- 18 12月, 2020 2 次提交
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由 ethanwu 提交于
Item key collision is allowed for some item types, like dir item and inode refs, but the overall item size is limited by the nodesize. item size(ins_len) passed from btrfs_insert_empty_items to btrfs_search_slot already contains size of btrfs_item. When btrfs_search_slot reaches leaf, we'll see if we need to split leaf. The check incorrectly reports that split leaf is required, because it treats the space required by the newly inserted item as btrfs_item + item data. But in item key collision case, only item data is actually needed, the newly inserted item could merge into the existing one. No new btrfs_item will be inserted. And split_leaf return EOVERFLOW from following code: if (extend && data_size + btrfs_item_size_nr(l, slot) + sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(fs_info)) return -EOVERFLOW; In most cases, when callers receive EOVERFLOW, they either return this error or handle in different ways. For example, in normal dir item creation the userspace will get errno EOVERFLOW; in inode ref case INODE_EXTREF is used instead. However, this is not the case for rename. To avoid the unrecoverable situation in rename, btrfs_check_dir_item_collision is called in early phase of rename. In this function, when item key collision is detected leaf space is checked: data_size = sizeof(*di) + name_len; if (data_size + btrfs_item_size_nr(leaf, slot) + sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root->fs_info)) the sizeof(struct btrfs_item) + btrfs_item_size_nr(leaf, slot) here refers to existing item size, the condition here correctly calculates the needed size for collision case rather than the wrong case above. The consequence of inconsistent condition check between btrfs_check_dir_item_collision and btrfs_search_slot when item key collision happens is that we might pass check here but fail later at btrfs_search_slot. Rename fails and volume is forced readonly [436149.586170] ------------[ cut here ]------------ [436149.586173] BTRFS: Transaction aborted (error -75) [436149.586196] WARNING: CPU: 0 PID: 16733 at fs/btrfs/inode.c:9870 btrfs_rename2+0x1938/0x1b70 [btrfs] [436149.586227] CPU: 0 PID: 16733 Comm: python Tainted: G D 4.18.0-rc5+ #1 [436149.586228] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/05/2016 [436149.586238] RIP: 0010:btrfs_rename2+0x1938/0x1b70 [btrfs] [436149.586254] RSP: 0018:ffffa327043a7ce0 EFLAGS: 00010286 [436149.586255] RAX: 0000000000000000 RBX: ffff8d8a17d13340 RCX: 0000000000000006 [436149.586256] RDX: 0000000000000007 RSI: 0000000000000096 RDI: ffff8d8a7fc164b0 [436149.586257] RBP: ffffa327043a7da0 R08: 0000000000000560 R09: 7265282064657472 [436149.586258] R10: 0000000000000000 R11: 6361736e61725420 R12: ffff8d8a0d4c8b08 [436149.586258] R13: ffff8d8a17d13340 R14: ffff8d8a33e0a540 R15: 00000000000001fe [436149.586260] FS: 00007fa313933740(0000) GS:ffff8d8a7fc00000(0000) knlGS:0000000000000000 [436149.586261] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [436149.586262] CR2: 000055d8d9c9a720 CR3: 000000007aae0003 CR4: 00000000003606f0 [436149.586295] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [436149.586296] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [436149.586296] Call Trace: [436149.586311] vfs_rename+0x383/0x920 [436149.586313] ? vfs_rename+0x383/0x920 [436149.586315] do_renameat2+0x4ca/0x590 [436149.586317] __x64_sys_rename+0x20/0x30 [436149.586324] do_syscall_64+0x5a/0x120 [436149.586330] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [436149.586332] RIP: 0033:0x7fa3133b1d37 [436149.586348] RSP: 002b:00007fffd3e43908 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 [436149.586349] RAX: ffffffffffffffda RBX: 00007fa3133b1d30 RCX: 00007fa3133b1d37 [436149.586350] RDX: 000055d8da06b5e0 RSI: 000055d8da225d60 RDI: 000055d8da2c4da0 [436149.586351] RBP: 000055d8da2252f0 R08: 00007fa313782000 R09: 00000000000177e0 [436149.586351] R10: 000055d8da010680 R11: 0000000000000246 R12: 00007fa313840b00 Thanks to Hans van Kranenburg for information about crc32 hash collision tools, I was able to reproduce the dir item collision with following python script. https://github.com/wutzuchieh/misc_tools/blob/master/crc32_forge.py Run it under a btrfs volume will trigger the abort transaction. It simply creates files and rename them to forged names that leads to hash collision. There are two ways to fix this. One is to simply revert the patch 878f2d2c ("Btrfs: fix max dir item size calculation") to make the condition consistent although that patch is correct about the size. The other way is to handle the leaf space check correctly when collision happens. I prefer the second one since it correct leaf space check in collision case. This fix will not account sizeof(struct btrfs_item) when the item already exists. There are two places where ins_len doesn't contain sizeof(struct btrfs_item), however. 1. extent-tree.c: lookup_inline_extent_backref 2. file-item.c: btrfs_csum_file_blocks to make the logic of btrfs_search_slot more clear, we add a flag search_for_extension in btrfs_path. This flag indicates that ins_len passed to btrfs_search_slot doesn't contain sizeof(struct btrfs_item). When key exists, btrfs_search_slot will use the actual size needed to calculate the required leaf space. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: Nethanwu <ethanwu@synology.com> Signed-off-by: NDavid Sterba <dsterba@suse.com> -
由 Filipe Manana 提交于
When cloning an inline extent there are cases where we can not just copy the inline extent from the source range to the target range (e.g. when the target range starts at an offset greater than zero). In such cases we copy the inline extent's data into a page of the destination inode and then dirty that page. However, after that we will need to start a transaction for each processed extent and, if we are ever low on available metadata space, we may need to flush existing delalloc for all dirty inodes in an attempt to release metadata space - if that happens we may deadlock: * the async reclaim task queued a delalloc work to flush delalloc for the destination inode of the clone operation; * the task executing that delalloc work gets blocked waiting for the range with the dirty page to be unlocked, which is currently locked by the task doing the clone operation; * the async reclaim task blocks waiting for the delalloc work to complete; * the cloning task is waiting on the waitqueue of its reservation ticket while holding the range with the dirty page locked in the inode's io_tree; * if metadata space is not released by some other task (like delalloc for some other inode completing for example), the clone task waits forever and as a consequence the delalloc work and async reclaim tasks will hang forever as well. Releasing more space on the other hand may require starting a transaction, which will hang as well when trying to reserve metadata space, resulting in a deadlock between all these tasks. When this happens, traces like the following show up in dmesg/syslog: [87452.323003] INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds. [87452.323644] Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 [87452.324248] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [87452.324852] task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000 [87452.325520] Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] [87452.326136] Call Trace: [87452.326737] __schedule+0x5d1/0xcf0 [87452.327390] schedule+0x45/0xe0 [87452.328174] lock_extent_bits+0x1e6/0x2d0 [btrfs] [87452.328894] ? finish_wait+0x90/0x90 [87452.329474] btrfs_invalidatepage+0x32c/0x390 [btrfs] [87452.330133] ? __mod_memcg_state+0x8e/0x160 [87452.330738] __extent_writepage+0x2d4/0x400 [btrfs] [87452.331405] extent_write_cache_pages+0x2b2/0x500 [btrfs] [87452.332007] ? lock_release+0x20e/0x4c0 [87452.332557] ? trace_hardirqs_on+0x1b/0xf0 [87452.333127] extent_writepages+0x43/0x90 [btrfs] [87452.333653] ? lock_acquire+0x1a3/0x490 [87452.334177] do_writepages+0x43/0xe0 [87452.334699] ? __filemap_fdatawrite_range+0xa4/0x100 [87452.335720] __filemap_fdatawrite_range+0xc5/0x100 [87452.336500] btrfs_run_delalloc_work+0x17/0x40 [btrfs] [87452.337216] btrfs_work_helper+0xf1/0x600 [btrfs] [87452.337838] process_one_work+0x24e/0x5e0 [87452.338437] worker_thread+0x50/0x3b0 [87452.339137] ? process_one_work+0x5e0/0x5e0 [87452.339884] kthread+0x153/0x170 [87452.340507] ? kthread_mod_delayed_work+0xc0/0xc0 [87452.341153] ret_from_fork+0x22/0x30 [87452.341806] INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds. [87452.342487] Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 [87452.343274] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [87452.344049] task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000 [87452.344974] Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] [87452.345655] Call Trace: [87452.346305] __schedule+0x5d1/0xcf0 [87452.346947] ? kvm_clock_read+0x14/0x30 [87452.347676] ? wait_for_completion+0x81/0x110 [87452.348389] schedule+0x45/0xe0 [87452.349077] schedule_timeout+0x30c/0x580 [87452.349718] ? _raw_spin_unlock_irqrestore+0x3c/0x60 [87452.350340] ? lock_acquire+0x1a3/0x490 [87452.351006] ? try_to_wake_up+0x7a/0xa20 [87452.351541] ? lock_release+0x20e/0x4c0 [87452.352040] ? lock_acquired+0x199/0x490 [87452.352517] ? wait_for_completion+0x81/0x110 [87452.353000] wait_for_completion+0xab/0x110 [87452.353490] start_delalloc_inodes+0x2af/0x390 [btrfs] [87452.353973] btrfs_start_delalloc_roots+0x12d/0x250 [btrfs] [87452.354455] flush_space+0x24f/0x660 [btrfs] [87452.355063] btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs] [87452.355565] process_one_work+0x24e/0x5e0 [87452.356024] worker_thread+0x20f/0x3b0 [87452.356487] ? process_one_work+0x5e0/0x5e0 [87452.356973] kthread+0x153/0x170 [87452.357434] ? kthread_mod_delayed_work+0xc0/0xc0 [87452.357880] ret_from_fork+0x22/0x30 (...) < stack traces of several tasks waiting for the locks of the inodes of the clone operation > (...) [92867.444138] RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 [92867.444624] RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73f97 [92867.445116] RDX: 0000000000000000 RSI: 0000560fbd5d7a40 RDI: 0000560fbd5d8960 [92867.445595] RBP: 00007ffc3371beb0 R08: 0000000000000001 R09: 0000000000000003 [92867.446070] R10: 00007ffc3371b996 R11: 0000000000000246 R12: 0000000000000000 [92867.446820] R13: 000000000000001f R14: 00007ffc3371bea0 R15: 00007ffc3371beb0 [92867.447361] task:fsstress state:D stack: 0 pid:2508238 ppid:2508153 flags:0x00004000 [92867.447920] Call Trace: [92867.448435] __schedule+0x5d1/0xcf0 [92867.448934] ? _raw_spin_unlock_irqrestore+0x3c/0x60 [92867.449423] schedule+0x45/0xe0 [92867.449916] __reserve_bytes+0x4a4/0xb10 [btrfs] [92867.450576] ? finish_wait+0x90/0x90 [92867.451202] btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs] [92867.451815] btrfs_block_rsv_add+0x1f/0x50 [btrfs] [92867.452412] start_transaction+0x2d1/0x760 [btrfs] [92867.453216] clone_copy_inline_extent+0x333/0x490 [btrfs] [92867.453848] ? lock_release+0x20e/0x4c0 [92867.454539] ? btrfs_search_slot+0x9a7/0xc30 [btrfs] [92867.455218] btrfs_clone+0x569/0x7e0 [btrfs] [92867.455952] btrfs_clone_files+0xf6/0x150 [btrfs] [92867.456588] btrfs_remap_file_range+0x324/0x3d0 [btrfs] [92867.457213] do_clone_file_range+0xd4/0x1f0 [92867.457828] vfs_clone_file_range+0x4d/0x230 [92867.458355] ? lock_release+0x20e/0x4c0 [92867.458890] ioctl_file_clone+0x8f/0xc0 [92867.459377] do_vfs_ioctl+0x342/0x750 [92867.459913] __x64_sys_ioctl+0x62/0xb0 [92867.460377] do_syscall_64+0x33/0x80 [92867.460842] entry_SYSCALL_64_after_hwframe+0x44/0xa9 (...) < stack traces of more tasks blocked on metadata reservation like the clone task above, because the async reclaim task has deadlocked > (...) Another thing to notice is that the worker task that is deadlocked when trying to flush the destination inode of the clone operation is at btrfs_invalidatepage(). This is simply because the clone operation has a destination offset greater than the i_size and we only update the i_size of the destination file after cloning an extent (just like we do in the buffered write path). Since the async reclaim path uses btrfs_start_delalloc_roots() to trigger the flushing of delalloc for all inodes that have delalloc, add a runtime flag to an inode to signal it should not be flushed, and for inodes with that flag set, start_delalloc_inodes() will simply skip them. When the cloning code needs to dirty a page to copy an inline extent, set that flag on the inode and then clear it when the clone operation finishes. This could be sporadically triggered with test case generic/269 from fstests, which exercises many fsstress processes running in parallel with several dd processes filling up the entire filesystem. CC: stable@vger.kernel.org # 5.9+ Fixes: 05a5a762 ("Btrfs: implement full reflink support for inline extents") Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NFilipe Manana <fdmanana@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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- 10 12月, 2020 38 次提交
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由 Qu Wenruo 提交于
Since btrfs scrub is utilizing its own infrastructure to submit read/write, scrub is independent from all other routines. This brings one very neat feature, allow us to read 4K data into offset 0 of a 64K page. So is the writeback routine. This makes scrub on subpage sector size much easier to implement, and thanks to previous commits which just changed the implementation to always do scrub based on sector size, now scrub can handle subpage filesystem without any problem. This patch will just remove the restriction on (sectorsize != PAGE_SIZE), to make scrub finally work on subpage filesystems. Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
Btrfs scrub is more flexible than buffered data write path, as we can read an unaligned subpage data into page offset 0. This ability makes subpage support much easier, we just need to check each scrub_page::page_len and ensure we only calculate hash for [0, page_len) of a page. There is a small thing to notice: for subpage case, we still do sector by sector scrub. This means we will submit a read bio for each sector to scrub, resulting in the same amount of read bios, just like on the 4K page systems. This behavior can be considered as a good thing, if we want everything to be the same as 4K page systems. But this also means, we're wasting the possibility to submit larger bio using 64K page size. This is another problem to consider in the future. Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
To support subpage tree block scrub, scrub_checksum_tree_block() only needs to learn 2 new tricks: - Follow sector size Now scrub_page only represents one sector, we need to follow it properly. - Run checksum on all sectors Since scrub_page only represents one sector, we need to run checksum on all sectors, not only (nodesize >> PAGE_SIZE). Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
