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2021-08-23btrfs: zoned: suppress reclaim error message on EAGAINNaohiro Aota1-1/+1
btrfs_relocate_chunk() can fail with -EAGAIN when e.g. send operations are running. The message can fail btrfs/187 and it's unnecessary because we anyway add it back to the reclaim list. btrfs_reclaim_bgs_work() `-> btrfs_relocate_chunk() `-> btrfs_relocate_block_group() `-> reloc_chunk_start() `-> if (fs_info->send_in_progress) `-> return -EAGAIN CC: stable@vger.kernel.org # 5.13+ Fixes: 18bb8bbf13c1 ("btrfs: zoned: automatically reclaim zones") Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-08-23btrfs: rescue: allow ibadroots to skip bad extent tree when reading block ↵Qu Wenruo1-0/+19
group items When extent tree gets corrupted, normally it's not extent tree root, but one toasted tree leaf/node. In that case, rescue=ibadroots mount option won't help as it can only handle the extent tree root corruption. This patch will enhance the behavior by: - Allow fill_dummy_bgs() to ignore -EEXIST error This means we may have some block group items read from disk, but then hit some error halfway. - Fallback to fill_dummy_bgs() if any error gets hit in btrfs_read_block_groups() Of course, this still needs rescue=ibadroots mount option. With that, rescue=ibadroots can handle extent tree corruption more gracefully and allow a better recover chance. Reported-by: Zhenyu Wu <wuzy001@gmail.com> Link: https://www.spinics.net/lists/linux-btrfs/msg114424.html Reviewed-by: Su Yue <l@damenly.su> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-08-23btrfs: make btrfs_finish_chunk_alloc private to block-group.cNikolay Borisov1-2/+91
One of the final things that must be done to add a new chunk is inserting its device extent items in the device tree. They describe the portion of allocated device physical space during phase 1 of chunk allocation. This is currently done in btrfs_finish_chunk_alloc whose name isn't very informative. What's more, this function is only used in block-group.c but is defined as public. There isn't anything special about it that would warrant it being defined in volumes.c. Just move btrfs_finish_chunk_alloc and alloc_chunk_dev_extent to block-group.c, make the former static and rename both functions to insert_dev_extents and insert_dev_extent respectively. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-07btrfs: don't block if we can't acquire the reclaim lockJohannes Thumshirn1-1/+9
If we can't acquire the reclaim_bgs_lock on block group reclaim, we block until it is free. This can potentially stall for a long time. While reclaim of block groups is necessary for a good user experience on a zoned file system, there still is no need to block as it is best effort only, just like when we're deleting unused block groups. CC: stable@vger.kernel.org # 5.13 Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-07btrfs: rework chunk allocation to avoid exhaustion of the system chunk arrayFilipe Manana1-36/+249
Commit eafa4fd0ad0607 ("btrfs: fix exhaustion of the system chunk array due to concurrent allocations") fixed a problem that resulted in exhausting the system chunk array in the superblock when there are many tasks allocating chunks in parallel. Basically too many tasks enter the first phase of chunk allocation without previous tasks having finished their second phase of allocation, resulting in too many system chunks being allocated. That was originally observed when running the fallocate tests of stress-ng on a PowerPC machine, using a node size of 64K. However that commit also introduced a deadlock where a task in phase 1 of the chunk allocation waited for another task that had allocated a system chunk to finish its phase 2, but that other task was waiting on an extent buffer lock held by the first task, therefore resulting in both tasks not making any progress. That change was later reverted by a patch with the subject "btrfs: fix deadlock with concurrent chunk allocations involving system chunks", since there is no simple and short solution to address it and the deadlock is relatively easy to trigger on zoned filesystems, while the system chunk array exhaustion is not so common. This change reworks the chunk allocation to avoid the system chunk array exhaustion. It accomplishes that by making the first phase of chunk allocation do the updates of the device items in the chunk btree and the insertion of the new chunk item in the chunk btree. This is done while under the protection of the chunk mutex (fs_info->chunk_mutex), in the same critical section that checks for available system space, allocates a new system chunk if needed and reserves system chunk space. This way we do not have chunk space reserved until the second phase completes. The same logic is applied to chunk removal as well, since it keeps reserved system space long after it is done updating the chunk btree. For direct allocation of system chunks, the previous behaviour remains, because otherwise we would deadlock on extent buffers of the chunk btree. Changes to the chunk btree are by large done by chunk allocation and chunk removal, which first reserve chunk system space and then later do changes to the chunk btree. The other remaining cases are uncommon and correspond to adding a device, removing a device and resizing a device. All these other cases do not pre-reserve system space, they modify the chunk btree right away, so they don't hold reserved space for a long period like chunk allocation and chunk removal do. The diff of this change is huge, but more than half of it is just addition of comments describing both how things work regarding chunk allocation and removal, including both the new behavior and the parts of the old behavior that did not change. CC: stable@vger.kernel.org # 5.12+ Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Tested-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-07btrfs: fix deadlock with concurrent chunk allocations involving system chunksFilipe Manana1-57/+1
When a task attempting to allocate a new chunk verifies that there is not currently enough free space in the system space_info and there is another task that allocated a new system chunk but it did not finish yet the creation of the respective block group, it waits for that other task to finish creating the block group. This is to avoid exhaustion of the system chunk array in the superblock, which is limited, when we have a thundering herd of tasks allocating new chunks. This problem was described and fixed by commit eafa4fd0ad0607 ("btrfs: fix exhaustion of the system chunk array due to concurrent allocations"). However there are two very similar scenarios where this can lead to a deadlock: 1) Task B allocated a new system chunk and task A is waiting on task B to finish creation of the respective system block group. However before task B ends its transaction handle and finishes the creation of the system block group, it attempts to allocate another chunk (like a data chunk for an fallocate operation for a very large range). Task B will be unable to progress and allocate the new chunk, because task A set space_info->chunk_alloc to 1 and therefore it loops at btrfs_chunk_alloc() waiting for task A to finish its chunk allocation and set space_info->chunk_alloc to 0, but task A is waiting on task B to finish creation of the new system block group, therefore resulting in a deadlock; 2) Task B allocated a new system chunk and task A is waiting on task B to finish creation of the respective system block group. By the time that task B enter the final phase of block group allocation, which happens at btrfs_create_pending_block_groups(), when it modifies the extent tree, the device tree or the chunk tree to insert the items for some new block group, it needs to allocate a new chunk, so it ends up at btrfs_chunk_alloc() and keeps looping there because task A has set space_info->chunk_alloc to 1, but task A is waiting for task B to finish creation of the new system block group and release the reserved system space, therefore resulting in a deadlock. In short, the problem is if a task B needs to allocate a new chunk after it previously allocated a new system chunk and if another task A