kernel.git/include/trace/events/btrfs.h, branch linux-5.4.y

btrfs: correct the order of prelim_ref arguments in btrfs__prelim_ref

2025-06-04T12:32:35Z

[ Upstream commit bc7e0975093567f51be8e1bdf4aa5900a3cf0b1e ] btrfs_prelim_ref() calls the old and new reference variables in the incorrect order. This causes a NULL pointer dereference because oldref is passed as NULL to trace_btrfs_prelim_ref_insert(). Note, trace_btrfs_prelim_ref_insert() is being called with newref as oldref (and oldref as NULL) on purpose in order to print out the values of newref. To reproduce: echo 1 > /sys/kernel/debug/tracing/events/btrfs/btrfs_prelim_ref_insert/enable Perform some writeback operations. Backtrace: BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 115949067 P4D 115949067 PUD 11594a067 PMD 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 1 UID: 0 PID: 1188 Comm: fsstress Not tainted 6.15.0-rc2-tester+ #47 PREEMPT(voluntary) 7ca2cef72d5e9c600f0c7718adb6462de8149622 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-2-gc13ff2cd-prebuilt.qemu.org 04/01/2014 RIP: 0010:trace_event_raw_event_btrfs__prelim_ref+0x72/0x130 Code: e8 43 81 9f ff 48 85 c0 74 78 4d 85 e4 0f 84 8f 00 00 00 49 8b 94 24 c0 06 00 00 48 8b 0a 48 89 48 08 48 8b 52 08 48 89 50 10 <49> 8b 55 18 48 89 50 18 49 8b 55 20 48 89 50 20 41 0f b6 55 28 88 RSP: 0018:ffffce44820077a0 EFLAGS: 00010286 RAX: ffff8c6b403f9014 RBX: ffff8c6b55825730 RCX: 304994edf9cf506b RDX: d8b11eb7f0fdb699 RSI: ffff8c6b403f9010 RDI: ffff8c6b403f9010 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000010 R10: 00000000ffffffff R11: 0000000000000000 R12: ffff8c6b4e8fb000 R13: 0000000000000000 R14: ffffce44820077a8 R15: ffff8c6b4abd1540 FS: 00007f4dc6813740(0000) GS:ffff8c6c1d378000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000018 CR3: 000000010eb42000 CR4: 0000000000750ef0 PKRU: 55555554 Call Trace: prelim_ref_insert+0x1c1/0x270 find_parent_nodes+0x12a6/0x1ee0 ? __entry_text_end+0x101f06/0x101f09 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 btrfs_is_data_extent_shared+0x167/0x640 ? fiemap_process_hole+0xd0/0x2c0 extent_fiemap+0xa5c/0xbc0 ? __entry_text_end+0x101f05/0x101f09 btrfs_fiemap+0x7e/0xd0 do_vfs_ioctl+0x425/0x9d0 __x64_sys_ioctl+0x75/0xc0 Signed-off-by: Goldwyn Rodrigues Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: tracepoints: output proper root owner for trace_find_free_extent()

2020-11-18T18:20:16Z

The current trace event always output result like this: find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=4(METADATA) find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=4(METADATA) find_free_extent: root=2(EXTENT_TREE) len=8192 empty_size=0 flags=1(DATA) find_free_extent: root=2(EXTENT_TREE) len=8192 empty_size=0 flags=1(DATA) find_free_extent: root=2(EXTENT_TREE) len=4096 empty_size=0 flags=1(DATA) find_free_extent: root=2(EXTENT_TREE) len=4096 empty_size=0 flags=1(DATA) T's saying we're allocating data extent for EXTENT tree, which is not even possible. It's because we always use EXTENT tree as the owner for trace_find_free_extent() without using the @root from btrfs_reserve_extent(). This patch will change the parameter to use proper @root for trace_find_free_extent(): Now it looks much better: find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP) find_free_extent: root=5(FS_TREE) len=8192 empty_size=0 flags=1(DATA) find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=1(DATA) find_free_extent: root=5(FS_TREE) len=4096 empty_size=0 flags=1(DATA) find_free_extent: root=5(FS_TREE) len=8192 empty_size=0 flags=1(DATA) find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP) find_free_extent: root=7(CSUM_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP) find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP) find_free_extent: root=1(ROOT_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP) Reported-by: Hans van Kranenburg CC: stable@vger.kernel.org # 5.4+ Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: tracepoints: Fix bad entry members of qgroup events

