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path: root/fs/btrfs/space-info.c
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8 daysbtrfs: change dump_block_groups() in btrfs_dump_space_info() from int to boolJohannes Thumshirn
btrfs_dump_space_info()'s parameter dump_block_groups is used as a boolean although it is defined as an integer. Change it from int to bool. Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Daniel Vacek <neelx@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>
8 daysbtrfs: rename err to ret in calc_pct_ratio()David Sterba
Unify naming of return value to the preferred way. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
8 daysbtrfs: make btrfs_should_periodic_reclaim() staticJohannes Thumshirn
btrfs_should_periodic_reclaim() is not used outside of space-info.c so make it static and remove the prototype from space-info.h. 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>
2025-05-15btrfs: add support for reclaiming from sub-space space_infoNaohiro Aota
Modify btrfs_async_{data,metadata}_reclaim() to run the reclaim process on the sub-spaces as well. 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>
2025-05-15btrfs: tweak extent/chunk allocation for space_info sub-spaceNaohiro Aota
Make the extent allocator and the chunk allocator aware of the sub-space. It now uses BTRFS_SUB_GROUP_DATA_RELOC sub-space for data relocation block group, and uses BTRFS_SUB_GROUP_TREELOG for metadata tree-log block group. And, it needs to check the space_info is the right one when a block group candidate is given. Also, new block group should now belong to the specified one. Now that, block_group->space_info is always set before btrfs_add_bg_to_space_info(), we no longer need to "find" the space_info. So, rename the variable name to address that as well. 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>
2025-05-15btrfs: introduce tree-log sub-space_infoNaohiro Aota
Introduce the tree-log sub-space_info, which is sub-space of metadata space_info and dedicated for tree-log node allocation. 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>
2025-05-15btrfs: introduce btrfs_space_info sub-groupNaohiro Aota
Current code assumes we have only one space_info for each block group type (DATA, METADATA, and SYSTEM). We sometime need multiple space infos to manage special block groups. One example is handling the data relocation block group for the zoned mode. That block group is dedicated for writing relocated data and we cannot allocate any regular extent from that block group, which is implemented in the zoned extent allocator. This block group still belongs to the normal data space_info. So, when all the normal data block groups are full and there is some free space in the dedicated block group, the space_info looks to have some free space, while it cannot allocate normal extent anymore. That results in a strange ENOSPC error. We need to have a space_info for the relocation data block group to represent the situation properly. Adds a basic infrastructure for having a "sub-group" of a space_info: creation and removing. A sub-group space_info belongs to one of the primary space_infos and has the same flags as its parent. This commit first introduces the relocation data sub-space_info, and the next commit will introduce tree-log sub-space_info. In the future, it could be useful to implement tiered storage for btrfs e.g. by implementing a sub-group space_info for block groups resides on a fast storage. 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>
2025-05-15btrfs: add space_info argument to btrfs_chunk_alloc()Naohiro Aota
Take a btrfs_space_info argument in btrfs_chunk_alloc(). New block group will belong to that space_info. Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15btrfs: factor out do_async_reclaim_{data,metadata}_space()Naohiro Aota
Factor out the main part of btrfs_async_reclaim_data_space() to do_async_reclaim_data_space(), so it can take data space_info parameter it is working on. Do the same for metadata. There is no functional change. 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>
2025-05-15btrfs: factor out init_space_info() from create_space_info()Naohiro Aota
Factor out initialization of the space_info struct, which is used in a later patch. There is no functional change. 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>
2025-05-15btrfs: pass btrfs_space_info to btrfs_reserve_data_bytes()Naohiro Aota
Pass struct btrfs_space_info to btrfs_reserve_data_bytes() to allow reserving the data from multiple data space_info candidates. This is a preparation for the following commits and there is no functional change. 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>
