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path: root/fs/btrfs/inode.c
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2020-03-13btrfs: fix log context list corruption after rename whiteout errorFilipe Manana
During a rename whiteout, if btrfs_whiteout_for_rename() returns an error we can end up returning from btrfs_rename() with the log context object still in the root's log context list - this happens if 'sync_log' was set to true before we called btrfs_whiteout_for_rename() and it is dangerous because we end up with a corrupt linked list (root->log_ctxs) as the log context object was allocated on the stack. After btrfs_rename() returns, any task that is running btrfs_sync_log() concurrently can end up crashing because that linked list is traversed by btrfs_sync_log() (through btrfs_remove_all_log_ctxs()). That results in the same issue that commit e6c617102c7e4 ("Btrfs: fix log context list corruption after rename exchange operation") fixed. Fixes: d4682ba03ef618 ("Btrfs: sync log after logging new name") CC: stable@vger.kernel.org # 4.19+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-03btrfs: fix RAID direct I/O reads with alternate csumsOmar Sandoval
btrfs_lookup_and_bind_dio_csum() does pointer arithmetic which assumes 32-bit checksums. If using a larger checksum, this leads to spurious failures when a direct I/O read crosses a stripe. This is easy to reproduce: # mkfs.btrfs -f --checksum blake2 -d raid0 /dev/vdc /dev/vdd ... # mount /dev/vdc /mnt # cd /mnt # dd if=/dev/urandom of=foo bs=1M count=1 status=none # dd if=foo of=/dev/null bs=1M iflag=direct status=none dd: error reading 'foo': Input/output error # dmesg | tail -1 [ 135.821568] BTRFS warning (device vdc): csum failed root 5 ino 257 off 421888 ... Fix it by using the actual checksum size. Fixes: 1e25a2e3ca0d ("btrfs: don't assume ordered sums to be 4 bytes") CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-21Btrfs: fix deadlock during fast fsync when logging prealloc extents beyond eofFilipe Manana
While logging the prealloc extents of an inode during a fast fsync we call btrfs_truncate_inode_items(), through btrfs_log_prealloc_extents(), while holding a read lock on a leaf of the inode's root (not the log root, the fs/subvol root), and then that function locks the file range in the inode's iotree. This can lead to a deadlock when: * the fsync is ranged * the file has prealloc extents beyond eof * writeback for a range different from the fsync range starts during the fsync * the size of the file is not sector size aligned Because when finishing an ordered extent we lock first a file range and then try to COW the fs/subvol tree to insert an extent item. The following diagram shows how the deadlock can happen. CPU 1 CPU 2 btrfs_sync_file() --> for range [0, 1MiB) --> inode has a size of 1MiB and has 1 prealloc extent beyond the i_size, starting at offset 4MiB flushes all delalloc for the range [0MiB, 1MiB) and waits for the respective ordered extents to complete --> before task at CPU 1 locks the inode, a write into file range [1MiB, 2MiB + 1KiB) is made --> i_size is updated to 2MiB + 1KiB --> writeback is started for that range, [1MiB, 2MiB + 4KiB) --> end offset rounded up to be sector size aligned btrfs_log_dentry_safe() btrfs_log_inode_parent() btrfs_log_inode() btrfs_log_changed_extents() btrfs_log_prealloc_extents() --> does a search on the inode's root --> holds a read lock on leaf X btrfs_finish_ordered_io() --> locks range [1MiB, 2MiB + 4KiB) --> end offset rounded up to be sector size aligned --> tries to cow leaf X, through insert_reserved_file_extent() --> already locked by the task at CPU 1 btrfs_truncate_inode_items() --> gets an i_size of 2MiB + 1KiB, which is not sector size aligned --> tries to lock file range [2MiB, (u64)-1) --> the start range is rounded down from 2MiB + 1K to 2MiB to be sector size aligned --> but the subrange [2MiB, 2MiB + 4KiB) is already locked by task at CPU 2 which is waiting to get a write lock on leaf X for which we are holding a read lock *** deadlock *** This results in a stack trace like the following, triggered by test case generic/561 from fstests: [ 2779.973608] INFO: task kworker/u8:6:247 blocked for more than 120 seconds. [ 2779.979536] Not tainted 5.6.0-rc2-btrfs-next-53 #1 [ 2779.984503] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 2779.990136] kworker/u8:6 D 0 247 2 0x80004000 [ 2779.990457] Workqueue: btrfs-endio-write btrfs_work_helper [btrfs] [ 2779.990466] Call Trace: [ 2779.990491] ? __schedule+0x384/0xa30 [ 2779.990521] schedule+0x33/0xe0 [ 2779.990616] btrfs_tree_read_lock+0x19e/0x2e0 [btrfs] [ 2779.990632] ? remove_wait_queue+0x60/0x60 [ 2779.990730] btrfs_read_lock_root_node+0x2f/0x40 [btrfs] [ 2779.990782] btrfs_search_slot+0x510/0x1000 [btrfs] [ 2779.990869] btrfs_lookup_file_extent+0x4a/0x70 [btrfs] [ 2779.990944] __btrfs_drop_extents+0x161/0x1060 [btrfs] [ 2779.990987] ? mark_held_locks+0x6d/0xc0 [ 2779.990994] ? __slab_alloc.isra.49+0x99/0x100 [ 2779.991060] ? insert_reserved_file_extent.constprop.19+0x64/0x300 [btrfs] [ 2779.991145] insert_reserved_file_extent.constprop.19+0x97/0x300 [btrfs] [ 2779.991222] ? start_transaction+0xdd/0x5c0 [btrfs] [ 2779.991291] btrfs_finish_ordered_io+0x4f4/0x840 [btrfs] [ 2779.991405] btrfs_work_helper+0xaa/0x720 [btrfs] [ 2779.991432] process_one_work+0x26d/0x6a0 [ 2779.991460] worker_thread+0x4f/0x3e0 [ 2779.991481] ? process_one_work+0x6a0/0x6a0 [ 2779.991489] kthread+0x103/0x140 [ 2779.991499] ? kthread_create_worker_on_cpu+0x70/0x70 [ 2779.991515] ret_from_fork+0x3a/0x50 (...) [ 2780.026211] INFO: task fsstress:17375 blocked for more than 120 seconds. [ 2780.027480] Not tainted 5.6.0-rc2-btrfs-next-53 #1 [ 2780.028482] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 2780.030035] fsstress D 0 17375 17373 0x00004000 [ 2780.030038] Call Trace: [ 2780.030044] ? __schedule+0x384/0xa30 [ 2780.030052] schedule+0x33/0xe0 [ 2780.030075] lock_extent_bits+0x20c/0x320 [btrfs] [ 2780.030094] ? btrfs_truncate_inode_items+0xf4/0x1150 [btrfs] [ 2780.030098] ? rcu_read_lock_sched_held+0x59/0xa0 [ 2780.030102] ? remove_wait_queue+0x60/0x60 [ 2780.030122] btrfs_truncate_inode_items+0x133/0x1150 [btrfs] [ 2780.030151] ? btrfs_set_path_blocking+0xb2/0x160 [btrfs] [ 2780.030165] ? btrfs_search_slot+0x379/0x1000 [btrfs] [ 2780.030195] btrfs_log_changed_extents.isra.8+0x841/0x93e [btrfs] [ 2780.030202] ? do_raw_spin_unlock+0x49/0xc0 [ 2780.030215] ? btrfs_get_num_csums+0x10/0x10 [btrfs] [ 2780.030239] btrfs_log_inode+0xf83/0x1124 [btrfs] [ 2780.030251] ? __mutex_unlock_slowpath+0x45/0x2a0 [ 2780.030275] btrfs_log_inode_parent+0x2a0/0xe40 [btrfs] [ 2780.030282] ? dget_parent+0xa1/0x370 [ 2780.030309] btrfs_log_dentry_safe+0x4a/0x70 [btrfs] [ 2780.030329] btrfs_sync_file+0x3f3/0x490 [btrfs] [ 2780.030339] do_fsync+0x38/0x60 [ 2780.030343] __x64_sys_fdatasync+0x13/0x20 [ 2780.030345] do_syscall_64+0x5c/0x280 [ 2780.030348] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 2780.030356] RIP: 0033:0x7f2d80f6d5f0 [ 2780.030361] Code: Bad RIP value. [ 2780.030362] RSP: 002b:00007ffdba3c8548 EFLAGS: 00000246 ORIG_RAX: 000000000000004b [ 2780.030364] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f2d80f6d5f0 [ 2780.030365] RDX: 00007ffdba3c84b0 RSI: 00007ffdba3c84b0 RDI: 0000000000000003 [ 2780.030367] RBP: 000000000000004a R08: 0000000000000001 R09: 00007ffdba3c855c [ 2780.030368] R10: 0000000000000078 R11: 0000000000000246 R12: 00000000000001f4 [ 2780.030369] R13: 0000000051eb851f R14: 00007ffdba3c85f0 R15: 0000557a49220d90 So fix this by making btrfs_truncate_inode_items() not lock the range in the inode's iotree when the target root is a log root, since it's not needed to lock the range for log roots as the protection from the inode's lock and log_mutex are all that's needed. Fixes: 28553fa992cb28 ("Btrfs: fix race between shrinking truncate and fiemap") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-19btrfs: fix bytes_may_use underflow in prealloc error condtitionJosef Bacik