2019-10-17T12:09:37Z

[BUG] For btrfs:qgroup_meta_reserve event, the trace event can output garbage: qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE) type=DATA diff=2 qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE) type=0x258792 diff=2 The @type can be completely garbage, as DATA type is not possible for trace_qgroup_meta_reserve() trace event. [CAUSE] Ther are several problems related to qgroup trace events: - Unassigned entry member Member entry::type of trace_qgroup_update_reserve() and trace_qgourp_meta_reserve() is not assigned - Redundant entry member Member entry::type is completely useless in trace_qgroup_meta_convert() Fixes: 4ee0d8832c2e ("btrfs: qgroup: Update trace events for metadata reservation") CC: stable@vger.kernel.org # 4.10+ Reviewed-by: Nikolay Borisov Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: add a flush step for delayed iputs

2019-09-09T12:59:10Z

Delayed iputs could very well free up enough space without needing to commit the transaction, so make this step it's own step. This will allow us to skip the step for evictions in a later patch. Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: Remove unused locking functions

2019-09-09T12:58:59Z

Those were split out of btrfs_clear_lock_blocking_rw by aa12c02778a9 ("btrfs: split btrfs_clear_lock_blocking_rw to read and write helpers") however at that time this function was unused due to commit 523983401644 ("Btrfs: kill btrfs_clear_path_blocking"). Put the final nail in the coffin of those 2 functions. Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: extent-tree: Add trace events for space info numbers update

2019-07-01T11:34:58Z

Add trace event for update_bytes_pinned() and update_bytes_may_use() to detect underflow better. The output would be something like (only showing data part): ## Buffered write start, 16K total ## 2255.954 xfs_io/860 btrfs:update_bytes_may_use:(nil)U: type=DATA old=0 diff=4096 2257.169 sudo/860 btrfs:update_bytes_may_use:(nil)U: type=DATA old=4096 diff=4096 2257.346 sudo/860 btrfs:update_bytes_may_use:(nil)U: type=DATA old=8192 diff=4096 2257.542 sudo/860 btrfs:update_bytes_may_use:(nil)U: type=DATA old=12288 diff=4096 ## Delalloc start ## 3727.853 kworker/u8:3-e/700 btrfs:update_bytes_may_use:(nil)U: type=DATA old=16384 diff=-16384 ## Space cache update ## 3733.132 sudo/862 btrfs:update_bytes_may_use:(nil)U: type=DATA old=0 diff=65536 3733.169 sudo/862 btrfs:update_bytes_may_use:(nil)U: type=DATA old=65536 diff=-65536 3739.868 sudo/862 btrfs:update_bytes_may_use:(nil)U: type=DATA old=0 diff=65536 3739.891 sudo/862 btrfs:update_bytes_may_use:(nil)U: type=DATA old=65536 diff=-65536 These two trace events will allow bcc tool to probe btrfs_space_info changes and detect underflow with more details (e.g. backtrace for each update). Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

Merge tag 'for-5.2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2019-05-07T18:34:19Z

