- 24 Feb, 2017 10 commits
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Filipe Manana authored
If we have a file with an implicit hole (NO_HOLES feature enabled) that has an extent following the hole, delayed writes against regions of the file behind the hole happened before but were not yet flushed and then we truncate the file to a smaller size that lies inside the hole, we end up persisting a wrong disk_i_size value for our inode that leads to data loss after umounting and mounting again the filesystem or after the inode is evicted and loaded again. This happens because at inode.c:btrfs_truncate_inode_items() we end up setting last_size to the offset of the extent that we deleted and that followed the hole. We then pass that value to btrfs_ordered_update_i_size() which updates the inode's disk_i_size to a value smaller then the offset of the buffered (delayed) writes. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "pwrite -S 0x01 0K 32K" /mnt/foo $ xfs_io -d -c "pwrite -S 0x02 -b 32K 64K 32K" /mnt/foo $ xfs_io -c "truncate 60K" /mnt/foo --> inode's disk_i_size updated to 0 $ md5sum /mnt/foo 3c5ca3c3ab42f4b04d7e7eb0b0d4d806 /mnt/foo $ umount /dev/sdb $ mount /dev/sdb /mnt $ md5sum /mnt/foo d41d8cd98f00b204e9800998ecf8427e /mnt/foo --> Empty file, all data lost! Cc: <stable@vger.kernel.org> # 3.14+ Fixes: 16e7549f ("Btrfs: incompatible format change to remove hole extents") Signed-off-by:
Filipe Manana <fdmanana@suse.com> Reviewed-by:
Liu Bo <bo.li.liu@oracle.com>
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Filipe Manana authored
When using the NO_HOLES feature, during an incremental send we often issue write operations for holes when we should not, because that range is already a hole in the destination snapshot. While that does not change the contents of the file at the receiver, it avoids preservation of file holes, leading to wasted disk space and extra IO during send/receive. A couple examples where the holes are not preserved follows. $ mkfs.btrfs -O no-holes -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "pwrite -S 0xaa 0 4K" /mnt/foo $ xfs_io -f -c "pwrite -S 0xaa 0 4K" -c "pwrite -S 0xbb 1028K 4K" /mnt/bar $ btrfs subvolume snapshot -r /mnt /mnt/snap1 # Now add one new extent to our first test file, increasing its size and # leaving a 1Mb hole between the first extent and this new extent. $ xfs_io -c "pwrite -S 0xbb 1028K 4K" /mnt/foo # Now overwrite the last extent of our second test file. $ xfs_io -c "pwrite -S 0xcc 1028K 4K" /mnt/bar $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ xfs_io -r -c "fiemap -v" /mnt/snap2/foo /mnt/snap2/foo: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..7]: 25088..25095 8 0x2000 1: [8..2055]: hole 2048 2: [2056..2063]: 24576..24583 8 0x2001 $ xfs_io -r -c "fiemap -v" /mnt/snap2/bar /mnt/snap2/bar: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..7]: 25096..25103 8 0x2000 1: [8..2055]: hole 2048 2: [2056..2063]: 24584..24591 8 0x2001 $ btrfs send /mnt/snap1 -f /tmp/1.snap $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/2.snap $ umount /mnt # It's not relevant to enable no-holes in the new filesystem. $ mkfs.btrfs -O no-holes -f /dev/sdc $ mount /dev/sdc /mnt $ btrfs receive /mnt -f /tmp/1.snap $ btrfs receive /mnt -f /tmp/2.snap $ xfs_io -r -c "fiemap -v" /mnt/snap2/foo /mnt/snap2/foo: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..7]: 24576..24583 8 0x2000 1: [8..2063]: 25624..27679 2056 0x1 $ xfs_io -r -c "fiemap -v" /mnt/snap2/bar /mnt/snap2/bar: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..7]: 24584..24591 8 0x2000 1: [8..2063]: 27680..29735 2056 0x1 The holes do not exist in the second filesystem and they were replaced with extents filled with the byte 0x00, making each file take 1032Kb of space instead of 8Kb. So fix this by not issuing the write operations consisting of buffers filled with the byte 0x00 when the destination snapshot already has a hole for the respective range. A test case for fstests will follow soon. Signed-off-by: -
Filipe Manana authored
Before we destroy all work queues (and wait for their tasks to complete) we were destroying the work queues used for metadata I/O operations, which can result in a use-after-free problem because most tasks from all work queues do metadata I/O operations. For example, the tasks from the caching workers work queue (fs_info->caching_workers), which is destroyed only after the work queue used for metadata reads (fs_info->endio_meta_workers) is destroyed, do metadata reads, which result in attempts to queue tasks into the later work queue, triggering a use-after-free with a trace like the following: [23114.613543] general protection fault: 0000 [#1] PREEMPT SMP [23114.614442] Modules linked in: dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio libcrc32c btrfs xor raid6_pq dm_flakey dm_mod crc32c_generic acpi_cpufreq tpm_tis tpm_tis_core tpm ppdev parport_pc parport i2c_piix4 processor sg evdev i2c_core psmouse pcspkr serio_raw button loop autofs4 ext4 crc16 jbd2 mbcache sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix virtio_pci libata virtio_ring virtio e1000 scsi_mod floppy [last unloaded: scsi_debug] [23114.616932] CPU: 9 PID: 