For scrub_pages() and scrub_pages_for_parity(), we currently allocate one scrub_page structure for one page. This is fine if we only read/write one sector one time. But for cases like scrubbing RAID56, we need to read/write the full stripe, which is in 64K size for now. For subpage size, we will submit the read in just one page, which is normally a good thing, but for RAID56 case, it only expects to see one sector, not the full stripe in its endio function. This could lead to wrong parity checksum for RAID56 on subpage. To make the existing code work well for subpage case, here we take a shortcut by always allocating a full page for one sector. This should provide the base to make RAID56 work for subpage case. The cost is pretty obvious now, for one RAID56 stripe now we always need 16 pages. For support subpage situation (64K page size, 4K sector size), this means we need full one megabyte to scrub just one RAID56 stripe. And for data scrub, each 4K sector will also need one 64K page. This is mostly just a workaround, the proper fix for this is a much larger project, using scrub_block to replace scrub_page, and allow scrub_block to handle multi pages, csums, and csum_bitmap to avoid allocating one page for each sector. Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
Btrfs on-disk format chose to use u64 for almost everything, but there are a other restrictions that won't let us use more than u32 for things like extent length (the maximum length is 128MiB for non-hole extents), or stripe length (we have device number limit). This means if we don't have extra handling to convert u64 to u32, we will always have some questionable operations like "u32 = u64 >> sectorsize_bits" in the code. This patch will try to address the problem by reducing the width for the following members/parameters: - scrub_parity::stripe_len - @len of scrub_pages() - @extent_len of scrub_remap_extent() - @len of scrub_parity_mark_sectors_error() - @len of scrub_parity_mark_sectors_data() - @len of scrub_extent() - @len of scrub_pages_for_parity() - @len of scrub_extent_for_parity() For members extracted from on-disk structure, like map->stripe_len, they will be kept as is. Since that modification would require on-disk format change. There will be cases like "u32 = u64 - u64" or "u32 = u64", for such call sites, extra ASSERT() is added to be extra safe for debug builds. Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
Refactor btrfs_lookup_bio_sums() by: - Remove the @file_offset parameter There are two factors making the @file_offset parameter useless: * For csum lookup in csum tree, file offset makes no sense We only need disk_bytenr, which is unrelated to file_offset * page_offset (file offset) of each bvec is not contiguous. Pages can be added to the same bio as long as their on-disk bytenr is contiguous, meaning we could have pages at different file offsets in the same bio. Thus passing file_offset makes no sense any more. The only user of file_offset is for data reloc inode, we will use a new function, search_file_offset_in_bio(), to handle it. - Extract the csum tree lookup into search_csum_tree() The new function will handle the csum search in csum tree. The return value is the same as btrfs_find_ordered_sum(), returning the number of found sectors which have checksum. - Change how we do the main loop The only needed info from bio is: * the on-disk bytenr * the length After extracting the above info, we can do the search without bio at all, which makes the main loop much simpler: for (cur_disk_bytenr = orig_disk_bytenr; cur_disk_bytenr < orig_disk_bytenr + orig_len; cur_disk_bytenr += count * sectorsize) { /* Lookup csum tree */ count = search_csum_tree(fs_info, path, cur_disk_bytenr, search_len, csum_dst); if (!count) { /* Csum hole handling */ } } - Use single variable as the source to calculate all other offsets Instead of all different type of variables, we use only one main variable, cur_disk_bytenr, which represents the current disk bytenr. All involved values can be calculated from that variable, and all those variable will only be visible in the inner loop. The above refactoring makes btrfs_lookup_bio_sums() way more robust than it used to be, especially related to the file offset lookup. Now file_offset lookup is only related to data reloc inode, otherwise we don't need to bother file_offset at all. Signed-off-by: NQu Wenruo <wqu@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com> -
由 Qu Wenruo 提交于
The function btrfs_lookup_bio_sums() is only called for read bios. While btrfs_find_ordered_sum() is to search ordered extent sums, which is only for write path. This means to read a page we either: - Submit read bio if it's not uptodate This means we only need to search csum tree for checksums. - The page is already uptodate It can be marked uptodate for previous read, or being marked dirty. As we always mark page uptodate for dirty page. In that case, we don't need to submit read bio at all, thus no need to search any checksums. Remove the btrfs_find_ordered_sum() call in btrfs_lookup_bio_sums(). And since btrfs_lookup_bio_sums() is the only caller for btrfs_find_ordered_sum(), also remove the implementation. Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NQu Wenruo <wqu@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
For subpage sized extent buffer, we have ensured no extent buffer will cross page boundary, thus we would only need one page for any extent buffer. Update function num_extent_pages to handle such case. Now num_extent_pages() returns 1 for subpage sized extent buffer. Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
As a preparation for subpage sector size support (allowing filesystem with sector size smaller than page size to be mounted) if the sector size is smaller than page size, we don't allow tree block to be read if it crosses 64K(*) boundary. The 64K is selected because: - we are only going to support 64K page size for subpage for now - 64K is also the maximum supported node size This ensures that tree blocks are always contained in one page for a system with 64K page size, which can greatly simplify the handling. Otherwise we would have to do complex multi-page handling of tree blocks. Currently there is no way to create such tree blocks. In kernel we have avoided such tree blocks allocation even on 4K page size, as it can lead to RAID56 stripe scrubbing. While btrfs-progs have fixed its chunk allocator since 2016 for convert, and has extra checks to do the same behavior as the kernel. Just add such graceful checks in case of an ancient filesystem. Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
Btrfs only support 64K as maximum node size, thus for 4K page system, we would have at most 16 pages for one extent buffer. For a system using 64K page size, we would really have just one page. While we always use 16 pages for extent_buffer::pages, this means for systems using 64K pages, we are wasting memory for 15 page pointers which will never be used. Calculate the array size based on page size and the node size maximum. - for systems using 4K page size, it will stay 16 pages - for systems using 64K page size, it will be 1 page Move the definition of BTRFS_MAX_METADATA_BLOCKSIZE to btrfs_tree.h, to avoid circular inclusion of ctree.h. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