is currently waiting for task B to complete the allocation of the new system chunk. Unfortunately this deadlock scenario introduced by the previous fix for the system chunk array exhaustion problem does not have a simple and short fix, and requires a big change to rework the chunk allocation code so that chunk btree updates are all made in the first phase of chunk allocation. And since this deadlock regression is being frequently hit on zoned filesystems and the system chunk array exhaustion problem is triggered in more extreme cases (originally observed on PowerPC with a node size of 64K when running the fallocate tests from stress-ng), revert the changes from that commit. The next patch in the series, with a subject of "btrfs: rework chunk allocation to avoid exhaustion of the system chunk array" does the necessary changes to fix the system chunk array exhaustion problem. Reported-by: Naohiro Aota <naohiro.aota@wdc.com> Link: https://lore.kernel.org/linux-btrfs/20210621015922.ewgbffxuawia7liz@naota-xeon/ Fixes: eafa4fd0ad0607 ("btrfs: fix exhaustion of the system chunk array due to concurrent allocations") CC: stable@vger.kernel.org # 5.12+ Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Tested-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-07btrfs: zoned: print unusable percentage when reclaiming block groupsJohannes Thumshirn1-2/+12
When we're automatically reclaiming a zone, because its zone_unusable value is above the reclaim threshold, we're only logging how much percent of the zone's capacity are used, but not how much of the capacity is unusable. Also print the percentage of the unusable space in the block group before we're reclaiming it. Example: BTRFS info (device sdg): reclaiming chunk 230686720 with 13% used 86% unusable CC: stable@vger.kernel.org # 5.13 Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-07btrfs: zoned: fix types for u64 division in btrfs_reclaim_bgs_workDavid Sterba1-1/+1
The types in calculation of the used percentage in the reclaiming messages are both u64, though bg->length is either 1GiB (non-zoned) or the zone size in the zoned mode. The upper limit on zone size is 8GiB so this could theoretically overflow in the future, right now the values fit. Fixes: 18bb8bbf13c1 ("btrfs: zoned: automatically reclaim zones") CC: stable@vger.kernel.org # 5.13 Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-06-22btrfs: rip out btrfs_space_info::total_bytes_pinnedJosef Bacik1-3/+0
We used this in may_commit_transaction() in order to determine if we needed to commit the transaction. However we no longer have that logic and thus have no use of this counter anymore, so delete it. Reviewed-by: Nikolay Borisov <nborisov@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>
2021-06-22btrfs: ensure relocation never runs while we have send operations runningFilipe Manana1-2/+8
Relocation and send do not play well together because while send is running a block group can be relocated, a transaction committed and the respective disk extents get re-allocated and written to or discarded while send is about to do something with the extents. This was explained in commit 9e967495e0e0ae ("Btrfs: prevent send failures and crashes due to concurrent relocation"), which prevented balance and send from running in parallel but it did not address one remaining case where chunk relocation can happen: shrinking a device (and device deletion which shrinks a device's size to 0 before deleting the device). We also have now one more case where relocation is triggered: on zoned filesystems partially used block groups get relocated by a background thread, introduced in commit 18bb8bbf13c183 ("btrfs: zoned: automatically reclaim zones"). So make sure that instead of preventing balance from running when there are ongoing send operations, we prevent relocation from happening. This uses the infrastructure recently added by a patch that has the subject: "btrfs: add cancellable chunk relocation support". Also it adds a spinlock used exclusively for the exclusivity between send and relocation, as before fs_info->balance_mutex was used, which would make an attempt to run send to block waiting for balance to finish, which can take a lot of time on large filesystems. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-06-21btrfs: make free space cache size consistent across different PAGE_SIZEQu Wenruo1-9/+9
Currently free space cache inode size is determined by two factors: - block group size - PAGE_SIZE This means, for the same sized block groups, with different PAGE_SIZE, it will result in different inode sizes. This will not be a good thing for subpage support, so change the requirement for PAGE_SIZE to sectorsize. Now for the same 4K sectorsize btrfs, it should result the same inode size no matter what the PAGE_SIZE is. Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-06-17btrfs: zoned: fix negative space_info->bytes_readonlyNaohiro Aota1-4/+4
Consider we have a using block group on zoned btrfs. |<- ZU ->|<- used ->|<---free--->| `- Alloc offset ZU: Zone unusable Marking the block group read-only will migrate the zone unusable bytes to the read-only bytes. So, we will have this. |<- RO ->|<- used ->|<--- RO --->| RO: Read only When marking it back to read-write, btrfs_dec_block_group_ro() subtracts the above "RO" bytes from the space_info->bytes_readonly. And, it moves the zone unusable bytes back and again subtracts those bytes from the space_info->bytes_readonly, leading to negative bytes_readonly. This can be observed in the output as eg.: Data, single: total=512.00MiB, used=165.21MiB, zone_unusable=16.00EiB Data, single: total=536870912, used=173256704, zone_unusable=18446744073603186688 This commit fixes the issue by reordering the operations. Link: https://github.com/naota/linux/issues/37 Reported-by: David Sterba <dsterba@suse.com> Fixes: 169e0da91a21 ("btrfs: zoned: track unusable bytes for zones") CC: stable@vger.kernel.org # 5.12+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-04-20btrfs: zoned: automatically reclaim zonesJohannes Thumshirn1-0/+101
When a file gets deleted on a zoned file system, the space freed is not returned back into the block group's free space, but is migrated to zone_unusable. As this zone_unusable space is behind the current write pointer it is not possible to use it for new allocations. In the current implementation a zone is reset once all of the block group's space is accounted as zone unusable. This behaviour can lead to premature ENOSPC errors on a busy file system. Instead of only reclaiming the zone once it is completely unusable, kick off a reclaim job once the amount of unusable bytes exceeds a user configurable threshold between 51% and 100%. It can be set per mounted filesystem via the sysfs tunable bg_reclaim_threshold which is set to 75% by default. Similar to reclaiming unused block groups, these dirty block groups are added to a to_reclaim list and then on a transaction commit, the reclaim process is triggered but after we deleted unused block groups, which will free space for the relocation process. 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>
2021-04-20btrfs: rename delete_unused_bgs_mutex to reclaim_bgs_lockJohannes Thumshirn1-3/+3
As a preparation for extending the block group deletion use case, rename the unused_bgs_mutex to reclaim_bgs_lock. Reviewed-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Josef Bacik <josef@toxicpanda.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>
2021-04-19btrfs: fix exhaustion of the system chunk array due to concurrent allocationsFilipe Manana1-1/+57