4537 Comm: kworker/u32:8 Not tainted 4.9.0-rc7-btrfs-next-36+ #1 [23114.616932] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014 [23114.616932] Workqueue: btrfs-cache btrfs_cache_helper [btrfs] [23114.616932] task: ffff880221d45780 task.stack: ffffc9000bc50000 [23114.616932] RIP: 0010:[<ffffffffa037c1bf>] [<ffffffffa037c1bf>] btrfs_queue_work+0x2c/0x190 [btrfs] [23114.616932] RSP: 0018:ffff88023f443d60 EFLAGS: 00010246 [23114.616932] RAX: 0000000000000000 RBX: 6b6b6b6b6b6b6b6b RCX: 0000000000000102 [23114.616932] RDX: ffffffffa0419000 RSI: ffff88011df534f0 RDI: ffff880101f01c00 [23114.616932] RBP: ffff88023f443d80 R08: 00000000000f7000 R09: 000000000000ffff [23114.616932] R10: ffff88023f443d48 R11: 0000000000001000 R12: ffff88011df534f0 [23114.616932] R13: ffff880135963868 R14: 0000000000001000 R15: 0000000000001000 [23114.616932] FS: 0000000000000000(0000) GS:ffff88023f440000(0000) knlGS:0000000000000000 [23114.616932] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [23114.616932] CR2: 00007f0fb9f8e520 CR3: 0000000001a0b000 CR4: 00000000000006e0 [23114.616932] Stack: [23114.616932] ffff880101f01c00 ffff88011df534f0 ffff880135963868 0000000000001000 [23114.616932] ffff88023f443da0 ffffffffa03470af ffff880149b37200 ffff880135963868 [23114.616932] ffff88023f443db8 ffffffff8125293c ffff880149b37200 ffff88023f443de0 [23114.616932] Call Trace: [23114.616932] <IRQ> [23114.616932] [<ffffffffa03470af>] end_workqueue_bio+0xd5/0xda [btrfs] [23114.616932] [<ffffffff8125293c>] bio_endio+0x54/0x57 [23114.616932] [<ffffffffa0377929>] btrfs_end_bio+0xf7/0x106 [btrfs] [23114.616932] [<ffffffff8125293c>] bio_endio+0x54/0x57 [23114.616932] [<ffffffff8125955f>] blk_update_request+0x21a/0x30f [23114.616932] [<ffffffffa0022316>] scsi_end_request+0x31/0x182 [scsi_mod] [23114.616932] [<ffffffffa00235fc>] scsi_io_completion+0x1ce/0x4c8 [scsi_mod] [23114.616932] [<ffffffffa001ba9d>] scsi_finish_command+0x104/0x10d [scsi_mod] [23114.616932] [<ffffffffa002311f>] scsi_softirq_done+0x101/0x10a [scsi_mod] [23114.616932] [<ffffffff8125fbd9>] blk_done_softirq+0x82/0x8d [23114.616932] [<ffffffff814c8a4b>] __do_softirq+0x1ab/0x412 [23114.616932] [<ffffffff8105b01d>] irq_exit+0x49/0x99 [23114.616932] [<ffffffff81035135>] smp_call_function_single_interrupt+0x24/0x26 [23114.616932] [<ffffffff814c7ec9>] call_function_single_interrupt+0x89/0x90 [23114.616932] <EOI> [23114.616932] [<ffffffffa0023262>] ? scsi_request_fn+0x13a/0x2a1 [scsi_mod] [23114.616932] [<ffffffff814c5966>] ? _raw_spin_unlock_irq+0x2c/0x4a [23114.616932] [<ffffffff814c596c>] ? _raw_spin_unlock_irq+0x32/0x4a [23114.616932] [<ffffffff814c5966>] ? _raw_spin_unlock_irq+0x2c/0x4a [23114.616932] [<ffffffffa0023262>] scsi_request_fn+0x13a/0x2a1 [scsi_mod] [23114.616932] [<ffffffff8125590e>] __blk_run_queue_uncond+0x22/0x2b [23114.616932] [<ffffffff81255930>] __blk_run_queue+0x19/0x1b [23114.616932] [<ffffffff8125ab01>] blk_queue_bio+0x268/0x282 [23114.616932] [<ffffffff81258f44>] generic_make_request+0xbd/0x160 [23114.616932] [<ffffffff812590e7>] submit_bio+0x100/0x11d [23114.616932] [<ffffffff81298603>] ? __this_cpu_preempt_check+0x13/0x15 [23114.616932] [<ffffffff812a1805>] ? __percpu_counter_add+0x8e/0xa7 [23114.616932] [<ffffffffa03bfd47>] btrfsic_submit_bio+0x1a/0x1d [btrfs] [23114.616932] [<ffffffffa0377db2>] btrfs_map_bio+0x1f4/0x26d [btrfs] [23114.616932] [<ffffffffa0348a33>] btree_submit_bio_hook+0x74/0xbf [btrfs] [23114.616932] [<ffffffffa03489bf>] ? btrfs_wq_submit_bio+0x160/0x160 [btrfs] [23114.616932] [<ffffffffa03697a9>] submit_one_bio+0x6b/0x89 [btrfs] [23114.616932] [<ffffffffa036f5be>] read_extent_buffer_pages+0x170/0x1ec [btrfs] [23114.616932] [<ffffffffa03471fa>] ? free_root_pointers+0x64/0x64 [btrfs] [23114.616932] [<ffffffffa0348adf>] readahead_tree_block+0x3f/0x4c [btrfs] [23114.616932] [<ffffffffa032e115>] read_block_for_search.isra.20+0x1ce/0x23d [btrfs] [23114.616932] [<ffffffffa032fab8>] btrfs_search_slot+0x65f/0x774 [btrfs] [23114.616932] [<ffffffffa036eff1>] ? free_extent_buffer+0x73/0x7e [btrfs] [23114.616932] [<ffffffffa0331ba4>] btrfs_next_old_leaf+0xa1/0x33c [btrfs] [23114.616932] [<ffffffffa0331e4f>] btrfs_next_leaf+0x10/0x12 [btrfs] [23114.616932] [<ffffffffa0336aa6>] caching_thread+0x22d/0x416 [btrfs] [23114.616932] [<ffffffffa037bce9>] btrfs_scrubparity_helper+0x187/0x3b6 [btrfs] [23114.616932] [<ffffffffa037c036>] btrfs_cache_helper+0xe/0x10 [btrfs] [23114.616932] [<ffffffff8106cf96>] process_one_work+0x273/0x4e4 [23114.616932] [<ffffffff8106d6db>] worker_thread+0x1eb/0x2ca [23114.616932] [<ffffffff8106d4f0>] ? rescuer_thread+0x2b6/0x2b6 [23114.616932] [<ffffffff81072a81>] kthread+0xd5/0xdd [23114.616932] [<ffffffff810729ac>] ? __kthread_unpark+0x5a/0x5a [23114.616932] [<ffffffff814c6257>] ret_from_fork+0x27/0x40 [23114.616932] Code: 1f 44 00 00 55 48 89 e5 41 56 41 55 41 54 53 49 89 f4 48 8b 46 70 a8 04 74 09 48 8b 5f 08 48 85 db 75 03 48 8b 1f 49 89 5c 24 68 <83> 7b 64 ff 74 04 f0 ff 43 58 49 83 7c 24 08 00 74 2c 4c 8d 6b [23114.616932] RIP [<ffffffffa037c1bf>] btrfs_queue_work+0x2c/0x190 [btrfs] [23114.616932] RSP <ffff88023f443d60> [23114.689493] ---[ end trace 6e48b6bc707ca34b ]--- [23114.690166] Kernel panic - not syncing: Fatal