- 19 Apr, 2021 37 commits
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Filipe Manana authored
btrfs_orphan_cleanup() has a comment referring to find_dead_roots, but function does not exists since commit cb517eab ("Btrfs: cleanup the similar code of the fs root read"). What we use now to find and load dead roots is btrfs_find_orphan_roots(). So update the comment and make it a bit more detailed about why we can not delete an orphan item for a root. Signed-off-by:
Filipe Manana <fdmanana@suse.com> Signed-off-by:
David Sterba <dsterba@suse.com>
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Filipe Manana authored
We used to encode two different numbers in the tree mod log counter used for sequence numbers, one in the upper 32 bits and the other one in the lower 32 bits. However that is no longer the case, we stopped doing that since commit fcebe456 ("Btrfs: rework qgroup accounting"). So update the debug message at btrfs_check_delayed_seq to stop extracting the two 32 bits counters and print instead the 64 bits sequence numbers. Signed-off-by:
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Filipe Manana authored
There are two places outside the tree mod log module that extract the lowest sequence number of the tree mod log. These places end up duplicating code and open coding the logic and internal implementation details of the tree mod log. So add a helper to the tree mod log module and header that returns the lowest sequence number or 0 if there aren't any tree mod log users at the moment. Signed-off-by:
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Filipe Manana authored
At btrfs_tree_mod_log_free_eb() we check if we are dealing with a leaf, and if so, return immediately and do nothing. However this check can be removed, because after it we call tree_mod_need_log(), which returns false when given an extent buffer that corresponds to a leaf. So just remove the leaf check and pass the extent buffer to tree_mod_need_log(). Signed-off-by:
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Filipe Manana authored
Instead of exposing implementation details of the tree mod log to check if there are active tree mod log users at btrfs_free_tree_block(), use the new bit BTRFS_FS_TREE_MOD_LOG_USERS for fs_info->flags instead. This way extent-tree.c does not need to known about any of the internals of the tree mod log and avoids taking a lock unnecessarily as well. Signed-off-by:
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Filipe Manana authored
The tree modification log functions are called very frequently, basically they are called every time a btree is modified (a pointer added or removed to a node, a new root for a btree is set, etc). Because of that, to avoid heavy lock contention on the lock that protects the list of tree mod log users, we have checks that test the emptiness of the list with a full memory barrier before the checks, so that when there are no tree mod log users we avoid taking the lock. Replace the memory barrier and list emptiness check with a test for a new bit set at fs_info->flags. This bit is used to indicate when there are tree mod log users, set whenever a user is added to the list and cleared when the last user is removed from the list. This makes the intention a bit more obvious and possibly more efficient (assuming test_bit() may be cheaper than a full memory barrier on some architectures). Signed-off-by:
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Filipe Manana authored
Several functions of the tree modification log use integers as booleans, so change them to use booleans instead, making their use more clear. Reviewed-by:
Anand Jain <anand.jain@oracle.com> Signed-off-by:
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Filipe Manana authored
The tree modification log, which records modifications done to btrees, is quite large and currently spread all over ctree.c, which is a huge file already. To make things better organized, move all that code into its own separate source and header files. Functions and definitions that are used outside of the module (mostly by ctree.c) are renamed so that they start with a "btrfs_" prefix. Everything else remains unchanged. This makes it easier to go over the tree modification log code every time I need to go read it to fix a bug. Reviewed-by:
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Ira Weiny authored
btrfsic_read_block() (which calls kmap()) and btrfsic_release_block_ctx() (which calls kunmap()) are always called within a single thread of execution. Therefore the mappings created within these calls can be a thread local mapping. Convert the kmap() of bloc_ctx->pagev to kmap_local_page(). Luckily the unmap loops backwards through the array pointer so no adjustment needs to be made to the unmapping order. Signed-off-by:
Ira Weiny <ira.weiny@intel.com> Reviewed-by:
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Ira Weiny authored
Again there is an array of pointers which must be unmapped in the correct order. Convert the kmap()'s to kmap_local_page() and adjust the unmapping to work backwards through the unmapping loop. Signed-off-by:
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Ira Weiny authored