In btree_write_cache_pages() we have a btree page submission routine buried deeply in a nested loop. This patch will extract that part of code into a helper function, submit_eb_page(), to do the same work. Since submit_eb_page() now can return >0 for successful extent buffer submission, remove the "ASSERT(ret <= 0);" line. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
Currently btrfs_verify_data_csum() just passes the whole page to check_data_csum(), which is fine since we only support sectorsize == PAGE_SIZE. To support subpage, we need to properly honor per-sector checksum verification, just like what we did in dio read path. This patch will do the csum verification in a for loop, starts with pg_off == start - page_offset(page), with sectorsize increase for each loop. For sectorsize == PAGE_SIZE case, the pg_off will always be 0, and we will only loop once. For subpage case, we do the iterate over each sector and if we found any error, we return error. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
Parameter icsum for check_data_csum() is a little hard to understand. So is the phy_offset for btrfs_verify_data_csum(). Both parameters are calculated values for csum lookup. Instead of some calculated value, just pass bio_offset and let the final and only user, check_data_csum(), calculate whatever it needs. Since we are here, also make the bio_offset parameter and some related variables to be u32 (unsigned int). As bio size is limited by its bi_size, which is unsigned int, and has extra size limit check during various bio operations. Thus we are ensured that bio_offset won't overflow u32. Thus for all involved functions, not only rename the parameter from @phy_offset to @bio_offset, but also reduce its width to u32, so we won't have suspicious "u32 = u64 >> sector_bits;" lines anymore. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
The parameter bio_offset of extent_submit_bio_start_t is very confusing. If it's really bio_offset (offset to bio), then it should be u32. But in fact, it's only utilized by dio read, and that member is used as file offset, which must be u64. Rename it to dio_file_offset since the only user uses it as file offset, and add comment for who is using it. Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Boris Burkov 提交于
A lock dependency loop exists between the root tree lock, the extent tree lock, and the free space tree lock. The root tree lock depends on the free space tree lock because btrfs_create_tree holds the new tree's lock while adding it to the root tree. The extent tree lock depends on the root tree lock because during umount, we write out space cache v1, which writes inodes in the root tree, which results in holding the root tree lock while doing a lookup in the extent tree. Finally, the free space tree depends on the extent tree because populate_free_space_tree holds a locked path in the extent tree and then does a lookup in the free space tree to add the new item. The simplest of the three to break is the one during tree creation: we unlock the leaf before inserting the tree node into the root tree, which fixes the lockdep warning. [30.480136] ====================================================== [30.480830] WARNING: possible circular locking dependency detected [30.481457] 5.9.0-rc8+ #76 Not tainted [30.481897] ------------------------------------------------------ [30.482500] mount/520 is trying to acquire lock: [30.483064] ffff9babebe03908 (btrfs-free-space-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 [30.484054] but task is already holding lock: [30.484637] ffff9babebe24468 (btrfs-extent-01#2){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 [30.485581] which lock already depends on the new lock. [30.486397] the existing dependency chain (in reverse order) is: [30.487205] -> #2 (btrfs-extent-01#2){++++}-{3:3}: [30.487825] down_read_nested+0x43/0x150 [30.488306] __btrfs_tree_read_lock+0x39/0x180 [30.488868] __btrfs_read_lock_root_node+0x3a/0x50 [30.489477] btrfs_search_slot+0x464/0x9b0 [30.490009] check_committed_ref+0x59/0x1d0 [30.490603] btrfs_cross_ref_exist+0x65/0xb0 [30.491108] run_delalloc_nocow+0x405/0x930 [30.491651] btrfs_run_delalloc_range+0x60/0x6b0 [30.492203] writepage_delalloc+0xd4/0x150 [30.492688] __extent_writepage+0x18d/0x3a0 [30.493199] extent_write_cache_pages+0x2af/0x450 [30.493743] extent_writepages+0x34/0x70 [30.494231] do_writepages+0x31/0xd0 [30.494642] __filemap_fdatawrite_range+0xad/0xe0 [30.495194] btrfs_fdatawrite_range+0x1b/0x50 [30.495677] __btrfs_write_out_cache+0x40d/0x460 [30.496227] btrfs_write_out_cache+0x8b/0x110 [30.496716] btrfs_start_dirty_block_groups+0x211/0x4e0 [30.497317] btrfs_commit_transaction+0xc0/0xba0 [30.497861] sync_filesystem+0x71/0x90 [30.498303] btrfs_remount+0x81/0x433 [30.498767] reconfigure_super+0x9f/0x210 [30.499261] path_mount+0x9d1/0xa30 [30.499722] do_mount+0x55/0x70 [30.500158] __x64_sys_mount+0xc4/0xe0 [30.500616] do_syscall_64+0x33/0x40 [30.501091] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [30.501629] -> #1 (btrfs-root-00){++++}-{3:3}: [30.502241] down_read_nested+0x43/0x150 [30.502727] __btrfs_tree_read_lock+0x39/0x180 [30.503291] __btrfs_read_lock_root_node+0x3a/0x50 [30.503903] btrfs_search_slot+0x464/0x9b0 [30.504405] btrfs_insert_empty_items+0x60/0xa0 [30.504973] btrfs_insert_item+0x60/0xd0 [30.505412] btrfs_create_tree+0x1b6/0x210 [30.505913] btrfs_create_free_space_tree+0x54/0x110 [30.506460] btrfs_mount_rw+0x15d/0x20f [30.506937] btrfs_remount+0x356/0x433 [30.507369] reconfigure_super+0x9f/0x210 [30.507868] path_mount+0x9d1/0xa30 [30.508264] do_mount+0x55/0x70 [30.508668] __x64_sys_mount+0xc4/0xe0 [30.509186] do_syscall_64+0x33/0x40 [30.509652] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [30.510271] -> #0 (btrfs-free-space-00){++++}-{3:3}: [30.510972] __lock_acquire+0x11ad/0x1b60 [30.511432] lock_acquire+0xa2/0x360 [30.511917] down_read_nested+0x43/0x150 [30.512383] __btrfs_tree_read_lock+0x39/0x180 [30.512947] __btrfs_read_lock_root_node+0x3a/0x50 [30.513455] btrfs_search_slot+0x464/0x9b0 [30.513947] search_free_space_info+0x45/0x90 [30.514465] __add_to_free_space_tree+0x92/0x39d [30.515010] btrfs_create_free_space_tree.cold.22+0x1ee/0x45d [30.515639] btrfs_mount_rw+0x15d/0x20f [30.516142] btrfs_remount+0x356/0x433 [30.516538] reconfigure_super+0x9f/0x210 [30.517065] path_mount+0x9d1/0xa30 [30.517438] do_mount+0x55/0x70 [30.517824] __x64_sys_mount+0xc4/0xe0 [30.518293] do_syscall_64+0x33/0x40 [30.518776] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [30.519335] other info that might help us debug this: [30.520210] Chain exists of: btrfs-free-space-00 --> btrfs-root-00 --> btrfs-extent-01#2 [30.521407] Possible unsafe locking scenario: [30.522037] CPU0 CPU1 [30.522456] ---- ---- [30.522941] lock(btrfs-extent-01#2); [30.523311] lock(btrfs-root-00); [30.523952] lock(btrfs-extent-01#2); [30.524620] lock(btrfs-free-space-00); [30.525068] *** DEADLOCK *** [30.525669] 5 locks held by mount/520: [30.526116] #0: ffff9babebc520e0 (&type->s_umount_key#37){+.+.}-{3:3}, at: path_mount+0x7ef/0xa30 [30.527056] #1: ffff9babebc52640 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x3d5/0x5c0 [30.527960] #2: ffff9babeae8f2e8 (&cache->free_space_lock#2){+.+.}-{3:3}, at: btrfs_create_free_space_tree.cold.22+0x101/0x45d [30.529118] #3: ffff9babebe24468 (btrfs-extent-01#2){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 [30.530113] #4: ffff9babebd52eb8 (btrfs-extent-00){++++}-{3:3}, at: btrfs_try_tree_read_lock+0x16/0x100 [30.531124] stack backtrace: [30.531528] CPU: 0 PID: 520 Comm: mount Not tainted 5.9.0-rc8+ #76 [30.532166] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-4.module_el8.1.0+248+298dec18 04/01/2014 [30.533215] Call Trace: [30.533452] dump_stack+0x8d/0xc0 [30.533797] check_noncircular+0x13c/0x150 [30.534233] __lock_acquire+0x11ad/0x1b60 [30.534667] lock_acquire+0xa2/0x360 [30.535063] ? __btrfs_tree_read_lock+0x39/0x180 [30.535525] down_read_nested+0x43/0x150 [30.535939] ? __btrfs_tree_read_lock+0x39/0x180 [30.536400] __btrfs_tree_read_lock+0x39/0x180 [30.536862] __btrfs_read_lock_root_node+0x3a/0x50 [30.537304] btrfs_search_slot+0x464/0x9b0 [30.537713] ? trace_hardirqs_on+0x1c/0xf0 [30.538148] search_free_space_info+0x45/0x90 [30.538572] __add_to_free_space_tree+0x92/0x39d [30.539071] ? printk+0x48/0x4a [30.539367] btrfs_create_free_space_tree.cold.22+0x1ee/0x45d [30.539972] btrfs_mount_rw+0x15d/0x20f [30.540350] btrfs_remount+0x356/0x433 [30.540773] ? shrink_dcache_sb+0xd9/0x100 [30.541203] reconfigure_super+0x9f/0x210 [30.541642] path_mount+0x9d1/0xa30 [30.542040] do_mount+0x55/0x70 [30.542366] __x64_sys_mount+0xc4/0xe0 [30.542822] do_syscall_64+0x33/0x40 [30.543197] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [30.543691] RIP: 0033:0x7f109f7ab93a [30.546042] RSP: 002b:00007ffc47c4f858 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 [30.546770] RAX: ffffffffffffffda RBX: 00007f109f8cf264 RCX: 00007f109f7ab93a [30.547485] RDX: 0000557e6fc10770 RSI: 0000557e6fc19cf0 RDI: 0000557e6fc19cd0 [30.548185] RBP: 0000557e6fc10520 R08: 0000557e6fc18e30 R09: 0000557e6fc18cb0 [30.548911] R10: 0000000000200020 R11: 0000000000000246 R12: 0000000000000000 [30.549606] R13: 0000557e6fc19cd0 R14: 0000557e6fc10770 R15: 0000557e6fc10520 Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Signed-off-by: NDavid Sterba <dsterba@suse.com> -
由 Boris Burkov 提交于
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: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Boris Burkov 提交于
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: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Boris Burkov 提交于
If the remount is ro->ro, rw->ro, or rw->rw, we will not create or clear the free space tree. This can be surprising, so print a warning to dmesg to make the failure more visible. It is also important to ensure that the space cache options (SPACE_CACHE, FREE_SPACE_TREE) are consistent, so ensure those are set to properly match the current on disk state (which won't be changing). Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Boris Burkov 提交于
To make the contents of /proc/mounts better match the actual state of the filesystem, base the display of the space cache mount options off the contents of the super block rather than the last mount options passed in. Since there are many scenarios where the mount will ignore a space cache option, simply showing the passed in option is misleading. For example, if we mount with -o remount,space_cache=v2 on a read-write file system without an existing free space tree, we won't build a free space tree, but /proc/mounts will read space_cache=v2 (until we mount again and it goes away) cache_generation is set iff space_cache=v1, FREE_SPACE_TREE is set iff space_cache=v2, and if neither is the case, we print nospace_cache. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Boris Burkov 提交于
When mounting, btrfs uses the cache_generation in the super block to determine if space cache v1 is in use. However, by mounting with nospace_cache or space_cache=v2, it is possible to disable space cache v1, which does not result in un-setting cache_generation back to 0. In order to base some logic, like mount option printing in /proc/mounts, on the current state of the space cache rather than just the values of the mount option, keep the value of cache_generation consistent with the status of space cache v1. We ensure that cache_generation > 0 iff the file system is using space_cache v1. This requires committing a transaction on any mount which changes whether we are using v1. (v1->nospace_cache, v1->v2, nospace_cache->v1, v2->v1). Since the mechanism for writing out the cache generation is transaction commit, but we want some finer grained control over when we un-set it, we can't just rely on the SPACE_CACHE mount option, and introduce an fs_info flag that mount can use when it wants to unset the generation. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Boris Burkov 提交于
A user might want to revert to v1 or nospace_cache on a root filesystem, and much like turning on the free space tree, that can only be done remounting from ro->rw. Support clearing the free space tree on such mounts by moving it into the shared remount logic. Since the CLEAR_CACHE option sticks around across remounts, this change would result in clearing the tree for ever on every remount, which is not desirable. To fix that, add CLEAR_CACHE to the oneshot options we clear at mount end, which has the other bonus of not cluttering the /proc/mounts output with clear_cache. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Boris Burkov 提交于
Some options only apply during mount time and are cleared at the end of mount. For now, the example is USEBACKUPROOT, but CLEAR_CACHE also fits the bill, and this is a preparation patch for also clearing that option. One subtlety is that the current code only resets USEBACKUPROOT on rw mounts, but the option is meaningfully "consumed" by a ro mount, so it feels appropriate to clear in that case as well. A subsequent read-write remount would not go through open_ctree, which is the only place that checks the option, so the change should be benign. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Boris Burkov 提交于
When a user attempts to remount a btrfs filesystem with 'mount -o remount,space_cache=v2', that operation silently succeeds. Unfortunately, this is misleading, because the remount does not create the free space tree. /proc/mounts will incorrectly show space_cache=v2, but on the next mount, the file system will revert to the old space_cache. For now, we handle only the easier case, where the existing mount is read-only and the new mount is read-write. In that case, we can create the free space tree without contending with the block groups changing as we go. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Boris Burkov 提交于
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: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Boris Burkov 提交于
When we mount a rw filesystem, we start the orphan cleanup process in tree root and filesystem tree. However, when we remount a ro file system rw, we only clean the former. Move the calls to btrfs_orphan_cleanup() on tree_root and fs_root to the shared rw mount routine to effectively add them on ro->rw remount. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Boris Burkov 提交于