2025-05-15btrfs: fix typo in space info explanationMark Harmstone
There's an explanation of how space info works at the top of fs/btrfs/space-info.c, which makes reference to a variable called bytes_may_reserve. There's nothing called that in the code, and wasn't at time the comment was written; as far I can tell this is a typo, and it should actually be bytes_may_use. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Mark Harmstone <maharmstone@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-03-18btrfs: update include and forward declarations in headersDavid Sterba
Pass over all header files and add missing forward declarations, includes or fix include types. Signed-off-by: David Sterba <dsterba@suse.com>
2025-01-13btrfs: zoned: reclaim unused zone by zone resettingNaohiro Aota
On the zoned mode, once used and freed region is still not reusable after the freeing. The underlying zone needs to be reset before reusing. Btrfs resets a zone when it removes a block group, and then new block group is allocated on the zones to reuse the zones. But, it is sometime too late to catch up with a write side. This commit introduces a new space-info reclaim method ZONE_RESET. That will pick a block group from the unused list and reset its zone to reuse the zone_unusable space. It is faster than removing the block group and re-creating a new block group on the same zones. For the first implementation, the ZONE_RESET is only applied to a block group whose region is fully zone_unusable. Reclaiming partial zone_unusable block group could be implemented later. Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-01-13btrfs: drop fs_info argument from btrfs_update_space_info_*()Naohiro Aota
Since commit e1e577aafe41 ("btrfs: store fs_info in space_info"), we have the fs_info in a space_info. So, we can drop fs_info argument from btrfs_update_space_info_*. There is no behavior change. 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>
2025-01-13btrfs: factor out btrfs_return_free_space()Naohiro Aota
Factor out a part of unpin_extent_range() that returns space back to the space info, prioritizing global block reserve. Also, move the "len" variable into the loop to clarify we don't need to carry it beyond an iteration. 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>
2024-11-11btrfs: drop unused parameter fs_info from do_reclaim_sweep()David Sterba
The parameter is unused and we can get it from space info if needed. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11btrfs: drop unused parameter fs_info from wait_reserve_ticket()David Sterba
The parameter is not used, we can also reach it from the space info if needed in the future. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11btrfs: correct typos in multiple comments across various filesShen Lichuan
Fix some confusing spelling errors that were currently identified, the details are as follows: block-group.c: 2800: uncompressible ==> incompressible extent-tree.c: 3131: EXTEMT ==> EXTENT extent_io.c: 3124: utlizing ==> utilizing extent_map.c: 1323: ealier ==> earlier extent_map.c: 1325: possiblity ==> possibility fiemap.c: 189: emmitted ==> emitted fiemap.c: 197: emmitted ==> emitted fiemap.c: 203: emmitted ==> emitted transaction.h: 36: trasaction ==> transaction volumes.c: 5312: filesysmte ==> filesystem zoned.c: 1977: trasnsaction ==> transaction Signed-off-by: Shen Lichuan <shenlichuan@vivo.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-09-10btrfs: constify more pointer parametersDavid Sterba
Continue adding const to parameters. This is for clarity and minor addition to safety. There are some minor effects, in the assembly code and .ko measured on release config. Signed-off-by: David Sterba <dsterba@suse.com>
2024-08-27btrfs: fix uninitialized return value from btrfs_reclaim_sweep()Filipe Manana
The return variable 'ret' at btrfs_reclaim_sweep() is never assigned if none of the space infos is reclaimable (for example if periodic reclaim is disabled, which is the default), so we return an undefined value. This can be fixed my making btrfs_reclaim_sweep() not return any value as well as do_reclaim_sweep() because: 1) do_reclaim_sweep() always returns 0, so we can make it return void; 2) The only caller of btrfs_reclaim_sweep() (btrfs_reclaim_bgs()) doesn't care about its return value, and in its context there's nothing to do about any errors anyway. Therefore remove the return value from btrfs_reclaim_sweep() and do_reclaim_sweep(). Fixes: e4ca3932ae90 ("btrfs: periodic block_group reclaim") Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-29btrfs: zoned: fix zone_unusable accounting on making block group read-write ↵Naohiro Aota
