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path: root/fs/btrfs/block-group.h
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2020-07-27btrfs: convert block group refcount to refcount_tJosef Bacik
We have refcount_t now with the associated library to handle refcounts, which gives us extra debugging around reference count mistakes that may be made. For example it'll warn on any transition from 0->1 or 0->-1, which is handy for noticing cases where we've messed up reference counting. Convert the block group ref counting from an atomic_t to refcount_t and use the appropriate helpers. 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>
2020-05-25btrfs: move the block group freeze/unfreeze helpers into block-group.cFilipe Manana
The helpers btrfs_freeze_block_group() and btrfs_unfreeze_block_group() used to be named btrfs_get_block_group_trimming() and btrfs_put_block_group_trimming() respectively. At the time they were added to free-space-cache.c, by commit e33e17ee1098 ("btrfs: add missing discards when unpinning extents with -o discard") because all the trimming related functions were in free-space-cache.c. Now that the helpers were renamed and are used in scrub context as well, move them to block-group.c, a much more logical location for them. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25btrfs: rename member 'trimming' of block group to a more generic nameFilipe Manana
Back in 2014, commit 04216820fe83d5 ("Btrfs: fix race between fs trimming and block group remove/allocation"), I added the 'trimming' member to the block group structure. Its purpose was to prevent races between trimming and block group deletion/allocation by pinning the block group in a way that prevents its logical address and device extents from being reused while trimming is in progress for a block group, so that if another task deletes the block group and then another task allocates a new block group that gets the same logical address and device extents while the trimming task is still in progress. After the previous fix for scrub (patch "btrfs: fix a race between scrub and block group removal/allocation"), scrub now also has the same needs that trimming has, so the member name 'trimming' no longer makes sense. Since there is already a 'pinned' member in the block group that refers to space reservations (pinned bytes), rename the member to 'frozen', add a comment on top of it to describe its general purpose and rename the helpers to increment and decrement the counter as well, to match the new member name. The next patch in the series will move the helpers into a more suitable file (from free-space-cache.c to block-group.c). Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: Move and unexport btrfs_rmap_blockNikolay Borisov
It's used only during initial block group reading to map physical address of super block to a list of logical ones. Make it private to block-group.c, add proper kernel doc and ensure it's exported only for tests. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: only keep track of data extents for async discardDennis Zhou
As mentioned earlier, discarding data can be done either by issuing an explicit discard or implicitly by reusing the LBA. Metadata block_groups see much more frequent reuse due to well it being metadata. So instead of explicitly discarding metadata block_groups, just leave them be and let the latter implicit discarding be done for them. For mixed block_groups, block_groups which contain both metadata and data, we let them be as higher fragmentation is expected. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: discard one region at a time in async discardDennis Zhou
The prior two patches added discarding via a background workqueue. This just piggybacked off of the fstrim code to trim the whole block at once. Well inevitably this is worse performance wise and will aggressively overtrim. But it was nice to plumb the other infrastructure to keep the patches easier to review. This adds the real goal of this series which is discarding slowly (ie. a slow long running fstrim). The discarding is split into two phases, extents and then bitmaps. The reason for this is two fold. First, the bitmap regions overlap the extent regions. Second, discarding the extents first will let the newly trimmed bitmaps have the highest chance of coalescing when being readded to the free space cache. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: add the beginning of async discard, discard workqueueDennis Zhou
When discard is enabled, everytime a pinned extent is released back to the block_group's free space cache, a discard is issued for the extent. This is an overeager approach when it comes to discarding and helping the SSD maintain enough free space to prevent severe garbage collection situations. This adds the beginning of async discard. Instead of issuing a discard prior to returning it to the free space, it is just marked as untrimmed. The block_group is then added to a LRU which then feeds into a workqueue to issue discards at a much slower rate. Full discarding of unused block groups is still done and will be addressed in a future patch of the series. For now, we don't persist the discard state of extents and bitmaps. Therefore, our failure recovery mode will be to consider extents