Mounting rw and remounting from ro to rw naturally share invariants and functionality which result in a correctly setup rw filesystem. Luckily, there is even a strong unity in the code which implements them. In mount's open_ctree, these operations mostly happen after an early return for ro file systems, and in remount, they happen in a section devoted to remounting ro->rw, after some remount specific validation passes. However, there are unfortunately a few differences. There are small deviations in the order of some of the operations, remount does not start orphan cleanup in root_tree or fs_tree, remount does not create the free space tree, and remount does not handle "one-shot" mount options like clear_cache and uuid tree rescan. Since we want to add building the free space tree to remount, and also to start the same orphan cleanup process on a filesystem mounted as ro then remounted rw, we would benefit from unifying the logic between the two code paths. This patch only lifts the existing common functionality, and leaves a natural path for fixing the discrepancies. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NBoris Burkov <boris@bur.io> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Filipe Manana 提交于
Early on during a transaction commit we acquire the tree_log_mutex and hold it until after we write the super blocks. But before writing the extent buffers dirtied by the transaction and the super blocks we unblock the transaction by setting its state to TRANS_STATE_UNBLOCKED and setting fs_info->running_transaction to NULL. This means that after that and before writing the super blocks, new transactions can start. However if any transaction wants to log an inode, it will block waiting for the transaction commit to write its dirty extent buffers and the super blocks because the tree_log_mutex is only released after those operations are complete, and starting a new log transaction blocks on that mutex (at start_log_trans()). Writing the dirty extent buffers and the super blocks can take a very significant amount of time to complete, but we could allow the tasks wanting to log an inode to proceed with most of their steps: 1) create the log trees 2) log metadata in the trees 3) write their dirty extent buffers They only need to wait for the previous transaction commit to complete (write its super blocks) before they attempt to write their super blocks, otherwise we could end up with a corrupt filesystem after a crash. So change start_log_trans() to use the root tree's log_mutex to serialize for the creation of the log root tree instead of using the tree_log_mutex, and make btrfs_sync_log() acquire the tree_log_mutex before writing the super blocks. This allows for inode logging to wait much less time when there is a previous transaction that is still committing, often not having to wait at all, as by the time when we try to sync the log the previous transaction already wrote its super blocks. This patch belongs to a patch set that is comprised of the following patches: btrfs: fix race causing unnecessary inode logging during link and rename btrfs: fix race that results in logging old extents during a fast fsync btrfs: fix race that causes unnecessary logging of ancestor inodes btrfs: fix race that makes inode logging fallback to transaction commit btrfs: fix race leading to unnecessary transaction commit when logging inode btrfs: do not block inode logging for so long during transaction commit The following script that uses dbench was used to measure the impact of the whole patchset: $ cat test-dbench.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/btrfs MOUNT_OPTIONS="-o ssd" echo "performance" | \ tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor mkfs.btrfs -f -m single -d single $DEV mount $MOUNT_OPTIONS $DEV $MNT dbench -D $MNT -t 300 64 umount $MNT The test was run on a machine with 12 cores, 64G of ram, using a NVMe device and a non-debug kernel configuration (Debian's default). Before patch set: Operation Count AvgLat MaxLat ---------------------------------------- NTCreateX 11277211 0.250 85.340 Close 8283172 0.002 6.479 Rename 477515 1.935 86.026 Unlink 2277936 0.770 87.071 Deltree 256 15.732 81.379 Mkdir 128 0.003 0.009 Qpathinfo 10221180 0.056 44.404 Qfileinfo 1789967 0.002 4.066 Qfsinfo 1874399 0.003 9.176 Sfileinfo 918589 0.061 10.247 Find 3951758 0.341 54.040 WriteX 5616547 0.047 85.079 ReadX 17676028 0.005 9.704 LockX 36704 0.003 1.800 UnlockX 36704 0.002 0.687 Flush 790541 14.115 676.236 Throughput 1179.19 MB/sec 64 clients 64 procs max_latency=676.240 ms After patch set: Operation Count AvgLat MaxLat ---------------------------------------- NTCreateX 12687926 0.171 86.526 Close 9320780 0.002 8.063 Rename 537253 1.444 78.576 Unlink 2561827 0.559 87.228 Deltree 374 11.499 73.549 Mkdir 187 0.003 0.005 Qpathinfo 11500300 0.061 36.801 Qfileinfo 2017118 0.002 7.189 Qfsinfo 2108641 0.003 4.825 Sfileinfo 1033574 0.008 8.065 Find 4446553 0.408 47.835 WriteX 6335667 0.045 84.388 ReadX 19887312 0.003 9.215 LockX 41312 0.003 1.394 UnlockX 41312 0.002 1.425 Flush 889233 13.014 623.259 Throughput 1339.32 MB/sec 64 clients 64 procs max_latency=623.265 ms +12.7% throughput, -8.2% max latency Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com> -
由 Filipe Manana 提交于
When logging an inode we may often have to fallback to a full transaction commit, either because a new block group was allocated, there is some case we can not deal with without a transaction commit or some error like an ENOMEM happened. However after we fallback to a transaction commit, we have a time window where we can make the next attempt to log any inode commit the next transaction unnecessarily, adding additional overhead and increasing latency. A sequence of steps that leads to this issue is the following: 1) The current open transaction has a generation of 1000; 2) A new block group is allocated, and as a consequence we must make sure any attempts to commit a log fallback to a transaction commit, so btrfs_set_log_full_commit() is called from btrfs_make_block_group(). This sets fs_info->last_trans_log_full_commit to 1000; 3) Task A is holding a handle on transaction 1000 and tries to log inode X. Once it gets to start_log_trans(), it calls btrfs_need_log_full_commit() which returns true, since fs_info->last_trans_log_full_commit has a value of 1000. So we end up returning EAGAIN and propagating it up to btrfs_sync_file(), where we commit transaction 1000; 4) The transaction commit task (task A) sets the transaction state to unblocked (TRANS_STATE_UNBLOCKED); 5) Some other task, task B, starts a new transaction with a generation of 1001; 6) Some stuff is done with transaction 1001, some btree blocks COWed, etc; 7) Transaction 1000 has not fully committed yet, we are still writing all the extent buffers it created; 8) Some new task, task C, starts an fsync of inode Y, gets a handle for transaction 1001, and it gets to btrfs_log_inode_parent() which does the following check: if (fs_info->last_trans_log_full_commit > last_committed) { ret = 1; goto end_no_trans; } At that point last_trans_log_full_commit has a value of 1000 and last_committed (value of fs_info->last_trans_committed) has a value of 999, since transaction 1000 has not yet committed - it is either still writing out dirty extent buffers, its super blocks or unpinning extents. As a consequence we return 1, which gets propagated up to btrfs_sync_file(), which will then call btrfs_commit_transaction() for transaction 1001. As a consequence we have an unnecessary second transaction commit, we previously committed transaction 1000 and now commit transaction 1001 as well, resulting in more overhead and increased latency. So fix this double transaction commit issue simply by removing that check, because all we need to do is wait for the previous transaction to finish its commit, which we already do later when starting the log transaction at start_log_trans(), because there we acquire the