- 19 Apr, 2021 40 commits
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Josef Bacik authored
btrfs_update_reloc_root will will return errors in the future, so handle an error properly in prepare_to_merge. Signed-off-by:
Josef Bacik <josef@toxicpanda.com> Reviewed-by:
David Sterba <dsterba@suse.com> Signed-off-by:
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Josef Bacik authored
btrfs_update_reloc_root will will return errors in the future, so handle the error properly in insert_dirty_subvol. Signed-off-by:
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Josef Bacik authored
This will be able to return errors in the future, so change it to return an error and handle the errors appropriately. Signed-off-by:
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Josef Bacik authored
btrfs_update_reloc_root will will return errors in the future, so handle the error properly in commit_fs_roots. Reviewed-by:
Qu Wenruo <wqu@suse.com> Signed-off-by:
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Josef Bacik authored
If we fail to setup a root->reloc_root in a different thread that path will error out, however it still leaves root->reloc_root NULL but would still appear set up in the transaction. Subsequent calls to btrfs_record_root_in_transaction would succeed without attempting to create the reloc root, as the transid has already been updated. Handle this case by making sure we have a root->reloc_root set after a btrfs_record_root_in_transaction call so we don't end up dereferencing a NULL pointer. Reported-by:
Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Signed-off-by:
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Josef Bacik authored
We do memory allocations here, read blocks from disk, all sorts of operations that could easily fail at any given point. Instead of panicing the box, simply return the error back up the chain, all callers at this point have proper error handling. Signed-off-by:
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Josef Bacik authored
create_reloc_root will return errors in the future, and __add_reloc_root can return ENOMEM or EEXIST, so handle these errors properly. Signed-off-by:
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Josef Bacik authored
We can create a reloc root when we record the root in the trans, which can fail for all sorts of different reasons. Propagate this error up the chain of callers. Future patches will fix the callers of btrfs_record_root_in_trans() to handle the error. Reviewed-by:
Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by:
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Josef Bacik authored
record_root_in_trans can currently fail, so handle this failure properly. Reviewed-by:
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Josef Bacik authored
record_root_in_trans can fail currently, handle this failure properly. Signed-off-by:
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Josef Bacik authored
record_root_in_trans can fail currently, so handle this failure properly. Reviewed-by:
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Josef Bacik authored
btrfs_record_root_in_trans will return errors in the future, so handle the error properly in start_transaction. Reviewed-by:
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Josef Bacik authored
btrfs_record_root_in_trans will return errors in the future, so handle the error properly in relocate_tree_block. Reviewed-by:
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Josef Bacik authored
btrfs_record_root_in_trans will return errors in the future, so handle the error properly in create_subvol. Signed-off-by:
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Josef Bacik authored
btrfs_record_root_in_trans will return errors in the future, so handle the error properly in btrfs_recover_log_trees. This appears tricky, however we have a reference count on the destination root, so if this fails we need to continue on in the loop to make sure the proper cleanup is done. Reviewed-by:
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Josef Bacik authored
btrfs_record_root_in_trans will return errors in the future, so handle the error properly in btrfs_delete_subvolume. Reviewed-by:
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Josef Bacik authored
btrfs_record_root_in_trans will return errors in the future, so handle the error properly in btrfs_rename. Signed-off-by:
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Josef Bacik authored
btrfs_record_root_in_trans will return errors in the future, so handle the error properly in btrfs_rename_exchange. Reviewed-by:
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Josef Bacik authored
Generally speaking this shouldn't ever fail, the corresponding fs root for the reloc root will already be in memory, so we won't get ENOMEM here. However if there is no corresponding root for the reloc root then we could get ENOMEM when we try to allocate it or we could get ENOENT when we look it up and see that it doesn't exist. Convert these BUG_ON()'s into ASSERT()'s and add proper error handling for the case of corruption. Signed-off-by:
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Josef Bacik authored
We will record the fs root or the reloc root in the trans in select_reloc_root. These will actually return errors in the following patches, so check their return value here and return it up the stack. Reviewed-by:
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Josef Bacik authored
We have several BUG_ON()'s in select_reloc_root() that can be tripped if there is an extent tree corruption. Convert these to ASSERT()'s, because if we hit it during testing it really is bad, or could indicate a problem with the backref walking code. However if users hit these problems it generally indicates corruption, I've hit a few machines in the fleet that trip over these with clearly corrupted extent trees, so be nice and print out an error message and return an error instead of bringing the whole box down. Signed-off-by:
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Josef Bacik authored
Currently select_reloc_root() doesn't return an error, but followup patches will make it possible for it to return an error. We do have proper error recovery in do_relocation however, so handle the possibility of select_reloc_root() having an error properly instead of BUG_ON(!root). I've also adjusted select_reloc_root() to return ERR_PTR(-ENOENT) if we don't find a root, instead of NULL, to make the error case easier to deal with. I've replaced the BUG_ON(!root) with an ASSERT(0) for this case as it indicates we messed up the backref walking code, but it could also indicate corruption. Signed-off-by:
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Josef Bacik authored
We have a couple of BUG_ON()'s in relocate_tree_block() that can be tripped if we have file system corruption. Convert these to ASSERT()'s so developers still get yelled at when they break the backref code, but error out nicely for users so the whole box doesn't go down. Reviewed-by:
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Josef Bacik authored
A few of these are checking for correctness, and won't be triggered by corrupted file systems, so convert them to ASSERT() instead of BUG_ON() and add a comment explaining their existence. Reviewed-by:
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Matthew Wilcox (Oracle) authored
Implement readahead_batch_length() to determine the number of bytes in the current batch of readahead pages and use it in btrfs. Also use the readahead_pos to get the offset. Signed-off-by:
Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by:
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Wan Jiabing authored
There are two forward declarations deep in extent_io.h, move them to the beginning and remove the duplicate one. Reviewed-by:
Nikolay Borisov <nborisov@suse.com> Signed-off-by:
Wan Jiabing <wanjiabing@vivo.com> Reviewed-by:
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Qu Wenruo authored
This patch adds an overview how btrfs subpage support works: - limitations - behavior - basic implementation points Signed-off-by:
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Qu Wenruo authored
Current set_btree_ioerr() only accepts @page parameter and grabs extent buffer from page::private. This works fine for sector size == PAGE_SIZE case, but not for subpage case. Add an extra parameter, @eb, for callers to pass extent buffer to this function, so that subpage code can reuse this function. And also add subpage special handling to update btrfs_subpage::error_bitmap. Signed-off-by:
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Qu Wenruo authored