I hit the following warning while running my error injection stress testing: WARNING: CPU: 3 PID: 1453 at fs/btrfs/space-info.h:108 btrfs_free_reserved_data_space_noquota+0xfd/0x160 [btrfs] RIP: 0010:btrfs_free_reserved_data_space_noquota+0xfd/0x160 [btrfs] Call Trace: btrfs_free_reserved_data_space+0x4f/0x70 [btrfs] __btrfs_prealloc_file_range+0x378/0x470 [btrfs] elfcorehdr_read+0x40/0x40 ? elfcorehdr_read+0x40/0x40 ? btrfs_commit_transaction+0xca/0xa50 [btrfs] ? dput+0xb4/0x2a0 ? btrfs_log_dentry_safe+0x55/0x70 [btrfs] ? btrfs_sync_file+0x30e/0x420 [btrfs] ? do_fsync+0x38/0x70 ? __x64_sys_fdatasync+0x13/0x20 ? do_syscall_64+0x5b/0x1b0 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens if we fail to insert our reserved file extent. At this point we've already converted our reservation from ->bytes_may_use to ->bytes_reserved. However once we break we will attempt to free everything from [cur_offset, end] from ->bytes_may_use, but our extent reservation will overlap part of this. Fix this problem by adding ins.offset (our extent allocation size) to cur_offset so we remove the actual remaining part from ->bytes_may_use. I validated this fix using my inject-error.py script python inject-error.py -o should_fail_bio -t cache_save_setup -t \ __btrfs_prealloc_file_range \ -t insert_reserved_file_extent.constprop.0 \ -r "-5" ./run-fsstress.sh where run-fsstress.sh simply mounts and runs fsstress on a disk. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-17btrfs: don't set path->leave_spinning for truncateJosef Bacik
The only time we actually leave the path spinning is if we're truncating a small amount and don't actually free an extent, which is not a common occurrence. We have to set the path blocking in order to add the delayed ref anyway, so the first extent we find we set the path to blocking and stay blocking for the duration of the operation. With the upcoming file extent map stuff there will be another case that we have to have the path blocking, so just swap to blocking always. Note: this patch also fixes a warning after 28553fa992cb ("Btrfs: fix race between shrinking truncate and fiemap") got merged that inserts extent locks around truncation so the path must not leave spinning locks after btrfs_search_slot. [70.794783] BUG: sleeping function called from invalid context at mm/slab.h:565 [70.794834] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1141, name: rsync [70.794863] 5 locks held by rsync/1141: [70.794876] #0: ffff888417b9c408 (sb_writers#17){.+.+}, at: mnt_want_write+0x20/0x50 [70.795030] #1: ffff888428de28e8 (&type->i_mutex_dir_key#13/1){+.+.}, at: lock_rename+0xf1/0x100 [70.795051] #2: ffff888417b9c608 (sb_internal#2){.+.+}, at: start_transaction+0x394/0x560 [70.795124] #3: ffff888403081768 (btrfs-fs-01){++++}, at: btrfs_try_tree_write_lock+0x2f/0x160 [70.795203] #4: ffff888403086568 (btrfs-fs-00){++++}, at: btrfs_try_tree_write_lock+0x2f/0x160 [70.795222] CPU: 5 PID: 1141 Comm: rsync Not tainted 5.6.0-rc2-backup+ #2 [70.795362] Call Trace: [70.795374] dump_stack+0x71/0xa0 [70.795445] ___might_sleep.part.96.cold.106+0xa6/0xb6 [70.795459] kmem_cache_alloc+0x1d3/0x290 [70.795471] alloc_extent_state+0x22/0x1c0 [70.795544] __clear_extent_bit+0x3ba/0x580 [70.795557] ? _raw_spin_unlock_irq+0x24/0x30 [70.795569] btrfs_truncate_inode_items+0x339/0xe50 [70.795647] btrfs_evict_inode+0x269/0x540 [70.795659] ? dput.part.38+0x29/0x460 [70.795671] evict+0xcd/0x190 [70.795682] __dentry_kill+0xd6/0x180 [70.795754] dput.part.38+0x2ad/0x460 [70.795765] do_renameat2+0x3cb/0x540 [70.795777] __x64_sys_rename+0x1c/0x20 Reported-by: Dave Jones <davej@codemonkey.org.uk> Fixes: 28553fa992cb ("Btrfs: fix race between shrinking truncate and fiemap") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add note ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-12Btrfs: fix race between shrinking truncate and fiemapFilipe Manana
When there is a fiemap executing in parallel with a shrinking truncate we can end up in a situation where we have extent maps for which we no longer have corresponding file extent items. This is generally harmless and at the moment the only consequences are missing file extent items representing holes after we expand the file size again after the truncate operation removed the prealloc extent items, and stale information for future fiemap calls (reporting extents that no longer exist or may have been reallocated to other files for example). Consider the following example: 1) Our inode has a size of 128KiB, one 128KiB extent at file offset 0 and a 1MiB prealloc extent at file offset 128KiB; 2) Task A starts doing a shrinking truncate of our inode to reduce it to a size of 64KiB. Before it searches the subvolume tree for file extent items to delete, it drops all the extent maps in the range from 64KiB to (u64)-1 by calling btrfs_drop_extent_cache(); 3) Task B starts doing a fiemap against our inode. When looking up for the inode's extent maps in the range from 128KiB to (u64)-1, it doesn't find any in the inode's extent map tree, since they were removed by task A. Because it didn't find any in the extent map tree, it scans the inode's subvolume tree for file extent items, and it finds the 1MiB prealloc extent at file offset 128KiB, then it creates an extent map based on that file extent item and adds it to inode's extent map tree (this ends up being done by btrfs_get_extent() <- btrfs_get_extent_fiemap() <- get_extent_skip_holes()); 4) Task A then drops the prealloc extent at file offset 128KiB and shrinks the 128KiB extent file offset 0 to a length of 64KiB. The truncation operation finishes and we end up with an extent map representing a 1MiB prealloc extent at file offset 128KiB, despite we don't have any more that extent; After this the two types of problems we have are: 1) Future calls to fiemap always report that a 1MiB prealloc extent exists at file offset 128KiB. This is stale information, no longer correct; 2) If the size of the file is increased, by a truncate operation that increases the file size or by a write into a file offset > 64KiB for example, we end up not inserting file extent items to represent holes for any range between 128KiB and 128KiB + 1MiB, since the hole expansion function, btrfs_cont_expand() will skip hole insertion for any range for which an extent map exists that represents a prealloc extent. This causes fsck to complain about missing file extent items when not using the NO_HOLES feature. The second issue could be often triggered by test case generic/561 from fstests, which runs fsstress and duperemove in parallel, and duperemove does frequent fiemap calls. Essentially the problems happens because fiemap does not acquire the inode's lock while truncate does, and fiemap locks the file range in the inode's iotree while truncate does not. So fix the issue by making btrfs_truncate_inode_items() lock the file range from the new file size to (u64)-1, so that it serializes with fiemap. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-31btrfs: do not do delalloc reservation under page lockJosef Bacik
We ran into a deadlock in production with the fixup worker. The stack traces were as follows: Thread responsible for the writeout, waiting on the page lock [<0>] io_schedule+0x12/0x40 [<0>] __lock_page+0x109/0x1e0 [<0>] extent_write_cache_pages+0x206/0x360 [<0>] extent_writepages+0x40/0x60 [<0>] do_writepages+0x31/0xb0 [<0>] __writeback_single_inode+0x3d/0x350 [<0>] writeback_sb_inodes+0x19d/0x3c0 [<0>] __writeback_inodes_wb+0x5d/0xb0 [<0>] wb_writeback+0x231/0x2c0 [<0>] wb_workfn+0x308/0x3c0 [<0>] process_one_work+0x1e0/0x390 [<0>] worker_thread+0x2b/0x3c0 [<0>] kthread+0x113/0x130 [<0>] ret_from_fork+0x35/0x40 [<0>] 0xffffffffffffffff Thread of the fixup worker who is holding the page lock [<0>] start_delalloc_inodes+0x241/0x2d0 [<0>] btrfs_start_delalloc_roots+0x179/0x230 [<0>] btrfs_alloc_data_chunk_ondemand+0x11b/0x2e0 [<0>] btrfs_check_data_free_space+0x53/0xa0 [<0>] btrfs_delalloc_reserve_space+0x20/0x70 [<0>] btrfs_writepage_fixup_worker+0x1fc/0x2a0 [<0>] normal_work_helper+0x11c/0x360 [<0>] process_one_work+0x1e0/0x390 [<0>] worker_thread+0x2b/0x3c0 [<0>] kthread+0x113/0x130 [<0>] ret_from_fork+0x35/0x40 [<0>] 0xffffffffffffffff Thankfully the stars have to align just right to hit this. First you have to end up in the fixup worker, which is tricky by itself (my reproducer does DIO reads into a MMAP'ed region, so not a common operation). Then you have to have less than a page size of free data space and 0 unallocated space so you go down the "commit the transaction to free up pinned space" path. This was accomplished by a random balance that was running on the host. Then you get this deadlock. I'm still in the process of trying to force the deadlock to happen on demand, but I've hit other issues. I can still trigger the fixup worker path itself so this patch has been tested in that regard, so the normal case is fine. Fixes: 87826df0ec36 ("btrfs: delalloc for page dirtied out-of-band in fixup worker") Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-31Btrfs: keep pages dirty when using btrfs_writepage_fixup_workerChris Mason