tree_log_mutex lock, which is held by a transaction commit and only released after the transaction commits its super blocks. Another issue that check has is that it reads last_trans_log_full_commit without using READ_ONCE(), which is incorrect since that member of struct btrfs_fs_info is always updated with WRITE_ONCE() through the helper btrfs_set_log_full_commit(). This double transaction commit issue can actually be triggered quite often in long runs of dbench, since besides the creation of new block groups that force inode logging to fallback to a transaction commit, there are cases where dbench asks to fsync a directory which had files in it that were previously renamed or subdirectories that were removed, resulting in the inode logging to fallback to a full transaction commit. This patch belongs to a patch set that is comprised of the following patches: btrfs: fix race causing unnecessary inode logging during link and rename btrfs: fix race that results in logging old extents during a fast fsync btrfs: fix race that causes unnecessary logging of ancestor inodes btrfs: fix race that makes inode logging fallback to transaction commit btrfs: fix race leading to unnecessary transaction commit when logging inode btrfs: do not block inode logging for so long during transaction commit Performance results are mentioned in the change log of the last patch. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com> -
由 Filipe Manana 提交于
When logging an inode and the previous transaction is still committing, we have a time window where we can end up incorrectly think an inode has its last_unlink_trans field with a value greater than the last transaction committed, which results in the logging to fallback to a full transaction commit, which is usually much more expensive than doing a log commit. The race is described by the following steps: 1) We are at transaction 1000; 2) We modify an inode X (a directory) using transaction 1000 and set its last_unlink_trans field to 1000, because for example we removed one of its subdirectories; 3) We create a new inode Y with a dentry in inode X using transaction 1000, so its generation field is set to 1000; 4) The commit for transaction 1000 is started by task A; 5) The task committing transaction 1000 sets the transaction state to unblocked, writes the dirty extent buffers and the super blocks, then unlocks tree_log_mutex; 6) Some task starts a new transaction with a generation of 1001; 7) We do some modification to inode Y (using transaction 1001); 8) The transaction 1000 commit starts unpinning extents. At this point fs_info->last_trans_committed still has a value of 999; 9) Task B starts an fsync on inode Y, and gets a handle for transaction 1001. When it gets to check_parent_dirs_for_sync() it does the checking of the ancestor dentries because the following check does not evaluate to true: if (S_ISREG(inode->vfs_inode.i_mode) && inode->generation <= last_committed && inode->last_unlink_trans <= last_committed) goto out; The generation value for inode Y is 1000 and last_committed, which has the value read from fs_info->last_trans_committed, has a value of 999, so that check evaluates to false and we proceed to check the ancestor inodes. Once we get to the first ancestor, inode X, we call btrfs_must_commit_transaction() on it, which evaluates to true: static bool btrfs_must_commit_transaction(...) { struct btrfs_fs_info *fs_info = inode->root->fs_info; bool ret = false; mutex_lock(&inode->log_mutex); if (inode->last_unlink_trans > fs_info->last_trans_committed) { /* * Make sure any commits to the log are forced to be full * commits. */ btrfs_set_log_full_commit(trans); ret = true; } (...) because inode's X last_unlink_trans has a value of 1000 and fs_info->last_trans_committed still has a value of 999, it returns true to check_parent_dirs_for_sync(), making it return 1 which is propagated up to btrfs_sync_file(), causing it to fallback to a full transaction commit of transaction 1001. We should have not fallen back to commit transaction 1001, since inode X had last_unlink_trans set to 1000 and the super blocks for transaction 1000 were already written. So while not resulting in a functional problem, it leads to a lot more work and higher latencies for a fsync since committing a transaction is usually more expensive than committing a log (if other filesystem changes happened under that transaction). Similar problem happens when logging directories, for the same reason as btrfs_must_commit_transaction() returns true on an inode with its last_unlink_trans having the generation of the previous transaction and that transaction is still committing, unpinning its freed extents. So fix this by comparing last_unlink_trans with the id of the current transaction instead of fs_info->last_trans_committed. This case is often hit when running dbench for a long enough duration, as it does lots of rename and rmdir operations (both update the field last_unlink_trans of an inode) and fsyncs of files and directories. This patch belongs to a patch set that is comprised of the following patches: btrfs: fix race causing unnecessary inode logging during link and rename btrfs: fix race that results in logging old extents during a fast fsync btrfs: fix race that causes unnecessary logging of ancestor inodes btrfs: fix race that makes inode logging fallback to transaction commit btrfs: fix race leading to unnecessary transaction commit when logging inode btrfs: do not block inode logging for so long during transaction commit Performance results are mentioned in the change log of the last patch. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com> -
由 Filipe Manana 提交于
When logging an inode and we are checking if we need to log ancestors that are new, if the previous transaction is still committing we have a time window where we can unnecessarily log ancestor inodes that were created in the previous transaction. The race is described by the following steps: 1) We are at transaction 1000; 2) Directory inode X is created, its generation is set to 1000; 3) The commit for transaction 1000 is started by task A; 4) The task committing transaction 1000 sets the transaction state to unblocked, writes the dirty extent buffers and the super blocks, then unlocks tree_log_mutex; 5) Inode Y, a regular file, is created under directory inode X, this results in starting a new transaction with a generation of 1001; 6) The transaction 1000 commit is unpinning extents. At this point fs_info->last_trans_committed still has a value of 999; 7) Task B calls fsync on inode Y and gets a handle for transaction 1001; 8) Task B ends up at log_all_new_ancestors() and then because inode Y has only one hard link, ends up at log_new_ancestors_fast(). There it reads a value of 999 from fs_info->last_trans_committed, and sees that the parent inode X has a generation of 1000, so we end up logging inode X: if (inode->generation > fs_info->last_trans_committed) { ret = btrfs_log_inode(trans, root, inode, LOG_INODE_EXISTS, ctx); (...) which is not necessary since it was created in the past transaction, with a generation of 1000, and that transaction has already committed its super blocks - it's still unpinning extents so it has not yet updated fs_info->last_trans_committed from 999 to 1000. So this just causes us to spend more time logging and allocating and writing more tree blocks for the log tree. So fix this by comparing an inode's generation with the generation of the transaction our transaction handle refers to - if the inode's generation matches the generation of the current transaction than we know it is a new inode we need to log, otherwise don't log it. This case is often hit when running dbench for a long enough duration. This patch belongs to a patch set that is comprised of the following patches: btrfs: fix race causing unnecessary inode logging during link and rename btrfs: fix race that results in logging old extents during a fast fsync btrfs: fix race that causes unnecessary logging of ancestor inodes btrfs: fix race that makes inode logging fallback to transaction commit btrfs: fix race leading to unnecessary transaction commit when logging inode btrfs: do not block inode logging for so long during transaction commit Performance results are mentioned in the change log of the last patch. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com> -