For set_extent_buffer_dirty() to support subpage sized metadata, just call btrfs_page_set_dirty() to handle both cases. For clear_extent_buffer_dirty(), it needs to clear the page dirty if and only if all extent buffers in the page range are no longer dirty. Also do the same for page error. This is pretty different from the existing clear_extent_buffer_dirty() routine, so add a new helper function, clear_subpage_extent_buffer_dirty() to do this for subpage metadata. Also since the main part of clearing page dirty code is still the same, extract that into btree_clear_page_dirty() so that it can be utilized for both cases. But there is a special race between set_extent_buffer_dirty() and clear_extent_buffer_dirty(), where we can clear the page dirty. [POSSIBLE RACE WINDOW] For the race window between clear_subpage_extent_buffer_dirty() and set_extent_buffer_dirty(), due to the fact that we can't call clear_page_dirty_for_io() under subpage spin lock, we can race like below: T1 (eb1 in the same page) | T2 (eb2 in the same page) -------------------------------+------------------------------ set_extent_buffer_dirty() | clear_extent_buffer_dirty() |- was_dirty = false; | |- clear_subpagE_extent_buffer_dirty() | | |- btrfs_clear_and_test_dirty() | | | Since eb2 is the last dirty page | | | we got: | | | last == true; | | | |- btrfs_page_set_dirty() | | | We set the page dirty and | | | subpage dirty bitmap | | | | |- if (last) | | | Since we don't have subpage lock | | | held, now @last is no longer | | | correct | | |- btree_clear_page_dirty() | | Now PageDirty == false, even if | | we have dirty_bitmap not zero. |- ASSERT(PageDirty()); | ^^^^ CRASH The solution here is to also lock the eb->pages[0] for subpage case of set_extent_buffer_dirty(), to prevent racing with clear_extent_buffer_dirty(). Signed-off-by: -
Qu Wenruo authored
There are quite some assert checks on page uptodate in extent buffer write accessors. They ensure the destination page is already uptodate. This is fine for regular sector size case, but not for subpage case, as for subpage we only mark the page uptodate if the page contains no hole and all its extent buffers are uptodate. So instead of checking PageUptodate(), for subpage case we check the uptodate bitmap of btrfs_subpage structure. To make the check more elegant, introduce a helper, assert_eb_page_uptodate() to do the check for both subpage and regular sector size cases. The following functions are involved: - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer() - extent_buffer_test_bit() - extent_buffer_bitmap_set() - extent_buffer_bitmap_clear() Signed-off-by:
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Qu Wenruo authored
In alloc_extent_buffer(), we make sure that the newly allocated page is never dirty. This is fine for sector size == PAGE_SIZE case, but for subpage it's possible that one extent buffer in the page is dirty, thus the whole page is marked dirty, and could cause false alert. To support subpage, call btrfs_page_test_dirty() to handle both cases. Signed-off-by:
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Qu Wenruo authored
Add a new helper, csum_dirty_subpage_buffers(), to iterate through all dirty extent buffers in one bvec. Also extract the code of calculating csum for one extent buffer into csum_one_extent_buffer(), so that both the existing csum_dirty_buffer() and the new csum_dirty_subpage_buffers() can reuse the same routine. Signed-off-by:
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Qu Wenruo authored
For btree_set_page_dirty(), we should also check the extent buffer sanity for subpage support. Unlike the regular sector size case, since one page can contain multiple extent buffers, we need to make sure there is at least one dirty extent buffer in the page. So this patch will iterate through the btrfs_subpage::dirty_bitmap to get the extent buffers, and check if any dirty extent buffer in the page range has EXTENT_BUFFER_DIRTY and proper refs. Signed-off-by:
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Qu Wenruo authored
Introduces the following functions to handle subpage writeback status: - btrfs_subpage_set_writeback() - btrfs_subpage_clear_writeback() - btrfs_subpage_test_writeback() These helpers can only be called when the range is ensured to be inside the page. - btrfs_page_set_writeback() - btrfs_page_clear_writeback() - btrfs_page_test_writeback() These helpers can handle both regular sector size and subpage without problem. Signed-off-by:
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Qu Wenruo authored
Introduce the following functions to handle subpage dirty status: - btrfs_subpage_set_dirty() - btrfs_subpage_clear_dirty() - btrfs_subpage_test_dirty() These helpers can only be called when the range is ensured to be inside the page. - btrfs_page_set_dirty() - btrfs_page_clear_dirty() - btrfs_page_test_dirty() These helpers can handle both regular sector size and subpage without problem. Thus they would be used to replace PageDirty() related calls in later patches. There is one special point to note here, just like set_page_dirty() and clear_page_dirty_for_io(), btrfs_*page_set_dirty() and btrfs_*page_clear_dirty() must be called with page locked. Signed-off-by:
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Qu Wenruo authored
In btrfs_invalidatepage() we re-declare @tree variable as btrfs_ordered_inode_tree. Since it's only used to do the spinlock, we can grab it from inode directly, and remove the unnecessary declaration completely. Reviewed-by:
Anand Jain <anand.jain@oracle.com> Signed-off-by:
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Qu Wenruo authored
In btrfs_invalidatepage() we introduce a temporary variable, new_len, to update ordered->truncated_len. But we can use min() to replace it completely and no need for the variable. Reviewed-by:
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Qu Wenruo authored
Export supported sector sizes in /sys/fs/btrfs/features/supported_sectorsizes. Currently all architectures have PAGE_SIZE, There's some disparity between read-only and read-write support but that will be unified in the future so there's only one file exporting the size. The read-only support for systems with 64K pages also works for 4K sector size. This new sysfs interface would help eg. mkfs.btrfs to print more accurate warnings about potentially incompatible option combinations. Reviewed-by:
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Filipe Manana authored
Currently a full send operation uses the standard btree readahead when iterating over the subvolume/snapshot btree, which despite bringing good performance benefits, it could be improved in a few aspects for use cases such as full send operations, which are guaranteed to visit every node and leaf of a btree, in ascending and sequential order. The limitations of that standard btree readahead implementation are the following: 1) It only triggers readahead for leaves that are physically close to the leaf being read, within a 64K range; 2) It only triggers readahead for the next or previous leaves if the leaf being read is not currently in memory; 3) It never triggers readahead for nodes. So add a new readahead mode that addresses all these points and use it for full send operations. The following test script was used to measure the improvement on a box using an average, consumer grade, spinning disk and with 16GiB of RAM: $ cat test.sh #!/bin/bash DEV=/dev/sdj MNT=/mnt/sdj MKFS_OPTIONS="--nodesize 16384" # default, just to be explicit MOUNT_OPTIONS="-o max_inline=2048" # default, just to be explicit mkfs.btrfs -f $MKFS_OPTIONS $DEV > /dev/null mount $MOUNT_OPTIONS $DEV $MNT # Create files with inline data to make it easier and faster to create # large btrees. add_files() { local total=$1 local start_offset=$2 local number_jobs=$3 local total_per_job=$(($total / $number_jobs)) echo "Creating $total new files using $number_jobs jobs" for ((n = 0; n < $number_jobs; n++)); do ( local start_num=$(($start_offset + $n * $total_per_job)) for ((i = 1; i <= $total_per_job; i++)); do local file_num=$((start_num + $i)) local file_path="$MNT/file_${file_num}" xfs_io -f -c "pwrite -S 0xab 0 2000" $file_path > /dev/null if [ $? -ne 0 ]; then echo "Failed creating file $file_path" break fi done ) & worker_pids[$n]=$! done wait ${worker_pids[@]} sync echo echo "btree node/leaf count: $(btrfs inspect-internal dump-tree -t 5 $DEV | egrep '^(node|leaf) ' | wc -l)" } initial_file_count=500000 add_files $initial_file_count 0 4 echo echo "Creating first snapshot..." btrfs subvolume snapshot -r $MNT $MNT/snap1 echo echo "Adding more files..." add_files $((initial_file_count / 4)) $initial_file_count 4 echo echo "Updating 1/50th of the initial files..." for ((i = 1; i < $initial_file_count; i += 50)); do xfs_io -c "pwrite -S 0xcd 0 20" $MNT/file_$i > /dev/null done echo echo "Creating second snapshot..." btrfs subvolume snapshot -r $MNT $MNT/snap2 umount $MNT echo 3 > /proc/sys/vm/drop_caches blockdev --flushbufs $DEV &> /dev/null hdparm -F $DEV &> /dev/null mount $MOUNT_OPTIONS $DEV $MNT echo echo "Testing full send..." start=$(date +%s) btrfs send $MNT/snap1 > /dev/null end=$(date +%s) echo echo "Full send took $((end - start)) seconds" umount $MNT The durations of the full send operation in seconds were the following: Before this change: 217 seconds After this change: 205 seconds (-5.7%) Signed-off-by:Filipe Manana <fdmanana@suse.com> Signed-off-by:
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Filipe Manana authored
When we are running out of space for updating the chunk tree, that is, when we are low on available space in the system space info, if we have many task concurrently allocating block groups, via fallocate for example, many of them can end up all allocating new system chunks when only one is needed. In extreme cases this can lead to exhaustion of the system chunk array, which has a size limit of 2048 bytes, and results in a transaction abort with errno EFBIG, producing a trace in dmesg like the following, which was triggered on a PowerPC machine with a node/leaf size of 64K: [1359.518899] ------------[ cut here ]------------ [1359.518980] BTRFS: Transaction aborted (error -27) [1359.519135] WARNING: CPU: 3 PID: 16463 at ../fs/btrfs/block-group.c:1968 btrfs_create_pending_block_groups+0x340/0x3c0 [btrfs] [1359.519152] Modules linked in: (...) [1359.519239] Supported: Yes, External [1359.519252] CPU: 3 PID: 16463 Comm: stress-ng Tainted: G X 5.3.18-47-default #1 SLE15-SP3 [1359.519274] NIP: c008000000e36fe8 LR: c008000000e36fe4 CTR: 00000000006de8e8 [1359.519293] REGS: c00000056890b700 TRAP: 0700 Tainted: G X (5.3.18-47-default) [1359.519317] MSR: 800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 48008222 XER: 00000007 [1359.519356] CFAR: c00000000013e170 IRQMASK: 0 [1359.519356] GPR00: c008000000e36fe4 c00000056890b990 c008000000e83200 0000000000000026 [1359.519356] GPR04: 0000000000000000 0000000000000000 0000d52a3b027651 0000000000000007 [1359.519356] GPR08: 0000000000000003 0000000000000001 0000000000000007 0000000000000000 [1359.519356] GPR12: 0000000000008000 c00000063fe44600 000000001015e028 000000001015dfd0 [1359.519356] GPR16: 000000000000404f 0000000000000001 0000000000010000 0000dd1e287affff [1359.519356] GPR20: 0000000000000001 c000000637c9a000 ffffffffffffffe5 0000000000000000 [1359.519356] GPR24: 0000000000000004 0000000000000000 0000000000000100 ffffffffffffffc0 [1359.519356] GPR28: c000000637c9a000 c000000630e09230 c000000630e091d8 c000000562188b08 [1359.519561] NIP [c008000000e36fe8] btrfs_create_pending_block_groups+0x340/0x3c0 [btrfs] [1359.519613] LR [c008000000e36fe4] btrfs_create_pending_block_groups+0x33c/0x3c0 [btrfs] [1359.519626] Call Trace: [1359.519671] [c00000056890b990] [c008000000e36fe4] btrfs_create_pending_block_groups+0x33c/0x3c0 [btrfs] (unreliable) [1359.519729] [c00000056890ba90] [c008000000d68d44] __btrfs_end_transaction+0xbc/0x2f0 [btrfs] [1359.519782] [c00000056890bae0] [c008000000e309ac] btrfs_alloc_data_chunk_ondemand+0x154/0x610 [btrfs] [1359.519844] [c00000056890bba0] [c008000000d8a0fc] btrfs_fallocate+0xe4/0x10e0 [btrfs] [1359.519891] [c00000056890bd00] [c0000000004a23b4] vfs_fallocate+0x174/0x350 [1359.519929] [c00000056890bd50] [c0000000004a3cf8] ksys_fallocate+0x68/0xf0 [1359.519957] [c00000056890bda0] [c0000000004a3da8] sys_fallocate+0x28/0x40 [1359.519988] [c00000056890bdc0] [c000000000038968] system_call_exception+0xe8/0x170 [1359.520021] [c00000056890be20] [c00000000000cb70] system_call_common+0xf0/0x278 [1359.520037] Instruction dump: [1359.520049] 7d0049ad 40c2fff4 7c0004ac 71490004 40820024 2f83fffb 419e0048 3c620000 [1359.520082] e863bcb8 7ec4b378 48010d91 e8410018 <0fe00000> 3c820000 e884bcc8 7ec6b378 [1359.520122] ---[ end trace d6c186e151022e20 ]--- The following steps explain how we can end up in this situation: 1) Task A is at check_system_chunk(), either because it is allocating a new data or metadata block group, at btrfs_chunk_alloc(), or because it is removing a block group or turning a block group RO. It does not matter why; 2) Task A sees that there is not enough free space in the system space_info object, that is 'left' is < 'thresh'. And at this point the system space_info has a value of 0 for its 'bytes_may_use' counter; 3) As a consequence task A calls btrfs_alloc_chunk() in order to allocate a new system block group (chunk) and then reserves 'thresh' bytes in the chunk block reserve with the call to btrfs_block_rsv_add(). This changes the chunk block reserve's 