For COW, btrfs expects pages dirty pages to have been through a few setup steps. This includes reserving space for the new block allocations and marking the range in the state tree for delayed allocation. A few places outside btrfs will dirty pages directly, especially when unmapping mmap'd pages. In order for these to properly go through COW, we run them through a fixup worker to wait for stable pages, and do the delalloc prep. 87826df0ec36 added a window where the dirty pages were cleaned, but pending more action from the fixup worker. We clear_page_dirty_for_io() before we call into writepage, so the page is no longer dirty. The commit changed it so now we leave the page clean between unlocking it here and the fixup worker starting at some point in the future. During this window, page migration can jump in and relocate the page. Once our fixup work actually starts, it finds page->mapping is NULL and we end up freeing the page without ever writing it. This leads to crc errors and other exciting problems, since it screws up the whole statemachine for waiting for ordered extents. The fix here is to keep the page dirty while we're waiting for the fixup worker to get to work. This is accomplished by returning -EAGAIN from btrfs_writepage_cow_fixup if we queued the page up for fixup, which will cause the writepage function to redirty the page. Because we now expect the page to be dirty once it gets to the fixup worker we must adjust the error cases to call clear_page_dirty_for_io() on the page. That is the bulk of the patch, but it is not the fix, the fix is the -EAGAIN from btrfs_writepage_cow_fixup. We cannot separate these two changes out because the error conditions change with the new expectations. Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: rename DISCARD mount option to to DISCARD_SYNCDennis Zhou
This series introduces async discard which will use the flag DISCARD_ASYNC, so rename the original flag to DISCARD_SYNC as it is synchronously done in transaction commit. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: drop create parameter to btrfs_get_extent()Omar Sandoval
We only pass this as 1 from __extent_writepage_io(). The parameter basically means "pretend I didn't pass in a page". This is silly since we can simply not pass in the page. Get rid of the parameter from btrfs_get_extent(), and since it's used as a get_extent_t callback, remove it from get_extent_t and btree_get_extent(), neither of which need it. While we're here, let's document btrfs_get_extent(). Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: make btrfs_ordered_extent naming consistent with btrfs_file_extent_itemOmar Sandoval
ordered->start, ordered->len, and ordered->disk_len correspond to fi->disk_bytenr, fi->num_bytes, and fi->disk_num_bytes, respectively. It's confusing to translate between the two naming schemes. Since a btrfs_ordered_extent is basically a pending btrfs_file_extent_item, let's make the former use the naming from the latter. Note that I didn't touch the names in tracepoints just in case there are scripts depending on the current naming. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: remove dead snapshot-aware defrag codeOmar Sandoval
Snapshot-aware defrag has been disabled since commit 8101c8dbf624 ("Btrfs: disable snapshot aware defrag for now") almost 6 years ago. Let's remove the dead code. If someone is up to the task of bringing it back, they can dig it up from git. This is logically a revert of commit 38c227d87c49 ("Btrfs: snapshot-aware defrag") except that now we have to clear the EXTENT_DEFRAG bit to avoid need_force_cow() returning true forever. The reasons to disable were caused by runtime problems (like long stalls or memory consumption) on heavily referenced extents (eg. thousands of snapshots). There were attempts to fix that but never finished. Current defrag breaks the extent references and some users prefer that behaviour over the one implemented by snapshot aware (ie. keeping links for defragmentation). To enable both usecases we'd need to extend defrag ioctl but let's do that properly from scratch. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> [ enhance ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: get rid of at_offset parameter to btrfs_lookup_bio_sums()Omar Sandoval
We can encode this in the offset parameter: -1 means use the page offsets, anything else is a valid offset. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: get rid of trivial __btrfs_lookup_bio_sums() wrappersOmar Sandoval
Currently, we have two wrappers for __btrfs_lookup_bio_sums(): btrfs_lookup_bio_sums_dio(), which is used for direct I/O, and btrfs_lookup_bio_sums(), which is used everywhere else. The only difference is that the _dio variant looks up csums starting at the given offset instead of using the page index, which isn't actually direct I/O-specific. Let's clean up the signature and return value of __btrfs_lookup_bio_sums(), rename it to btrfs_lookup_bio_sums(), and get rid of the trivial helpers. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: use simple_dir_inode_operations for placeholder subvolume directoryOmar Sandoval
When you snapshot a subvolume containing a subvolume, you get a placeholder directory where the subvolume would be. These directories have their own btrfs_dir_ro_inode_operations. Al pointed out [1] that these directories can use simple_lookup() instead of btrfs_lookup(), as they are always empty. Furthermore, they can use the default generic_permission() instead of btrfs_permission(); the additional checks in the latter don't matter because we can't write to the directory anyways. Finally, they can use the default generic_update_time() instead of btrfs_update_time(), as the inode doesn't exist on disk and doesn't need any special handling. All together, this means that we can get rid of btrfs_dir_ro_inode_operations and use simple_dir_inode_operations instead. 1: https://lore.kernel.org/linux-btrfs/20190929052934.GY26530@ZenIV.linux.org.uk/ Cc: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add comment ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: remove unused condition check in btrfs_page_mkwrite()Yunfeng Ye
The condition '!ret2' is always true. commit 717beb96d969 ("Btrfs: fix regression in btrfs_page_mkwrite() from vm_fault_t conversion") left behind the check after moving this code out of the goto, so remove the unused condition check. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: Don't discard unwritten extentsNikolay Borisov
All callers of btrfs_free_reserved_extent (respectively __btrfs_free_reserved_extent with in set to 0) pass in extents which have only been reserved but not yet written to. Namely, * in cow_file_range that function is called only if create_io_em fails or btrfs_add_ordered_extent fail, both of which happen _before_ any IO is submitted to the newly reserved range * in submit_compressed_extents the code flow is similar - out_free_reserve can be called only before btrfs_submit_compressed_write which is where any writes to the range could occur * btrfs_new_extent_direct also calls btrfs_free_reserved_extent only if extent_map fails, before any IO is issued * __btrfs_prealloc_file_range also calls btrfs_free_reserved_extent in case insertion of the metadata fails * btrfs_alloc_tree_block again can only be called in case in-memory operations fail, before any IO is submitted * btrfs_finish_ordered_io - this is the only caller where discarding the extent could have a material effect, since it can be called for an extent which was partially written. With this change the submission of discards is optimised since discards are now not being created for extents which are known to not have been touched on disk. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-08btrfs: fix invalid removal of root refJosef Bacik
If we have the following sequence of events btrfs sub create A btrfs sub create A/B btrfs sub snap A C mkdir C/foo mv A/B C/foo rm -rf * We will end up with a transaction abort. The reason for this is because we create a root ref for B pointing to A. When we create a snapshot of C we still have B in our tree, but because the root ref points to A and not C we will make it appear to be empty. The problem happens when we move B into C. This removes the root ref for B pointing to A and adds a ref of B pointing to C. When we rmdir C we'll see that we have a ref to our root and remove the root ref, despite not actually matching our reference name. Now btrfs_del_root_ref() allowing this to work is a bug as well, however we know that this inode does not actually point to a root ref in the first place, so we shouldn't be calling btrfs_del_root_ref() in the first place and instead simply look up our dir index for this item and do the rest of the removal. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-08btrfs: rework arguments of btrfs_unlink_subvolJosef Bacik