These kmaps are thread local and don't need to be atomic. So they can use the more efficient kmap_local_page(). However, the mapping of pages in the stripes and the additional parity and qstripe pages are a bit trickier because the unmapping must occur in the opposite order from the mapping. Furthermore, the pointer array in __raid_recover_end_io() may get reordered. Convert these calls to kmap_local_page() taking care to reverse the unmappings of any page arrays as well as being careful with the mappings of any special pages such as the parity and qstripe pages. Signed-off-by:
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Ira Weiny authored
Use a simple coccinelle script to help convert the most common kmap()/kunmap() patterns to kmap_local_page()/kunmap_local(). Note that some kmaps which were caught by this script needed to be handled by hand because of the strict unmapping order of kunmap_local() so they are not included in this patch. But this script got us started. There's another temp variable added for the final length write to the first page so it does not interfere with cpage_out that is used for mapping other pages. The development of this patch was aided by the follow script: // <smpl> // SPDX-License-Identifier: GPL-2.0-only // Find kmap and replace with kmap_local_page then mark kunmap // // Confidence: Low // Copyright: (C) 2021 Intel Corporation // URL: http://coccinelle.lip6.fr/ @ catch_all @ expression e, e2; @@ ( -kmap(e) +kmap_local_page(e) ) ... ( -kunmap(...) +kunmap_local() ) // </smpl> Signed-off-by:
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Johannes Thumshirn authored
The in_range() macro is defined twice in btrfs' source, once in ctree.h and once in misc.h. Remove the definition in ctree.h and include misc.h in the files depending on it. Signed-off-by:
Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by:
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Filipe Manana authored
Currently btrfs_inode_in_log() checks the list of modified extents of the inode, and has a comment mentioning why, as it used to be necessary to make sure if we did something like the following: mmap write range A mmap write range B msync range A (ranged fsync) msync range B (ranged fsync) we ended up with both ranges being logged. If we did not check it, then the second fsync would do nothing because btrfs_inode_in_log() would return true. This was added in 125c4cf9 ("Btrfs: set inode's logged_trans/last_log_commit after ranged fsync") and test case generic/325 from fstests exercises that scenario. However, as of commit 48778179 ("btrfs: make fast fsyncs wait only for writeback"), every ranged fsync is now turned into a full ranged fsync (operates on the range from 0 to LLONG_MAX), so it is now pointless to test of emptiness of the list of modified extents, and the comment is clearly outdated. So just remove the comment and list emptiness check, while also changing the function's return type to be a boolean instead of an integer. In case one day we get support for ranged fsyncs again, it will be easy to notice the check is necessary again, because it will make generic/325 always fail. Signed-off-by:
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Filipe Manana authored
We have a race between marking that an inode needs to be logged, either at btrfs_set_inode_last_trans() or at btrfs_page_mkwrite(), and between btrfs_sync_log(). The following steps describe how the race happens. 1) We are at transaction N; 2) Inode I was previously fsynced in the current transaction so it has: inode->logged_trans set to N; 3) The inode's root currently has: root->log_transid set to 1 root->last_log_commit set to 0 Which means only one log transaction was committed to far, log transaction 0. When a log tree is created we set ->log_transid and ->last_log_commit of its parent root to 0 (at btrfs_add_log_tree()); 4) One more range of pages is dirtied in inode I; 5) Some task A starts an fsync against some other inode J (same root), and so it joins log transaction 1. Before task A calls btrfs_sync_log()... 6) Task B starts an fsync against inode I, which currently has the full sync flag set, so it starts delalloc and waits for the ordered extent to complete before calling btrfs_inode_in_log() at btrfs_sync_file(); 7) During ordered extent completion we have btrfs_update_inode() called against inode I, which in turn calls btrfs_set_inode_last_trans(), which does the following: spin_lock(&inode->lock); inode->last_trans = trans->transaction->transid; inode->last_sub_trans = inode->root->log_transid; inode->last_log_commit = inode->root->last_log_commit; spin_unlock(&inode->lock); So ->last_trans is set to N and ->last_sub_trans set to 1. But before setting ->last_log_commit... 