again When btrfs makes a block group read-only, it adds all free regions in the block group to space_info->bytes_readonly. That free space excludes reserved and pinned regions. OTOH, when btrfs makes the block group read-write again, it moves all the unused regions into the block group's zone_unusable. That unused region includes reserved and pinned regions. As a result, it counts too much zone_unusable bytes. Fortunately (or unfortunately), having erroneous zone_unusable does not affect the calculation of space_info->bytes_readonly, because free space (num_bytes in btrfs_dec_block_group_ro) calculation is done based on the erroneous zone_unusable and it reduces the num_bytes just to cancel the error. This behavior can be easily discovered by adding a WARN_ON to check e.g, "bg->pinned > 0" in btrfs_dec_block_group_ro(), and running fstests test case like btrfs/282. Fix it by properly considering pinned and reserved in btrfs_dec_block_group_ro(). Also, add a WARN_ON and introduce btrfs_space_info_update_bytes_zone_unusable() to catch a similar mistake. Fixes: 169e0da91a21 ("btrfs: zoned: track unusable bytes for zones") CC: stable@vger.kernel.org # 5.15+ Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-29btrfs: do not subtract delalloc from avail bytesNaohiro Aota
The block group's avail bytes printed when dumping a space info subtract the delalloc_bytes. However, as shown in btrfs_add_reserved_bytes() and btrfs_free_reserved_bytes(), it is added or subtracted along with "reserved" for the delalloc case, which means the "delalloc_bytes" is a part of the "reserved" bytes. So, excluding it to calculate the avail space counts delalloc_bytes twice, which can lead to an invalid result. Fixes: e50b122b832b ("btrfs: print available space for a block group when dumping a space info") CC: stable@vger.kernel.org # 6.6+ Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: urgent periodic reclaim passBoris Burkov
Periodic reclaim attempts to avoid block_groups seeing active use with a sweep mark that gets cleared on allocation and set on a sweep. In urgent conditions where we have very little unallocated space (less than one chunk used by the threshold calculation for the unallocated target), we want to be able to override this mechanism. Introduce a second pass that only happens if we fail to find a reclaim candidate and reclaim is urgent. In that case, do a second pass where all block groups are eligible. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: prevent pathological periodic reclaim loopsBoris Burkov
Periodic reclaim runs the risk of getting stuck in a state where it keeps reclaiming the same block group over and over. This can happen if 1. reclaiming that block_group fails 2. reclaiming that block_group fails to move any extents into existing block_groups and just allocates a fresh chunk and moves everything. Currently, 1. is a very tight loop inside the reclaim worker. That is critical for edge triggered reclaim or else we risk forgetting about a reclaimable group. On the other hand, with level triggered reclaim we can break out of that loop and get it later. With that fixed, 2. applies to both failures and "successes" with no progress. If we have done a periodic reclaim on a space_info and nothing has changed in that space_info, there is not much point to trying again, so don't, until enough space gets free, which we capture with a heuristic of needing to net free 1 chunk. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: periodic block_group reclaimBoris Burkov
We currently employ a edge-triggered block group reclaim strategy which marks block groups for reclaim as they free down past a threshold. With a dynamic threshold, this is worse than doing it in a level-triggered fashion periodically. That is because the reclaim itself happens periodically, so the threshold at that point in time is what really matters, not the threshold at freeing time. If we mark the reclaim in a big pass, then sort by usage and do reclaim, we also benefit from a negative feedback loop preventing unnecessary reclaims as we crunch through the "best" candidates. Since this is quite a different model, it requires some additional support. The edge triggered reclaim has a good heuristic for not reclaiming fresh block groups, so we need to replace that with a typical GC sweep mark which skips block groups that have seen an allocation since the last sweep. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: dynamic block_group reclaim thresholdBoris Burkov