btrfs_unlink_subvol takes the name of the dentry and the root objectid based on what kind of inode this is, either a real subvolume link or a empty one that we inherited as a snapshot. We need to fix how we unlink in the case for BTRFS_EMPTY_SUBVOL_DIR_OBJECTID in the future, so rework btrfs_unlink_subvol to just take the dentry and handle getting the right objectid given the type of inode this is. There is no functional change here, simply pushing the work into btrfs_unlink_subvol() proper. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-30Btrfs: fix infinite loop during nocow writeback due to raceFilipe Manana
When starting writeback for a range that covers part of a preallocated extent, due to a race with writeback for another range that also covers another part of the same preallocated extent, we can end up in an infinite loop. Consider the following example where for inode 280 we have two dirty ranges: range A, from 294912 to 303103, 8192 bytes range B, from 348160 to 438271, 90112 bytes and we have the following file extent item layout for our inode: leaf 38895616 gen 24544 total ptrs 29 free space 13820 owner 5 (...) item 27 key (280 108 200704) itemoff 14598 itemsize 53 extent data disk bytenr 0 nr 0 type 1 (regular) extent data offset 0 nr 94208 ram 94208 item 28 key (280 108 294912) itemoff 14545 itemsize 53 extent data disk bytenr 10433052672 nr 81920 type 2 (prealloc) extent data offset 0 nr 81920 ram 81920 Then the following happens: 1) Writeback starts for range B (from 348160 to 438271), execution of run_delalloc_nocow() starts; 2) The first iteration of run_delalloc_nocow()'s whil loop leaves us at the extent item at slot 28, pointing to the prealloc extent item covering the range from 294912 to 376831. This extent covers part of our range; 3) An ordered extent is created against that extent, covering the file range from 348160 to 376831 (28672 bytes); 4) We adjust 'cur_offset' to 376832 and move on to the next iteration of the while loop; 5) The call to btrfs_lookup_file_extent() leaves us at the same leaf, pointing to slot 29, 1 slot after the last item (the extent item we processed in the previous iteration); 6) Because we are a slot beyond the last item, we call btrfs_next_leaf(), which releases the search path before doing a another search for the last key of the leaf (280 108 294912); 7) Right after btrfs_next_leaf() released the path, and before it did another search for the last key of the leaf, writeback for the range A (from 294912 to 303103) completes (it was previously started at some point); 8) Upon completion of the ordered extent for range A, the prealloc extent we previously found got split into two extent items, one covering the range from 294912 to 303103 (8192 bytes), with a type of regular extent (and no longer prealloc) and another covering the range from 303104 to 376831 (73728 bytes), with a type of prealloc and an offset of 8192 bytes. So our leaf now has the following layout: leaf 38895616 gen 24544 total ptrs 31 free space 13664 owner 5 (...) item 27 key (280 108 200704) itemoff 14598 itemsize 53 extent data disk bytenr 0 nr 0 type 1 extent data offset 0 nr 8192 ram 94208 item 28 key (280 108 208896) itemoff 14545 itemsize 53 extent data disk bytenr 10433142784 nr 86016 type 1 extent data offset 0 nr 86016 ram 86016 item 29 key (280 108 294912) itemoff 14492 itemsize 53 extent data disk bytenr 10433052672 nr 81920 type 1 extent data offset 0 nr 8192 ram 81920 item 30 key (280 108 303104) itemoff 14439 itemsize 53 extent data disk bytenr 10433052672 nr 81920 type 2 extent data offset 8192 nr 73728 ram 81920 9) After btrfs_next_leaf() returns, we have our path pointing to that same leaf and at slot 30, since it has a key we didn't have before and it's the first key greater then the key that was previously the last key of the leaf (key (280 108 294912)); 10) The extent item at slot 30 covers the range from 303104 to 376831 which is in our target range, so we process it, despite having already created an ordered extent against this extent for the file range from 348160 to 376831. This is because we skip to the next extent item only if its end is less than or equals to the start of our delalloc range, and not less than or equals to the current offset ('cur_offset'); 11) As a result we compute 'num_bytes' as: num_bytes = min(end + 1, extent_end) - cur_offset; = min(438271 + 1, 376832) - 376832 = 0 12) We then call create_io_em() for a 0 bytes range starting at offset 376832; 13) Then create_io_em() enters an infinite loop because its calls to btrfs_drop_extent_cache() do nothing due to the 0 length range passed to it. So no existing extent maps that cover the offset 376832 get removed, and therefore calls to add_extent_mapping() return -EEXIST, resulting in an infinite loop. This loop from create_io_em() is the following: do { btrfs_drop_extent_cache(BTRFS_I(inode), em->start, em->start + em->len - 1, 0); write_lock(&em_tree->lock); ret = add_extent_mapping(em_tree, em, 1); write_unlock(&em_tree->lock); /* * The caller has taken lock_extent(), who could race with us * to add em? */ } while (ret == -EEXIST); Also, each call to btrfs_drop_extent_cache() triggers a warning because the start offset passed to it (376832) is smaller then the end offset (376832 - 1) passed to it by -1, due to the 0 length: [258532.052621] ------------[ cut here ]------------ [258532.052643] WARNING: CPU: 0 PID: 9987 at fs/btrfs/file.c:602 btrfs_drop_extent_cache+0x3f4/0x590 [btrfs] (...) [258532.052672] CPU: 0 PID: 9987 Comm: fsx Tainted: G W 5.4.0-rc7-btrfs-next-64 #1 [258532.052673] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014 [258532.052691] RIP: 0010:btrfs_drop_extent_cache+0x3f4/0x590 [btrfs] (...) [258532.052695] RSP: 0018:ffffb4be0153f860 EFLAGS: 00010287 [258532.052700] RAX: ffff975b445ee360 RBX: ffff975b44eb3e08 RCX: 0000000000000000 [258532.052700] RDX: 0000000000038fff RSI: 0000000000039000 RDI: ffff975b445ee308 [258532.052700] RBP: 0000000000038fff R08: 0000000000000000 R09: 0000000000000001 [258532.052701] R10: ffff975b513c5c10 R11: 00000000e3c0cfa9 R12: 0000000000039000 [258532.052703] R13: ffff975b445ee360 R14: 00000000ffffffef R15: ffff975b445ee308 [258532.052705] FS: 00007f86a821de80(0000) GS:ffff975b76a00000(0000) knlGS:0000000000000000 [258532.052707] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [258532.052708] CR2: 00007fdacf0f3ab4 CR3: 00000001f9d26002 CR4: 00000000003606f0 [258532.052712] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [258532.052717] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [258532.052717] Call Trace: [258532.052718] ? preempt_schedule_common+0x32/0x70 [258532.052722] ? ___preempt_schedule+0x16/0x20 [258532.052741] create_io_em+0xff/0x180 [btrfs] [258532.052767] run_delalloc_nocow+0x942/0xb10 [btrfs] [258532.052791] btrfs_run_delalloc_range+0x30b/0x520 [btrfs] [258532.052812] ? find_lock_delalloc_range+0x221/0x250 [btrfs] [258532.052834] writepage_delalloc+0xe4/0x140 [btrfs] [258532.052855] __extent_writepage+0x110/0x4e0 [btrfs] [258532.052876] extent_write_cache_pages+0x21c/0x480 [btrfs] [258532.052906] extent_writepages+0x52/0xb0 [btrfs] [258532.052911] do_writepages+0x23/0x80 [258532.052915] __filemap_fdatawrite_range+0xd2/0x110 [258532.052938] btrfs_fdatawrite_range+0x1b/0x50 [btrfs] [258532.052954] start_ordered_ops+0x57/0xa0 [btrfs] [258532.052973] ? btrfs_sync_file+0x225/0x490 [btrfs] [258532.052988] btrfs_sync_file+0x225/0x490 [btrfs] [258532.052997] __x64_sys_msync+0x199/0x200 [258532.053004] do_syscall_64+0x5c/0x250 [258532.053007] entry_SYSCALL_64_after_hwframe+0x49/0xbe [258532.053010] RIP: 0033:0x7f86a7dfd760 (...) [258532.053014] RSP: 002b:00007ffd99af0368 EFLAGS: 00000246 ORIG_RAX: 000000000000001a [258532.053016] RAX: ffffffffffffffda RBX: 0000000000000ec9 RCX: 00007f86a7dfd760 [258532.053017] RDX: 0000000000000004 RSI: 000000000000836c RDI: 00007f86a8221000 [258532.053019] RBP: 0000000000021ec9 R08: 0000000000000003 R09: 00007f86a812037c [258532.053020] R10: 0000000000000001 R11: 0000000000000246 R12: 00000000000074a3 [258532.053021] R13: 00007f86a8221000 R14: 000000000000836c R15: 0000000000000001 [258532.053032] irq event stamp: 1653450494 [258532.053035] hardirqs last enabled at (1653450493): [<ffffffff9dec69f9>] _raw_spin_unlock_irq+0x29/0x50 [258532.053037] hardirqs last disabled at (1653450494): [<ffffffff9d4048ea>] trace_hardirqs_off_thunk+0x1a/0x20 [258532.053039] softirqs last enabled at (1653449852): [<ffffffff9e200466>] __do_softirq+0x466/0x6bd [258532.053042] softirqs last disabled at (1653449845): [<ffffffff9d4c8a0c>] irq_exit+0xec/0x120 [258532.053043] ---[ end trace 8476fce13d9ce20a ]--- Which results in flooding dmesg/syslog since btrfs_drop_extent_cache() uses WARN_ON() and not WARN_ON_ONCE(). So fix this issue by changing run_delalloc_nocow()'s loop to move to the next extent item when the current extent item ends at at offset less than or equals to the current offset instead of the start offset. Fixes: 80ff385665b7fc ("Btrfs: update nodatacow code v2") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: don't double lock the subvol_sem for rename exchangeJosef Bacik