8) Task A is at btrfs_sync_log(): - it increments root->log_transid to 2 - starts writeback for all log tree extent buffers - waits for the writeback to complete - writes the super blocks - updates root->last_log_commit to 1 It's a lot of slow steps between updating root->log_transid and root->last_log_commit; 9) The task doing the ordered extent completion, currently at btrfs_set_inode_last_trans(), then finally runs: inode->last_log_commit = inode->root->last_log_commit; spin_unlock(&inode->lock); Which results in inode->last_log_commit being set to 1. The ordered extent completes; 10) Task B is resumed, and it calls btrfs_inode_in_log() which returns true because we have all the following conditions met: inode->logged_trans == N which matches fs_info->generation && inode->last_subtrans (1) <= inode->last_log_commit (1) && inode->last_subtrans (1) <= root->last_log_commit (1) && list inode->extent_tree.modified_extents is empty And as a consequence we return without logging the inode, so the existing logged version of the inode does not point to the extent that was written after the previous fsync. It should be impossible in practice for one task be able to do so much progress in btrfs_sync_log() while another task is at btrfs_set_inode_last_trans() right after it reads root->log_transid and before it reads root->last_log_commit. Even if kernel preemption is enabled we know the task at btrfs_set_inode_last_trans() can not be preempted because it is holding the inode's spinlock. However there is another place where we do the same without holding the spinlock, which is in the memory mapped write path at: vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf) { (...) BTRFS_I(inode)->last_trans = fs_info->generation; BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid; BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit; (...) So with preemption happening after setting ->last_sub_trans and before setting ->last_log_commit, it is less of a stretch to have another task do enough progress at btrfs_sync_log() such that the task doing the memory mapped write ends up with ->last_sub_trans and ->last_log_commit set to the same value. It is still a big stretch to get there, as the task doing btrfs_sync_log() has to start writeback, wait for its completion and write the super blocks. So fix this in two different ways: 1) For btrfs_set_inode_last_trans(), simply set ->last_log_commit to the value of ->last_sub_trans minus 1; 2) For btrfs_page_mkwrite() only set the inode's ->last_sub_trans, just like we do for buffered and direct writes at btrfs_file_write_iter(), which is all we need to make sure multiple writes and fsyncs to an inode in the same transaction never result in an fsync missing that the inode changed and needs to be logged. Turn this into a helper function and use it both at btrfs_page_mkwrite() and at btrfs_file_write_iter() - this also fixes the problem that at btrfs_page_mkwrite() we were setting those fields without the protection of the inode's spinlock. This is an extremely unlikely race to happen in practice. Signed-off-by: -
Filipe Manana authored
When doing an fsync we flush all delalloc, lock the inode (VFS lock), flush any new delalloc that might have been created before taking the lock and then wait either for the ordered extents to complete or just for the writeback to complete (depending on whether the full sync flag is set or not). We then start logging the inode and assume that while we are doing it no one else is touching the inode's file extent items (or adding new ones). That is generally true because all operations that modify an inode acquire the inode's lock first, including buffered and direct IO writes. However there is one exception: memory mapped writes, which do not and can not acquire the inode's lock. This can cause two types of issues: ending up logging file extent items with overlapping ranges, which is detected by the tree checker and will result in aborting the transaction when starting writeback for a log tree's extent buffers, or a silent corruption where we log a version of the file that never existed. Scenario 1 - logging overlapping extents The following steps explain how we can end up with file extents items with overlapping ranges in a log tree due to a race between a fsync and memory mapped writes: 1) Task A starts an fsync on inode X, which has the full sync runtime flag set. First it starts by flushing all delalloc for the inode; 2) Task A then locks the inode and flushes any other delalloc that might have been created after the previous flush and waits for all ordered extents to complete; 3) In the inode's root we have the following leaf: Leaf N, generation == current transaction id: --------------------------------------------------------- | (...) [ file extent item, offset 640K, length 128K ] | --------------------------------------------------------- The last file extent item in leaf N covers the file range from 640K to 768K; 4) Task B does a memory mapped write for the page corresponding to the file range from 764K to 768K; 5) Task A starts logging the inode. At copy_inode_items_to_log() it uses btrfs_search_forward() to search for leafs modified in the current transaction that contain items for the inode. It finds leaf N and copies all the inode items from that leaf into the log tree. Now the log tree has a copy of the last file extent item from leaf N. At the end of the while loop at copy_inode_items_to_log(), we have the minimum key set to: min_key.objectid = <inode X number> min_key.type = BTRFS_EXTENT_DATA_KEY min_key.offset = 640K Then we increment the key's offset by 1 so that the next call to btrfs_search_forward() leaves us at the first key greater than the key we just processed. But before btrfs_search_forward() is called again... 6) Dellaloc for the page at offset 764K, dirtied by task B, is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) When the respective ordered extent completes, it trims the length of the existing file extent item for file offset 640K from 128K to 124K, and a new file extent item is added with a key offset of 764K and a length of 4K; 8) Task A calls btrfs_search_forward(), which returns us a path pointing to the leaf (can be leaf N or some other) containing the new file extent item for file offset 764K. We end up copying this item to the log tree, which overlaps with the last copied file extent item, which covers the file range from 640K to 768K. When writeback is triggered for log tree's extent buffers, the issue will be detected by the tree checker which will dump a trace and an error message on dmesg/syslog. If the writeback is triggered when syncing the log, which typically is, then we also end up aborting the current transaction. This is the same type of problem fixed in 0c713cba ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges"). Scenario 2 - logging a version of the file that never existed This scenario only happens when using the NO_HOLES feature and results in a silent corruption, in the sense that is not detectable by 'btrfs check' or the tree checker: 1) We have an inode I with a size of 1M and two file extent items, one covering an extent with disk_bytenr == X for the file range [0, 512K) and another one covering another extent with disk_bytenr == Y for the file range [512K, 1M); 2) A hole is punched for the file range [512K, 1M); 3) Task A starts an fsync of inode I, which has the full sync runtime flag set. It starts by flushing all existing delalloc, locks the inode (VFS lock), starts any new delalloc that might have been created before taking the lock and waits for all ordered extents to complete; 4) Some other task does a memory mapped write for the page corresponding to the file range [640K, 644K) for example; 5) Task A then logs all items of the inode with the call to copy_inode_items_to_log(); 6) In the meanwhile delalloc for the range [640K, 644K) is started. It can be started for several reasons: - The async reclaim task is attempting to satisfy metadata or data reservation requests, and it has reached a point where it decided to flush delalloc; - Due to memory pressure the VMM triggers writeback of dirty pages; - The system call sync_file_range(2) is called from user space. 7) The ordered extent for the range [640K, 644K) completes and a file extent item for that range is added to the subvolume tree, pointing to a 4K extent with a disk_bytenr == Z; 8) Task A then calls btrfs_log_holes(), to scan for implicit holes in the subvolume tree. It finds two implicit holes: - one for the file range [512K, 640K) - one for the file range [644K, 1M) As a result we end up neither logging a hole for the range [640K, 644K) nor logging the file extent item with a disk_bytenr == Z. This means that if we have a power failure and replay the log tree we end up getting the following file extent layout: [ disk_bytenr X ] [ hole ] [ disk_bytenr Y ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M Which does not corresponding to any layout the file ever had before the power failure. The only two valid layouts would be: [ disk_bytenr X ] [ hole ] 0 512K 512K 1M and [ disk_bytenr X ] [ hole ] [ disk_bytenr Z ] [ hole ] 0 512K 512K 640K 640K 644K 644K 1M This can be fixed by serializing memory mapped writes with fsync, and there are two ways to do it: 1) Make a fsync lock the entire file range, from 0 to (u64)-1 / LLONG_MAX in the inode's io tree. This prevents the race but also blocks any reads during the duration of the fsync, which has a negative impact for many common workloads; 2) Make an fsync write lock the i_mmap_lock semaphore in the inode. This semaphore was recently added by Josef's patch set: btrfs: add a i_mmap_lock to our inode btrfs: cleanup inode_lock/inode_unlock uses btrfs: exclude mmaps while doing remap btrfs: exclude mmap from happening during all fallocate operations and is used to solve races between memory mapped writes and clone/dedupe/fallocate. This also makes us have the same behaviour we have regarding other writes (buffered and direct IO) and fsync - block them while the inode logging is in progress. This change uses the second approach due to the performance impact of the first one. Signed-off-by: -
Josef Bacik authored
There's a small window where a deadlock can happen between fallocate and mmap. This is described in detail by Filipe: """ When doing a fallocate operation we lock the inode, flush delalloc within the target range, wait for any ordered extents to complete and then lock the file range. Before we lock the range and after we flush delalloc, there is a time window where another task can come in and do a memory mapped write for a page within the fallocate range. This means that after fallocate locks the range, there can be a dirty page in the range. More often than not, this does not cause any problem. The exception is when we are low on available metadata space, because an fallocate operation needs to start a transaction while holding the file range locked, either through btrfs_prealloc_file_range() or through the call to btrfs_fallocate_update_isize(). If that's the case, we