We can currently recover allocated block_groups by: - explicitly starting balance operations - "auto reclaim" via bg_reclaim_threshold The latter works by checking against a fixed threshold on frees. If we pass from above the threshold to below, relocation triggers and the block group will get reclaimed by the cleaner thread (assuming it is still eligible) Picking a threshold is challenging. Too high, and you end up trying to reclaim very full block_groups which is quite costly, and you don't do reclaim on block_groups that don't get quite THAT full, but could still be quite fragmented and stranding a lot of space. Too low, and you similarly miss out on reclaim even if you badly need it to avoid running out of unallocated space, if you have heavily fragmented block groups living above the threshold. No matter the threshold, it suffers from a workload that happens to bounce around that threshold, which can introduce arbitrary amounts of reclaim waste. To improve this situation, introduce a dynamic threshold. The basic idea behind this threshold is that it should be very lax when there is plenty of unallocated space, and increasingly aggressive as we approach zero unallocated space. To that end, it sets a target for unallocated space (10 chunks) and then linearly increases the threshold as the amount of space short of the target we are increases. The formula is: (target - unalloc) / target I tested this by running it on three interesting workloads: 1. bounce allocations around X% full. 2. fill up all the way and introduce full fragmentation. 3. write in a fragmented way until the filesystem is just about full. 1. and 2. attack the weaknesses of a fixed threshold; fixed either works perfectly or fully falls apart, depending on the threshold. Dynamic always handles these cases well. 3. attacks dynamic by checking whether it is too zealous to reclaim in conditions with low unallocated and low unused. It tends to claw back 1GiB of unallocated fairly aggressively, but not much more. Early versions of dynamic threshold struggled on this test. Additional work could be done to intelligently ratchet up the urgency of reclaim in very low unallocated conditions. Existing mechanisms are already useless in that case anyway. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: store fs_info in space_infoBoris Burkov
This is handy when computing space_info dynamic reclaim thresholds where we do not have access to a block group. We could add it to the various functions as a parameter, but it seems reasonable for space_info to have an fs_info pointer. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: add and use helper to commit the current transactionFilipe Manana
We have several places that attach to the current transaction with btrfs_attach_transaction_barrier() and then commit the transaction if there is one. Add a helper and use it to deduplicate this pattern. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: simplify range parameters of btrfs_wait_ordered_roots()David Sterba
The range is specified only in two ways, we can simplify the case for the whole filesystem range as a NULL block group parameter. Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: remove unused define EXTENT_SIZE_PER_ITEMDavid Sterba
This was added in c61a16a701a126 ("Btrfs: fix the confusion between delalloc bytes and metadata bytes") and removed in 03fe78cc2942c5 ("btrfs: use delalloc_bytes to determine flush amount for shrink_delalloc") where the calculation was reworked to use a non-constant numbers. This was found by 'make W=2'. Reviewed-by: Boris Burkov <boris@bur.io> Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-02btrfs: zoned: fix calc_available_free_space() for zoned modeNaohiro Aota
calc_available_free_space() returns the total size of metadata (or system) block groups, which can be allocated from unallocated disk space. The logic is wrong on zoned mode in two places. First, the calculation of data_chunk_size is wrong. We always allocate one zone as one chunk, and no partial allocation of a zone. So, we should use zone_size (= data_sinfo->chunk_size) as it is. Second, the result "avail" may not be zone aligned. Since we always allocate one zone as one chunk on zoned mode, returning non-zone size aligned bytes will result in less pressure on the async metadata reclaim process. This is serious for the nearly full state with a large zone size device. Allowing over-commit too much will result in less async reclaim work and end up in ENOSPC. We can align down to the zone size to avoid that. Fixes: cb6cbab79055 ("btrfs: adjust overcommit logic when very close to full") CC: stable@vger.kernel.org # 6.9 Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04btrfs: remove unused included headersDavid Sterba
With help of neovim, LSP and clangd we can identify header files that are not actually needed to be included in the .c files. This is focused only on removal (with minor fixups), further cleanups are possible but will require doing the header files properly with forward declarations, minimized includes and include-what-you-use care. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-02-22btrfs: fix data races when accessing the reserved amount of block reservesFilipe Manana