由 Filipe Manana 提交于
When logging the extents of an inode during a fast fsync, we have a time window where we can log extents that are from the previous transaction and already persisted. This only makes us waste time unnecessarily. The following sequence of steps shows how this can happen: 1) We are at transaction 1000; 2) An ordered extent E from inode I completes, that is it has gone through btrfs_finish_ordered_io(), and it set the extent maps' generation to 1000 when we unpin the extent, which is the generation of the current transaction; 3) The commit for transaction 1000 starts by task A; 4) The task committing transaction 1000 sets the transaction state to unblocked, writes the dirty extent buffers and the super blocks, then unlocks tree_log_mutex; 5) Some change is made to inode I, resulting in creation of a new transaction with a generation of 1001; 6) The transaction 1000 commit starts unpinning extents. At this point fs_info->last_trans_committed still has a value of 999; 7) Task B starts an fsync on inode I, and when it gets to btrfs_log_changed_extents() sees the extent map for extent E in the list of modified extents. It sees the extent map has a generation of 1000 and fs_info->last_trans_committed has a value of 999, so it proceeds to logging the respective file extent item and all the checksums covering its range. So we end up wasting time since the extent was already persisted and is reachable through the trees pointed to by the super block committed by transaction 1000. So just fix this by comparing the extent maps generation against the generation of the transaction handle - if it is smaller then the id in the handle, we know the extent was already persisted and we do not need to log it. This patch belongs to a patch set that is comprised of the following patches: btrfs: fix race causing unnecessary inode logging during link and rename btrfs: fix race that results in logging old extents during a fast fsync btrfs: fix race that causes unnecessary logging of ancestor inodes btrfs: fix race that makes inode logging fallback to transaction commit btrfs: fix race leading to unnecessary transaction commit when logging inode btrfs: do not block inode logging for so long during transaction commit Performance results are mentioned in the change log of the last patch. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Filipe Manana 提交于
When we are doing a rename or a link operation for an inode that was logged in the previous transaction and that transaction is still committing, we have a time window where we incorrectly consider that the inode was logged previously in the current transaction and therefore decide to log it to update it in the log. The following steps give an example on how this happens during a link operation: 1) Inode X is logged in transaction 1000, so its logged_trans field is set to 1000; 2) Task A starts to commit transaction 1000; 3) The state of transaction 1000 is changed to TRANS_STATE_UNBLOCKED; 4) Task B starts a link operation for inode X, and as a consequence it starts transaction 1001; 5) Task A is still committing transaction 1000, therefore the value stored at fs_info->last_trans_committed is still 999; 6) Task B calls btrfs_log_new_name(), it reads a value of 999 from fs_info->last_trans_committed and because the logged_trans field of inode X has a value of 1000, the function does not return immediately, instead it proceeds to logging the inode, which should not happen because the inode was logged in the previous transaction (1000) and not in the current one (1001). This is not a functional problem, just wasted time and space logging an inode that does not need to be logged, contributing to higher latency for link and rename operations. So fix this by comparing the inodes' logged_trans field with the generation of the current transaction instead of comparing with the value stored in fs_info->last_trans_committed. This case is often hit when running dbench for a long enough duration, as it does lots of rename operations. This patch belongs to a patch set that is comprised of the following patches: btrfs: fix race causing unnecessary inode logging during link and rename btrfs: fix race that results in logging old extents during a fast fsync btrfs: fix race that causes unnecessary logging of ancestor inodes btrfs: fix race that makes inode logging fallback to transaction commit btrfs: fix race leading to unnecessary transaction commit when logging inode btrfs: do not block inode logging for so long during transaction commit Performance results are mentioned in the change log of the last patch. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 David Sterba 提交于
After removing the inode number cache that was using the free space cache code, we can remove at least the recalc_thresholds callback from the ops. Both code and tests use the same callback function. It's moved before its first use. The use_bitmaps callback is still needed by tests to create some extents/bitmap setup. Signed-off-by: NDavid Sterba <dsterba@suse.com> -
由 Nikolay Borisov 提交于
Since it's being used solely for the freespace cache unconditionally set the flags required for it. Signed-off-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Nikolay Borisov 提交于
Following removal of the ino cache io_ctl_init will be called only on behalf of the freespace inode. In this case we always want to check CRCs so conditional code that depended on io_ctl::check_crc can be removed. Signed-off-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Nikolay Borisov 提交于
It's been deprecated since commit b547a88e ("btrfs: start deprecation of mount option inode_cache") which enumerates the reasons. A filesystem that uses the feature (mount -o inode_cache) tracks the inode numbers in bitmaps, that data stay on the filesystem after this patch. The size is roughly 5MiB for 1M inodes [1], which is considered small enough to be left there. Removal of the change can be implemented in btrfs-progs if needed. [1] https://lore.kernel.org/linux-btrfs/20201127145836.GZ6430@twin.jikos.cz/Signed-off-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> [ update changelog ] Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Nikolay Borisov 提交于
The former is going away as part of the inode map removal so switch callers to btrfs_find_free_objectid. No functional changes since with INODE_MAP disabled (default) find_free_objectid was called anyway. Signed-off-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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