can end up in a deadlock. The following list of steps explains how that happens: 1) A fallocate operation starts, locks the inode, flushes delalloc in the range and waits for ordered extents in the range to complete; 2) Before the fallocate task locks the file range, another task does a memory mapped write for a page in the fallocate target range. This is possible since memory mapped writes do not (and can not) lock the inode; 3) The fallocate task locks the file range. At this point there is one dirty page in the range (due to the memory mapped write); 4) When the fallocate task attempts to start a transaction, it blocks when attempting to reserve metadata space, since we are low on available metadata space. Before blocking (wait on its reservation ticket), it starts the async reclaim task (if not running already); 5) The async reclaim task is not able to release space through any other means, so it decides to flush delalloc for inodes with dirty pages. It finds that the inode used in the fallocate operation has a dirty page and therefore queues a job (fs_info->flush_workers workqueue) to flush delalloc for that inode and waits on that job to complete; 6) The flush job blocks when attempting to lock the file range because it is currently locked by the fallocate task; 7) The fallocate task keeps waiting for its metadata reservation, waiting for a wakeup on its reservation ticket. The async reclaim task is waiting on the flush job, which in turn is waiting for locking the file range that is currently locked by the fallocate task. So unless some other task is able to release enough metadata space, for example an ordered extent for some other inode completes, we end up in a deadlock between all these tasks. When this happens stack traces like the following show up in dmesg/syslog: INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000 Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] Call Trace: __schedule+0x5d1/0xcf0 schedule+0x45/0xe0 lock_extent_bits+0x1e6/0x2d0 [btrfs] ? finish_wait+0x90/0x90 btrfs_invalidatepage+0x32c/0x390 [btrfs] ? __mod_memcg_state+0x8e/0x160 __extent_writepage+0x2d4/0x400 [btrfs] extent_write_cache_pages+0x2b2/0x500 [btrfs] ? lock_release+0x20e/0x4c0 ? trace_hardirqs_on+0x1b/0xf0 extent_writepages+0x43/0x90 [btrfs] ? lock_acquire+0x1a3/0x490 do_writepages+0x43/0xe0 ? __filemap_fdatawrite_range+0xa4/0x100 __filemap_fdatawrite_range+0xc5/0x100 btrfs_run_delalloc_work+0x17/0x40 [btrfs] btrfs_work_helper+0xf1/0x600 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x50/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000 Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] Call Trace: __schedule+0x5d1/0xcf0 ? kvm_clock_read+0x14/0x30 ? wait_for_completion+0x81/0x110 schedule+0x45/0xe0 schedule_timeout+0x30c/0x580 ? _raw_spin_unlock_irqrestore+0x3c/0x60 ? lock_acquire+0x1a3/0x490 ? try_to_wake_up+0x7a/0xa20 ? lock_release+0x20e/0x4c0 ? lock_acquired+0x199/0x490 ? wait_for_completion+0x81/0x110 wait_for_completion+0xab/0x110 start_delalloc_inodes+0x2af/0x390 [btrfs] btrfs_start_delalloc_roots+0x12d/0x250 [btrfs] flush_space+0x24f/0x660 [btrfs] btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x20f/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 (...) several tasks waiting for the inode lock held by the fallocate task below (...) RIP: 0033:0x7f61efe73fff Code: Unable to access opcode bytes at RIP 0x7f61efe73fd5. RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000202 ORIG_RAX: 000000000000013c RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73fff RDX: 00000000ffffff9c RSI: 0000560fbd5d90a0 RDI: 00000000ffffff9c RBP: 00007ffc3371beb0 R08: 0000000000000001 R09: 0000000000000003 R10: 0000560fbd5d7ad0 R11: 0000000000000202 R12: 0000000000000001 R13: 000000000000005e R14: 00007ffc3371bea0 R15: 00007ffc3371beb0 task:fdm-stress state:D stack: 0 pid:2508243 ppid:2508153 flags:0x00000000 Call Trace: __schedule+0x5d1/0xcf0 ? _raw_spin_unlock_irqrestore+0x3c/0x60 schedule+0x45/0xe0 __reserve_bytes+0x4a4/0xb10 [btrfs] ? finish_wait+0x90/0x90 btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs] btrfs_block_rsv_add+0x1f/0x50 [btrfs] start_transaction+0x2d1/0x760 [btrfs] btrfs_replace_file_extents+0x120/0x930 [btrfs] ? btrfs_fallocate+0xdcf/0x1260 [btrfs] btrfs_fallocate+0xdfb/0x1260 [btrfs] ? filename_lookup+0xf1/0x180 vfs_fallocate+0x14f/0x440 ioctl_preallocate+0x92/0xc0 do_vfs_ioctl+0x66b/0x750 ? __do_sys_newfstat+0x53/0x60 __x64_sys_ioctl+0x62/0xb0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 """ Fix this by disallowing mmaps from happening while we're doing any of the fallocate operations on this inode. Reviewed-by:Josef Bacik <josef@toxicpanda.com> Signed-off-by:
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Josef Bacik authored