At space_info.c we have several places where we access the ->reserved field of a block reserve without taking the block reserve's spinlock first, which makes KCSAN warn about a data race since that field is always updated while holding the spinlock. The reports from KCSAN are like the following: [117.193526] BUG: KCSAN: data-race in btrfs_block_rsv_release [btrfs] / need_preemptive_reclaim [btrfs] [117.195148] read to 0x000000017f587190 of 8 bytes by task 6303 on cpu 3: [117.195172] need_preemptive_reclaim+0x222/0x2f0 [btrfs] [117.195992] __reserve_bytes+0xbb0/0xdc8 [btrfs] [117.196807] btrfs_reserve_metadata_bytes+0x4c/0x120 [btrfs] [117.197620] btrfs_block_rsv_add+0x78/0xa8 [btrfs] [117.198434] btrfs_delayed_update_inode+0x154/0x368 [btrfs] [117.199300] btrfs_update_inode+0x108/0x1c8 [btrfs] [117.200122] btrfs_dirty_inode+0xb4/0x140 [btrfs] [117.200937] btrfs_update_time+0x8c/0xb0 [btrfs] [117.201754] touch_atime+0x16c/0x1e0 [117.201789] filemap_read+0x674/0x728 [117.201823] btrfs_file_read_iter+0xf8/0x410 [btrfs] [117.202653] vfs_read+0x2b6/0x498 [117.203454] ksys_read+0xa2/0x150 [117.203473] __s390x_sys_read+0x68/0x88 [117.203495] do_syscall+0x1c6/0x210 [117.203517] __do_syscall+0xc8/0xf0 [117.203539] system_call+0x70/0x98 [117.203579] write to 0x000000017f587190 of 8 bytes by task 11 on cpu 0: [117.203604] btrfs_block_rsv_release+0x2e8/0x578 [btrfs] [117.204432] btrfs_delayed_inode_release_metadata+0x7c/0x1d0 [btrfs] [117.205259] __btrfs_update_delayed_inode+0x37c/0x5e0 [btrfs] [117.206093] btrfs_async_run_delayed_root+0x356/0x498 [btrfs] [117.206917] btrfs_work_helper+0x160/0x7a0 [btrfs] [117.207738] process_one_work+0x3b6/0x838 [117.207768] worker_thread+0x75e/0xb10 [117.207797] kthread+0x21a/0x230 [117.207830] __ret_from_fork+0x6c/0xb8 [117.207861] ret_from_fork+0xa/0x30 So add a helper to get the reserved amount of a block reserve while holding the lock. The value may be not be up to date anymore when used by need_preemptive_reclaim() and btrfs_preempt_reclaim_metadata_space(), but that's ok since the worst it can do is cause more reclaim work do be done sooner rather than later. Reading the field while holding the lock instead of using the data_race() annotation is used in order to prevent load tearing. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12btrfs: adjust overcommit logic when very close to fullJosef Bacik
A user reported some unpleasant behavior with very small file systems. The reproducer is this $ mkfs.btrfs -f -m single -b 8g /dev/vdb $ mount /dev/vdb /mnt/test $ dd if=/dev/zero of=/mnt/test/testfile bs=512M count=20 This will result in usage that looks like this Overall: Device size: 8.00GiB Device allocated: 8.00GiB Device unallocated: 1.00MiB Device missing: 0.00B Device slack: 2.00GiB Used: 5.47GiB Free (estimated): 2.52GiB (min: 2.52GiB) Free (statfs, df): 0.00B Data ratio: 1.00 Metadata ratio: 1.00 Global reserve: 5.50MiB (used: 0.00B) Multiple profiles: no Data,single: Size:7.99GiB, Used:5.46GiB (68.41%) /dev/vdb 7.99GiB Metadata,single: Size:8.00MiB, Used:5.77MiB (72.07%) /dev/vdb 8.00MiB System,single: Size:4.00MiB, Used:16.00KiB (0.39%) /dev/vdb 4.00MiB Unallocated: /dev/vdb 1.00MiB As you can see we've gotten ourselves quite full with metadata, with all of the disk being allocated for data. On smaller file systems there's not a lot of time before we get full, so our overcommit behavior bites us here. Generally speaking data reservations result in chunk allocations as we assume reservation == actual use for data. This means at any point we could end up with a chunk allocation for data, and if we're very close to full we could do this before we have a chance to figure out that we need another metadata chunk. Address this by adjusting the overcommit logic. Simply put we need to take away 1 chunk from the available chunk space in case of a data reservation. This will allow us to stop overcommitting before we potentially lose this space to a data allocation. With this fix in place we properly allocate a metadata chunk before we're completely full, allowing for enough slack space in metadata. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12btrfs: allow to run delayed refs by bytes to be released instead of countFilipe Manana