If we're rename exchanging two subvols we'll try to lock this lock twice, which is bad. Just lock once if either of the ino's are subvols. Fixes: cdd1fedf8261 ("btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: do not call synchronize_srcu() in inode_tree_delJosef Bacik
Testing with the new fsstress uncovered a pretty nasty deadlock with lookup and snapshot deletion. Process A unlink -> final iput -> inode_tree_del -> synchronize_srcu(subvol_srcu) Process B btrfs_lookup <- srcu_read_lock() acquired here -> btrfs_iget -> find inode that has I_FREEING set -> __wait_on_freeing_inode() We're holding the srcu_read_lock() while doing the iget in order to make sure our fs root doesn't go away, and then we are waiting for the inode to finish freeing. However because the free'ing process is doing a synchronize_srcu() we deadlock. Fix this by dropping the synchronize_srcu() in inode_tree_del(). We don't need people to stop accessing the fs root at this point, we're only adding our empty root to the dead roots list. A larger much more invasive fix is forthcoming to address how we deal with fs roots, but this fixes the immediate problem. Fixes: 76dda93c6ae2 ("Btrfs: add snapshot/subvolume destroy ioctl") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: remove extent_map::bdevDavid Sterba
We can now remove the bdev from extent_map. Previous patches made sure that bio_set_dev is correctly in all places and that we don't need to grab it from latest_bdev or pass it around inside the extent map. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: record all roots for rename exchange on a subvolJosef Bacik
Testing with the new fsstress support for subvolumes uncovered a pretty bad problem with rename exchange on subvolumes. We're modifying two different subvolumes, but we only start the transaction on one of them, so the other one is not added to the dirty root list. This is caught by btrfs_cow_block() with a warning because the root has not been updated, however if we do not modify this root again we'll end up pointing at an invalid root because the root item is never updated. Fix this by making sure we add the destination root to the trans list, the same as we do with normal renames. This fixes the corruption. Fixes: cdd1fedf8261 ("btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT") CC: stable@vger.kernel.org # 4.9+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: rename btrfs_block_group_cacheDavid Sterba
The type name is misleading, a single entry is named 'cache' while this normally means a collection of objects. Rename that everywhere. Also the identifier was quite long, making function prototypes harder to format. Suggested-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: sink write flags to cow_file_range_asyncDavid Sterba
In commit "Btrfs: use REQ_CGROUP_PUNT for worker thread submitted bios", cow_file_range_async gained wbc as a parameter and this makes passing write flags redundant. Set it inside the function and remove the parameter. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18Btrfs: remove unnecessary delalloc mutex for inodesFilipe Manana
The inode delalloc mutex was added a long time ago by commit f248679e86fea ("Btrfs: add a delalloc mutex to inodes for delalloc reservations"), and the reason for its introduction is not very clear from the change log. It claims it solves bogus warnings from lockdep, however it lacks an example report/warning from lockdep, or any explanation. Since we have enough concurrentcy protection from the locks of the space info and block reserve objects, and such lockdep warnings don't seem to exist anymore (at least on a 5.3 kernel I couldn't get them with fstests, ltp, fs_mark, etc), remove it, simplifying things a bit and decreasing the size of the btrfs_inode structure. With some quick fio tests doing direct IO and mmap writes I couldn't observe any significant performance increase either (direct IO writes that don't increase the file's size don't hold the inode's lock for their entire duration and mmap writes don't hold the inode's lock at all), which are the only type of writes that could see any performance gain due to less serialization. Review feedback from Josef: The problem was taking the i_mutex in mmap, which is how I was protecting delalloc reservations originally. The delalloc mutex didn't come with all of the other dependencies. That's what the lockdep messages were about, removing the lock isn't going to make them appear again. We _had_ to lock around this because we used to do tricks to keep from over-reserving, and if we didn't serialize delalloc reservations we'd end up with ugly accounting problems when we tried to clean things up. However with my recentish changes this isn't the case anymore. Every operation is responsible for reserving its space, and then adding it to the inode. Then cleaning up is straightforward and can't be mucked up by other users. So we no longer need the delalloc mutex to safe us from ourselves. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: get bdev from latest_dev for dio bh_resultDavid Sterba
To remove use of extent_map::bdev we need to find a replacement, and the latest_bdev is the only one we can use here, because inode::i_bdev and superblock::s_bdev are NULL. The DIO code uses bdev in two places: * to read blocksize to perform alignment checks in do_blockdev_direct_IO, but we do them in btrfs code before any call to DIO * in the following call chain: do_direct_IO get_more_blocks sdio->get_block() <-- this is btrfs_get_blocks_direct subsequently the map_bh->b_dev member is used in clean_bdev_aliases and dio_new_bio to set the bio's bdev to that of the buffer_head. However, because we have provided a submit function dio_bio_submit calls our submission function and ignores the bdev. So it's safe to pass any valid bdev that's used within the filesystem. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18Btrfs: fix metadata space leak on fixup worker failure to set range as delallocFilipe Manana
In the fixup worker, if we fail to mark the range as delalloc in the io tree, we must release the previously reserved metadata, as well as update the outstanding extents counter for the inode, otherwise we leak metadata space. In pratice we can't return an error from btrfs_set_extent_delalloc(), which is just a wrapper around __set_extent_bit(), as for most errors __set_extent_bit() does a BUG_ON() (or panics which hits a BUG_ON() as well) and returning an -EEXIST error doesn't happen in this case since the exclusive bits parameter always has a value of 0 through this code path. Nevertheless, just fix the error handling in the fixup worker, in case one day __set_extent_bit() can return an error to this code path. Fixes: f3038ee3a3f101 ("btrfs: Handle btrfs_set_extent_delalloc failure in fixup worker") CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: Rename btrfs_join_transaction_nolockNikolay Borisov
This function is used only during the final phase of freespace cache writeout. This is necessary since using the plain btrfs_join_transaction api is deadlock prone. The deadlock looks like: T1: btrfs_commit_transaction commit_cowonly_roots btrfs_write_dirty_block_groups btrfs_wait_cache_io __btrfs_wait_cache_io btrfs_wait_ordered_range <-- Triggers ordered IO for freespace inode and blocks transaction commit until freespace cache writeout T2: <-- after T1 has triggered the writeout finish_ordered_fn btrfs_finish_ordered_io btrfs_join_transaction <--- this would block waiting for current transaction to commit, but since trans commit is waiting for this writeout to finish The special purpose functions prevents it by simply skipping the "wait for writeout" since it's guaranteed the transaction won't proceed until we are done. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18Btrfs: use REQ_CGROUP_PUNT for worker thread submitted biosChris Mason
Async CRCs and compression submit IO through helper threads, which means they have IO priority inversions when cgroup IO controllers are in use. This flags all of the writes submitted by btrfs helper threads as REQ_CGROUP_PUNT. submit_bio() will punt these to dedicated per-blkcg work items to avoid the priority inversion. For the compression code, we take a reference on the wbc's blkg css and pass it down to the async workers. For the async CRCs, the bio already has the correct css, we just need to tell the block layer to use REQ_CGROUP_PUNT. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Chris Mason <clm@fb.com> Modified-and-reviewed-by: Tejun Heo <tj@kernel.org> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18Btrfs: only associate the locked page with one async_chunk structChris Mason
The btrfs writepages function collects a large range of pages flagged for delayed allocation, and then sends them down through the COW code for processing. When compression is on, we allocate one async_chunk structure for every 512K, and then run those pages through the compression code for IO submission. writepages starts all of this off with a single page, locked by the original call to extent_write_cache_pages(), and it's important to keep track of this page because it has already been through clear_page_dirty_for_io(). The btrfs async_chunk struct has a pointer to the locked_page, and when we're redirtying the page because compression had to fallback to uncompressed IO, we use page->index to decide if a given async_chunk struct really owns that page. But, this is racey. If a given delalloc range is broken up into two async_chunks (chunkA and chunkB), we can end up with something like this: compress_file_range(chunkA) submit_compress_extents(chunkA) submit compressed bios(chunkA) put_page(locked_page) compress_file_range(chunkB) ... Or: async_cow_submit submit_compressed_extents <--- falls back to buffered writeout cow_file_range extent_clear_unlock_delalloc __process_pages_contig put_page(locked_pages) async_cow_submit The end result is that chunkA is completed and cleaned up before chunkB even starts processing. This means we can free locked_page() and reuse it elsewhere. If we get really lucky, it'll have the same page->index in its new home as it did before. While we're processing chunkB, we might decide we need to fall back to uncompressed IO, and so compress_file_range() will call __set_page_dirty_nobufers() on chunkB->locked_page. Without cgroups in use, this creates as a phantom dirty page, which isn't great but isn't the end of the world. What can happen, it can go through the fixup worker and the whole COW machinery again: in submit_compressed_extents(): while (async extents) { ... cow_file_range if (!page_started ...) extent_write_locked_range else if (...) unlock_page continue; This hasn't been observed in practice but is still possible. With cgroups in use, we might crash in the accounting code because page->mapping->i_wb isn't set. BUG: unable to handle kernel NULL pointer dereference at 00000000000000d0 IP: percpu_counter_add_batch+0x11/0x70 PGD 66534e067 P4D 66534e067 PUD 66534f067 PMD 0 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC CPU: 16 PID: 2172 Comm: rm Not tainted RIP: 0010:percpu_counter_add_batch+0x11/0x70 RSP: 0018:ffffc9000a97bbe0 EFLAGS: 00010286 RAX: 0000000000000005 RBX: 0000000000000090 RCX: 0000000000026115 RDX: 0000000000000030 RSI: ffffffffffffffff RDI: 0000000000000090 RBP: 0000000000000000 R08: fffffffffffffff5 R09: 0000000000000000 R10: 00000000000260c0 R11: ffff881037fc26c0 R12: ffffffffffffffff R13: ffff880fe4111548 R14: ffffc9000a97bc90 R15: 0000000000000001 FS: 00007f5503ced480(0000) GS:ffff880ff7200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000d0 CR3: 00000001e0459005 CR4: 0000000000360ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: account_page_cleaned+0x15b/0x1f0 __cancel_dirty_page+0x146/0x200 truncate_cleanup_page+0x92/0xb0 truncate_inode_pages_range+0x202/0x7d0 btrfs_evict_inode+0x92/0x5a0 evict+0xc1/0x190 do_unlinkat+0x176/0x280 do_syscall_64+0x63/0x1a0 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The fix here is to make asyc_chunk->locked_page NULL everywhere but the one async_chunk struct that's allowed to do things to the locked page. Link: https://lore.kernel.org/linux-btrfs/c2419d01-5c84-3fb4-189e-4db519d08796@suse.com/ Fixes: 771ed689d2cd ("Btrfs: Optimize compressed writeback and reads") Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Chris Mason <clm@fb.com> [ update changelog from mail thread discussion ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18Btrfs: stop using btrfs_schedule_bio()Chris Mason
btrfs_schedule_bio() hands IO off to a helper thread to do the actual submit_bio() call. This has been used to make sure async crc and compression helpers don't get stuck on IO submission. To maintain good performance, over time the IO submission threads duplicated some IO scheduler characteristics such as high and low priority IOs and they also made some ugly assumptions about request allocation batch sizes. All of this cost at least one extra context switch during IO submission, and doesn't fit well with the modern blkmq IO stack. So, this commit stops using btrfs_schedule_bio(). We may need to adjust the number of async helper threads for crcs and compression, but long term it's a better path. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: drop unused parameter is_new from btrfs_igetDavid Sterba
The parameter is now always set to NULL and could be dropped. The last user was get_default_root but that got reworked in 05dbe6837b60 ("Btrfs: unify subvol= and subvolid= mounting") and the parameter became unused. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: get rid of unique workqueue helper functionsOmar Sandoval
Commit 9e0af2376434 ("Btrfs: fix task hang under heavy compressed write") worked around the issue that a recycled work item could get a false dependency on the original work item due to how the workqueue code guarantees non-reentrancy. It did so by giving different work functions to different types of work. However, the fixes in the previous few patches are more complete, as they prevent a work item from being recycled at all (except for a tiny window that the kernel workqueue code handles for us). This obsoletes the previous fix, so we don't need the unique helpers for correctness. The only other reason to keep them would be so they show up in stack traces, but they always seem to be optimized to a tail call, so they don't show up anyways. So, let's just get rid of the extra indirection. While we're here, rename normal_work_helper() to the more informative btrfs_work_helper(). Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-11Btrfs: fix log context list corruption after rename exchange operationFilipe Manana
During rename exchange we might have successfully log the new name in the source root's log tree, in which case we leave our log context (allocated on stack) in the root's list of log contextes. However we might fail to log the new name in the destination root, in which case we fallback to a transaction commit later and never sync the log of the source root, which causes the source root log context to remain in the list of log contextes. This later causes invalid memory accesses because the context was allocated on stack and after rename exchange finishes the stack gets reused and overwritten for other purposes. The kernel's linked list corruption detector (CONFIG_DEBUG_LIST=y) can detect this and report something like the following: [ 691.489929] ------------[ cut here ]------------ [ 691.489947] list_add corruption. prev->next should be next (ffff88819c944530), but was ffff8881c23f7be4. (prev=ffff8881c23f7a38). [ 691.489967] WARNING: CPU: 2 PID: 28933 at lib/list_debug.c:28 __list_add_valid+0x95/0xe0 (...) [ 691.489998] CPU: 2 PID: 28933 Comm: fsstress Not tainted 5.4.0-rc6-btrfs-next-62 #1 [ 691.490001] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014 [ 691.490003] RIP: 0010:__list_add_valid+0x95/0xe0 (...) [ 691.490007] RSP: 0018:ffff8881f0b3faf8 EFLAGS: 00010282 [ 691.490010] RAX: 0000000000000000 RBX: ffff88819c944530 RCX: 0000000000000000 [ 691.490011] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffffa2c497e0 [ 691.490013] RBP: ffff8881f0b3fe68 R08: ffffed103eaa4115 R09: ffffed103eaa4114 [ 691.490015] R10: ffff88819c944000 R11: ffffed103eaa4115 R12: 7fffffffffffffff [ 691.490016] R13: ffff8881b4035610 R14: ffff8881e7b84728 R15: 1ffff1103e167f7b [ 691.490019] FS: 00007f4b25ea2e80(0000) GS:ffff8881f5500000(0000) knlGS:0000000000000000 [ 691.490021] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 691.490022] CR2: 00007fffbb2d4eec CR3: 00000001f2a4a004 CR4: 00000000003606e0 [ 691.490025] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 691.490027] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 691.490029] Call Trace: [ 691.490058] btrfs_log_inode_parent+0x667/0x2730 [btrfs] [ 691.490083] ? join_transaction+0x24a/0xce0 [btrfs] [ 691.490107] ? btrfs_end_log_trans+0x80/0x80 [btrfs] [ 691.490111] ? dget_parent+0xb8/0x460 [ 691.490116] ? lock_downgrade+0x6b0/0x6b0 [ 691.490121] ? rwlock_bug.part.0+0x90/0x90 [ 691.490127] ? do_raw_spin_unlock+0x142/0x220 [ 691.490151] btrfs_log_dentry_safe+0x65/0x90 [btrfs] [ 691.490172] btrfs_sync_file+0x9f1/0xc00 [btrfs] [ 691.490195] ? btrfs_file_write_iter+0x1800/0x1800 [btrfs] [ 