When we are running out of space for updating the chunk tree, that is, when we are low on available space in the system space info, if we have many task concurrently allocating block groups, via fallocate for example, many of them can end up all allocating new system chunks when only one is needed. In extreme cases this can lead to exhaustion of the system chunk array, which has a size limit of 2048 bytes, and results in a transaction abort with errno EFBIG, producing a trace in dmesg like the following, which was triggered on a PowerPC machine with a node/leaf size of 64K: [1359.518899] ------------[ cut here ]------------ [1359.518980] BTRFS: Transaction aborted (error -27) [1359.519135] WARNING: CPU: 3 PID: 16463 at ../fs/btrfs/block-group.c:1968 btrfs_create_pending_block_groups+0x340/0x3c0 [btrfs] [1359.519152] Modules linked in: (...) [1359.519239] Supported: Yes, External [1359.519252] CPU: 3 PID: 16463 Comm: stress-ng Tainted: G X 5.3.18-47-default #1 SLE15-SP3 [1359.519274] NIP: c008000000e36fe8 LR: c008000000e36fe4 CTR: 00000000006de8e8 [1359.519293] REGS: c00000056890b700 TRAP: 0700 Tainted: G X (5.3.18-47-default) [1359.519317] MSR: 800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 48008222 XER: 00000007 [1359.519356] CFAR: c00000000013e170 IRQMASK: 0 [1359.519356] GPR00: c008000000e36fe4 c00000056890b990 c008000000e83200 0000000000000026 [1359.519356] GPR04: 0000000000000000 0000000000000000 0000d52a3b027651 0000000000000007 [1359.519356] GPR08: 0000000000000003 0000000000000001 0000000000000007 0000000000000000 [1359.519356] GPR12: 0000000000008000 c00000063fe44600 000000001015e028 000000001015dfd0 [1359.519356] GPR16: 000000000000404f 0000000000000001 0000000000010000 0000dd1e287affff [1359.519356] GPR20: 0000000000000001 c000000637c9a000 ffffffffffffffe5 0000000000000000 [1359.519356] GPR24: 0000000000000004 0000000000000000 0000000000000100 ffffffffffffffc0 [1359.519356] GPR28: c000000637c9a000 c000000630e09230 c000000630e091d8 c000000562188b08 [1359.519561] NIP [c008000000e36fe8] btrfs_create_pending_block_groups+0x340/0x3c0 [btrfs] [1359.519613] LR [c008000000e36fe4] btrfs_create_pending_block_groups+0x33c/0x3c0 [btrfs] [1359.519626] Call Trace: [1359.519671] [c00000056890b990] [c008000000e36fe4] btrfs_create_pending_block_groups+0x33c/0x3c0 [btrfs] (unreliable) [1359.519729] [c00000056890ba90] [c008000000d68d44] __btrfs_end_transaction+0xbc/0x2f0 [btrfs] [1359.519782] [c00000056890bae0] [c008000000e309ac] btrfs_alloc_data_chunk_ondemand+0x154/0x610 [btrfs] [1359.519844] [c00000056890bba0] [c008000000d8a0fc] btrfs_fallocate+0xe4/0x10e0 [btrfs] [1359.519891] [c00000056890bd00] [c0000000004a23b4] vfs_fallocate+0x174/0x350 [1359.519929] [c00000056890bd50] [c0000000004a3cf8] ksys_fallocate+0x68/0xf0 [1359.519957] [c00000056890bda0] [c0000000004a3da8] sys_fallocate+0x28/0x40 [1359.519988] [c00000056890bdc0] [c000000000038968] system_call_exception+0xe8/0x170 [1359.520021] [c00000056890be20] [c00000000000cb70] system_call_common+0xf0/0x278 [1359.520037] Instruction dump: [1359.520049] 7d0049ad 40c2fff4 7c0004ac 71490004 40820024 2f83fffb 419e0048 3c620000 [1359.520082] e863bcb8 7ec4b378 48010d91 e8410018 <0fe00000> 3c820000 e884bcc8 7ec6b378 [1359.520122] ---[ end trace d6c186e151022e20 ]--- The following steps explain how we can end up in this situation: 1) Task A is at check_system_chunk(), either because it is allocating a new data or metadata block group, at btrfs_chunk_alloc(), or because it is removing a block group or turning a block group RO. It does not matter why; 2) Task A sees that there is not enough free space in the system space_info object, that is 'left' is < 'thresh'. And at this point the system space_info has a value of 0 for its 'bytes_may_use' counter; 3) As a consequence task A calls btrfs_alloc_chunk() in order to allocate a new system block group (chunk) and then reserves 'thresh' bytes in the chunk block reserve with the call to btrfs_block_rsv_add(). This changes the chunk block reserve's 'reserved' and 'size' counters by an amount of 'thresh', and changes the 'bytes_may_use' counter of the system space_info object from 0 to 'thresh'. Also during its call to btrfs_alloc_chunk(), we end up increasing the value of the 'total_bytes' counter of the system space_info object by 8MiB (the size of a system chunk stripe). This happens through the call chain: btrfs_alloc_chunk() create_chunk() btrfs_make_block_group() btrfs_update_space_info() 4) After it finishes the first phase of the block group allocation, at btrfs_chunk_alloc(), task A unlocks the chunk mutex; 5) At this point the new system block group was added to the transaction handle's list of new block groups, but its block group item, device items and chunk item were not yet inserted in the extent, device and chunk trees, respectively. That only happens later when we call btrfs_finish_chunk_alloc() through a call to btrfs_create_pending_block_groups(); Note that only when we update the chunk tree, through the call to btrfs_finish_chunk_alloc(), we decrement the 'reserved' counter of the chunk block reserve as we COW/allocate extent buffers, through: btrfs_alloc_tree_block() btrfs_use_block_rsv() btrfs_block_rsv_use_bytes() And the system space_info's 'bytes_may_use' is decremented everytime we allocate an extent buffer for COW operations on the chunk tree, through: btrfs_alloc_tree_block() btrfs_reserve_extent() find_free_extent() btrfs_add_reserved_bytes() If we end up COWing less chunk btree nodes/leaves than expected, which is the typical case since the amount of space we reserve is always pessimistic to account for the worst possible case, we release the unused space through: btrfs_create_pending_block_groups() btrfs_trans_release_chunk_metadata() btrfs_block_rsv_release() block_rsv_release_bytes() btrfs_space_info_free_bytes_may_use() But before task A gets into btrfs_create_pending_block_groups()... 6) Many other tasks start allocating new block groups through fallocate, each one does the first phase of block group allocation in a serialized way, since btrfs_chunk_alloc() takes the chunk mutex before calling check_system_chunk() and btrfs_alloc_chunk(). However before everyone enters the final phase of the block group allocation, that is, before calling btrfs_create_pending_block_groups(), new tasks keep coming to allocate new block groups and while at check_system_chunk(), the system space_info's 'bytes_may_use' keeps increasing each time a task reserves space in the chunk block reserve. This means that eventually some other task can end up not seeing enough free space in the system space_info and decide to allocate yet another system chunk. This may repeat several times if yet more new tasks keep allocating new block groups before task A, and all the other tasks, finish the creation of the pending block groups, which is when reserved space in excess is released. Eventually this can result in exhaustion of system chunk array in the superblock, with btrfs_add_system_chunk() returning EFBIG, resulting later in a transaction abort. Even when we don't reach the extreme case of exhausting the system array, most, if not all, unnecessarily created system block groups end up being unused since when finishing creation of the first pending system block group, the creation of the following ones end up not needing to COW nodes/leaves of the chunk tree, so we never allocate and deallocate from them, resulting in them never being added to the list of unused block groups - as a consequence they don't get deleted by the cleaner kthread - the only exceptions are if we unmount and mount the filesystem again, which adds any unused block groups to the list of unused block groups, if a scrub is run, which also adds unused block groups to the unused list, and under some circumstances when using a zoned filesystem or async discard, which may also add unused block groups to the unused list. So fix this by: *) Tracking the number of reserved bytes for the chunk tree per transaction, which is the sum of reserved chunk bytes by each transaction handle currently being used; *) When there is not enough free space in the system space_info, if there are other transaction handles which reserved chunk space, wait for some of them to complete in order to have enough excess reserved space released, and then try again. Otherwise proceed with the creation of a new system chunk. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-04-19btrfs: replace open coded while loop with proper constructNikolay Borisov1-19/+23
btrfs_inc_block_group_ro wants to ensure that the current transaction is not running dirty block groups, if it is it waits and loops again. That logic is currently implemented using a goto label. Actually using a proper do {} while() construct doesn't hurt readability nor does it introduce excessive nesting and makes the relevant code stand out by being encompassed in the loop construct. No functional changes. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-22btrfs: fix race between writes to swap files and scrubFilipe Manana1-1/+32
When we active a swap file, at btrfs_swap_activate(), we acquire the exclusive operation lock to prevent the physical location of the swap file extents to be changed by operations such as balance and device replace/resize/remove. We also call there can_nocow_extent() which, among other things, checks if the block group of a swap file extent is currently RO, and if it is we can not use the extent, since a write into it would result in COWing the extent. However we have no protection against a scrub operation running after we activate the swap file, which can result in the swap file extents to be COWed while the scrub is running and operating on the respective block group, because scrub turns a block group into RO before it processes it and then back again to RW mode after processing it. That means an attempt to write into a swap file extent while scrub is processing the respective block group, will result in COWing the extent, changing its physical location on disk. Fix this by making sure that block groups that have extents that are used by active swap files can not be turned into RO mode, therefore making it not possible for a scrub to turn them into RO mode. When a scrub finds a block group that can not be turned to RO due to the existence of extents used by swap files, it proceeds to the next block group and logs a warning message that mentions the block group was skipped due to active swap files - this is the same approach we currently use for balance. Fixes: ed46ff3d42378 ("Btrfs: support swap files") CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: extend zoned allocator to use dedicated tree-log block groupNaohiro Aota1-0/+2
This is the 1/3 patch to enable tree log on zoned filesystems. The tree-log feature does not work on a zoned filesystem as is. Blocks for a tree-log tree are allocated mixed with other metadata blocks and btrfs writes and syncs the tree-log blocks to devices at the time of fsync(), which has a different timing than a global transaction commit. As a result, both writing tree-log blocks and writing other metadata blocks become non-sequential writes that zoned filesystems must avoid. Introduce a dedicated block group for tree-log blocks, so that tree-log blocks and other metadata blocks can be separate write streams. As a result, each write stream can now be written to devices separately. "fs_info->treelog_bg" tracks the dedicated block group and assigns "treelog_bg" on-demand on tree-log block allocation time. This commit extends the zoned block allocator to use the block group. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: extend btrfs_rmap_block for specifying a deviceNaohiro Aota1-5/+11
btrfs_rmap_block currently reverse-maps the physical addresses on all devices to the corresponding logical addresses. Extend the function to match to a specified device. The old functionality of querying all devices is left intact by specifying NULL as target device. A block_device instead of a btrfs_device is passed into btrfs_rmap_block, as this function is intended to reverse-map the result of a bio, which only has a block_device. Also export the function for later use. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: reset zones of unused block groupsNaohiro Aota1-2/+6
We must reset the zones of a deleted unused block group to rewind the zones' write pointers to the zones' start. To do this, we can use the DISCARD_SYNC code to do the reset when the filesystem is running on zoned devices. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: implement sequential extent allocationNaohiro Aota1-0/+4
Implement a sequential extent allocator for zoned filesystems. This allocator only needs to check if there is enough space in the block group after the allocation pointer to satisfy the extent allocation request. Therefore the allocator never manages bitmaps or clusters. Also, add assertions to the corresponding functions. As zone append writing is used, it would be unnecessary to track the allocation offset, as the allocator only needs to check available space. But by tracking and returning the offset as an allocated region, we can skip modification of ordered extents and checksum information when there is no IO reordering. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: track unusable bytes for zonesNaohiro Aota1-12/+39
In a zoned filesystem a once written then freed region is not usable until the underlying zone has been reset. So we need to distinguish such unusable space from usable free space. Therefore we need to introduce the "zone_unusable" field to the block group structure, and "bytes_zone_unusable" to the space_info structure to track the unusable space. Pinned bytes are always reclaimed to the unusable space. But, when an allocated region is returned before using e.g., the block group becomes read-only between allocation time and reservation time, we can safely return the region to the block group. For the situation, this commit introduces "btrfs_add_free_space_unused". This behaves the same as btrfs_add_free_space() on regular filesystem. On zoned filesystems, it rewinds the allocation offset. Because the read-only bytes tracks free but unusable bytes when the block group is read-only, we need to migrate the zone_unusable bytes to read-only bytes when a block group is marked read-only. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: calculate allocation offset for conventional zonesNaohiro Aota1-2/+2
Conventional zones do not have a write pointer, so we cannot use it to determine the allocation offset for sequential allocation if a block group contains a conventional zone. But instead, we can consider the end of the highest addressed extent in the block group for the allocation offset. For new block group, we cannot calculate the allocation offset by consulting the extent tree, because it can cause deadlock by taking extent buffer lock after chunk mutex, which is already taken in btrfs_make_block_group(). Since it is a new block group anyways, we can simply set the allocation offset to 0. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: load zone's allocation offsetNaohiro Aota1-0/+15
A zoned filesystem must allocate blocks at the zones' write pointer. The device's write pointer position can be mapped to a logical address within a block group. To facilitate this, add an "alloc_offset" to the block-group to track the logical addresses of the write pointer. This logical address is populated in btrfs_load_block_group_zone_info() from the write pointers of corresponding zones. For now, zoned filesystems the single profile. Supporting non-single profile with zone append writing is not trivial. For example, in the DUP profile, we send a zone append writing IO to two zones on a device. The device reply with written LBAs for the IOs. If the offsets of the returned addresses from the beginning of the zone are different, then it results in different logical addresses. We need fine-grained logical to physical mapping to support such separated physical address issue. Since it should require additional metadata type, disable non-single profiles for now. This commit supports the case all the zones in a block group are sequential. The next patch will handle the case having a conventional zone. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: release path before calling to btrfs_load_block_group_zone_infoJohannes Thumshirn1-21/+17
Since we have no write pointer in conventional zones, we cannot determine the allocation offset from it. Instead, we set the allocation offset after the highest addressed extent. This is done by reading the extent tree in btrfs_load_block_group_zone_info(). However, this function is called from btrfs_read_block_groups(), so the read lock for the tree node could be recursively taken. To avoid this unsafe locking scenario, release the path before reading the extent tree to get the allocation offset. Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Josef Bacik <josef@toxicpanda.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>