Darrick reported a potential issue to me where we could allow mmap writes after validating a page range matched in the case of dedupe. Generally we rely on lock page -> lock extent with the ordered flush to protect us, but this is done after we check the pages because we use the generic helpers, so we could modify the page in between doing the check and locking the range. There also exists a deadlock, as described by Filipe """ When cloning a file range, we lock the inodes, flush any delalloc within the respective file ranges, wait for any ordered extents and then lock the file ranges in both inodes. This means that right after we flush delalloc and before we lock the file ranges, memory mapped writes can come in and dirty pages in the file ranges of the clone operation. Most of the time this is harmless and causes no problems. However, if we are low on available metadata space, we can later end up in a deadlock when starting a transaction to replace file extent items. This happens if when allocating metadata space for the transaction, we need to wait for the async reclaim thread to release space and the reclaim thread needs to flush delalloc for the inode that got the memory mapped write and has its range locked by the clone task. Basically what happens is the following: 1) A clone operation locks inodes A and B, flushes delalloc for both inodes in the respective file ranges and waits for any ordered extents in those ranges to complete; 2) Before the clone task locks the file ranges, another task does a memory mapped write (which does not lock the inode) for one of the inodes of the clone operation. So now we have a dirty page in one of the ranges used by the clone operation; 3) The clone operation locks the file ranges for inodes A and B; 4) Later, when iterating over the file extents of inode A, the clone task attempts to start a transaction. There's not enough available free metadata space, so the async reclaim task is started (if not running already) and we wait for someone to wake us up on our reservation ticket; 5) The async reclaim task is not able to release space by any other means and decides to flush delalloc for the inode of the clone operation; 6) The workqueue job used to flush the inode blocks when starting delalloc for the inode, since the file range is currently locked by the clone task; 7) But the clone task is waiting on its reservation ticket and the async reclaim task is waiting on the flush job to complete, which can't progress since the clone task has the file range locked. So unless some other task is able to release space, for example an ordered extent for some other inode completes, we have a deadlock between all these tasks; When this happens stack traces like the following show up in dmesg/syslog: INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000 Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] Call Trace: __schedule+0x5d1/0xcf0 schedule+0x45/0xe0 lock_extent_bits+0x1e6/0x2d0 [btrfs] ? finish_wait+0x90/0x90 btrfs_invalidatepage+0x32c/0x390 [btrfs] ? __mod_memcg_state+0x8e/0x160 __extent_writepage+0x2d4/0x400 [btrfs] extent_write_cache_pages+0x2b2/0x500 [btrfs] ? lock_release+0x20e/0x4c0 ? trace_hardirqs_on+0x1b/0xf0 extent_writepages+0x43/0x90 [btrfs] ? lock_acquire+0x1a3/0x490 do_writepages+0x43/0xe0 ? __filemap_fdatawrite_range+0xa4/0x100 __filemap_fdatawrite_range+0xc5/0x100 btrfs_run_delalloc_work+0x17/0x40 [btrfs] btrfs_work_helper+0xf1/0x600 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x50/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds. Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000 Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] Call Trace: __schedule+0x5d1/0xcf0 ? kvm_clock_read+0x14/0x30 ? wait_for_completion+0x81/0x110 schedule+0x45/0xe0 schedule_timeout+0x30c/0x580 ? _raw_spin_unlock_irqrestore+0x3c/0x60 ? lock_acquire+0x1a3/0x490 ? try_to_wake_up+0x7a/0xa20 ? lock_release+0x20e/0x4c0 ? lock_acquired+0x199/0x490 ? wait_for_completion+0x81/0x110 wait_for_completion+0xab/0x110 start_delalloc_inodes+0x2af/0x390 [btrfs] btrfs_start_delalloc_roots+0x12d/0x250 [btrfs] flush_space+0x24f/0x660 [btrfs] btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs] process_one_work+0x24e/0x5e0 worker_thread+0x20f/0x3b0 ? process_one_work+0x5e0/0x5e0 kthread+0x153/0x170 ? kthread_mod_delayed_work+0xc0/0xc0 ret_from_fork+0x22/0x30 (...) several other tasks blocked on inode locks held by the clone task below (...) RIP: 0033:0x7f61efe73fff Code: Unable to access opcode bytes at RIP 0x7f61efe73fd5. RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000202 ORIG_RAX: 000000000000013c RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73fff RDX: 00000000ffffff9c RSI: 0000560fbd604690 RDI: 00000000ffffff9c RBP: 00007ffc3371beb0 R08: 0000000000000002 R09: 0000560fbd5d75f0 R10: 0000560fbd5d81f0 R11: 0000000000000202 R12: 0000000000000002 R13: 000000000000000b R14: 00007ffc3371bea0 R15: 00007ffc3371beb0 task: fdm-stress state:D stack: 0 pid:2508234 ppid:2508153 flags:0x00004000 Call Trace: __schedule+0x5d1/0xcf0 ? _raw_spin_unlock_irqrestore+0x3c/0x60 schedule+0x45/0xe0 __reserve_bytes+0x4a4/0xb10 [btrfs] ? finish_wait+0x90/0x90 btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs] btrfs_block_rsv_add+0x1f/0x50 [btrfs] start_transaction+0x2d1/0x760 [btrfs] btrfs_replace_file_extents+0x120/0x930 [btrfs] ? lock_release+0x20e/0x4c0 btrfs_clone+0x3e4/0x7e0 [btrfs] ? btrfs_lookup_first_ordered_extent+0x8e/0x100 [btrfs] btrfs_clone_files+0xf6/0x150 [btrfs] btrfs_remap_file_range+0x324/0x3d0 [btrfs] do_clone_file_range+0xd4/0x1f0 vfs_clone_file_range+0x4d/0x230 ? lock_release+0x20e/0x4c0 ioctl_file_clone+0x8f/0xc0 do_vfs_ioctl+0x342/0x750 __x64_sys_ioctl+0x62/0xb0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 """ Fix both of these issues by excluding mmaps from happening we are doing any sort of remap, which prevents this race completely. 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Josef Bacik authored