691.490198] ? rcu_read_lock_any_held.part.11+0x20/0x20 [ 691.490204] ? __do_sys_newstat+0x88/0xd0 [ 691.490207] ? cp_new_stat+0x5d0/0x5d0 [ 691.490218] ? do_fsync+0x38/0x60 [ 691.490220] do_fsync+0x38/0x60 [ 691.490224] __x64_sys_fdatasync+0x32/0x40 [ 691.490228] do_syscall_64+0x9f/0x540 [ 691.490233] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 691.490235] RIP: 0033:0x7f4b253ad5f0 (...) [ 691.490239] RSP: 002b:00007fffbb2d6078 EFLAGS: 00000246 ORIG_RAX: 000000000000004b [ 691.490242] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f4b253ad5f0 [ 691.490244] RDX: 00007fffbb2d5fe0 RSI: 00007fffbb2d5fe0 RDI: 0000000000000003 [ 691.490245] RBP: 000000000000000d R08: 0000000000000001 R09: 00007fffbb2d608c [ 691.490247] R10: 00000000000002e8 R11: 0000000000000246 R12: 00000000000001f4 [ 691.490248] R13: 0000000051eb851f R14: 00007fffbb2d6120 R15: 00005635a498bda0 This started happening recently when running some test cases from fstests like btrfs/004 for example, because support for rename exchange was added last week to fsstress from fstests. So fix this by deleting the log context for the source root from the list if we have logged the new name in the source root. Reported-by: Su Yue <Damenly_Su@gmx.com> Fixes: d4682ba03ef618 ("Btrfs: sync log after logging new name") CC: stable@vger.kernel.org # 4.19+ Tested-by: Su Yue <Damenly_Su@gmx.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-04btrfs: save i_size to avoid double evaluation of i_size_read in ↵Josef Bacik
compress_file_range We hit a regression while rolling out 5.2 internally where we were hitting the following panic kernel BUG at mm/page-writeback.c:2659! RIP: 0010:clear_page_dirty_for_io+0xe6/0x1f0 Call Trace: __process_pages_contig+0x25a/0x350 ? extent_clear_unlock_delalloc+0x43/0x70 submit_compressed_extents+0x359/0x4d0 normal_work_helper+0x15a/0x330 process_one_work+0x1f5/0x3f0 worker_thread+0x2d/0x3d0 ? rescuer_thread+0x340/0x340 kthread+0x111/0x130 ? kthread_create_on_node+0x60/0x60 ret_from_fork+0x1f/0x30 This is happening because the page is not locked when doing clear_page_dirty_for_io. Looking at the core dump it was because our async_extent had a ram_size of 24576 but our async_chunk range only spanned 20480, so we had a whole extra page in our ram_size for our async_extent. This happened because we try not to compress pages outside of our i_size, however a cleanup patch changed us to do actual_end = min_t(u64, i_size_read(inode), end + 1); which is problematic because i_size_read() can evaluate to different values in between checking and assigning. So either an expanding truncate or a fallocate could increase our i_size while we're doing writeout and actual_end would end up being past the range we have locked. I confirmed this was what was happening by installing a debug kernel that had actual_end = min_t(u64, i_size_read(inode), end + 1); if (actual_end > end + 1) { printk(KERN_ERR "KABOOM\n"); actual_end = end + 1; } and installing it onto 500 boxes of the tier that had been seeing the problem regularly. Last night I got my debug message and no panic, confirming what I expected. [ dsterba: the assembly confirms a tiny race window: mov 0x20(%rsp),%rax cmp %rax,0x48(%r15) # read movl $0x0,0x18(%rsp) mov %rax,%r12 mov %r14,%rax cmovbe 0x48(%r15),%r12 # eval Where r15 is inode and 0x48 is offset of i_size. The original fix was to revert 62b37622718c that would do an intermediate assignment and this would also avoid the doulble evaluation but is not future-proof, should the compiler merge the stores and call i_size_read anyway. There's a patch adding READ_ONCE to i_size_read but that's not being applied at the moment and we need to fix the bug. Instead, emulate READ_ONCE by two barrier()s that's what effectively happens. The assembly confirms single evaluation: mov 0x48(%rbp),%rax # read once mov 0x20(%rsp),%rcx mov $0x20,%edx cmp %rax,%rcx cmovbe %rcx,%rax mov %rax,(%rsp) mov %rax,%rcx mov %r14,%rax Where 0x48(%rbp) is inode->i_size stored to %eax. ] Fixes: 62b37622718c ("btrfs: Remove isize local variable in compress_file_range") CC: stable@vger.kernel.org # v5.1+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ changelog updated ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-15btrfs: qgroup: Always free PREALLOC META reserve in ↵Qu Wenruo
btrfs_delalloc_release_extents() [Background] Btrfs qgroup uses two types of reserved space for METADATA space, PERTRANS and PREALLOC. PERTRANS is metadata space reserved for each transaction started by btrfs_start_transaction(). While PREALLOC is for delalloc, where we reserve space before joining a transaction, and finally it will be converted to PERTRANS after the writeback is done. [Inconsistency] However there is inconsistency in how we handle PREALLOC metadata space. The most obvious one is: In btrfs_buffered_write(): btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes, true); We always free qgroup PREALLOC meta space. While in btrfs_truncate_block(): btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, (ret != 0)); We only free qgroup PREALLOC meta space when something went wrong. [The Correct Behavior] The correct behavior should be the one in btrfs_buffered_write(), we should always free PREALLOC metadata space. The reason is, the btrfs_delalloc_* mechanism works by: - Reserve metadata first, even it's not necessary In btrfs_delalloc_reserve_metadata() - Free the unused metadata space Normally in: btrfs_delalloc_release_extents() |- btrfs_inode_rsv_release() Here we do calculation on whether we should release or not. E.g. for 64K buffered write, the metadata rsv works like: /* The first page */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=0 total: num_bytes=calc_inode_reservations() /* The first page caused one outstanding extent, thus needs metadata rsv */ /* The 2nd page */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=calc_inode_reservations() total: not changed /* The 2nd page doesn't cause new outstanding extent, needs no new meta rsv, so we free what we have reserved */ /* The 3rd~16th pages */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=calc_inode_reservations() total: not changed (still space for one outstanding extent) This means, if btrfs_delalloc_release_extents() determines to free some space, then those space should be freed NOW. So for qgroup, we should call btrfs_qgroup_free_meta_prealloc() other than btrfs_qgroup_convert_reserved_meta(). The good news is: - The callers are not that hot The hottest caller is in btrfs_buffered_write(), which is already fixed by commit 336a8bb8e36a ("btrfs: Fix wrong btrfs_delalloc_release_extents parameter"). Thus it's not that easy to cause false EDQUOT. - The trans commit in advance for qgroup would hide the bug Since commit f5fef4593653 ("btrfs: qgroup: Make qgroup async transaction commit more aggressive"), when btrfs qgroup metadata free space is slow, it will try to commit transaction and free the wrongly converted PERTRANS space, so it's not that easy to hit such bug. [FIX] So to fix the problem, remove the @qgroup_free parameter for btrfs_delalloc_release_extents(), and always pass true to btrfs_inode_rsv_release(). Reported-by: Filipe Manana <fdmanana@suse.com> Fixes: 43b18595d660 ("btrfs: qgroup: Use separate meta reservation type for delalloc") CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-01btrfs: allocate new inode in NOFS contextJosef Bacik
A user reported a lockdep splat ====================================================== WARNING: possible circular locking dependency detected 5.2.11-gentoo #2 Not tainted ------------------------------------------------------ kswapd0/711 is trying to acquire lock: 000000007777a663 (sb_internal){.+.+}, at: start_transaction+0x3a8/0x500 but task is already holding lock: 000000000ba86300 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}: kmem_cache_alloc+0x1f/0x1c0 btrfs_alloc_inode+0x1f/0x260 alloc_inode+0x16/0xa0 new_inode+0xe/0xb0 btrfs_new_inode+0x70/0x610 btrfs_symlink+0xd0/0x420 vfs_symlink+0x9c/0x100 do_symlinkat+0x66/0xe0 do_syscall_64+0x55/0x1c0 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (sb_internal){.+.