2021-02-08btrfs: do not block on deleted bgs mutex in the cleanerJosef Bacik1-3/+8
While running some stress tests I started getting hung task messages. This is because the delete unused block groups code has to take the delete_unused_bgs_mutex to do it's work, which is taken by balance to make sure we don't delete block groups while we're balancing. The problem is that balance can take a while, and so we were getting hung task warnings. We don't need to block and run these things, and the cleaner is needed to do other work, so trylock on this mutex and just bail if we can't acquire it right away. Reviewed-by: Nikolay Borisov <nborisov@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>
2021-02-08btrfs: splice remaining dirty_bg's onto the transaction dirty bg listJosef Bacik1-7/+12
While doing error injection testing with my relocation patches I hit the following assert: assertion failed: list_empty(&block_group->dirty_list), in fs/btrfs/block-group.c:3356 ------------[ cut here ]------------ kernel BUG at fs/btrfs/ctree.h:3357! invalid opcode: 0000 [#1] SMP NOPTI CPU: 0 PID: 24351 Comm: umount Tainted: G W 5.10.0-rc3+ #193 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 RIP: 0010:assertfail.constprop.0+0x18/0x1a RSP: 0018:ffffa09b019c7e00 EFLAGS: 00010282 RAX: 0000000000000056 RBX: ffff8f6492c18000 RCX: 0000000000000000 RDX: ffff8f64fbc27c60 RSI: ffff8f64fbc19050 RDI: ffff8f64fbc19050 RBP: ffff8f6483bbdc00 R08: 0000000000000000 R09: 0000000000000000 R10: ffffa09b019c7c38 R11: ffffffff85d70928 R12: ffff8f6492c18100 R13: ffff8f6492c18148 R14: ffff8f6483bbdd70 R15: dead000000000100 FS: 00007fbfda4cdc40(0000) GS:ffff8f64fbc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbfda666fd0 CR3: 000000013cf66002 CR4: 0000000000370ef0 Call Trace: btrfs_free_block_groups.cold+0x55/0x55 close_ctree+0x2c5/0x306 ? fsnotify_destroy_marks+0x14/0x100 generic_shutdown_super+0x6c/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x36/0xa0 cleanup_mnt+0x12d/0x190 task_work_run+0x5c/0xa0 exit_to_user_mode_prepare+0x1b1/0x1d0 syscall_exit_to_user_mode+0x54/0x280 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happened because I injected an error in btrfs_cow_block() while running the dirty block groups. When we run the dirty block groups, we splice the list onto a local list to process. However if an error occurs, we only cleanup the transactions dirty block group list, not any pending block groups we have on our locally spliced list. In fact if we fail to allocate a path in this function we'll also fail to clean up the splice list. Fix this by splicing the list back onto the transaction dirty block group list so that the block groups are cleaned up. Then add a 'out' label and have the error conditions jump to out so that the errors are handled properly. This also has the side-effect of fixing a problem where we would clear 'ret' on error because we unconditionally ran btrfs_run_delayed_refs(). CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-08btrfs: handle space_info::total_bytes_pinned inside the delayed ref itselfJosef Bacik1-7/+3
Currently we pass things around to figure out if we maybe freeing data based on the state of the delayed refs head. This makes the accounting sort of confusing and hard to follow, as it's distinctly separate from the delayed ref heads stuff, but also depends on it entirely. Fix this by explicitly adjusting the space_info->total_bytes_pinned in the delayed refs code. We now have two places where we modify this counter, once where we create the delayed and destroy the delayed refs, and once when we pin and unpin the extents. This means there is a slight overlap between delayed refs and the pin/unpin mechanisms, but this is simply used by the ENOSPC infrastructure to determine if we need to commit the transaction, so there's no adverse affect from this, we might simply commit thinking it will give us enough space when it might not. CC: stable@vger.kernel.org # 5.10 Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-08btrfs: document fs_info in btrfs_rmap_blockNikolay Borisov1-1/+3
Fixes fs/btrfs/block-group.c:1570: warning: Function parameter or member 'fs_info' not described in 'btrfs_rmap_block' Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-25btrfs: fix possible free space tree corruption with online conversionJosef Bacik1-1/+9
While running btrfs/011 in a loop I would often ASSERT() while trying to add a new free space entry that already existed, or get an EEXIST while adding a new block to the extent tree, which is another indication of double allocation. This occurs because when we do the free space tree population, we create the new root and then populate the tree and commit the transaction. The problem is when you create a new root, the root node and commit root node are the same. During this initial transaction commit we will run all of the delayed refs that were paused during the free space tree generation, and thus begin to cache block groups. While caching block groups the caching thread will be reading from the main root for the free space tree, so as we make allocations we'll be changing the free space tree, which can cause us to add the same range twice which results in either the ASSERT(ret != -EEXIST); in __btrfs_add_free_space, or in a variety of different errors when running delayed refs because of a double allocation. Fix this by marking the fs_info as unsafe to load the free space tree, and fall back on the old slow method. We could be smarter than this, for example caching the block group while we're populating the free space tree, but since this is a serious problem I've opted for the simplest solution. CC: stable@vger.kernel.org # 4.9+ Fixes: a5ed91828518 ("Btrfs: implement the free space B-tree") Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-18btrfs: don't clear ret in btrfs_start_dirty_block_groupsJosef Bacik1-1/+2
If we fail to update a block group item in the loop we'll break, however we'll do btrfs_run_delayed_refs and lose our error value in ret, and thus not clean up properly. Fix this by only running the delayed refs if there was no failure. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09btrfs: skip space_cache v1 setup when not using itBoris Burkov1-0/+3
If we are not using space cache v1, we should not create the free space object or free space inodes. This comes up when we delete the existing free space objects/inodes when migrating to v2, only to see them get recreated for every dirtied block group. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09btrfs: remove free space items when disabling space cache v1Boris Burkov1-37/+2
When the filesystem transitions from space cache v1 to v2 or to nospace_cache, it removes the old cached data, but does not remove the FREE_SPACE items nor the free space inodes they point to. This doesn't cause any issues besides being a bit inefficient, since these items no longer do anything useful. To fix it, when we are mounting, and plan to disable the space cache, destroy each block group's free space item and free space inode. The code to remove the items is lifted from the existing use case of removing the block group, with a light adaptation to handle whether or not we have already looked up the free space inode. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09btrfs: only mark bg->needs_free_space if free space tree is onBoris Burkov1-1/+2
If we attempt to create a free space tree while any block groups have needs_free_space set, we will double add the new free space item and hit EEXIST. Previously, we only created the free space tree on a new mount, so we never hit the case, but if we try to create it on a remount, such block groups could exist and trip us up. We don't do anything with this field unless the free space tree is enabled, so there is no harm in not setting it. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09btrfs: implement log-structured superblock for ZONED modeNaohiro Aota1-0/+9
Superblock (and its copies) is the only data structure in btrfs which has a fixed location on a device. Since we cannot overwrite in a sequential write required zone, we cannot place superblock in the zone. One easy solution is limiting superblock and copies to be placed only in conventional zones. However, this method has two downsides: one is reduced number of superblock copies. The location of the second copy of superblock is 256GB, which is in a sequential write required zone on typical devices in the market today. So, the number of superblock and copies is limited to be two. Second downside is that we cannot support devices which have no conventional zones at all. To solve these two problems, we employ superblock log writing. It uses two adjacent zones as a circular buffer to write updated superblocks. Once the first zone is filled up, start writing into the second one. Then, when both zones are filled up and before starting to write to the first zone again, it reset the first zone. We can determine the position of the latest superblock by reading write pointer information from a device. One corner case is when both zones are full. For this situation, we read out the last superblock of each zone, and compare them to determine which zone is older. The following zones are reserved as the circular buffer on ZONED btrfs. - The primary superblock: zones 0 and 1 - The first copy: zones 16 and 17 - The second copy: zones 1024 or zone at 256GB which is minimum, and next to it If these reserved zones are conventional, superblock is written fixed at the start of the zone without logging. Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08btrfs: make btrfs_update_inode take btrfs_inodeNikolay Borisov1-1/+1
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08btrfs: protect fs_info->caching_block_groups by block_group_cache_lockJosef Bacik1-6/+6
I got the following lockdep splat ====================================================== WARNING: possible circular locking dependency detected 5.9.0+ #101 Not tainted ------------------------------------------------------ btrfs-cleaner/3445 is trying to acquire lock: ffff89dbec39ab48 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x32/0x170 but task is already holding lock: ffff89dbeaf28a88 (&fs_info->commit_root_sem){++++}-{3:3}, at: btrfs_find_all_roots+0x41/0x80 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&fs_info->commit_root_sem){++++}-{3:3}: down_write+0x3d/0x70 btrfs_cache_block_group+0x2d5/0x510 find_free_extent+0xb6e/0x12f0 btrfs_reserve_extent+0xb3/0x1b0 btrfs_alloc_tree_block+0xb1/0x330 alloc_tree_block_no_bg_flush+0x4f/0x60 __btrfs_cow_block+0x11d/0x580 btrfs_cow_block+0x10c/0x220 commit_cowonly_roots+0x47/0x2e0 btrfs_commit_transaction+0x595/0xbd0 sync_filesystem+0x74/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x36/0xa0 cleanup_mnt+0x12d/0x190 task_work_run+0x5c/0xa0 exit_to_user_mode_prepare+0x1df/0x200 syscall_exit_to_user_mode+0x54/0x280 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&space_info->groups_sem){++++}-{3:3}: down_read+0x40/0x130 find_free_extent+0x2ed/0x12f0 btrfs_reserve_extent+0xb3/0x1b0 btrfs_alloc_tree_block+0xb1/0x330 alloc_tree_block_no_bg_flush+0x4f/0x60 __btrfs_cow_block+0x11d/0x580 btrfs_cow_block+0x10c/0x220 commit_cowonly_roots+0x47/0x2e0 btrfs_commit_transaction+0x595/0xbd0 sync_filesystem+0x74/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x36/0xa0 cleanup_mnt+0x12d/0x190 task_work_run+0x5c/0xa0 exit_to_user_mode_prepare+0x1df/0x200 syscall_exit_to_user_mode+0x54/0x280 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (btrfs-root-00){++++}-{3:3}: __lock_acquire+0x1167/0x2150 lock_acquire+0xb9/0x3d0 down_read_nested+0x43/0x130 __btrfs_tree_read_lock+0x32/0x170 __btrfs_read_lock_root_node+0x3a/0x50 btrfs_search_slot+0x614/0x9d0 btrfs_find_root+0x35/0x1b0 btrfs_read_tree_root+0x61/0x120 btrfs_get_root_ref+0x14b/0x600 find_parent_nodes+0x3e6/0x1b30 btrfs_find_all_roots_safe+0xb4/0x130 btrfs_find_all_roots+0x60/0x80 btrfs_qgroup_trace_extent_post+0x27/0x40 btrfs_add_delayed_data_ref+0x3fd/0x460 btrfs_free_extent+0x42/0x100 __btrfs_mod_ref+0x1d7/0x2f0 walk_up_proc+0x11c/0x400 walk_up_tree+0xf0/0x180 btrfs_drop_snapshot+0x1c7/0x780 btrfs_clean_one_deleted_snapshot+0xfb/0x110 cleaner_kthread+0xd4/0x140 kthread+0x13a/0x150 ret_from_fork+0x1f/0x30 other info that might help us debug this: Chain exists of: btrfs-root-00 --> &space_info->groups_sem --> &fs_info->commit_root_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->commit_root_sem); lock(&space_info->groups_sem); lock(&fs_info->commit_root_sem); lock(btrfs-root-00); *** DEADLOCK *** 3 locks held by btrfs-cleaner/3445: #0: ffff89dbeaf28838 (&fs_info->cleaner_mutex){+.+.}-{3:3}, at: cleaner_kthread+0x6e/0x140 #1: ffff89dbeb6c7640 (sb_internal){.+.+}-{0:0}, at: start_transaction+0x40b/0x5c0 #2: ffff89dbeaf28a88 (&fs_info->commit_root_sem){++++}-{3:3}, at: btrfs_find_all_roots+0x41/0x80 stack backtrace: CPU: 0 PID: 3445 Comm: btrfs-cleaner Not tainted 5.9.0+ #101 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack+0x8b/0xb0 check_noncircular+0xcf/0xf0 __lock_acquire+0x1167/0x2150 ? __bfs+0x42/0x210 lock_acquire+0xb9/0x3d0 ? __btrfs_tree_read_lock+0x32/0x170 down_read_nested+0x43/0x130 ? __btrfs_tree_read_lock+0x32/0x170 __btrfs_tree_read_lock+0x32/0x170 __btrfs_read_lock_root_node+0x3a/0x50 btrfs_search_slot+0x614/0x9d0 ? find_held_lock+0x2b/0x80 btrfs_find_root+0x35/0x1b0 ? do_raw_spin_unlock+0x4b/0xa0 btrfs_read_tree_root+0x61/0x120 btrfs_get_root_ref+0x14b/0x600 find_parent_nodes+0x3e6/0x1b30 btrfs_find_all_roots_safe+0xb4/0x130 btrfs_find_all_roots+0x60/0x80 btrfs_qgroup_trace_extent_post+0x27/0x40 btrfs_add_delayed_data_ref+0x3fd/0x460 btrfs_free_extent+0x42/0x100 __btrfs_mod_ref+0x1d7/0x2f0 walk_up_proc+0x11c/0x400 walk_up_tree+0xf0/0x180 btrfs_drop_snapshot+0x1c7/0x780 ? btrfs_clean_one_deleted_snapshot+0x73/0x110 btrfs_clean_one_deleted_snapshot+0xfb/0x110 cleaner_kthread+0xd4/0x140 ? btrfs_alloc_root+0x50/0x50 kthread+0x13a/0x150 ? kthread_create_worker_on_cpu+0x40/0x40 ret_from_fork+0x1f/0x30 while testing another lockdep fix. This happens because we're using the commit_root_sem to protect fs_info->caching_block_groups, which creates a dependency on the groups_sem -> commit_root_sem, which is problematic because we will allocate blocks while holding tree roots. Fix this by making the list itself protected by the fs_info->block_group_cache_lock. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08btrfs: load free space cache asynchronouslyJosef Bacik1-70/+53
While documenting the usage of the commit_root_sem, I noticed that we do not actually take the commit_root_sem in the case of the free space cache. This is problematic because we're supposed to hold that sem while we're reading the commit roots, which is what we do for the free space cache. The reason I did it inline when I originally wrote the code was because there's the case of unpinning where we need to make sure that the free space cache is loaded if we're going to use the free space cache. But we can accomplish the same thing by simply waiting for the cache to be loaded. Rework this code to load the free space cache asynchronously. This allows us to greatly cleanup the caching code because now it's all shared by the various caching methods. We also are now in a position to have the commit_root semaphore held while we're loading the free space cache. And finally our modification of ->last_byte_to_unpin is removed because it can be handled in the proper way on commit. Some care must be taken when replaying the log, when we expect that the free space cache will be read entirely before we start excluding space to replay. This could lead to overwriting space during replay. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08btrfs: load free space cache into a temporary ctlJosef Bacik1-28/+1
The free space cache has been special in that we would load it right away instead of farming the work off to a worker thread. This resulted in some weirdness that had to be taken into account for this fact, namely that if we every found a block group being cached the fast way we had to wait for it to finish, because we could get the cache before it had been validated and we may throw the cache away. To handle this particular case instead create a temporary btrfs_free_space_ctl to load the free space cache into. Then once we've validated that it makes sense, copy it's contents into the actual block_group->free_space_ctl. This allows us to avoid the problems of needing to wait for the caching to complete, we can clean up the discard extent handling stuff in __load_free_space_cache, and we no longer need to do the merge_space_tree() because the space is added one by one into the real free_space_ctl. This will allow further reworks of how we handle loading the free space cache. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08btrfs: introduce mount option rescue=ignorebadrootsJosef Bacik1-0/+48
In the face of extent root corruption, or any other core fs wide root corruption we will fail to mount the file system. This makes recovery kind of a pain, because you need to fall back to userspace tools to scrape off data. Instead provide a mechanism to gracefully handle bad roots, so we can at least mount read-only and possibly recover data from the file system. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-26btrfs: drop the path before adding block group sysfs filesJosef Bacik1-0/+1
Dave reported a problem with my rwsem conversion patch where we got the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.9.0-default+ #1297 Not tainted ------------------------------------------------------ kswapd0/76 is trying to acquire lock: ffff9d5d25df2530 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs] but task is already holding lock: ffffffffa40cbba0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (fs_reclaim){+.+.}-{0:0}: __lock_acquire+0x582/0xac0 lock_acquire+0xca/0x430 fs_reclaim_acquire.part.0+0x25/0x30 kmem_cache_alloc+0x30/0x9c0 alloc_inode+0x81/0x90 iget_locked+0xcd/0x1a0 kernfs_get_inode+0x1b/0x130 kernfs_get_tree+0x136/0x210 sysfs_get_tree+0x1a/0x50 vfs_get_tree+0x1d/0xb0 path_mount+0x70f/0xa80 do_mount+0x75/0x90 __x64_sys_mount+0x8e/0xd0 do_syscall_64+0x2d/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (kernfs_mutex){+.+.}-{3:3}: __lock_acquire+0x582/0xac0 lock_acquire+0xca/0x430 __mutex_lock+0xa0/0xaf0 kernfs_add_one+0x23/0x150 kernfs_create_dir_ns+0x58/0x80 sysfs_create_dir_ns+0x70/0xd0 kobject_add_internal+0xbb/0x2d0 kobject_add+0x7a/0xd0 btrfs_sysfs_add_block_group_type+0x141/0x1d0 [btrfs] btrfs_read_block_groups+0x1f1/0x8c0 [btrfs] open_ctree+0x981/0x1108 [btrfs] btrfs_mount_root.cold+0xe/0xb0 [btrfs] legacy_get_tree+0x2d/0x60 vfs_get_tree+0x1d/0xb0 fc_mount+0xe/0x40 vfs_kern_mount.part.0+0x71/0x90 btrfs_mount+0x13b/0x3e0 [btrfs] legacy_get_tree+0x2d/0x60 vfs_get_tree+0x1d/0xb0 path_mount+0x70f/0xa80 do_mount+0x75/0x90 __x64_sys_mount+0x8e/0xd0 do_syscall_64+0x2d/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (btrfs-extent-00){++++}-{3:3}: __lock_acquire+0x582/0xac0 lock_acquire+0xca/0x430 down_read_nested+0x45/0x220 __btrfs_tree_read_lock+0x35/0x1c0 [btrfs] __btrfs_read_lock_root_node+0x3a/0x50 [btrfs] btrfs_search_slot+0x6d4/0xfd0 [btrfs] check_committed_ref+0x69/0x200 [btrfs] btrfs_cross_ref_exist+0x65/0xb0 [btrfs] run_delalloc_nocow+0x446/0x9b0 [btrfs] btrfs_run_delalloc_range+0x61/0x6a0 [btrfs] writepage_delalloc+0xae/0x160 [btrfs] __extent_writepage+0x262/0x420 [btrfs] extent_write_cache_pages+0x2b6/0x510 [btrfs] extent_writepages+0x43/0x90 [btrfs] do_writepages+0x40/0xe0 __writeback_single_inode+0x62/0x610 writeback_sb_inodes+0x20f/0x500 wb_writeback+0xef/0x4a0 wb_do_writeback+0x49/0x2e0 wb_workfn+0x81/0x340 process_one_work+0x233/0x5d0 worker_thread+0x50/0x3b0 kthread+0x137/0x150 ret_from_fork+0x1f/0x30 -> #1 (btrfs-fs-00){++++}-{3:3}: __lock_acquire+0x582/0xac0 lock_acquire+0xca/0x430 down_read_nested+0x45/0x220 __btrfs_tree_read_lock+0x35/0x1c0 [btrfs] __btrfs_read_lock_root_node+0x3a/0x50 [btrfs] btrfs_search_slot+0x6d4/0xfd0 [btrfs] btrfs_lookup_inode+0x3a/0xc0 [btrfs] __btrfs_update_delayed_inode+0x93/0x2c0 [btrfs] __btrfs_commit_inode_delayed_items+0x7de/0x850 [btrfs] __btrfs_run_delayed_items+0x8e/0x140 [btrfs] btrfs_commit_transaction+0x367/0xbc0 [btrfs] btrfs_mksubvol+0x2db/0x470 [btrfs] btrfs_mksnapshot+0x7b/0xb0 [btrfs] __btrfs_ioctl_snap_create+0x16f/0x1a0 [btrfs] btrfs_ioctl_snap_create_v2+0xb0/0xf0 [btrfs] btrfs_ioctl+0xd0b/0x2690 [btrfs] __x64_sys_ioctl+0x6f/0xa0 do_syscall_64+0x2d/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&delayed_node->mutex){+.+.}-{3:3}: check_prev_add+0x91/0xc60 validate_chain+0xa6e/0x2a20 __lock_acquire+0x582/0xac0 lock_acquire+0xca/0x430 __mutex_lock+0xa0/0xaf0 __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs] btrfs_evict_inode+0x3cc/0x560 [btrfs] evict+0xd6/0x1c0 dispose_list+0x48/0x70 prune_icache_sb+0x54/0x80 super_cache_scan+0x121/0x1a0 do_shrink_slab+0x16d/0x3b0 shrink_slab+0xb1/0x2e0 shrink_node+0x230/0x6a0 balance_pgdat+0x325/0x750 kswapd+0x206/0x4d0 kthread+0x137/0x150 ret_from_fork+0x1f/0x30 other info that might help us debug this: Chain exists of: &delayed_node->mutex --> kernfs_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(kernfs_mutex); lock(fs_reclaim); lock(&delayed_node->mutex); *** DEADLOCK *** 3 locks held by kswapd0/76: #0: ffffffffa40cbba0 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 #1: ffffffffa40b8b58 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x54/0x2e0 #2: ffff9d5d322390e8 (&type->s_umount_key#26){++++}-{3:3}, at: trylock_super+0x16/0x50 stack backtrace: CPU: 2 PID: 76 Comm: kswapd0 Not tainted 5.9.0-default+ #1297 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014 Call Trace: dump_stack+0x77/0x97 check_noncircular+0xff/0x110 ? save_trace+0x50/0x470 check_prev_add+0x91/0xc60 validate_chain+0xa6e/0x2a20 ? save_trace+0x50/0x470 __lock_acquire+0x582/0xac0 lock_acquire+0xca/0x430 ? __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs] __mutex_lock+0xa0/0xaf0 ? __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs] ? __lock_acquire+0x582/0xac0 ? __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs] ? btrfs_evict_inode+0x30b/0x560 [btrfs] ? __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs] __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs] btrfs_evict_inode+0x3cc/0x560 [btrfs] evict+0xd6/0x1c0 dispose_list+0x48/0x70 prune_icache_sb+0x54/0x80 super_cache_scan+0x121/0x1a0 do_shrink_slab+0x16d/0x3b0 shrink_slab+0xb1/0x2e0 shrink_node+0x230/0x6a0 balance_pgdat+0x325/0x750 kswapd+0x206/0x4d0 ? finish_wait+0x90/0x90 ? balance_pgdat+0x750/0x750 kthread+0x137/0x150 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x1f/0x30 This happens because we are still holding the path open when we start adding the sysfs files for the block groups, which creates a dependency on fs_reclaim via the tree lock. Fix this by dropping the path before we start doing anything with sysfs. Reported-by: David Sterba <dsterba@suse.com> CC: stable@vger.kernel.org # 5.8+ Reviewed-by: Anand Jain <anand.jain@oracle.com> 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>
2020-10-07btrfs: do not create raid sysfs entries under any locksJosef Bacik1-6/+25
While running xfstests btrfs/177 I got the following lockdep splat ====================================================== WARNING: possible circular locking dependency detected 5.9.0-rc3+ #5 Not tainted ------------------------------------------------------ kswapd0/100 is trying to acquire lock: ffff97066aa56760 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x330 but task is already holding lock: ffffffff9fd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (fs_reclaim){+.+.}-{0:0}: fs_reclaim_acquire+0x65/0x80 slab_pre_alloc_hook.constprop.0+0x20/0x200 kmem_cache_alloc+0x37/0x270 alloc_inode+0x82/0xb0 iget_locked+0x10d/0x2c0 kernfs_get_inode+0x1b/0x130 kernfs_get_tree+0x136/0x240 sysfs_get_tree+0x16/0x40 vfs_get_tree+0x28/0xc0 path_mount+0x434/0xc00 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (kernfs_mutex){+.+.