'reserved' and 'size' counters by an amount of 'thresh', and changes the 'bytes_may_use' counter of the system space_info object from 0 to 'thresh'. Also during its call to btrfs_alloc_chunk(), we end up increasing the value of the 'total_bytes' counter of the system space_info object by 8MiB (the size of a system chunk stripe). This happens through the call chain: btrfs_alloc_chunk() create_chunk() btrfs_make_block_group() btrfs_update_space_info() 4) After it finishes the first phase of the block group allocation, at btrfs_chunk_alloc(), task A unlocks the chunk mutex; 5) At this point the new system block group was added to the transaction handle's list of new block groups, but its block group item, device items and chunk item were not yet inserted in the extent, device and chunk trees, respectively. That only happens later when we call btrfs_finish_chunk_alloc() through a call to btrfs_create_pending_block_groups(); Note that only when we update the chunk tree, through the call to btrfs_finish_chunk_alloc(), we decrement the 'reserved' counter of the chunk block reserve as we COW/allocate extent buffers, through: btrfs_alloc_tree_block() btrfs_use_block_rsv() btrfs_block_rsv_use_bytes() And the system space_info's 'bytes_may_use' is decremented everytime we allocate an extent buffer for COW operations on the chunk tree, through: btrfs_alloc_tree_block() btrfs_reserve_extent() find_free_extent() btrfs_add_reserved_bytes() If we end up COWing less chunk btree nodes/leaves than expected, which is the typical case since the amount of space we reserve is always pessimistic to account for the worst possible case, we release the unused space through: btrfs_create_pending_block_groups() btrfs_trans_release_chunk_metadata() btrfs_block_rsv_release() block_rsv_release_bytes() btrfs_space_info_free_bytes_may_use() But before task A gets into btrfs_create_pending_block_groups()... 6) Many other tasks start allocating new block groups through fallocate, each one does the first phase of block group allocation in a serialized way, since btrfs_chunk_alloc() takes the chunk mutex before calling check_system_chunk() and btrfs_alloc_chunk(). However before everyone enters the final phase of the block group allocation, that is, before calling btrfs_create_pending_block_groups(), new tasks keep coming to allocate new block groups and while at check_system_chunk(), the system space_info's 'bytes_may_use' keeps increasing each time a task reserves space in the chunk block reserve. This means that eventually some other task can end up not seeing enough free space in the system space_info and decide to allocate yet another system chunk. This may repeat several times if yet more new tasks keep allocating new block groups before task A, and all the other tasks, finish the creation of the pending block groups, which is when reserved space in excess is released. Eventually this can result in exhaustion of system chunk array in the superblock, with btrfs_add_system_chunk() returning EFBIG, resulting later in a transaction abort. Even when we don't reach the extreme case of exhausting the system array, most, if not all, unnecessarily created system block groups end up being unused since when finishing creation of the first pending system block group, the creation of the following ones end up not needing to COW nodes/leaves of the chunk tree, so we never allocate and deallocate from them, resulting in them never being added to the list of unused block groups - as a consequence they don't get deleted by the cleaner kthread - the only exceptions are if we unmount and mount the filesystem again, which adds any unused block groups to the list of unused block groups, if a scrub is run, which also adds unused block groups to the unused list, and under some circumstances when using a zoned filesystem or async discard, which may also add unused block groups to the unused list. So fix this by: *) Tracking the number of reserved bytes for the chunk tree per transaction, which is the sum of reserved chunk bytes by each transaction handle currently being used; *) When there is not enough free space in the system space_info, if there are other transaction handles which reserved chunk space, wait for some of them to complete in order to have enough excess reserved space released, and then try again. Otherwise proceed with the creation of a new system chunk. Signed-off-by:
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