A few places we intermix btrfs_inode_lock with a inode_unlock, and some places we just use inode_lock/inode_unlock instead of btrfs_inode_lock. None of these places are using this incorrectly, but as we adjust some of these callers it would be nice to keep everything consistent, so convert everybody to use btrfs_inode_lock/btrfs_inode_unlock. Reviewed-by:
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Josef Bacik authored
We need to be able to exclude page_mkwrite from happening concurrently with certain operations. To facilitate this, add a i_mmap_lock to our inode, down_read() it in our mkwrite, and add a new ILOCK flag to indicate that we want to take the i_mmap_lock as well. I used pahole to check the size of the btrfs_inode, the sizes are as follows no lockdep: before: 1120 (3 per 4k page) after: 1160 (3 per 4k page) lockdep: before: 2072 (1 per 4k page) after: 2224 (1 per 4k page) We're slightly larger but it doesn't change how many objects we can fit per page. Reviewed-by:
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Goldwyn Rodrigues authored
The parameter mirror is not used and does not make sense for checksum verification of the given bio. Signed-off-by:
Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by:
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Goldwyn Rodrigues authored
force_cow can be calculated from inode and does not need to be passed as an argument. This simplifies run_delalloc_nocow() call from btrfs_run_delalloc_range() A new function, should_nocow() checks if the range should be NOCOWed or not. The function returns true iff either BTRFS_INODE_NODATA or BTRFS_INODE_PREALLOC, but is not a defrag extent. Tested-by:
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Nikolay Borisov authored
Reviewed-by:
Nikolay Borisov <nborisov@suse.com> Reviewed-by:
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Jiapeng Chong authored
Fix the following coccicheck warnings: ./fs/btrfs/volumes.c:1462:10-11: WARNING: return of 0/1 in function 'dev_extent_hole_check_zoned' with return type bool. Reported-by:
Abaci Robot <abaci@linux.alibaba.com> Signed-off-by:
Jiapeng Chong <jiapeng.chong@linux.alibaba.com> Reviewed-by:
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Filipe Manana authored
Currently we do not do btree read ahead when doing an incremental send, however we know that we will read and process any node or leaf in the send root that has a generation greater than the generation of the parent root. So triggering read ahead for such nodes and leafs is beneficial for an incremental send. This change does that, triggers read ahead of any node or leaf in the send root that has a generation greater then the generation of the parent root. As for the parent root, no readahead is triggered because knowing in advance which nodes/leaves are going to be read is not so linear and there's often a large time window between visiting nodes or leaves of the parent root. So I opted to leave out the parent root, and triggering read ahead for its nodes/leaves seemed to have not made significant difference. 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 echo 3 > /proc/sys/vm/drop_caches blockdev --flushbufs $DEV &> /dev/null hdparm -F $DEV &> /dev/null mount $MOUNT_OPTIONS $DEV $MNT echo echo "Testing incremental send..." start=$(date +%s) btrfs send -p $MNT/snap1 $MNT/snap2 > /dev/null end=$(date +%s) echo echo "Incremental send took $((end - start)) seconds" umount $MNT Before this change, incremental send duration: with $initial_file_count == 200000: 51 seconds with $initial_file_count == 500000: 168 seconds After this change, incremental send duration: with $initial_file_count == 200000: 39 seconds (-26.7%) with $initial_file_count == 500000: 125 seconds (-29.4%) For $initial_file_count == 200000 there are 62600 nodes and leaves in the btree of the first snapshot, and 77759 nodes and leaves in the btree of the second snapshot. The root nodes were at level 2. While for $initial_file_count == 500000 there are 152476 nodes and leaves in the btree of the first snapshot, and 190511 nodes and leaves in the btree of the second snapshot. The root nodes were at level 2 as well. Signed-off-by: -
Filipe Manana authored
When doing a full send we know that we are going to be reading every node and leaf of the send root, so we benefit from enabling read ahead for the btree. This change enables read ahead for full send operations only, incremental sends will have read ahead enabled in a different way by a separate patch. 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 echo 3 > /proc/sys/vm/drop_caches blockdev --flushbufs $DEV &> /dev/null hdparm -F $DEV &> /dev/null mount $MOUNT_OPTIONS $DEV $MNT echo echo "Testing incremental send..." start=$(date +%s) btrfs send -p $MNT/snap1 $MNT/snap2 > /dev/null end=$(date +%s) echo echo "Incremental send took $((end - start)) seconds" umount $MNT Before this change, full send duration: with $initial_file_count == 200000: 165 seconds with $initial_file_count == 500000: 407 seconds After this change, full send duration: with $initial_file_count == 200000: 149 seconds (-10.2%) with $initial_file_count == 500000: 353 seconds (-14.2%) For $initial_file_count == 200000 there are 62600 nodes and leaves in the btree of the first snapshot, while for $initial_file_count == 500000 there are 152476 nodes and leaves. The roots were at level 2. Signed-off-by: -
