for-6.8-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: do not ASSERT() if the newly created subvolume already got read
btrfs: forbid deleting live subvol qgroup
btrfs: forbid creating subvol qgroups
btrfs: send: return EOPNOTSUPP on unknown flags
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[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: 2dfb1e43f57d ("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>
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