When running delayed references, through btrfs_run_delayed_refs(), we can specify how many to run, run all existing delayed references and keep running delayed references while we can find any. This is controlled with the value of the 'count' argument, where a value of 0 means to run all delayed references that exist by the time btrfs_run_delayed_refs() is called, (unsigned long)-1 means to keep running delayed references while we are able find any, and any other value to run that exact number of delayed references. Typically a specific value other than 0 or -1 is used when flushing space to try to release a certain amount of bytes for a ticket. In this case we just simply calculate how many delayed reference heads correspond to a specific amount of bytes, with calc_delayed_refs_nr(). However that only takes into account the space reserved for the reference heads themselves, and does not account for the space reserved for deleting checksums from the csum tree (see add_delayed_ref_head() and update_existing_head_ref()) in case we are going to delete a data extent. This means we may end up running more delayed references than necessary in case we process delayed references for deleting a data extent. So change the logic of btrfs_run_delayed_refs() to take a bytes argument to specify how many bytes of delayed references to run/release, using the special values of 0 to mean all existing delayed references and U64_MAX (or (u64)-1) to keep running delayed references while we can find any. This prevents running more delayed references than necessary, when we have delayed references for deleting data extents, but also makes the upcoming changes/patches simpler and it's preparatory work for them. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12btrfs: pass a space_info argument to btrfs_reserve_metadata_bytes()Filipe Manana
We are passing a block reserve argument to btrfs_reserve_metadata_bytes() which is not really used, all we need is to pass the space_info associated to the block reserve, we don't change the block reserve at all. Not only it's pointless to pass the block reserve, it's also confusing as one might think that the reserved bytes will end up being added to the passed block reserve, when that's not the case. The pattern for reserving space and adding it to a block reserve is to first reserve space with btrfs_reserve_metadata_bytes() and if that succeeds, then add the space to a block reserve by calling btrfs_block_rsv_add_bytes(). Also the reverse of btrfs_reserve_metadata_bytes(), which is btrfs_space_info_free_bytes_may_use(), takes a space_info argument and not a block reserve, so one more reason to pass a space_info and not a block reserve to btrfs_reserve_metadata_bytes(). So change btrfs_reserve_metadata_bytes() and its callers to pass a space_info argument instead of a block reserve argument. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12btrfs: reformat remaining kdoc style commentsDavid Sterba
Function name in the comment does not bring much value to code not exposed as API and we don't stick to the kdoc format anymore. Update formatting of parameter descriptions. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21btrfs: zoned: re-enable metadata over-commit for zoned modeNaohiro Aota
Now that, we can re-enable metadata over-commit. As we moved the activation from the reservation time to the write time, we no longer need to ensure all the reserved bytes is properly activated. Without the metadata over-commit, it suffers from lower performance because it needs to flush the delalloc items more often and allocate more block groups. Re-enabling metadata over-commit will solve the issue. Fixes: 79417d040f4f ("btrfs: zoned: disable metadata overcommit for zoned") CC: stable@vger.kernel.org # 6.1+ 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>
2023-08-21btrfs: zoned: don't activate non-DATA BG on allocationNaohiro Aota
Now that a non-DATA block group is activated at write time, don't activate it on allocation time. 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>
2023-08-21btrfs: avoid starting and committing empty transaction when flushing spaceFilipe Manana
When flushing space and we are in the COMMIT_TRANS state, we join a transaction with btrfs_join_transaction() and then commit the returned transaction. However btrfs_join_transaction() starts a new transaction if there is none currently open, which is pointless since comitting a new, empty transaction, doesn't achieve anything, it only wastes time, IO and creates an unnecessary rotation of the backup roots. So use btrfs_attach_transaction_barrier() to avoid starting a new transaction. This also waits for any ongoing transaction that is committing (state >= TRANS_STATE_COMMIT_DOING) to fully complete, and therefore wait for all the extents that were pinned during the transaction's lifetime to be unpinned. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21btrfs: avoid starting new transaction when flushing delayed items and refsFilipe Manana