exception in interrupt [23114.691283] Kernel Offset: disabled [23114.691918] ---[ end Kernel panic - not syncing: Fatal exception in interrupt The following diagram shows the sequence of operations that lead to the use-after-free problem from the above trace: CPU 1 CPU 2 CPU 3 caching_thread() close_ctree() btrfs_stop_all_workers() btrfs_destroy_workqueue( fs_info->endio_meta_workers) btrfs_search_slot() read_block_for_search() readahead_tree_block() read_extent_buffer_pages() submit_one_bio() btree_submit_bio_hook() btrfs_bio_wq_end_io() --> sets the bio's bi_end_io callback to end_workqueue_bio() --> bio is submitted bio completes and its bi_end_io callback is invoked --> end_workqueue_bio() --> attempts to queue a task on fs_info->endio_meta_workers btrfs_destroy_workqueue( fs_info->caching_workers) So fix this by destroying the queues used for metadata I/O tasks only after destroying all the other queues. Signed-off-by: -
Filipe Manana authored
At close_ctree() we free the block groups and then only after we wait for any running worker kthreads to finish and shutdown the workqueues. This behaviour is racy and it triggers an assertion failure when freeing block groups because while we are doing it we can have for example a block group caching kthread running, and in that case the block group's reference count can still be greater than 1 by the time we assert its reference count is 1, leading to an assertion failure: [19041.198004] assertion failed: atomic_read(&block_group->count) == 1, file: fs/btrfs/extent-tree.c, line: 9799 [19041.200584] ------------[ cut here ]------------ [19041.201692] kernel BUG at fs/btrfs/ctree.h:3418! [19041.202830] invalid opcode: 0000 [#1] PREEMPT SMP [19041.203929] Modules linked in: btrfs xor raid6_pq dm_flakey dm_mod crc32c_generic ppdev sg psmouse acpi_cpufreq pcspkr parport_pc evdev tpm_tis parport tpm_tis_core i2c_piix4 i2c_core tpm serio_raw processor button loop autofs4 ext4 crc16 jbd2 mbcache sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix virtio_pci libata virtio_ring virtio e1000 scsi_mod floppy [last unloaded: btrfs] [19041.208082] CPU: 6 PID: 29051 Comm: umount Not tainted 4.9.0-rc7-btrfs-next-36+ #1 [19041.208082] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014 [19041.208082] task: ffff88015f028980 task.stack: ffffc9000ad34000 [19041.208082] RIP: 0010:[<ffffffffa03e319e>] [<ffffffffa03e319e>] assfail.constprop.41+0x1c/0x1e [btrfs] [19041.208082] RSP: 0018:ffffc9000ad37d60 EFLAGS: 00010286 [19041.208082] RAX: 0000000000000061 RBX: ffff88015ecb4000 RCX: 0000000000000001 [19041.208082] RDX: ffff88023f392fb8 RSI: ffffffff817ef7ba RDI: 00000000ffffffff [19041.208082] RBP: ffffc9000ad37d60 R08: 0000000000000001 R09: 0000000000000000 [19041.208082] R10: ffffc9000ad37cb0 R11: ffffffff82f2b66d R12: ffff88023431d170 [19041.208082] R13: ffff88015ecb40c0 R14: ffff88023431d000 R15: ffff88015ecb4100 [19041.208082] FS: 00007f44f3d42840(0000) GS:ffff88023f380000(0000) knlGS:0000000000000000 [19041.208082] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [19041.208082] CR2: 00007f65d623b000 CR3: 00000002166f2000 CR4: 00000000000006e0 [19041.208082] Stack: [19041.208082] ffffc9000ad37d98 ffffffffa035989f ffff88015ecb4000 ffff88015ecb5630 [19041.208082] ffff88014f6be000 0000000000000000 00007ffcf0ba6a10 ffffc9000ad37df8 [19041.208082] ffffffffa0368cd4 ffff88014e9658e0 ffffc9000ad37e08 ffffffff811a634d [19041.208082] Call Trace: [19041.208082] [<ffffffffa035989f>] btrfs_free_block_groups+0x17f/0x392 [btrfs] [19041.208082] [<ffffffffa0368cd4>] close_ctree+0x1c5/0x2e1 [btrfs] [19041.208082] [<ffffffff811a634d>] ? evict_inodes+0x132/0x141 [19041.208082] [<ffffffffa034356d>] btrfs_put_super+0x15/0x17 [btrfs] [19041.208082] [<ffffffff8118fc32>] generic_shutdown_super+0x6a/0xeb [19041.208082] [<ffffffff8119004f>] kill_anon_super+0x12/0x1c [19041.208082] [<ffffffffa0343370>] btrfs_kill_super+0x16/0x21 [btrfs] [19041.208082] [<ffffffff8118fad1>] deactivate_locked_super+0x3b/0x68 [19041.208082] [<ffffffff8118fb34>] deactivate_super+0x36/0x39 [19041.208082] [<ffffffff811a9946>] cleanup_mnt+0x58/0x76 [19041.208082] [<ffffffff811a99a2>] __cleanup_mnt+0x12/0x14 [19041.208082] [<ffffffff81071573>] task_work_run+0x6f/0x95 [19041.208082] [<ffffffff81001897>] prepare_exit_to_usermode+0xa3/0xc1 [19041.208082] [<ffffffff81001a23>] syscall_return_slowpath+0x16e/0x1d2 [19041.208082] [<ffffffff814c607d>] entry_SYSCALL_64_fastpath+0xab/0xad [19041.208082] Code: c7 ae a0 3e a0 48 89 e5 e8 4e 74 d4 e0 0f 0b 55 89 f1 48 c7 c2 0b a4 3e a0 48 89 fe 48 c7 c7 a4 a6 3e a0 48 89 e5 e8 30 74 d4 e0 <0f> 0b 55 31 d2 48 89 e5 e8 d5 b9 f7 ff 5d c3 48 63 f6 55 31 c9 [19041.208082] RIP [<ffffffffa03e319e>] assfail.constprop.41+0x1c/0x1e [btrfs] [19041.208082] RSP <ffffc9000ad37d60> [19041.279264] ---[ end trace 23330586f16f064d ]--- This started happening as of kernel 4.8, since commit f3bca802 ("Btrfs: add ASSERT for block group's memory leak") introduced these assertions. So fix this by freeing the block groups only after waiting for all worker kthreads to complete and shutdown the workqueues. Signed-off-by:
-
Filipe Manana authored