untrimmed. This lets us handle failure and unmounting as one in the same. On a number of Facebook webservers, I collected data every minute accounting the time we spent in btrfs_finish_extent_commit() (col. 1) and in btrfs_commit_transaction() (col. 2). btrfs_finish_extent_commit() is where we discard extents synchronously before returning them to the free space cache. discard=sync: p99 total per minute p99 total per minute Drive | extent_commit() (ms) | commit_trans() (ms) --------------------------------------------------------------- Drive A | 434 | 1170 Drive B | 880 | 2330 Drive C | 2943 | 3920 Drive D | 4763 | 5701 discard=async: p99 total per minute p99 total per minute Drive | extent_commit() (ms) | commit_trans() (ms) -------------------------------------------------------------- Drive A | 134 | 956 Drive B | 64 | 1972 Drive C | 59 | 1032 Drive D | 62 | 1200 While it's not great that the stats are cumulative over 1m, all of these servers are running the same workload and and the delta between the two are substantial. We are spending significantly less time in btrfs_finish_extent_commit() which is responsible for discarding. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: scrub: Don't check free space before marking a block group ROQu Wenruo
[BUG] When running btrfs/072 with only one online CPU, it has a pretty high chance to fail: btrfs/072 12s ... _check_dmesg: something found in dmesg (see xfstests-dev/results//btrfs/072.dmesg) - output mismatch (see xfstests-dev/results//btrfs/072.out.bad) --- tests/btrfs/072.out 2019-10-22 15:18:14.008965340 +0800 +++ /xfstests-dev/results//btrfs/072.out.bad 2019-11-14 15:56:45.877152240 +0800 @@ -1,2 +1,3 @@ QA output created by 072 Silence is golden +Scrub find errors in "-m dup -d single" test ... And with the following call trace: BTRFS info (device dm-5): scrub: started on devid 1 ------------[ cut here ]------------ BTRFS: Transaction aborted (error -27) WARNING: CPU: 0 PID: 55087 at fs/btrfs/block-group.c:1890 btrfs_create_pending_block_groups+0x3e6/0x470 [btrfs] CPU: 0 PID: 55087 Comm: btrfs Tainted: G W O 5.4.0-rc1-custom+ #13 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:btrfs_create_pending_block_groups+0x3e6/0x470 [btrfs] Call Trace: __btrfs_end_transaction+0xdb/0x310 [btrfs] btrfs_end_transaction+0x10/0x20 [btrfs] btrfs_inc_block_group_ro+0x1c9/0x210 [btrfs] scrub_enumerate_chunks+0x264/0x940 [btrfs] btrfs_scrub_dev+0x45c/0x8f0 [btrfs] btrfs_ioctl+0x31a1/0x3fb0 [btrfs] do_vfs_ioctl+0x636/0xaa0 ksys_ioctl+0x67/0x90 __x64_sys_ioctl+0x43/0x50 do_syscall_64+0x79/0xe0 entry_SYSCALL_64_after_hwframe+0x49/0xbe ---[ end trace 166c865cec7688e7 ]--- [CAUSE] The error number -27 is -EFBIG, returned from the following call chain: btrfs_end_transaction() |- __btrfs_end_transaction() |- btrfs_create_pending_block_groups() |- btrfs_finish_chunk_alloc() |- btrfs_add_system_chunk() This happens because we have used up all space of btrfs_super_block::sys_chunk_array. The root cause is, we have the following bad loop of creating tons of system chunks: 1. The only SYSTEM chunk is being scrubbed It's very common to have only one SYSTEM chunk. 2. New SYSTEM bg will be allocated As btrfs_inc_block_group_ro() will check if we have enough space after marking current bg RO. If not, then allocate a new chunk. 3. New SYSTEM bg is still empty, will be reclaimed During the reclaim, we will mark it RO again. 4. That newly allocated empty SYSTEM bg get scrubbed We go back to step 2, as the bg is already mark RO but still not cleaned up yet. If the cleaner kthread doesn't get executed fast enough (e.g. only one CPU), then we will get more and more empty SYSTEM chunks, using up all the space of btrfs_super_block::sys_chunk_array. [FIX] Since scrub/dev-replace doesn't always need to allocate new extent, especially chunk tree extent, so we don't really need to do chunk pre-allocation. To break above spiral, here we introduce a new parameter to btrfs_inc_block_group(), @do_chunk_alloc, which indicates whether we need extra chunk pre-allocation. For relocation, we pass @do_chunk_alloc=true, while for scrub, we pass @do_chunk_alloc=false. This should keep unnecessary empty chunks from popping up for scrub. Also, since there are two parameters for btrfs_inc_block_group_ro(), add more comment for it. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: rename btrfs_block_group_cacheDavid Sterba
The type name is misleading, a single entry is named 'cache' while this normally means a collection of objects. Rename that everywhere. Also the identifier was quite long, making function prototypes harder to format. Suggested-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: add dedicated members for start and length of a block groupDavid Sterba
The on-disk format of block group item makes use of the key that stores the offset and length. This is further used in the code, although this makes thing harder to understand. The key is also packed so the offset/length is not properly aligned as u64. Add start (key.objectid) and length (key.offset) members to block group and remove the embedded key. When the item is searched or written, a local variable for key is used. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: remove embedded block_group_cache::itemDavid Sterba