+}: __sb_start_write+0xf6/0x150 start_transaction+0x3a8/0x500 btrfs_commit_inode_delayed_inode+0x59/0x110 btrfs_evict_inode+0x19e/0x4c0 evict+0xbc/0x1f0 inode_lru_isolate+0x113/0x190 __list_lru_walk_one.isra.4+0x5c/0x100 list_lru_walk_one+0x32/0x50 prune_icache_sb+0x36/0x80 super_cache_scan+0x14a/0x1d0 do_shrink_slab+0x131/0x320 shrink_node+0xf7/0x380 balance_pgdat+0x2d5/0x640 kswapd+0x2ba/0x5e0 kthread+0x147/0x160 ret_from_fork+0x24/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(sb_internal); lock(fs_reclaim); lock(sb_internal); *** DEADLOCK *** 3 locks held by kswapd0/711: #0: 000000000ba86300 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30 #1: 000000004a5100f8 (shrinker_rwsem){++++}, at: shrink_node+0x9a/0x380 #2: 00000000f956fa46 (&type->s_umount_key#30){++++}, at: super_cache_scan+0x35/0x1d0 stack backtrace: CPU: 7 PID: 711 Comm: kswapd0 Not tainted 5.2.11-gentoo #2 Hardware name: Dell Inc. Precision Tower 3620/0MWYPT, BIOS 2.4.2 09/29/2017 Call Trace: dump_stack+0x85/0xc7 print_circular_bug.cold.40+0x1d9/0x235 __lock_acquire+0x18b1/0x1f00 lock_acquire+0xa6/0x170 ? start_transaction+0x3a8/0x500 __sb_start_write+0xf6/0x150 ? start_transaction+0x3a8/0x500 start_transaction+0x3a8/0x500 btrfs_commit_inode_delayed_inode+0x59/0x110 btrfs_evict_inode+0x19e/0x4c0 ? var_wake_function+0x20/0x20 evict+0xbc/0x1f0 inode_lru_isolate+0x113/0x190 ? discard_new_inode+0xc0/0xc0 __list_lru_walk_one.isra.4+0x5c/0x100 ? discard_new_inode+0xc0/0xc0 list_lru_walk_one+0x32/0x50 prune_icache_sb+0x36/0x80 super_cache_scan+0x14a/0x1d0 do_shrink_slab+0x131/0x320 shrink_node+0xf7/0x380 balance_pgdat+0x2d5/0x640 kswapd+0x2ba/0x5e0 ? __wake_up_common_lock+0x90/0x90 kthread+0x147/0x160 ? balance_pgdat+0x640/0x640 ? __kthread_create_on_node+0x160/0x160 ret_from_fork+0x24/0x30 This is because btrfs_new_inode() calls new_inode() under the transaction. We could probably move the new_inode() outside of this but for now just wrap it in memalloc_nofs_save(). Reported-by: Zdenek Sojka <zsojka@seznam.cz> Fixes: 712e36c5f2a7 ("btrfs: use GFP_KERNEL in btrfs_alloc_inode") CC: stable@vger.kernel.org # 4.16+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: stop clearing EXTENT_DIRTY in inode I/O treeOmar Sandoval
Since commit fee187d9d9dd ("Btrfs: do not set EXTENT_DIRTY along with EXTENT_DELALLOC"), we never set EXTENT_DIRTY in inode->io_tree, so we can simplify and stop trying to clear it. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: tie extent buffer and it's token togetherDavid Sterba
Further simplifaction of the get/set helpers is possible when the token is uniquely tied to an extent buffer. A condition and an assignment can be avoided. The initializations are moved closer to the first use when the extent buffer is valid. There's one exception in __push_leaf_left where the token is reused. Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: move cond_wake_up functions out of ctreeDavid Sterba
The file ctree.h serves as a header for everything and has become quite bloated. Split some helpers that are generic and create a new file that should be the catch-all for code that's not btrfs-specific. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: fix allocation of free space cache v1 bitmap pagesChristophe Leroy
Various notifications of type "BUG kmalloc-4096 () : Redzone overwritten" have been observed recently in various parts of the kernel. After some time, it has been made a relation with the use of BTRFS filesystem and with SLUB_DEBUG turned on. [ 22.809700] BUG kmalloc-4096 (Tainted: G W ): Redzone overwritten [ 22.810286] INFO: 0xbe1a5921-0xfbfc06cd. First byte 0x0 instead of 0xcc [ 22.810866] INFO: Allocated in __load_free_space_cache+0x588/0x780 [btrfs] age=22 cpu=0 pid=224 [ 22.811193] __slab_alloc.constprop.26+0x44/0x70 [ 22.811345] kmem_cache_alloc_trace+0xf0/0x2ec [ 22.811588] __load_free_space_cache+0x588/0x780 [btrfs] [ 22.811848] load_free_space_cache+0xf4/0x1b0 [btrfs] [ 22.812090] cache_block_group+0x1d0/0x3d0 [btrfs] [ 22.812321] find_free_extent+0x680/0x12a4 [btrfs] [ 22.812549] btrfs_reserve_extent+0xec/0x220 [btrfs] [ 22.812785] btrfs_alloc_tree_block+0x178/0x5f4 [btrfs] [ 22.813032] __btrfs_cow_block+0x150/0x5d4 [btrfs] [ 22.813262] btrfs_cow_block+0x194/0x298 [btrfs] [ 22.813484] commit_cowonly_roots+0x44/0x294 [btrfs] [ 22.813718] btrfs_commit_transaction+0x63c/0xc0c [btrfs] [ 22.813973] close_ctree+0xf8/0x2a4 [btrfs] [ 22.814107] generic_shutdown_super+0x80/0x110 [ 22.814250] kill_anon_super+0x18/0x30 [ 22.814437] btrfs_kill_super+0x18/0x90 [btrfs] [ 22.814590] INFO: Freed in proc_cgroup_show+0xc0/0x248 age=41 cpu=0 pid=83 [ 22.814841] proc_cgroup_show+0xc0/0x248 [ 22.814967] proc_single_show+0x54/0x98 [ 22.815086] seq_read+0x278/0x45c [ 22.815190] __vfs_read+0x28/0x17c [ 22.815289] vfs_read+0xa8/0x14c [ 22.815381] ksys_read+0x50/0x94 [ 22.815475] ret_from_syscall+0x0/0x38 Commit 69d2480456d1 ("btrfs: use copy_page for copying pages instead of memcpy") changed the way bitmap blocks are copied. But allthough bitmaps have the size of a page, they were allocated with kzalloc(). Most of the time, kzalloc() allocates aligned blocks of memory, so copy_page() can be used. But when some debug options like SLAB_DEBUG are activated, kzalloc() may return unaligned pointer. On powerpc, memcpy(), copy_page() and other copying functions use 'dcbz' instruction which provides an entire zeroed cacheline to avoid memory read when the intention is to overwrite a full line. Functions like memcpy() are writen to care about partial cachelines at the start and end of the destination, but copy_page() assumes it gets pages. As pages are naturally cache aligned, copy_page() doesn't care about partial lines. This means that when copy_page() is called with a misaligned pointer, a few leading bytes are zeroed. To fix it, allocate bitmaps through kmem_cache instead of using kzalloc() The cache pool is created with PAGE_SIZE alignment constraint. Reported-by: Erhard F. <erhard_f@mailbox.org> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204371 Fixes: 69d2480456d1 ("btrfs: use copy_page for copying pages instead of memcpy") Cc: stable@vger.kernel.org # 4.19+ Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: David Sterba <dsterba@suse.com> [ rename to btrfs_free_space_bitmap ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: improve error handling in run_delalloc_nocowNikolay Borisov
Correctly handle failure cases when adding an ordered extents in case of REGULAR or PREALLOC extents. Remove the BUG_ON. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: comment and minor simplifications in run_delalloc_nocowNikolay Borisov
Add a comment explaining why we keep the BUG also use the already read and cached value of extent ram bytes stored in 'ram_bytes'. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: streamline code in run_delalloc_nocow in case of inline extentsNikolay Borisov
The extent range check right after the "out_check" label is redundant, because the only way it can trigger is if we have an inline extent. In this case it makes more sense to actually move it in the branch explictly dealing with inlines extents. What's more, the nested 'if (nocow)' can never be true because for inline extents we always do COW and there is no chance 'nocow' can be true, just remove that check. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: simplify extent type checks in run_delalloc_nocowNikolay Borisov
There is no point in checking the type of the extent again just to set the 'type' variable, when this check has already been performed before. Instead, extend the original if branch with an 'else' clause. This allows to remove one local variable and make it obvious how the code flow differs for prealloc/regular extents. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: improve comments around nocow pathNikolay Borisov
run_delalloc_nocow contains numerous, somewhat subtle, checks when figuring out whether a particular extent should be CoW'ed or not. This patch explicitly states the assumptions those checks verify. As a result also document 2 of the more subtle checks in check_committed_ref as well. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: refactor variable scope in run_delalloc_nocowNikolay Borisov
Of the 22 (!!!) local variables declared in this function only 9 have function-wide context. Of the remaining 13, 12 are needed in the main while loop of the function and 1 is needed in a tiny if branch, only in case we have prealloc extent. This commit reduces the lifespan of every variable to its bare minimum. It also renames the 'nolock' boolean to freespace_inode to clearly indicate its purpose. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: rename the btrfs_calc_*_metadata_size helpersJosef Bacik
btrfs_calc_trunc_metadata_size differs from trans_metadata_size in that it doesn't take into account any splitting at the levels, because truncate will never split nodes. However truncate _and_ changing will never split nodes, so rename btrfs_calc_trunc_metadata_size to btrfs_calc_metadata_size. Also btrfs_calc_trans_metadata_size is purely for inserting items, so rename this to btrfs_calc_insert_metadata_size. Making these clearer will help when I start using them differently in upcoming patches. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
generated by cgit (git 2.34.1) at 2024-05-27 18:56:54 +0000