We log holes explicitly by using file extent items, however when replaying a log tree, if a logged file extent item corresponds to a hole and the NO_HOLES feature is enabled we do not need to copy the file extent item into the fs/subvolume tree, as the absence of such file extent items is the purpose of the NO_HOLES feature. So skip the copying of file extent items representing holes when the NO_HOLES feature is enabled. Signed-off-by: -
Robbie Ko authored
When falling back from a nocow write to a regular cow write, we were leaking the subvolume writers counter in 2 situations, preventing snapshot creation from ever completing in the future, as it waits for that counter to go down to zero before the snapshot creation starts. Signed-off-by:
Robbie Ko <robbieko@synology.com> Reviewed-by:
-
Filipe Manana authored
Very often we have the checksums for an extent spread in multiple items in the checksums tree, and currently the algorithm to delete them starts by looking for them one by one and then deleting them one by one, which is not optimal since each deletion involves shifting all the other items in the leaf and when the leaf reaches some low threshold, to move items off the leaf into its left and right neighbor leafs. Also, after each item deletion we release our search path and start a new search for other checksums items. So optimize this by deleting in bulk all the items in the same leaf that contain checksums for the extent being freed. Signed-off-by:
-
Robbie Ko authored
When both the parent and send snapshots have a directory inode with the same number but different generations (therefore they are different inodes) and both have an entry with the same name, an incremental send stream will contain an invalid rmdir operation that refers to the orphanized name of the inode from the parent snapshot. The following example scenario shows how this happens. Parent snapshot: . |---- d259_old/ (ino 259, gen 9) | |---- d1/ (ino 258, gen 9) | |---- f (ino 257, gen 9) Send snapshot: . |---- d258/ (ino 258, gen 7) |---- d259/ (ino 259, gen 7) |---- d1/ (ino 257, gen 7) When the kernel is processing inode 258 it notices that in both snapshots there is an inode numbered 259 that is a parent of an inode 258. However it ignores the fact that the inodes numbered 259 have different generations in both snapshots, which means they are effectively different inodes. Then it checks that both inodes 259 have a dentry named "d1" and because of that it issues a rmdir operation with orphanized name of the inode 258 from the parent snapshot. This happens at send.c:process_record_refs(), which calls send.c:did_overwrite_first_ref() that returns true and because of that later on at process_recorded_refs() such rmdir operation is issued because the inode being currently processed (258) is a directory and it was deleted in the send snapshot (and replaced with another inode that has the same number and is a directory too). Fix this issue by comparing the generations of parent directory inodes that have the same number and make send.c:did_overwrite_first_ref() when the generations are different. The following steps reproduce the problem. $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ touch /mnt/f $ mkdir /mnt/d1 $ mkdir /mnt/d259_old $ mv /mnt/d1 /mnt/d259_old/d1 $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ btrfs send /mnt/snap1 -f /tmp/1.snap $ umount /mnt $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt $ mkdir /mnt/d1 $ mkdir /mnt/dir258 $ mkdir /mnt/dir259 $ mv /mnt/d1 /mnt/dir259/d1 $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs receive /mnt/ -f /tmp/1.snap # Take note that once the filesystem is created, its current # generation has value 7 so the inodes from the second snapshot all have # a generation value of 7. And after receiving the first snapshot # the filesystem is at a generation value of 10, because the call to # create the second snapshot bumps the generation to 8 (the snapshot # creation ioctl does a transaction commit), the receive command calls # the snapshot creation ioctl to create the first snapshot, which bumps # the filesystem's generation to 9, and finally when the receive # operation finishes it calls an ioctl to transition the first snapshot # (snap1) from RW mode to RO mode, which does another transaction commit # and bumps the filesystem's generation to 10. This means all the inodes # in the first snapshot (snap1) have a generation value of 9. $ rm -f /tmp/1.snap $ btrfs send /mnt/snap1 -f /tmp/1.snap $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/2.snap $ umount /mnt $ mkfs.btrfs -f /dev/sdd $ mount /dev/sdd /mnt $ btrfs receive /mnt -f /tmp/1.snap $ btrfs receive -vv /mnt -f /tmp/2.snap receiving snapshot mysnap2 uuid=9c03962f-f620-0047-9f98-32e5a87116d9, ctransid=7 parent_uuid=d17a6e3f-14e5-df4f-be39-a7951a5399aa, parent_ctransid=9 utimes unlink f mkdir o257-7-0 mkdir o259-7-0 rename o257-7-0 -> o259-7-0/d1 chown o259-7-0/d1 - uid=0, gid=0 chmod o259-7-0/d1 - mode=0755 utimes o259-7-0/d1 rmdir o258-9-0 ERROR: rmdir o258-9-0 failed: No such file or directory Signed-off-by: -
Filipe Manana authored
When we are checking if we need to delay the rename operation for an inode we not checking if a parent inode that exists in the send and parent snapshots is really the same inode or not, that is, we are not comparing the generation number of the parent inode in the send and parent snapshots. Not only this results in unnecessarily delaying a rename operation but also can later on make us generate an incorrect name for a new inode in the send snapshot that has the same number as another inode in the parent snapshot but a different generation. Here follows an example where this happens. Parent snapshot: . (ino 256, gen 3) |--- dir258/ (ino 258, gen 7) | |--- dir257/ (ino 257, gen 7) | |--- dir259/ (ino 259, gen 7) Send snapshot: . (ino 256, gen 3) |--- file258 (ino 258, gen 10) | |--- new_dir259/ (ino 259, gen 10) |--- dir257/ (ino 257, gen 7) The following steps happen when computing the incremental send stream: 1) When processing inode 257, its new parent is created using its orphan name (o257-21-0), and the rename operation for inode 257 is delayed because its new parent (inode 259) was not yet processed - this decision to delay the rename operation does not make much sense because the inode 259 in the send snapshot is a new inode, it's not the same as inode 259 in the parent snapshot. 2) When processing inode 258 we end up delaying its rmdir operation, because inode 257 was not yet renamed (moved away from the directory inode 258 represents). We also create the new inode 258 using its orphan name "o258-10-0", then rename it to its final name of "file258" and then issue a truncate operation for it. However this truncate operation contains an incorrect name, which corresponds to the orphan name and not to the final name, which makes the receiver fail. This happens because when we attempt to compute the inode's current name we verify that there's another inode with the same number (258) that has its rmdir operation pending and because of that we generate an orphan name for the new inode 258 (we do this in the function get_cur_path()). Fix this by not delayed the rename operation of an inode if it has parents with the same number but different generations in both snapshots. The following steps reproduce this example scenario. $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ mkdir /mnt/dir257 $ mkdir /mnt/dir258 $ mkdir /mnt/dir259 $ mv /mnt/dir257 /mnt/dir258/dir257 $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ mv /mnt/dir258/dir257 /mnt/dir257 $ rmdir /mnt/dir258 $ rmdir /mnt/dir259 # Remount the filesystem so that the next created inodes will have the # numbers 258 and 259. This is because when a filesystem is mounted, # btrfs sets the subvolume's inode counter to a value corresponding to # the highest inode number in the subvolume plus 1. This inode counter # is used to assign a unique number to each new inode and it's # incremented by 1 after very inode creation. # Note: we unmount and then mount instead of doing a mount with # "-o remount" because otherwise the inode counter remains at value 260. $ umount /mnt $ mount /dev/sdb /mnt $ touch /mnt/file258 $ mkdir /mnt/new_dir259 $ mv /mnt/dir257 /mnt/new_dir259/dir257 $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs send /mnt/snap1 -f /tmp/1.snap $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/2.snap $ umount /mnt $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt $ btrfs receive /mnt -f /tmo/1.snap $ btrfs receive /mnt -f /tmo/2.snap -vv receiving snapshot mysnap2 uuid=e059b6d1-7f55-f140-8d7c-9a3039d23c97, ctransid=10 parent_uuid=77e98cb6-8762-814f-9e05-e8ba877fc0b0, parent_ctransid=7 utimes mkdir o259-10-0 rename dir258 -> o258-7-0 utimes mkfile o258-10-0 rename o258-10-0 -> file258 utimes truncate o258-10-0 size=0 ERROR: truncate o258-10-0 failed: No such file or directory Reported-by: -
Robbie Ko authored
Under certain situations, an incremental send operation can fail due to a premature attempt to create a new top level inode (a direct child of the subvolume/snapshot root) whose name collides with another inode that was removed from the send snapshot. Consider the following example scenario. Parent snapshot: . (ino 256, gen 8) |---- a1/ (ino 257, gen 9) |---- a2/ (ino 258, gen 9) Send snapshot: . (ino 256, gen 3) |---- a2/ (ino 257, gen 7) In this scenario, when receiving the incremental send stream, the btrfs receive command fails like this (ran in verbose mode, -vv argument): rmdir a1 mkfile o257-7-0 rename o257-7-0 -> a2 ERROR: rename o257-7-0 -> a2 failed: Is a directory What happens when computing the incremental send stream is: 1) An operation to remove the directory with inode number 257 and generation 9 is issued. 2) An operation to create the inode with number 257 and generation 7 is issued. This creates the inode with an orphanized name of "o257-7-0". 