- 21 Jun, 2021 40 commits
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Qu Wenruo authored
In __process_pages_contig() we update page status according to page_ops. That update process is a bunch of 'if' branches, which lie inside two loops, this makes it pretty hard to expand for later subpage operations. So this patch will extract these operations into its own function, process_one_pages(). Also since we're refactoring __process_pages_contig(), also move the new helper and __process_pages_contig() before the first caller of them, to remove the forward declaration. Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> # [ppc64] Tested-by: Anand Jain <anand.jain@oracle.com> # [aarch64] Reviewed-by:
Josef Bacik <josef@toxicpanda.com> Signed-off-by:
Qu Wenruo <wqu@suse.com> Reviewed-by:
David Sterba <dsterba@suse.com> Signed-off-by:
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Qu Wenruo authored
As a preparation for incoming subpage support, we need bytenr passed to __process_pages_contig() directly, not the current page index. So change the parameter and all callers to pass bytenr in. With the modification, here we need to replace the old @index_ret with @processed_end for __process_pages_contig(), but this brings a small problem. Normally we follow the inclusive return value, meaning @processed_end should be the last byte we processed. If parameter @start is 0, and we failed to lock any page, then we would return @processed_end as -1, causing more problems for __unlock_for_delalloc(). So here for @processed_end, we use two different return value patterns. If we have locked any page, @processed_end will be the last byte of locked page. Or it will be @start otherwise. This change will impact lock_delalloc_pages(), so it needs to check @processed_end to only unlock the range if we have locked any. Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> # [ppc64] Tested-by: Anand Jain <anand.jain@oracle.com> # [aarch64] Signed-off-by:
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Qu Wenruo authored
[BUG] When running subpage preparation patches on x86, btrfs/125 will hang forever with one ordered extent never finished. [CAUSE] The test case btrfs/125 itself will always fail as the fix is never merged. When the test fails at balance, btrfs needs to cleanup the ordered extent in btrfs_cleanup_ordered_extents() for data reloc inode. The problem is in the sequence how we cleanup the page Order bit. Currently it works like: btrfs_cleanup_ordered_extents() |- find_get_page(); |- btrfs_page_clear_ordered(page); | Now the page doesn't have Ordered bit anymore. | !!! This also includes the first (locked) page !!! | |- offset += PAGE_SIZE | This is to skip the first page |- __endio_write_update_ordered() |- btrfs_mark_ordered_io_finished(NULL) Except the first page, all ordered extents are finished. Then the locked page is cleaned up in __extent_writepage(): __extent_writepage() |- If (PageError(page)) |- end_extent_writepage() |- btrfs_mark_ordered_io_finished(page) |- if (btrfs_test_page_ordered(page)) |- !!! The page gets skipped !!! The ordered extent is not decreased as the page doesn't have ordered bit anymore. This leaves the ordered extent with bytes_left == sectorsize, thus never finish. [FIX] The fix is to ensure we never clear page Ordered bit without running the ordered extent accounting. Here we choose to skip the locked page in btrfs_cleanup_ordered_extents() so that later end_extent_writepage() can properly finish the ordered extent. Signed-off-by: -
Qu Wenruo authored
Inside btrfs we use Private2 page status to indicate we have an ordered extent with pending IO for the sector. But the page status name, Private2, tells us nothing about the bit itself, so this patch will rename it to Ordered. And with extra comment about the bit added, so reader who is still uncertain about the page Ordered status, will find the comment pretty easily. Reviewed-by:
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Qu Wenruo authored
This patch will refactor btrfs_invalidatepage() for the incoming subpage support. The involved modifications are: - Use while() loop instead of "goto again;" - Use single variable to determine whether to delete extent states Each branch will also have comments why we can or cannot delete the extent states - Do qgroup free and extent states deletion per-loop Current code can only work for PAGE_SIZE == sectorsize case. This refactor also makes it clear what we do for different sectors: - Sectors without ordered extent We're completely safe to remove all extent states for the sector(s) - Sectors with ordered extent, but no Private2 bit This means the endio has already been executed, we can't remove all extent states for the sector(s). - Sectors with ordere extent, still has Private2 bit This means we need to decrease the ordered extent accounting. And then it comes to two different variants: * We have finished and removed the ordered extent Then it's the same as "sectors without ordered extent" * We didn't finished the ordered extent We can remove some extent states, but not all. Signed-off-by: -
Qu Wenruo authored
Although we already have btrfs_lookup_first_ordered_extent() and btrfs_lookup_ordered_extent(), they all have their own limitations: - btrfs_lookup_ordered_extent() can't do extra range check It's only designed to lookup any ordered extent before certain bytenr. - btrfs_lookup_first_ordered_extent() may not return the first ordered extent in the range It doesn't ensure the first ordered extent is returned. The existing callers are only interested in exhausting all ordered extents in a range, the order is not important. For incoming btrfs_invalidatepage() refactoring, we need a way to properly iterate all ordered extents in their bytenr order of a range. So this patch will introduce a new function, btrfs_lookup_first_ordered_range(), to do ordered extent with bytenr order awareness and extra range check. Signed-off-by:
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Qu Wenruo authored
The existing comments in btrfs_invalidatepage() don't really get to the point, especially for what Private2 is really representing and how the race avoidance is done. The truth is, there are only three entrances to do ordered extent accounting: - btrfs_writepage_endio_finish_ordered() - __endio_write_update_ordered() Those two entrance are just endio functions for dio and buffered write. - btrfs_invalidatepage() But there is a pitfall, in endio functions there is no check on whether the ordered extent is already accounted. They just blindly clear the Private2 bit and do the accounting. So it's all btrfs_invalidatepage()'s responsibility to make sure we won't do double account for the same sector. That's why in btrfs_invalidatepage() we have to wait for page writeback, this will ensure all submitted bios have finished, thus their endio functions have finished the accounting on the ordered extent. Then we also check page Private2 to ensure that, we only run ordered extent accounting on pages who has no bio submitted. This patch will rework related comments to make it more clear on the race and how we use wait_on_page_writeback() and Private2 to prevent double accounting on ordered extent. Reviewed-by:
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Qu Wenruo authored
Btrfs has two endio functions to mark certain io range finished for ordered extents: - __endio_write_update_ordered() This is for direct IO - btrfs_writepage_endio_finish_ordered() This for buffered IO. However they go different routines to handle ordered extent io: - Whether to iterate through all ordered extents __endio_write_update_ordered() will but btrfs_writepage_endio_finish_ordered() will not. In fact, iterating through all ordered extents will benefit later subpage support, while for current PAGE_SIZE == sectorsize requirement this behavior makes no difference. - Whether to update page Private2 flag __endio_write_update_ordered() will not update page Private2 flag as for iomap direct IO, the page can not be even mapped. While btrfs_writepage_endio_finish_ordered() will clear Private2 to prevent double accounting against btrfs_invalidatepage(). Those differences are pretty subtle, and the ordered extent iterations code in callers makes code much harder to read. So this patch will introduce a new function, btrfs_mark_ordered_io_finished(), to do the heavy lifting: - Iterate through all ordered extents in the range - Do the ordered extent accounting - Queue the work for finished ordered extent This function has two new feature: - Proper underflow detection and recovery The old underflow detection will only detect the problem, then continue. No proper info like root/inode/ordered extent info, nor noisy enough to be caught by fstests. Furthermore when underflow happens, the ordered extent will never finish. New error detection will reset the bytes_left to 0, do proper kernel warning, and output extra info including root, ino, ordered extent range, the underflow value. - Prevent double accounting based on Private2 flag Now if we find a range without Private2 flag, we will skip to next range. As that means someone else has already finished the accounting of ordered extent. This makes no difference for current code, but will be a critical part for incoming subpage support, as we can call btrfs_mark_ordered_io_finished() for multiple sectors if they are beyond inode size. Thus such double accounting prevention is a key feature for subpage. Now both endio functions only need to call that new function. And since the only caller of btrfs_dec_test_first_ordered_pending() is removed, also remove btrfs_dec_test_first_ordered_pending() completely. Signed-off-by:
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Qu Wenruo authored
Currently we use page Private2 bit to indicate that we have ordered extent for the page range. But the lifespan of it is not consistent, during regular writeback path, there are two locations to clear the same PagePrivate2: T ----- Page marked Dirty | + ----- Page marked Private2, through btrfs_run_dealloc_range() | + ----- Page cleared Private2, through btrfs_writepage_cow_fixup() | in __extent_writepage_io() | ^^^ Private2 cleared for the first time | + ----- Page marked Writeback, through btrfs_set_range_writeback() | in __extent_writepage_io(). | + ----- Page cleared Private2, through | btrfs_writepage_endio_finish_ordered() | ^^^ Private2 cleared for the second time. | + ----- Page cleared Writeback, through btrfs_writepage_endio_finish_ordered() Currently PagePrivate2 is mostly to prevent ordered extent accounting being executed for both endio and invalidatepage. Thus only the one who cleared page Private2 is responsible for ordered extent accounting. But the fact is, in btrfs_writepage_endio_finish_ordered(), page Private2 is cleared and ordered extent accounting is executed unconditionally. The race prevention only happens through btrfs_invalidatepage(), where we wait for the page writeback first, before checking the Private2 bit. This means, Private2 is also protected by Writeback bit, and there is no need for btrfs_writepage_cow_fixup() to clear Priavte2. This patch will change btrfs_writepage_cow_fixup() to just check PagePrivate2, not to clear it. The clearing will happen in either btrfs_invalidatepage() or btrfs_writepage_endio_finish_ordered(). This makes the Private2 bit easier to understand, just meaning the page has unfinished ordered extent attached to it. And this patch is a hard requirement for the incoming refactoring for how we finished ordered IO for endio context, as the coming patch will check Private2 to determine if we need to do the ordered extent accounting. Thus this patch is definitely needed or we will hang due to unfinished ordered extent. Reviewed-by: -
Qu Wenruo authored
There is a pretty bad abuse of btrfs_writepage_endio_finish_ordered() in end_compressed_bio_write(). It passes compressed pages to btrfs_writepage_endio_finish_ordered(), which is only supposed to accept inode pages. Thankfully the important info here is the inode, so let's pass btrfs_inode directly into btrfs_writepage_endio_finish_ordered(), and make @page parameter optional. By this, end_compressed_bio_write() can happily pass page=NULL while still getting everything done properly. Also, to cooperate with such modification, replace @page parameter for trace_btrfs_writepage_end_io_hook() with btrfs_inode. Although this removes page_index info, the existing start/len should be enough for most usage. Signed-off-by:
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Qu Wenruo authored
For subpage metadata, we're reusing two functions for subpage metadata write: - end_bio_extent_buffer_writepage() - write_one_eb() But the truth is, for subpage we just call end_bio_subpage_eb_writepage() without using any bit in end_bio_extent_buffer_writepage(). For write_one_eb(), it's pretty similar, but with a small part of code reused. There is really no need to pollute the existing code path if we're not really using most of them. So this patch will do the following change to separate the subpage metadata write path from regular write path by: - Use end_bio_subpage_eb_writepage() directly as endio in write_one_subpage_eb() - Directly call write_one_subpage_eb() in submit_eb_subpage() Signed-off-by:
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Qu Wenruo authored
There is a lot of code inside extent_io.c needs both "struct bio **bio_ret" and "unsigned long prev_bio_flags", along with some parameters like "unsigned long bio_flags". Such strange parameters are here for bio assembly. For example, we have such inode page layout: 0 4K 8K 12K |<-- Extent A-->|<- EB->| Then what we do is: - Page [0, 4K) *bio_ret = NULL So we allocate a new bio to bio_ret, Add page [0, 4K) to *bio_ret. - Page [4K, 8K) *bio_ret != NULL We found this page is continuous to *bio_ret, and if we're not at stripe boundary, we add page [4K, 8K) to *bio_ret. - Page [8K, 12K) *bio_ret != NULL But we found this page is not continuous, so we submit *bio_ret, then allocate a new bio, and add page [8K, 12K) to the new bio. This means we need to record both the bio and its bio_flag, but we record them manually using those strange parameter list, other than encapsulating them into their own structure. So this patch will introduce a new structure, btrfs_bio_ctrl, to record both the bio, and its bio_flags. Also, in above case, for all pages added to the bio, we need to check if the new page crosses stripe boundary. This check itself can be time consuming, and we don't really need to do that for each page. This patch also integrates the stripe boundary check into btrfs_bio_ctrl. When a new bio is allocated, the stripe and ordered extent boundary is also calculated, so no matter how large the bio will be, we only calculate the boundaries once, to save some CPU time. The following functions/structures are affected: - struct extent_page_data Replace its bio pointer with structure btrfs_bio_ctrl (embedded structure, not pointer) - end_write_bio() - flush_write_bio() Just change how bio is fetched - btrfs_bio_add_page() Use pre-calculated boundaries instead of re-calculating them. And use @bio_ctrl to replace @bio and @prev_bio_flags. - calc_bio_boundaries() New function - submit_extent_page() callers - btrfs_do_readpage() callers - contiguous_readpages() callers To Use @bio_ctrl to replace @bio and @prev_bio_flags, and how to grab bio. - btrfs_bio_fits_in_ordered_extent() Removed, as now the ordered extent size limit is done at bio allocation time, no need to check for each page range. Signed-off-by:
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Qu Wenruo authored
Function btrfs_bio_fits_in_stripe() now requires a bio with at least one page added. Or btrfs_get_chunk_map() will fail with -ENOENT. But in fact this requirement is not needed at all, as we can just pass sectorsize for btrfs_get_chunk_map(). This tiny behavior change is important for later subpage refactoring on submit_extent_page(). As for 64K page size, we can have a page range with pgoff=0 and size=64K. If the logical bytenr is just 16K before the stripe boundary, we have to split the page range into two bios. This means, we must check page range against stripe boundary, even adding the range to an empty bio. This tiny refactoring is for the incoming changes, but on its own, regular sectorsize == PAGE_SIZE is not affected anyway. Reviewed-by:
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Qu Wenruo authored
The parameter @len is not really used in btrfs_bio_fits_in_stripe(), just remove it. It got removed in 42034313 ("btrfs: let callers of btrfs_get_io_geometry pass the em"), before that btrfs_get_chunk_map utilized it. Reviewed-by:
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Qu Wenruo authored
Currently free space cache inode size is determined by two factors: - block group size - PAGE_SIZE This means, for the same sized block groups, with different PAGE_SIZE, it will result in different inode sizes. This will not be a good thing for subpage support, so change the requirement for PAGE_SIZE to sectorsize. Now for the same 4K sectorsize btrfs, it should result the same inode size no matter what the PAGE_SIZE is. Signed-off-by:
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Qu Wenruo authored
[BUG] For the following file layout, scrub will not be able to repair all these two repairable error, but in fact make one corruption even unrepairable: inode offset 0 4k 8K Mirror 1 |XXXXXX| | Mirror 2 | |XXXXXX| [CAUSE] The root cause is the hard coded PAGE_SIZE, which makes scrub repair to go crazy for subpage. For above case, when reading the first sector, we use PAGE_SIZE other than sectorsize to read, which makes us to read the full range [0, 64K). In fact, after 8K there may be no data at all, we can just get some garbage. Then when doing the repair, we also writeback a full page from mirror 2, this means, we will also writeback the corrupted data in mirror 2 back to mirror 1, leaving the range [4K, 8K) unrepairable. [FIX] This patch will modify the following PAGE_SIZE use with sectorsize: - scrub_print_warning_inode() Remove the min() and replace PAGE_SIZE with sectorsize. The min() makes no sense, as csum is done for the full sector with padding. This fixes a bug that subpage report extra length like: checksum error at logical 298844160 on dev /dev/mapper/arm_nvme-test, physical 575668224, root 5, inode 257, offset 0, length 12288, links 1 (path: file) Where the error is only 1 sector. - scrub_handle_errored_block() Comments with PAGE|page involved, all changed to sector. - scrub_setup_recheck_block() - scrub_repair_page_from_good_copy() - scrub_add_page_to_wr_bio() - scrub_wr_submit() - scrub_add_page_to_rd_bio() - scrub_block_complete() Replace PAGE_SIZE with sectorsize. This solves several problems where we read/write extra range for subpage case. RAID56 code is excluded intentionally, as RAID56 has extra PAGE_SIZE usage, and is not really safe enough. Thus we will reject RAID56 for subpage in later commit. Signed-off-by:
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Nikolay Borisov authored
Instead of calling list_entry with head->prev simply call list_last_entry which makes it obvious which member of the list is being referred. This allows to remove the extra 'prev' pointer. Signed-off-by:
Nikolay Borisov <nborisov@suse.com> Reviewed-by:
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Anand Jain authored
Commit e5d74902 ("btrfs: derive maximum output size in the compression implementation") removed @max_out argument in btrfs_compress_pages() but its comment remained, remove it. Signed-off-by:
Anand Jain <anand.jain@oracle.com> Reviewed-by:
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Anand Jain authored
Patch "btrfs: reduce compressed_bio member's types" reduced some member's size. Function arguments @len, @compressed_len and @nr_pages can be declared as unsigned int. Signed-off-by:
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Anand Jain authored
Patch "btrfs: reduce compressed_bio member's types" reduced some member's size. Declare the variables @compressed_len, @nr_pages and @pg_index size as an unsigned int in the function btrfs_submit_compressed_read. Signed-off-by:
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Anand Jain authored
Patch "btrfs: reduce compressed_bio member's types" reduced the @nr_pages size to unsigned int, its cascading effects are updated here. Signed-off-by:
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Filipe Manana authored
When logging an inode we always log all its xattrs, so that we are able to figure out which ones should be deleted during log replay. However this is unnecessary when we are doing a fast fsync and no xattrs were added, changed or deleted since the last time we logged the inode in the current transaction. So skip the logging of xattrs when the inode was previously logged in the current transaction and no xattrs were added, changed or deleted. If any changes to xattrs happened, than the inode has BTRFS_INODE_COPY_EVERYTHING set in its runtime flags and the xattrs get logged. This saves time on scanning for xattrs, allocating memory, COWing log tree extent buffers and adding more lock contention on the extent buffers when there are multiple tasks logging in parallel. The use of xattrs is common when using ACLs, some applications, or when using security modules like SELinux where every inode gets a security xattr added to it. The following test script, using fio, was used on a box with 12 cores, 64G of RAM, a NVMe device and the default non-debug kernel config from Debian. It uses 8 concurrent jobs each writing in blocks of 64K to its own 4G file, each file with a single xattr of 50 bytes (about the same size for an ACL or SELinux xattr), doing random buffered writes with an fsync after each write. $ cat test.sh #!/bin/bash DEV=/dev/nvme0n1 MNT=/mnt/test MOUNT_OPTIONS="-o ssd" MKFS_OPTIONS="-d single -m single" NUM_JOBS=8 FILE_SIZE=4G cat <<EOF > /tmp/fio-job.ini [writers] rw=randwrite fsync=1 fallocate=none group_reporting=1 direct=0 bs=64K ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS EOF echo "performance" | \ tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor mkfs.btrfs -f $MKFS_OPTIONS $DEV > /dev/null mount $MOUNT_OPTIONS $DEV $MNT echo "Creating files before fio runs, each with 1 xattr of 50 bytes" for ((i = 0; i < $NUM_JOBS; i++)); do path="$MNT/writers.$i.0" truncate -s $FILE_SIZE $path setfattr -n user.xa1 -v $(printf '%0.sX' $(seq 50)) $path done fio /tmp/fio-job.ini umount $MNT fio output before this change: WRITE: bw=120MiB/s (126MB/s), 120MiB/s-120MiB/s (126MB/s-126MB/s), io=32.0GiB (34.4GB), run=272145-272145msec fio output after this change: WRITE: bw=142MiB/s (149MB/s), 142MiB/s-142MiB/s (149MB/s-149MB/s), io=32.0GiB (34.4GB), run=230408-230408msec +16.8% throughput, -16.6% runtime Signed-off-by:Filipe Manana <fdmanana@suse.com> Signed-off-by:
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David Sterba authored
Accept device name "cancel" as a request to cancel running device deletion operation. The string is literal, in case there's a real device named "cancel", pass it as full absolute path or as "./cancel" This works for v1 and v2 ioctls when the device is specified by name. Moving chunks from the device uses relocation, use the conditional exclusive operation start and cancellation helpers Reviewed-by:
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David Sterba authored
Accept literal string "cancel" as resize operation and interpret that as a request to cancel the running operation. If it's running, wait until it finishes current work and return ECANCELED. Shrinking resize uses relocation to move the chunks away, use the conditional exclusive operation start and cancellation helpers. Reviewed-by:
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David Sterba authored
To support optional cancellation of some operations, add helper that will wrap all the combinations. In normal mode it's same as btrfs_exclop_start, in cancellation mode it checks if it's already running and request cancellation and waits until completion. The error codes can be returned to to user space and semantics is not changed, adding ECANCELED. This should be evaluated as an error and that the operation has not completed and the operation should be restarted or the filesystem status reviewed. Signed-off-by: -
David Sterba authored
Add try-lock for exclusive operation start to allow callers to do more checks. The same operation must already be running. The try-lock and unlock must pair and are a substitute for btrfs_exclop_start, thus it must also pair with btrfs_exclop_finish to release the exclop context. Reviewed-by:
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David Sterba authored
Add support code that will allow canceling relocation on the chunk granularity. This is different and independent of balance, that also uses relocation but is a higher level operation and manages it's own state and pause/cancellation requests. Relocation is used for resize (shrink) and device deletion so this will be a common point to implement cancellation for both. The context is entirely in btrfs_relocate_block_group and btrfs_recover_relocation, enclosing one chunk relocation. The status bit is set and unset between the chunks. As relocation can take long, the effects may not be immediate and the request and actual action can slightly race. The fs_info::reloc_cancel_req is only supposed to be increased and does not pair with decrement like fs_info::balance_cancel_req. Reviewed-by:
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David Sterba authored
The exclusive operation is now atomically checked and set using bit operations. Switch it to protection by spinlock. The super block lock is not frequently used and adding a new lock seems like an overkill so it should be safe to reuse it. The reason to use spinlock is to enhance the locking context so more checks can be done, eg. allowing the same exclusive operation enter the exclop section and cancel the running one. This will be used for resize and device delete. Reviewed-by:
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David Sterba authored
Move header offsetof() to the expression that calculates the address so it's part of get_eb_offset_in_page where the 2nd parameter is the member offset. Reviewed-by:
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David Sterba authored
The verification copies the calculated checksum bytes to a temporary buffer but this is not necessary. We can map the eb header on the first page and use the checksum bytes directly. This saves at least one function call and boundary checks so it could lead to a minor performance improvement. Reviewed-by:
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David Sterba authored
The s_id is already printed by message helpers. Reviewed-by:
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David Sterba authored
Several members of compressed_bio are of type that's unnecessarily big for the values that they'd hold: - the size of the uncompressed and compressed data is 128K now, we can keep is as int - same for number of pages - the compress type fits to a byte - the errors is 0/1 The size of the unpatched structure is 80 bytes with several holes. Reordering nr_pages next to the pages the hole after pending_bios is filled and the resulting size is 56 bytes. This keeps the csums array aligned to 8 bytes, which is nice. Further size optimizations may be possible but right now it looks good to me: struct compressed_bio { refcount_t pending_bios; /* 0 4 */ unsigned int nr_pages; /* 4 4 */ struct page * * compressed_pages; /* 8 8 */ struct inode * inode; /* 16 8 */ u64 start; /* 24 8 */ unsigned int len; /* 32 4 */ unsigned int compressed_len; /* 36 4 */ u8 compress_type; /* 40 1 */ u8 errors; /* 41 1 */ /* XXX 2 bytes hole, try to pack */ int mirror_num; /* 44 4 */ struct bio * orig_bio; /* 48 8 */ u8 sums[]; /* 56 0 */ /* size: 56, cachelines: 1, members: 12 */ /* sum members: 54, holes: 1, sum holes: 2 */ /* last cacheline: 56 bytes */ }; Reviewed-by: -
David Sterba authored
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David Sterba authored
There are common values set for the stripe constraints, some of them are already factored out. Do that for increment and mirror_num as well. Reviewed-by:
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David Sterba authored