The members ::used and ::flags are now in the block group cache structure, the last one is chunk_objectid, but that's set to a fixed value and otherwise unused. The item is constructed from a local variable before write, so we can remove the embedded one from block group. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: move block_group_item::used to block groupDavid Sterba
For unknown reasons, the member 'used' in the block group struct is stored in the b-tree item and accessed everywhere using the special accessor helper. Let's unify it and make it a regular member and only update the item before writing it to the tree. The item is still being used for flags and chunk_objectid, there's some duplication until the item is removed in following patches. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: move struct io_ctl to free-space-cache.hDavid Sterba
The io_ctl structure is used for free space management, and used only by the v1 space cache code, but unfortunatlly the full definition is required by block-group.h so it can't be moved to free-space-cache.c without additional changes. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: unexport the temporary exported functionsJosef Bacik
These were renamed and exported to facilitate logical migration of different code chunks into block-group.c. Now that all the users are in one file go ahead and rename them back, move the code around, and make them static. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: migrate the block group cleanup codeJosef Bacik
This can now be easily migrated as well. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ refresh on top of sysfs cleanups ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: migrate the alloc_profile helpersJosef Bacik
These feel more at home in block-group.c. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ refresh, adjust btrfs_get_alloc_profile exports ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: migrate the chunk allocation codeJosef Bacik
This feels more at home in block-group.c than in extent-tree.c. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com>i [ refresh ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: export block group accounting helpersJosef Bacik
Want to move these functions into block-group.c, so export them. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: migrate the dirty bg writeout codeJosef Bacik
This can be easily migrated over now. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update comments ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: migrate inc/dec_block_group_ro codeJosef Bacik
This can easily be moved now. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ refresh ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: temporarily export btrfs_get_restripe_targetJosef Bacik
This gets used by a few different logical chunks of the block group code, export it while we move things around. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: migrate the block group read/creation codeJosef Bacik
All of the prep work has been done so we can now cleanly move this chunk over. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ refresh, add btrfs_get_alloc_profile export, comment updates ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: migrate the block group removal codeJosef Bacik
This is the removal code and the unused bgs code. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ refresh, move clear_incompat_bg_bits ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: temporarily export inc_block_group_roJosef Bacik
This is used in a few logical parts of the block group code, temporarily export it so we can move things in pieces. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: migrate the block group caching codeJosef Bacik
We can now just copy it over to block-group.c. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: temporarily export fragment_free_spaceJosef Bacik
This is used in caching and reading block groups, so export it while we move these chunks independently. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: export the caching control helpersJosef Bacik
Man a lot of people use this stuff. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: export the block group caching helpersJosef Bacik
This will make it so we can move them easily. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ coding style updates ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: migrate nocow and reservation helpersJosef Bacik
These are relatively straightforward as well. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: migrate the block group ref counting stuffJosef Bacik
Another easy set to move over to block-group.c. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: migrate the block group lookup codeJosef Bacik
Move these bits first as they are the easiest to move. Export two of the helpers so they can be moved all at once. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ minor style updates ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: move basic block_group definitions to their own headerJosef Bacik
This is prep work for moving all of the block group cache code into its own file. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ minor comment updates ] Signed-off-by: David Sterba <dsterba@suse.com>