3) An operation rename the new inode 257 to its final name, "a2", is issued. This is incorrect because inode 258, which has the same name and it's a child of the same parent (root inode 256), was not yet processed and therefore no rmdir operation for it was yet issued. The rename operation is issued because we fail to detect that the name of the new inode 257 collides with inode 258, because their parent, a subvolume/snapshot root (inode 256) has a different generation in both snapshots. So fix this by ignoring the generation value of a parent directory that matches a root inode (number 256) when we are checking if the name of the inode currently being processed collides with the name of some other inode that was not yet processed. We can achieve this scenario of different inodes with the same number but different generation values either by mounting a filesystem with the inode cache option (-o inode_cache) or by creating and sending snapshots across different filesystems, like in the following example: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ mkdir /mnt/a1 $ mkdir /mnt/a2 $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ btrfs send /mnt/snap1 -f /tmp/1.snap $ umount /mnt $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt $ touch /mnt/a2 $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs receive /mnt -f /tmp/1.snap # Take note that once the filesystem is created, its current # generation has value 7 so the inode from the second snapshot has # a generation value of 7. And after receiving the first snapshot # the filesystem is at a generation value of 10, because the call to # create the second snapshot bumps the generation to 8 (the snapshot # creation ioctl does a transaction commit), the receive command calls # the snapshot creation ioctl to create the first snapshot, which bumps # the filesystem's generation to 9, and finally when the receive # operation finishes it calls an ioctl to transition the first snapshot # (snap1) from RW mode to RO mode, which does another transaction commit # and bumps the filesystem's generation to 10. $ rm -f /tmp/1.snap $ btrfs send /mnt/snap1 -f /tmp/1.snap $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/2.snap $ umount /mnt $ mkfs.btrfs -f /dev/sdd $ mount /dev/sdd /mnt $ btrfs receive /mnt /tmp/1.snap # Receive of snapshot snap2 used to fail. $ btrfs receive /mnt /tmp/2.snap Signed-off-by:
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- 22 Feb, 2017 2 commits
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Liu Bo authored
'BTRFS_ORDERED_REGULAR' was introduced for the cow case in patch 'Btrfs: specify a new ordered extent type for create_io_em', but it missed the directIO cow case. Signed-off-by:
Chris Mason <clm@fb.com>
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Filipe Manana authored
If we are deduping two ranges of the same file we need to make sure that we lock all pages in ascending order, that is, lock first the pages from the range with lower offset and then the pages from the other range, as otherwise we can deadlock with a concurrent task that is starting delalloc (writeback). Example trace: [74073.052218] INFO: task kworker/u32:10:17997 blocked for more than 120 seconds. [74073.053889] Tainted: G W 4.9.0-rc7-btrfs-next-36+ #1 [74073.055071] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [74073.056696] kworker/u32:10 D 0 17997 2 0x00000000 [74073.058606] Workqueue: writeback wb_workfn (flush-btrfs-53176) [74073.061370] ffff880031e79858 ffff8802159d2580 ffff880237004580 ffff880031e79240 [74073.064784] ffff88023f4978c0 ffffc9000817b638 ffffffff814c15e1 0000000000000000 [74073.068386] ffff88023f4978d8 ffff88023f4978c0 000000000017b620 ffff880031e79240 [74073.071712] Call Trace: [74073.072884] [<ffffffff814c15e1>] ? __schedule+0x48f/0x6f4 [74073.075395] [<ffffffff814c1c8b>] ? bit_wait+0x2f/0x2f [74073.077511] [<ffffffff814c18d2>] schedule+0x8c/0xa0 [74073.079440] [<ffffffff814c4b36>] schedule_timeout+0x43/0xff [74073.081637] [<ffffffff8110953e>] ? time_hardirqs_on+0x9/0x14 [74073.083809] [<ffffffff81095c67>] ? trace_hardirqs_on_caller+0x16/0x197 [74073.086314] [<ffffffff810bde98>] ? timekeeping_get_ns+0x1e/0x32 [74073.100654] [<ffffffff810be048>] ? ktime_get+0x41/0x52 [74073.102619] [<ffffffff814c10f0>] io_schedule_timeout+0xa0/0x102 [74073.104771] [<ffffffff814c10f0>] ? io_schedule_timeout+0xa0/0x102 [74073.106969] [<ffffffff814c1ca6>] bit_wait_io+0x1b/0x39 [74073.108954] [<ffffffff814c1fb8>] __wait_on_bit_lock+0x4f/0x99 [74073.110981] [<ffffffff8112b692>] __lock_page+0x6b/0x6d [74073.112833] [<ffffffff8108ceb4>] ? autoremove_wake_function+0x3a/0x3a [74073.115010] [<ffffffffa031178b>] lock_page+0x2f/0x32 [btrfs] [74073.116999] [<ffffffffa0311d9f>] lock_delalloc_pages+0xc7/0x1a0 [btrfs] [74073.119243] [<ffffffffa0313d15>] find_lock_delalloc_range+0xc3/0x1a4 [btrfs] [74073.121636] [<ffffffffa0313e81>] writepage_delalloc.isra.31+0x8b/0x134 [btrfs] [74073.124229] [<ffffffffa0315d69>] __extent_writepage+0x1c1/0x2bf [btrfs] [74073.126372] [<ffffffffa03160f2>] extent_write_cache_pages.isra.30.constprop.49+0x28b/0x36c [btrfs] [74073.129371] [<ffffffffa03165b9>] extent_writepages+0x4b/0x5c [btrfs] [74073.131440] [<ffffffffa02fcb59>] ? insert_reserved_file_extent.constprop.42+0x261/0x261 [btrfs] [74073.134303] [<ffffffff811b4ce4>] ? writeback_sb_inodes+0xe0/0x4a1 [74073.136298] [<ffffffffa02fab7f>] btrfs_writepages+0x28/0x2a [btrfs] [74073.138248] [<ffffffff81138200>] do_writepages+0x23/0x2c [74073.139910] [<ffffffff811b3cab>] __writeback_single_inode+0x105/0x6d2 [74073.142003] [<ffffffff811b4e96>] writeback_sb_inodes+0x292/0x4a1 [74073.136298] [<ffffffffa02fab7f>] btrfs_writepages+0x28/0x2a [btrfs] [74073.138248] [<ffffffff81138200>] do_writepages+0x23/0x2c [74073.139910] [<ffffffff811b3cab>] __writeback_single_inode+0x105/0x6d2 [74073.142003] [<ffffffff811b4e96>] writeback_sb_inodes+0x292/0x4a1 [74073.143911] [<ffffffff811b511b>] __writeback_inodes_wb+0x76/0xae [74073.145787] [<ffffffff811b53ca>] wb_writeback+0x1cc/0x4d7 [74073.147452] [<ffffffff811b60cd>] wb_workfn+0x194/0x37d [74073.149084] [<ffffffff811b60cd>] ? wb_workfn+0x194/0x37d [74073.150726] [<ffffffff8106ce77>] ? process_one_work+0x154/0x4e4 [74073.152694] [<ffffffff8106cf96>] process_one_work+0x273/0x4e4 [74073.154452] [<ffffffff8106d6db>] worker_thread+0x1eb/0x2ca [74073.156138] [<ffffffff8106d4f0>] ? rescuer_thread+0x2b6/0x2b6 [74073.157837] [<ffffffff81072a81>] kthread+0xd5/0xdd [74073.159339] [<ffffffff810729ac>] ? __kthread_unpark+0x5a/0x5a [74073.161088] [<ffffffff814c6257>] ret_from_fork+0x27/0x40 [74073.162680] INFO: lockdep is turned off. [74073.163855] INFO: task do-dedup:30264 blocked for more than 120 seconds. [74073.181180] Tainted: G W 4.9.0-rc7-btrfs-next-36+ #1 [74073.181180] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [74073.185296] fdm-stress D 0 30264 29974 0x00000000 [74073.186810] ffff880089595118 ffff880211b8eac0 ffff880237030380 ffff880089594b00 [74073.188998] ffff88023f2978c0 ffffc900063abb68 ffffffff814c15e1 0000000000000000 [74073.191070] ffff88023f2978d8 ffff88023f2978c0 00000000003abb50 ffff880089594b00 [74073.193286] Call Trace: [74073.193990] [<ffffffff814c15e1>] ? __schedule+0x48f/0x6f4 [74073.195418] [<ffffffff814c1c8b>] ? bit_wait+0x2f/0x2f [74073.196796] [<ffffffff814c18d2>] schedule+0x8c/0xa0 [74073.198163] [<ffffffff814c4b36>] schedule_timeout+0x43/0xff [74073.199621] [<ffffffff81095df5>] ? trace_hardirqs_on+0xd/0xf [74073.201100] [<ffffffff810bde98>] ? timekeeping_get_ns+0x1e/0x32 [74073.202686] [<ffffffff810be048>] ? ktime_get+0x41/0x52 [74073.204051] [<ffffffff814c10f0>] io_schedule_timeout+0xa0/0x102 [74073.205585] [<ffffffff814c10f0>] ? io_schedule_timeout+0xa0/0x102 [74073.207123] [<ffffffff814c1ca6>] bit_wait_io+0x1b/0x39 [74073.208238] [<ffffffff814c1fb8>] __wait_on_bit_lock+0x4f/0x99 [74073.208871] [<ffffffff8112b692>] __lock_page+0x6b/0x6d [74073.209430] [<ffffffff8108ceb4>] ? autoremove_wake_function+0x3a/0x3a [74073.210101] [<ffffffff8112b800>] lock_page+0x2f/0x32 [74073.210636] [<ffffffff8112c502>] pagecache_get_page+0x5e/0x153 [74073.211270] [<ffffffffa03257eb>] gather_extent_pages+0x4e/0x109 [btrfs] [74073.212166] [<ffffffffa032a04c>] btrfs_dedupe_file_range+0x1e1/0x4dd [btrfs] [74073.213257] [<ffffffff8118d9b5>] vfs_dedupe_file_range+0x1c1/0x221 [74073.214086] [<ffffffff8119e0c4>] do_vfs_ioctl+0x442/0x600 [74073.214767] [<ffffffff811a7874>] ? rcu_read_unlock+0x5b/0x5d [74073.215619] [<ffffffff811a7953>] ? __fget+0x6b/0x77 [74073.216338] [<ffffffff8119e2d9>] SyS_ioctl+0x57/0x79 [74073.217149] [<ffffffff814c5fea>] entry_SYSCALL_64_fastpath+0x18/0xad [74073.218102] [<ffffffff81109552>] ? time_hardirqs_off+0x9/0x14 [74073.218968] [<ffffffff810938ce>] ? trace_hardirqs_off_caller+0x1f/0xaa [74073.219938] INFO: lockdep is turned off. What happened was the following: CPU 1 CPU 2 btrfs_dedupe_file_range() --> using same inode as source and target --> src range is [768K, 1Mb[ --> dst range is [0, 256K[ btrfs_cmp_data_prepare() --> calls gather_extent_pages() for range [768K, 1Mb[ and locks all pages in that range do_writepages() btrfs_writepages() extent_writepages() extent_write_cache_pages() __extent_writepage() writepage_delalloc() find_lock_delalloc_range() --> finds range [0, 1Mb[ lock_delalloc_pages() --> locks all pages in the range [0, 768K[ --> tries to lock page at offset 768K --> deadlock --> calls gather_extent_pages() to lock pages in the range [0, 256K[ --> deadlock, task at CPU 1 already locked that range and it's trying to lock the range we locked previously So fix this by making sure that during a dedup we always lock first the pages from the range with lower offset. Signed-off-by:
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- 17 Feb, 2017 28 commits
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Jeff Mahoney authored
Commit e5d6b12f (Btrfs: don't WARN() in btrfs_transaction_abort() for IO errors) added a pr_debug call to be printed when a transaction is aborted with -EIO instead of WARN. btrfs_debug prints which file system the message is associated with so let's use that instead. Signed-off-by:
Jeff Mahoney <jeffm@suse.com> Signed-off-by:
David Sterba <dsterba@suse.com>
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Jeff Mahoney authored
btrfs_truncate_free_space_cache always allocates a btrfs_path structure but only uses it when the caller passes a block group. Let's move the allocation and free into the conditional. Signed-off-by:
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Jeff Mahoney authored
The free space cache APIs accept a root but always use the tree root. Also, btrfs_truncate_free_space_cache accepts a root AND an inode but the inode always points to the root anyway, so let's just pass the inode. Signed-off-by:
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Jeff Mahoney authored