When flushing space we join a transaction to flush delayed items and delayed references, in order to try to release space. However using btrfs_join_transaction() not only joins an existing transaction as well as it starts a new transaction if there is none open. If there is no transaction open, we don't have neither delayed items nor delayed references, so creating a new transaction is a waste of time, IO and creates an unnecessary rotation of the backup roots without gaining any benefits (including releasing space). So use btrfs_join_transaction_nostart() when attempting to flush delayed items and references. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21btrfs: fail priority metadata ticket with real fs errorFilipe Manana
At priority_reclaim_metadata_space(), if we were not able to satisfy the the ticket after going through the various flushing states and we notice the fs went into an error state, likely due to a transaction abort during the flushing, set the ticket's error to the error that caused the transaction abort instead of an unconditional -EROFS. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21btrfs: don't steal space from global rsv after a transaction abortFilipe Manana
When doing a priority metadata space reclaim, while we are going through the flush states and running their respective operations, it's possible that a transaction abort happened, for example when running delayed refs we hit -ENOSPC or in the critical section of transaction commit we failed with -ENOSPC or some other error. In these cases a transaction was aborted and the fs turned into error state. If that happened, then it makes no sense to steal from the global block reserve and return success to the caller if the stealing was successful - the caller will later get an error when attempting to modify the fs. Instead make the ticket fail if we have the fs in error state and don't attempt to steal from the global rsv, as it's not only it's pointless, it also simplifies debugging some -ENOSPC problems. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21btrfs: print available space across all block groups when dumping space infoFilipe Manana
When dumping a space info also sum the available space for all block groups and then print it. This often useful for debugging -ENOSPC related problems. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21btrfs: print available space for a block group when dumping a space infoFilipe Manana
When dumping a space info, we iterate over all its block groups and then print their size and the amounts of bytes used, reserved, pinned, etc. When debugging -ENOSPC problems it's also useful to know how much space is available (free), so calculate that and print it as well. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-08-21btrfs: print block group super and delalloc bytes when dumping space infoFilipe Manana
When dumping a space info's block groups, also print the number of bytes used for super blocks and delalloc. This is often useful for debugging -ENOSPC problems. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-04-17btrfs: add helper to calculate space for delayed referencesFilipe Manana
Instead of duplicating the logic for calculating how much space is required for a given number of delayed references, add an inline helper to encapsulate that logic and use it everywhere we are calculating the space required. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-04-17btrfs: constify fs_info argument for the reclaim items calculation helpersFilipe Manana
Now that btrfs_calc_insert_metadata_size() can take a const fs_info argument, make the fs_info argument of calc_reclaim_items_nr() and of calc_delayed_refs_nr() const as well. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-04-17btrfs: accurately calculate number of delayed refs when flushingFilipe Manana
When flushing a limited number of delayed references (FLUSH_DELAYED_REFS_NR state), we are assuming each delayed reference is holding a number of bytes matching the needed space for inserting for a single metadata item (the result of btrfs_calc_insert_metadata_size()). That is not correct when using the free space tree, as in that case we have to multiply that value by 2 since we need to touch the free space tree as well. This is the same computation as we do at btrfs_update_delayed_refs_rsv() and at btrfs_delayed_refs_rsv_release(). So correct the computation for the amount of delayed references we need to flush in case we have the free space tree. This does not fix a functional issue, instead it makes the flush code flush less delayed references, only the minimum necessary to satisfy a ticket. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>