}-{3:3}: __mutex_lock+0x7e/0x7e0 kernfs_add_one+0x23/0x150 kernfs_create_dir_ns+0x7a/0xb0 sysfs_create_dir_ns+0x60/0xb0 kobject_add_internal+0xc0/0x2c0 kobject_add+0x6e/0x90 btrfs_sysfs_add_block_group_type+0x102/0x160 btrfs_make_block_group+0x167/0x230 btrfs_alloc_chunk+0x54f/0xb80 btrfs_chunk_alloc+0x18e/0x3a0 find_free_extent+0xdf6/0x1210 btrfs_reserve_extent+0xb3/0x1b0 btrfs_alloc_tree_block+0xb0/0x310 alloc_tree_block_no_bg_flush+0x4a/0x60 __btrfs_cow_block+0x11a/0x530 btrfs_cow_block+0x104/0x220 btrfs_search_slot+0x52e/0x9d0 btrfs_insert_empty_items+0x64/0xb0 btrfs_new_inode+0x225/0x730 btrfs_create+0xab/0x1f0 lookup_open.isra.0+0x52d/0x690 path_openat+0x2a7/0x9e0 do_filp_open+0x75/0x100 do_sys_openat2+0x7b/0x130 __x64_sys_openat+0x46/0x70 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}: __mutex_lock+0x7e/0x7e0 btrfs_chunk_alloc+0x125/0x3a0 find_free_extent+0xdf6/0x1210 btrfs_reserve_extent+0xb3/0x1b0 btrfs_alloc_tree_block+0xb0/0x310 alloc_tree_block_no_bg_flush+0x4a/0x60 __btrfs_cow_block+0x11a/0x530 btrfs_cow_block+0x104/0x220 btrfs_search_slot+0x52e/0x9d0 btrfs_lookup_inode+0x2a/0x8f __btrfs_update_delayed_inode+0x80/0x240 btrfs_commit_inode_delayed_inode+0x119/0x120 btrfs_evict_inode+0x357/0x500 evict+0xcf/0x1f0 do_unlinkat+0x1a9/0x2b0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&delayed_node->mutex){+.+.}-{3:3}: __lock_acquire+0x119c/0x1fc0 lock_acquire+0xa7/0x3d0 __mutex_lock+0x7e/0x7e0 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 kthread+0x138/0x160 ret_from_fork+0x1f/0x30 other info that might help us debug this: Chain exists of: &delayed_node->mutex --> kernfs_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(kernfs_mutex); lock(fs_reclaim); lock(&delayed_node->mutex); *** DEADLOCK *** 3 locks held by kswapd0/100: #0: ffffffff9fd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 #1: ffffffff9fd65c50 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x115/0x290 #2: ffff9706629780e0 (&type->s_umount_key#36){++++}-{3:3}, at: super_cache_scan+0x38/0x1e0 stack backtrace: CPU: 1 PID: 100 Comm: kswapd0 Not tainted 5.9.0-rc3+ #5 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack+0x8b/0xb8 check_noncircular+0x12d/0x150 __lock_acquire+0x119c/0x1fc0 lock_acquire+0xa7/0x3d0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 __mutex_lock+0x7e/0x7e0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? lock_acquire+0xa7/0x3d0 ? find_held_lock+0x2b/0x80 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 ? _raw_spin_unlock_irqrestore+0x41/0x50 ? add_wait_queue_exclusive+0x70/0x70 ? balance_pgdat+0x670/0x670 kthread+0x138/0x160 ? kthread_create_worker_on_cpu+0x40/0x40 ret_from_fork+0x1f/0x30 This happens because when we link in a block group with a new raid index type we'll create the corresponding sysfs entries for it. This is problematic because while restriping we're holding the chunk_mutex, and while mounting we're holding the tree locks. Fixing this isn't pretty, we move the call to the sysfs stuff into the btrfs_create_pending_block_groups() work, where we're not holding any locks. This creates a slight race where other threads could see that there's no sysfs kobj for that raid type, and race to create the sysfs dir. Fix this by wrapping the creation in space_info->lock, so we only get one thread calling kobject_add() for the new directory. We don't worry about the lock on cleanup as it only gets deleted on unmount. On mount it's more straightforward, we loop through the space_infos already, just check every raid index in each space_info and added the sysfs entries for the corresponding block groups. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: kill the RCU protection for fs_info->space_infoJosef Bacik1-14/+2
We have this thing wrapped in an RCU lock, but it's really not needed. We create all the space_info's on mount, and we destroy them on unmount. The list never changes and we're protected from messing with it by the normal mount/umount path, so kill the RCU stuff around it. Reviewed-by: Nikolay Borisov <nborisov@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>
2020-10-07btrfs: make read_block_group_item return voidMarcos Paulo de Souza1-6/+2
Since it's inclusion on 9afc66498a0b ("btrfs: block-group: refactor how we read one block group item") this function always returned 0, so there is no need to check for the returned value. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: call btrfs_try_granting_tickets when reserving spaceJosef Bacik1-0/+7
If we have compression on we could free up more space than we reserved, and thus be able to make a space reservation. Add the call for this scenario. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: call btrfs_try_granting_tickets when freeing reserved bytesJosef Bacik1-0/+2
We were missing a call to btrfs_try_granting_tickets in btrfs_free_reserved_bytes, so add it to handle the case where we're able to satisfy an allocation because we've freed a pending reservation. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: delete duplicated words + other fixes in commentsRandy Dunlap1-1/+1
Delete repeated words in fs/btrfs/. {to, the, a, and old} and change "into 2 part" to "into 2 parts". Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27btrfs: block-group: fix free-space bitmap thresholdMarcos Paulo de Souza1-1/+3
[BUG] After commit 9afc66498a0b ("btrfs: block-group: refactor how we read one block group item"), cache->length is being assigned after calling btrfs_create_block_group_cache. This causes a problem since set_free_space_tree_thresholds calculates the free-space threshold to decide if the free-space tree should convert from extents to bitmaps. The current code calls set_free_space_tree_thresholds with cache->length being 0, which then makes cache->bitmap_high_thresh zero. This implies the system will always use bitmap instead of extents, which is not desired if the block group is not fragmented. This behavior can be seen by a test that expects to repair systems with FREE_SPACE_EXTENT and FREE_SPACE_BITMAP, but the current code only created FREE_SPACE_BITMAP. [FIX] Call set_free_space_tree_thresholds after setting cache->length. There is now a WARN_ON in set_free_space_tree_thresholds to help preventing the same mistake to happen again in the future. Link: https://github.com/kdave/btrfs-progs/issues/251 Fixes: 9afc66498a0b ("btrfs: block-group: refactor how we read one block group item") CC: stable@vger.kernel.org # 5.8+ Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27btrfs: if we're restriping, use the target restripe profileJosef Bacik1-5/+2
Previously we depended on some weird behavior in our chunk allocator to force the allocation of new stripes, so by the time we got to doing the reduce we would usually already have a chunk with the proper target. However that behavior causes other problems and needs to be removed. First however we need to remove this check to only restripe if we already have those available profiles, because if we're allocating our first chunk it obviously will not be available. Simply use the target as specified, and if that fails it'll be because we're out of space. Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27btrfs: don't adjust bg flags and use default allocation profilesJosef Bacik1-50/+2
btrfs/061 has been failing consistently for me recently with a transaction abort. We run out of space in the system chunk array, which means we've allocated way too many system chunks than we need. Chris added this a long time ago for balance as a poor mans restriping. If you had a single disk and then added another disk and then did a balance, update_block_group_flags would then figure out which RAID level you needed. Fast forward to today and we have restriping behavior, so we can explicitly tell the fs that we're trying to change the raid level. This is accomplished through the normal get_alloc_profile path. Furthermore this code actually causes btrfs/061 to fail, because we do things like mkfs -m dup -d single with multiple devices. This trips this check alloc_flags = update_block_group_flags(fs_info, cache->flags); if (alloc_flags != cache->flags) { ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE); in btrfs_inc_block_group_ro. Because we're balancing and scrubbing, but not actually restriping, we keep forcing chunk allocation of RAID1 chunks. This eventually causes us to run out of system space and the file system aborts and flips read only. We don't need this poor mans restriping any more, simply use the normal get_alloc_profile helper, which will get the correct alloc_flags and thus make the right decision for chunk allocation. This keeps us from allocating a billion system chunks and falling over. Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>