btrfs_inc_block_group_ro is either passed the extent root or the dev root, but it doesn't do anything with the dev tree. Let's convert to passing an fs_info and using the extent root. Signed-off-by:
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Jeff Mahoney authored
We don't need to pass a root to flush_space since it always uses the fs_root. Signed-off-by:
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Jeff Mahoney authored
Outside of interactions with qgroups, the roots passed in extent-tree.c are usually passed to ensure that we don't do refcounts on log trees or to get the allocation profile for an allocation request. Otherwise, it operates on the extent root. This patch converts some more routines in extent-tree.c that are always called with the extent root to accept an fs_info instead. Signed-off-by:
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Qu Wenruo authored
Just as Filipe pointed out, the most time consuming parts of qgroup are btrfs_qgroup_account_extents() and btrfs_qgroup_prepare_account_extents(). Which both call btrfs_find_all_roots() to get old_roots and new_roots ulist. What makes things worse is, we're calling that expensive btrfs_find_all_roots() at transaction committing time with TRANS_STATE_COMMIT_DOING, which will blocks all incoming transaction. Such behavior is necessary for @new_roots search as current btrfs_find_all_roots() can't do it correctly so we do call it just before switch commit roots. However for @old_roots search, it's not necessary as such search is based on commit_root, so it will always be correct and we can move it out of transaction committing. This patch moves the @old_roots search part out of commit_transaction(), so in theory we can half the time qgroup time consumption at commit_transaction(). But please note that, this won't speedup qgroup overall, the total time consumption is still the same, just reduce the performance stall. Cc: Filipe Manana <fdmanana@suse.com> Signed-off-by:
Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by:
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David Sterba authored
Never used. Reviewed-by:
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David Sterba authored
Both unused after the call to update_cache_item has been moved to __btrfs_wait_cache_io. Reviewed-by:
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David Sterba authored
bitmap_list is unused since the io_ctl framework. Reviewed-by:
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David Sterba authored
Unused since the helper has been split, eb used in the caller. Reviewed-by:
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David Sterba authored
Never used. Reviewed-by:
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David Sterba authored
After the page locking has been reworked, we get all pages prepared via cmp_pages. Reviewed-by:
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David Sterba authored
Never used. Reviewed-by:
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David Sterba authored
Never used. Reviewed-by:
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David Sterba authored
The name parameters have never been used, as the name is passed via the dentry. Reviewed-by:
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David Sterba authored
The 'device' used to be added in that function, but now it's done by the caller. Reviewed-by:
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David Sterba authored
We grab fs_info from other parameters. Reviewed-by:
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David Sterba authored
Never used for anything meaningful since we have our own superblock filler. Reviewed-by:
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David Sterba authored
The 'tree' was used to call locking hook that does not exist anymore. Reviewed-by:
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David Sterba authored
Never used. Reviewed-by:
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David Sterba authored
The logic has been updated in "Btrfs: make mapping->writeback_index point to the last written page" (a9132667) and page is not needed anymore. Reviewed-by:
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David Sterba authored
This used to hold number of maximum pages to allocate, but this is now limited by BIO_MAX_PAGES. The local are now unused and removed as well. Reviewed-by:
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David Sterba authored
Not needed. Reviewed-by:
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David Sterba authored
Never needed. Reviewed-by:
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David Sterba authored
None of the checks need to know the ro/rw status as they're all not changing the superblock. Moreover, we can access the sb flags directly if we'd need to decide by the ro/rw status. Reviewed-by:
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David Sterba authored
Added but never used. Reviewed-by:
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David Sterba authored
Unused since qgroup refactoring that split data and metadata accounting, the btrfs_qgroup_free helper. Reviewed-by:
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