When a log recovery is in progress, lots of operations have to take that into account, so we keep this status per tree during the operation. Long time ago error handling revamp patch 79787eaa ("btrfs: replace many BUG_ONs with proper error handling") removed clearing of the status in an error branch. Add it back as was intended in e02119d5 ("Btrfs: Add a write ahead tree log to optimize synchronous operations"). There are probably no visible effects, log replay is done only during mount and if it fails all structures are cleared so the stale status won't be kept. Fixes: 79787eaa ("btrfs: replace many BUG_ONs with proper error handling") Reviewed-by:
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David Sterba authored
The defrag loop processes leaves in batches and starting transaction for each. The whole defragmentation on a given root is protected by a bit but in case the transaction fails, the bit is not cleared In case the transaction fails the bit would prevent starting defragmentation again, so make sure it's cleared. CC: stable@vger.kernel.org # 4.4+ Reviewed-by:
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David Sterba authored
The type of discard_bitmap_bytes and discard_extent_bytes is u64 so the format should be %llu, though the actual values would hardly ever overflow to negative values. Reviewed-by:
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Josef Bacik authored
While stress testing our error handling I noticed that sometimes we would still commit the transaction even though we had aborted the transaction. Currently we track if a trans handle has dirtied any metadata, and if it hasn't we mark the filesystem as having an error (so no new transactions can be started), but we will allow the current transaction to complete as we do not mark the transaction itself as having been aborted. This sounds good in theory, but we were not properly tracking IO errors in btrfs_finish_ordered_io, and thus committing the transaction with bogus free space data. This isn't necessarily a problem per-se with the free space cache, as the other guards in place would have kept us from accepting the free space cache as valid, but highlights a real world case where we had a bug and could have corrupted the filesystem because of it. This "skip abort on empty trans handle" is nice in theory, but assumes we have perfect error handling everywhere, which we clearly do not. Also we do not allow further transactions to be started, so all this does is save the last transaction that was happening, which doesn't necessarily gain us anything other than the potential for real corruption. Remove this particular bit of code, if we decide we need to abort the transaction then abort the current one and keep us from doing real harm to the file system, regardless of whether this specific trans handle dirtied anything or not. Signed-off-by:
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Filipe Manana authored
At btrfs_truncate() where we truncate the inode either to the same size or to a smaller size, we always set the full sync flag on the inode. This is needed in case the truncation drops or trims any file extent items that start beyond or cross the new inode size, so that the next fsync drops all inode items from the log and scans again the fs/subvolume tree to find all items that must be logged. However if the truncation does not drop or trims any file extent items, we do not need to set the full sync flag and force the next fsync to use the slow code path. So do not set the full sync flag in such cases. One use case where it is frequent to do truncations that do not change the inode size and do not drop any extents (no prealloc extents beyond i_size) is when running Microsoft's SQL Server inside a Docker container. One example workload is the one Philipp Fent reported recently, in the thread with a link below. In this workload a large number of fsyncs are preceded by such truncate operations. After this change I constantly get the runtime for that workload from Philipp to be reduced by about -12%, for example from 184 seconds down to 162 seconds. Link: https://lore.kernel.org/linux-btrfs/93c4600e-5263-5cba-adf0-6f47526e7561@in.tum.de/Tested-by:
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Filipe Manana authored
The comment at the top of btrfs_truncate() mentions that csum items are dropped or truncated to the new i_size, but this is wrong and non sense, as they are unrelated to the i_size and are located in the csums tree and not on a tree with inode items (fs/subvolume tree or a log tree). Instead that claim applies to file extent items, so fix the comment to refer to them instead. While at it make the whole comment for the function more descriptive and follow the kernel doc style. Tested-by:
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