Nikolay Borisov authored
btrfs_block_rsv_add can return only ENOSPC since it's called with NO_FLUSH modifier. This so simplify the logic in btrfs_delayed_inode_reserve_metadata to exploit this invariant. Signed-off-by:
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Nikolay Borisov authored
It's only used for tracepoint to obtain the inode number, but we already have the ino from btrfs_delayed_node::inode_id. Reviewed-by:
Qu Wenruo <wqu@suse.com> Signed-off-by:
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Nikolay Borisov authored
It's no longer expected to call this function with an open transaction so all the workarounds concerning this can be removed. In fact it'll constitute a bug to call this function with a transaction already held so WARN in this case. Reviewed-by:
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Anand Jain authored
Drop function declarations at the beginning of the file scrub.c. These functions are defined before they are used in the same file and don't need forward declaration. No functional changes. Reviewed-by:
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Anand Jain authored
btrfs_extent_readonly() checks if the block group is readonly, the bool return type should be used. Reviewed-by:
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Anand Jain authored
btrfs_extent_readonly() is used by can_nocow_extent() in inode.c. So move it from extent-tree.c to inode.c and declare it as static. Signed-off-by:
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Nikolay Borisov authored
btrfs_inc_block_group_ro wants to ensure that the current transaction is not running dirty block groups, if it is it waits and loops again. That logic is currently implemented using a goto label. Actually using a proper do {} while() construct doesn't hurt readability nor does it introduce excessive nesting and makes the relevant code stand out by being encompassed in the loop construct. No functional changes. Signed-off-by: -
Nikolay Borisov authored
No point in duplicating the functionality just use the generic helper that has the same semantics. Signed-off-by:
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Nikolay Borisov authored
Signed-off-by:
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Nikolay Borisov authored
Signed-off-by:
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Qu Wenruo authored
There is small error in comment about BTRFS_ORDERED_* flags, added in commit 3c198fe0 ("btrfs: rework the order of btrfs_ordered_extent::flags") but the fixup did not get merged in time. The 4 types are for ordered extent itself, not for direct io. Only 3 types support direct io, REGULAR/NOCOW/PREALLOC. Fix the comment to reflect that. Signed-off-by:
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- 18 Apr, 2021 3 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/soc/socLinus Torvalds authored
Pull ARM SoC fixes from Arnd Bergmann: "Another smaller set of fixes for three of the Arm platforms: TI OMAP: Fix swapped mmc device order also for omap3 that got changed with the recent PROBE_PREFER_ASYNCHRONOUS changes. While eventually the aliases should be board specific, all the mmc device instances are all there in the SoC, and we do probe them by default so that PM runtime can idle the devices if left enabled from the bootloader. Qualcomm Snapdragon: This bypasses the recently introduced interconnect handling in the GENI (serial engine) driver when running off ACPI, as this causes the GENI probe to fail and the Lenovo Yoga C630 to boot without keyboard and touchpad. Allwinner: One 32kHz clock fix for the beelink gs1, a CD polarity fix for the SoPine, some MAINTAINERS maintainance, and a clk / reset switch to our headers" * tag 'arm-fixes-5.12-3' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: arm64: dts: allwinner: h6: beelink-gs1: Remove ext. 32 kHz osc reference MAINTAINERS: Match on allwinner keyword MAINTAINERS: Add our new mailing-list arm64: dts: allwinner: Fix SD card CD GPIO for SOPine systems arm64: dts: allwinner: h6: Switch to macros for RSB clock/reset indices ARM: OMAP2+: Fix uninitialized sr_inst ARM: dts: Fix swapped mmc order for omap3 ARM: OMAP2+: Fix warning for omap_init_time_of() soc: qcom: geni: shield geni_icc_get() for ACPI boot -
git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds authored
Pull ARM fixes from Russell King: - Halve maximum number of CPUs if DEBUG_KMAP_LOCAL is enabled - Fix conversion for_each_membock() to for_each_mem_range() - Fix footbridge PCI mapping - Avoid uprobes hooking on thumb instructions * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 9071/1: uprobes: Don't hook on thumb instructions ARM: footbridge: fix PCI interrupt mapping ARM: 9069/1: NOMMU: Fix conversion for_each_membock() to for_each_mem_range() ARM: 9063/1: mm: reduce maximum number of CPUs if DEBUG_KMAP_LOCAL is enabled
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