Pull btrfs updates from David Sterba: "This time the majority of changes are cleanups, though there's still a number of changes of user interest. User visible changes: - better read time and write checks to catch errors early and before writing data to disk (to catch potential memory corruption on data that get checksummed) - qgroups + metadata relocation: last speed up patch int the series to address the slowness, there should be no overhead comparing balance with and without qgroups - FIEMAP ioctl does not start a transaction unnecessarily, this can result in a speed up and less blocking due to IO - LOGICAL_INO (v1, v2) does not start transaction unnecessarily, this can speed up the mentioned ioctl and scrub as well - fsync on files with many (but not too many) hardlinks is faster, finer decision if the links should be fsynced individually or completely - send tries harder to find ranges to clone - trim/discard will skip unallocated chunks that haven't been touched since the last mount Fixes: - send flushes delayed allocation before start, otherwise it could miss some changes in case of a very recent rw->ro switch of a subvolume - fix fallocate with qgroups that could lead to space accounting underflow, reported as a warning - trim/discard ioctl honours the requested range - starting send and dedupe on a subvolume at the same time will let only one of them succeed, this is to prevent changes that send could miss due to dedupe; both operations are restartable Core changes: - more tree-checker validations, errors reported by fuzzing tools: - device item - inode item - block group profiles - tracepoints for extent buffer locking - async cow preallocates memory to avoid errors happening too deep in the call chain - metadata reservations for delalloc reworked to better adapt in many-writers/low-space scenarios - improved space flushing logic for intense DIO vs buffered workloads - lots of cleanups - removed unused struct members - redundant argument removal - properties and xattrs - extent buffer locking - selftests - use common file type conversions - many-argument functions reduction" * tag 'for-5.2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (227 commits) btrfs: Use kvmalloc for allocating compressed path context btrfs: Factor out common extent locking code in submit_compressed_extents btrfs: Set io_tree only once in submit_compressed_extents btrfs: Replace clear_extent_bit with unlock_extent btrfs: Make compress_file_range take only struct async_chunk btrfs: Remove fs_info from struct async_chunk btrfs: Rename async_cow to async_chunk btrfs: Preallocate chunks in cow_file_range_async btrfs: reserve delalloc metadata differently btrfs: track DIO bytes in flight btrfs: merge calls of btrfs_setxattr and btrfs_setxattr_trans in btrfs_set_prop btrfs: delete unused function btrfs_set_prop_trans btrfs: start transaction in xattr_handler_set_prop btrfs: drop local copy of inode i_mode btrfs: drop old_fsflags in btrfs_ioctl_setflags btrfs: modify local copy of btrfs_inode flags btrfs: drop useless inode i_flags copy and restore btrfs: start transaction in btrfs_ioctl_setflags() btrfs: export btrfs_set_prop btrfs: refactor btrfs_set_props to validate externally ...

btrfs: trace: Introduce trace events for all btrfs tree locking events

2019-04-29T17:02:43Z

Unlike btrfs_tree_lock() and btrfs_tree_read_lock(), the remaining functions in locking.c will not sleep, thus doesn't make much sense to record their execution time. Those events are introduced mainly for user space tool to audit and detect lock leakage or dead lock. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: trace: Introduce trace events for sleepable tree lock

2019-04-29T17:02:43Z

There are two tree lock events which can sleep: - btrfs_tree_read_lock() - btrfs_tree_lock() Sometimes we may need to look into the concurrency picture of the fs. For that case, we need the execution time of above two functions and the owner of @eb. Here we introduce a trace events for user space tools like bcc, to get the execution time of above two functions, and get detailed owner info where eBPF code can't. All the overhead is hidden behind the trace events, so if events are not enabled, there is no overhead. These trace events also output bytenr and generation, allow them to be pared with unlock events to pin down deadlock. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: Remove EXTENT_WRITEBACK

2019-04-29T17:02:20Z

This flag was introduced in a52d9a8033c4 ("Btrfs: Extent based page cache code.") and subsequently it's usage effectively was removed by 1edbb734b4e0 ("Btrfs: reduce CPU usage in the extent_state tree") and f2a97a9dbd86 ("btrfs: remove all unused functions"). Just remove it, no functional changes. Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba