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2020-03-13btrfs: fix log context list corruption after rename whiteout errorFilipe Manana1-0/+4
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 Sandoval1-1/+3
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 Manana1-5/+5
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 btrfs_wait_ordered_range() so that it waits for all ordered extentsFilipe Manana1-1/+6
In btrfs_wait_ordered_range() once we find an ordered extent that has finished with an error we exit the loop and don't wait for any other ordered extents that might be still in progress. All the users of btrfs_wait_ordered_range() expect that there are no more ordered extents in progress after that function returns. So past fixes such like the ones from the two following commits: ff612ba7849964 ("btrfs: fix panic during relocation after ENOSPC before writeback happens") 28aeeac1dd3080 ("Btrfs: fix panic when starting bg cache writeout after IO error") don't work when there are multiple ordered extents in the range. Fix that by making btrfs_wait_ordered_range() wait for all ordered extents even after it finds one that had an error. Link: https://github.com/kdave/btrfs-progs/issues/228#issuecomment-569777554 CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Qu Wenruo <wqu@suse.com> 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 Bacik1-3/+13
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>
2020-02-19btrfs: handle logged extent failure properlyJosef Bacik1-0/+2
If we're allocating a logged extent we attempt to insert an extent record for the file extent directly. We increase space_info->bytes_reserved, because the extent entry addition will call btrfs_update_block_group(), which will convert the ->bytes_reserved to ->bytes_used. However if we fail at any point while inserting the extent entry we will bail and leave space on ->bytes_reserved, which will trigger a WARN_ON() on umount. Fix this by pinning the space if we fail to insert, which is what happens in every other failure case that involves adding the extent entry. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> 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>
2020-02-19btrfs: do not check delayed items are empty for single transaction cleanupJosef Bacik1-1/+0
btrfs_assert_delayed_root_empty() will check if the delayed root is completely empty, but this is a filesystem-wide check. On cleanup we may have allowed other transactions to begin, for whatever reason, and thus the delayed root is not empty. So remove this check from cleanup_one_transation(). This however can stay in btrfs_cleanup_transaction(), because it checks only after all of the transactions have been properly cleaned up, and thus is valid. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> 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>
2020-02-19btrfs: reset fs_root to NULL on error in open_ctreeJosef Bacik1-0/+1
While running my error injection script I hit a panic when we tried to clean up the fs_root when freeing the fs_root. This is because fs_info->fs_root == PTR_ERR(-EIO), which isn't great. Fix this by setting fs_info->fs_root = NULL; if we fail to read the root. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> 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>
2020-02-19btrfs: destroy qgroup extent records on transaction abortJeff Mahoney4-0/+17
We clean up the delayed references when we abort a transaction but we leave the pending qgroup extent records behind, leaking memory. This patch destroys the extent records when we destroy the delayed refs and makes sure ensure they're gone before releasing the transaction. Fixes: 3368d001ba5d ("btrfs: qgroup: Record possible quota-related extent for qgroup.") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jeff Mahoney <jeffm@suse.com> [ Rebased to latest upstream, remove to_qgroup() helper, use rbtree_postorder_for_each_entry_safe() wrapper ] Signed-off-by: Qu Wenruo <wqu@suse.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 Bacik1-2/+0
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: sysfs, move device id directories to UUID/devinfoAnand Jain1-1/+1
Originally it was planned to create device id directories under UUID/devinfo, but it got under UUID/devices by mistake. We really want it under definfo so the bare device node names are not mixed with device ids and are easy to enumerate. Fixes: 668e48af7a94 ("btrfs: sysfs, add devid/dev_state kobject and device attributes") Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-12btrfs: sysfs, add UUID/devinfo kobjectAnand Jain2-0/+16
Create directory /sys/fs/btrfs/UUID/devinfo to hold devices directories by the id (unlike /devices). Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-12Btrfs: fix race between shrinking truncate and fiemapFilipe Manana1-0/+8
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>
2020-02-12btrfs: log message when rw remount is attempted with unclean tree-logDavid Sterba1-0/+2
A remount to a read-write filesystem is not safe when there's tree-log to be replayed. Files that could be opened until now might be affected by the changes in the tree-log. A regular mount is needed to replay the log so the filesystem presents the consistent view with the pending changes included. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-12btrfs: print message when tree-log replay startsDavid Sterba1-0/+1
There's no logged information about tree-log replay although this is something that points to previous unclean unmount. Other filesystems report that as well. Suggested-by: Chris Murphy <lists@colorremedies.com> CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-12Btrfs: fix race between using extent maps and merging themFilipe Manana1-0/+11
We have a few cases where we allow an extent map that is in an extent map tree to be merged with other extents in the tree. Such cases include the unpinning of an extent after the respective ordered extent completed or after logging an extent during a fast fsync. This can lead to subtle and dangerous problems because when doing the merge some other task might be using the same extent map and as consequence see an inconsistent state of the extent map - for example sees the new length but has seen the old start offset. With luck this triggers a BUG_ON(), and not some silent bug, such as the following one in __do_readpage(): $ cat -n fs/btrfs/extent_io.c 3061 static int __do_readpage(struct extent_io_tree *tree, 3062 struct page *page, (...) 3127 em = __get_extent_map(inode, page, pg_offset, cur, 3128 end - cur + 1, get_extent, em_cached); 3129 if (IS_ERR_OR_NULL(em)) { 3130 SetPageError(page); 3131 unlock_extent(tree, cur, end); 3132 break; 3133 } 3134 extent_offset = cur - em->start; 3135 BUG_ON(extent_map_end(em) <= cur); (...) Consider the following example scenario, where we end up hitting the BUG_ON() in __do_readpage(). We have an inode with a size of 8KiB and 2 extent maps: extent A: file offset 0, length 4KiB, disk_bytenr = X, persisted on disk by a previous transaction extent B: file offset 4KiB, length 4KiB, disk_bytenr = X + 4KiB, not yet persisted but writeback started for it already. The extent map is pinned since there's writeback and an ordered extent in progress, so it can not be merged with extent map A yet The following sequence of steps leads to the BUG_ON(): 1) The ordered extent for extent B completes, the respective page gets its writeback bit cleared and the extent map is unpinned, at that point it is not yet merged with extent map A because it's in the list of modified extents; 2) Due to memory pressure, or some other reason, the MM subsystem releases the page corresponding to extent B - btrfs_releasepage() is called and returns 1, meaning the page can be released as it's not dirty, not under writeback anymore and the extent range is not locked in the inode's iotree. However the extent map is not released, either because we are not in a context that allows memory allocations to block or because the inode's size is smaller than 16MiB - in this case our inode has a size of 8KiB; 3) Task B needs to read extent B and ends up __do_readpage() through the btrfs_readpage() callback. At __do_readpage() it gets a reference to extent map B; 4) Task A, doing a fast fsync, calls clear_em_loggin() against extent map B while holding the write lock on the inode's extent map tree - this results in try_merge_map() being called and since it's possible to merge extent map B with extent map A now (the extent map B was removed from the list of modified extents), the merging begins - it sets extent map B's start offset to 0 (was 4KiB), but before it increments the map's length to 8KiB (4kb + 4KiB), task A is at: BUG_ON(extent_map_end(em) <= cur); The call to extent_map_end() sees the extent map has a start of 0 and a length still at 4KiB, so it returns 4KiB and 'cur' is 4KiB, so the BUG_ON() is triggered. So it's dangerous to modify an extent map that is in the tree, because some other task might have got a reference to it before and still using it, and needs to see a consistent map while using it. Generally this is very rare since most paths that lookup and use extent maps also have the file range locked in the inode's iotree. The fsync path is pretty much the only exception where we don't do it to avoid serialization with concurrent reads. Fix this by not allowing an extent map do be merged if if it's being used by tasks other then the one attempting to merge the extent map (when the reference count of the extent map is greater than 2). Reported-by: ryusuke1925 <st13s20@gm.ibaraki-ct.ac.jp> Reported-by: Koki Mitani <koki.mitani.xg@hco.ntt.co.jp> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206211 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>
2020-02-12btrfs: ref-verify: fix memory leaksWenwen Wang1-0/+5
In btrfs_ref_tree_mod(), 'ref' and 'ra' are allocated through kzalloc() and kmalloc(), respectively. In the following code, if an error occurs, the execution will be redirected to 'out' or 'out_unlock' and the function will be exited. However, on some of the paths, 'ref' and 'ra' are not deallocated, leading to memory leaks. For example, if 'action' is BTRFS_ADD_DELAYED_EXTENT, add_block_entry() will be invoked. If the return value indicates an error, the execution will be redirected to 'out'. But, 'ref' is not deallocated on this path, causing a memory leak. To fix the above issues, deallocate both 'ref' and 'ra' before exiting from the function when an error is encountered. CC: stable@vger.kernel.org # 4.15+ Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-02btrfs: do not zero f_bavail if we have available spaceJosef Bacik1-1/+9
There was some logic added a while ago to clear out f_bavail in statfs() if we did not have enough free metadata space to satisfy our global reserve. This was incorrect at the time, however didn't really pose a problem for normal file systems because we would often allocate chunks if we got this low on free metadata space, and thus wouldn't really hit this case unless we were actually full. Fast forward to today and now we are much better about not allocating metadata chunks all of the time. Couple this with d792b0f19711 ("btrfs: always reserve our entire size for the global reserve") which now means we'll easily have a larger global reserve than our free space, we are now more likely to trip over this while still having plenty of space. Fix this by skipping this logic if the global rsv's space_info is not full. space_info->full is 0 unless we've attempted to allocate a chunk for that space_info and that has failed. If this happens then the space for the global reserve is definitely sacred and we need to report b_avail == 0, but before then we can just use our calculated b_avail. Reported-by: Martin Steigerwald <martin@lichtvoll.de> Fixes: ca8a51b3a979 ("btrfs: statfs: report zero available if metadata are exhausted") CC: stable@vger.kernel.org # 4.5+ Reviewed-by: Qu Wenruo <wqu@suse.com> Tested-By: Martin Steigerwald <martin@lichtvoll.de> 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: send, fix emission of invalid clone operations within the same fileFilipe Manana1-1/+2
When doing an incremental send and a file has extents shared with itself at different file offsets, it's possible for send to emit clone operations that will fail at the destination because the source range goes beyond the file's current size. This happens when the file size has increased in the send snapshot, there is a hole between the shared extents and both shared extents are at file offsets which are greater the file's size in the parent snapshot. Example: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt/sdb $ xfs_io -f -c "pwrite -S 0xf1 0 64K" /mnt/sdb/foobar $ btrfs subvolume snapshot -r /mnt/sdb /mnt/sdb/base $ btrfs send -f /tmp/1.snap /mnt/sdb/base # Create a 320K extent at file offset 512K. $ xfs_io -c "pwrite -S 0xab 512K 64K" /mnt/sdb/foobar $ xfs_io -c "pwrite -S 0xcd 576K 64K" /mnt/sdb/foobar $ xfs_io -c "pwrite -S 0xef 640K 64K" /mnt/sdb/foobar $ xfs_io -c "pwrite -S 0x64 704K 64K" /mnt/sdb/foobar $ xfs_io -c "pwrite -S 0x73 768K 64K" /mnt/sdb/foobar # Clone part of that 320K extent into a lower file offset (192K). # This file offset is greater than the file's size in the parent # snapshot (64K). Also the clone range is a bit behind the offset of # the 320K extent so that we leave a hole between the shared extents. $ xfs_io -c "reflink /mnt/sdb/foobar 448K 192K 192K" /mnt/sdb/foobar $ btrfs subvolume snapshot -r /mnt/sdb /mnt/sdb/incr $ btrfs send -p /mnt/sdb/base -f /tmp/2.snap /mnt/sdb/incr $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt/sdc $ btrfs receive -f /tmp/1.snap /mnt/sdc $ btrfs receive -f /tmp/2.snap /mnt/sdc ERROR: failed to clone extents to foobar: Invalid argument The problem is that after processing the extent at file offset 256K, which refers to the first 128K of the 320K extent created by the buffered write operations, we have 'cur_inode_next_write_offset' set to 384K, which corresponds to the end offset of the partially shared extent (256K + 128K) and to the current file size in the receiver. Then when we process the extent at offset 512K, we do extent backreference iteration to figure out if we can clone the extent from some other inode or from the same inode, and we consider the extent at offset 256K of the same inode as a valid source for a clone operation, which is not correct because at that point the current file size in the receiver is 384K, which corresponds to the end of last processed extent (at file offset 256K), so using a clone source range from 256K to 256K + 320K is invalid because that goes past the current size of the file (384K) - this makes the receiver get an -EINVAL error when attempting the clone operation. So fix this by excluding clone sources that have a range that goes beyond the current file size in the receiver when iterating extent backreferences. A test case for fstests follows soon. Fixes: 11f2069c113e02 ("Btrfs: send, allow clone operations within the same file") CC: stable@vger.kernel.org # 5.5+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-31btrfs: do not do delalloc reservation under page lockJosef Bacik1-16/+60
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: drop the -EBUSY case in __extent_writepage_ioJosef Bacik1-5/+1
Now that we only return 0 or -EAGAIN from btrfs_writepage_cow_fixup, we do not need this -EBUSY case. 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 Mason1-17/+44
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>
2020-01-31btrfs: take overcommit into account in inc_block_group_roJosef Bacik3-19/+39
inc_block_group_ro does a calculation to see if we have enough room left over if we mark this block group as read only in order to see if it's ok to mark the block group as read only. The problem is this calculation _only_ works for data, where our used is always less than our total. For metadata we will overcommit, so this will almost always fail for metadata. Fix this by exporting btrfs_can_overcommit, and then see if we have enough space to remove the remaining free space in the block group we are trying to mark read only. If we do then we can mark this block group as read only. 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>
2020-01-31btrfs: fix force usage in inc_block_group_roJosef Bacik1-2/+2
For some reason we've translated the do_chunk_alloc that goes into btrfs_inc_block_group_ro to force in inc_block_group_ro, but these are two different things. force for inc_block_group_ro is used when we are forcing the block group read only no matter what, for example when the underlying chunk is marked read only. We need to not do the space check here as this block group needs to be read only. btrfs_inc_block_group_ro() has a do_chunk_alloc flag that indicates that we need to pre-allocate a chunk before marking the block group read only. This has nothing to do with forcing, and in fact we _always_ want to do the space check in this case, so unconditionally pass false for force in this case. Then fixup inc_block_group_ro to honor force as it's expected and documented to do. 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>
2020-01-31btrfs: Correctly handle empty trees in find_first_clear_extent_bitNikolay Borisov2-14/+27
Raviu reported that running his regular fs_trim segfaulted with the following backtrace: [ 237.525947] assertion failed: prev, in ../fs/btrfs/extent_io.c:1595 [ 237.525984] ------------[ cut here ]------------ [ 237.525985] kernel BUG at ../fs/btrfs/ctree.h:3117! [ 237.525992] invalid opcode: 0000 [#1] SMP PTI [ 237.525998] CPU: 4 PID: 4423 Comm: fstrim Tainted: G U OE 5.4.14-8-vanilla #1 [ 237.526001] Hardware name: ASUSTeK COMPUTER INC. [ 237.526044] RIP: 0010:assfail.constprop.58+0x18/0x1a [btrfs] [ 237.526079] Call Trace: [ 237.526120] find_first_clear_extent_bit+0x13d/0x150 [btrfs] [ 237.526148] btrfs_trim_fs+0x211/0x3f0 [btrfs] [ 237.526184] btrfs_ioctl_fitrim+0x103/0x170 [btrfs] [ 237.526219] btrfs_ioctl+0x129a/0x2ed0 [btrfs] [ 237.526227] ? filemap_map_pages+0x190/0x3d0 [ 237.526232] ? do_filp_open+0xaf/0x110 [ 237.526238] ? _copy_to_user+0x22/0x30 [ 237.526242] ? cp_new_stat+0x150/0x180 [ 237.526247] ? do_vfs_ioctl+0xa4/0x640 [ 237.526278] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs] [ 237.526283] do_vfs_ioctl+0xa4/0x640 [ 237.526288] ? __do_sys_newfstat+0x3c/0x60 [ 237.526292] ksys_ioctl+0x70/0x80 [ 237.526297] __x64_sys_ioctl+0x16/0x20 [ 237.526303] do_syscall_64+0x5a/0x1c0 [ 237.526310] entry_SYSCALL_64_after_hwframe+0x49/0xbe That was due to btrfs_fs_device::aloc_tree being empty. Initially I thought this wasn't possible and as a percaution have put the assert in find_first_clear_extent_bit. Turns out this is indeed possible and could happen when a file system with SINGLE data/metadata profile has a 2nd device added. Until balance is run or a new chunk is allocated on this device it will be completely empty. In this case find_first_clear_extent_bit should return the full range [0, -1ULL] and let the caller handle this i.e for trim the end will be capped at the size of actual device. Link: https://lore.kernel.org/linux-btrfs/izW2WNyvy1dEDweBICizKnd2KDwDiDyY2EYQr4YCwk7pkuIpthx-JRn65MPBde00ND6V0_Lh8mW0kZwzDiLDv25pUYWxkskWNJnVP0kgdMA=@protonmail.com/ Fixes: 45bfcfc168f8 ("btrfs: Implement find_first_clear_extent_bit") CC: stable@vger.kernel.org # 5.2+ Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-31btrfs: flush write bio if we loop in extent_write_cache_pagesJosef Bacik1-1/+10
There exists a deadlock with range_cyclic that has existed forever. If we loop around with a bio already built we could deadlock with a writer who has the page locked that we're attempting to write but is waiting on a page in our bio to be written out. The task traces are as follows PID: 1329874 TASK: ffff889ebcdf3800 CPU: 33 COMMAND: "kworker/u113:5" #0 [ffffc900297bb658] __schedule at ffffffff81a4c33f #1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3 #2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42 #3 [ffffc900297bb708] __lock_page at ffffffff811f145b #4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502 #5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684 #6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff #7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0 #8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2 #9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd PID: 2167901 TASK: ffff889dc6a59c00 CPU: 14 COMMAND: "aio-dio-invalid" #0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f #1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3 #2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42 #3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6 #4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7 #5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359 #6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933 #7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8 #8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d #9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032 I used drgn to find the respective pages we were stuck on page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901 page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874 As you can see the kworker is waiting for bit 0 (PG_locked) on index 7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index 8148. aio-dio-invalid has 7680, and the kworker epd looks like the following crash> struct extent_page_data ffffc900297bbbb0 struct extent_page_data { bio = 0xffff889f747ed830, tree = 0xffff889eed6ba448, extent_locked = 0, sync_io = 0 } Probably worth mentioning as well that it waits for writeback of the page to complete while holding a lock on it (at prepare_pages()). Using drgn I walked the bio pages looking for page 0xffffea00fbfc7500 which is the one we're waiting for writeback on bio = Object(prog, 'struct bio', address=0xffff889f747ed830) for i in range(0, bio.bi_vcnt.value_()): bv = bio.bi_io_vec[i] if bv.bv_page.value_() == 0xffffea00fbfc7500: print("FOUND IT") which validated what I suspected. The fix for this is simple, flush the epd before we loop back around to the beginning of the file during writeout. Fixes: b293f02e1423 ("Btrfs: Add writepages support") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-31Btrfs: fix race between adding and putting tree mod seq elements and nodesFilipe Manana5-16/+8
There is a race between adding and removing elements to the tree mod log list and rbtree that can lead to use-after-free problems. Consider the following example that explains how/why the problems happens: 1) Task A has mod log element with sequence number 200. It currently is the only element in the mod log list; 2) Task A calls btrfs_put_tree_mod_seq() because it no longer needs to access the tree mod log. When it enters the function, it initializes 'min_seq' to (u64)-1. Then it acquires the lock 'tree_mod_seq_lock' before checking if there are other elements in the mod seq list. Since the list it empty, 'min_seq' remains set to (u64)-1. Then it unlocks the lock 'tree_mod_seq_lock'; 3) Before task A acquires the lock 'tree_mod_log_lock', task B adds itself to the mod seq list through btrfs_get_tree_mod_seq() and gets a sequence number of 201; 4) Some other task, name it task C, modifies a btree and because there elements in the mod seq list, it adds a tree mod elem to the tree mod log rbtree. That node added to the mod log rbtree is assigned a sequence number of 202; 5) Task B, which is doing fiemap and resolving indirect back references, calls btrfs get_old_root(), with 'time_seq' == 201, which in turn calls tree_mod_log_search() - the search returns the mod log node from the rbtree with sequence number 202, created by task C; 6) Task A now acquires the lock 'tree_mod_log_lock', starts iterating the mod log rbtree and finds the node with sequence number 202. Since 202 is less than the previously computed 'min_seq', (u64)-1, it removes the node and frees it; 7) Task B still has a pointer to the node with sequence number 202, and it dereferences the pointer itself and through the call to __tree_mod_log_rewind(), resulting in a use-after-free problem. This issue can be triggered sporadically with the test case generic/561 from fstests, and it happens more frequently with a higher number of duperemove processes. When it happens to me, it either freezes the VM or it produces a trace like the following before crashing: [ 1245.321140] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI [ 1245.321200] CPU: 1 PID: 26997 Comm: pool Not tainted 5.5.0-rc6-btrfs-next-52 #1 [ 1245.321235] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014 [ 1245.321287] RIP: 0010:rb_next+0x16/0x50 [ 1245.321307] Code: .... [ 1245.321372] RSP: 0018:ffffa151c4d039b0 EFLAGS: 00010202 [ 1245.321388] RAX: 6b6b6b6b6b6b6b6b RBX: ffff8ae221363c80 RCX: 6b6b6b6b6b6b6b6b [ 1245.321409] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8ae221363c80 [ 1245.321439] RBP: ffff8ae20fcc4688 R08: 0000000000000002 R09: 0000000000000000 [ 1245.321475] R10: ffff8ae20b120910 R11: 00000000243f8bb1 R12: 0000000000000038 [ 1245.321506] R13: ffff8ae221363c80 R14: 000000000000075f R15: ffff8ae223f762b8 [ 1245.321539] FS: 00007fdee1ec7700(0000) GS:ffff8ae236c80000(0000) knlGS:0000000000000000 [ 1245.321591] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1245.321614] CR2: 00007fded4030c48 CR3: 000000021da16003 CR4: 00000000003606e0 [ 1245.321642] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1245.321668] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1245.321706] Call Trace: [ 1245.321798] __tree_mod_log_rewind+0xbf/0x280 [btrfs] [ 1245.321841] btrfs_search_old_slot+0x105/0xd00 [btrfs] [ 1245.321877] resolve_indirect_refs+0x1eb/0xc60 [btrfs] [ 1245.321912] find_parent_nodes+0x3dc/0x11b0 [btrfs] [ 1245.321947] btrfs_check_shared+0x115/0x1c0 [btrfs] [ 1245.321980] ? extent_fiemap+0x59d/0x6d0 [btrfs] [ 1245.322029] extent_fiemap+0x59d/0x6d0 [btrfs] [ 1245.322066] do_vfs_ioctl+0x45a/0x750 [ 1245.322081] ksys_ioctl+0x70/0x80 [ 1245.322092] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 1245.322113] __x64_sys_ioctl+0x16/0x20 [ 1245.322126] do_syscall_64+0x5c/0x280 [ 1245.322139] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 1245.322155] RIP: 0033:0x7fdee3942dd7 [ 1245.322177] Code: .... [ 1245.322258] RSP: 002b:00007fdee1ec6c88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 1245.322294] RAX: ffffffffffffffda RBX: 00007fded40210d8 RCX: 00007fdee3942dd7 [ 1245.322314] RDX: 00007fded40210d8 RSI: 00000000c020660b RDI: 0000000000000004 [ 1245.322337] RBP: 0000562aa89e7510 R08: 0000000000000000 R09: 00007fdee1ec6d44 [ 1245.322369] R10: 0000000000000073 R11: 0000000000000246 R12: 00007fdee1ec6d48 [ 1245.322390] R13: 00007fdee1ec6d40 R14: 00007fded40210d0 R15: 00007fdee1ec6d50 [ 1245.322423] Modules linked in: .... [ 1245.323443] ---[ end trace 01de1e9ec5dff3cd ]--- Fix this by ensuring that btrfs_put_tree_mod_seq() computes the minimum sequence number and iterates the rbtree while holding the lock 'tree_mod_log_lock' in write mode. Also get rid of the 'tree_mod_seq_lock' lock, since it is now redundant. Fixes: bd989ba359f2ac ("Btrfs: add tree modification log functions") Fixes: 097b8a7c9e48e2 ("Btrfs: join tree mod log code with the code holding back delayed refs") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: free block groups after free'ing fs treesJosef Bacik1-2/+9
Sometimes when running generic/475 we would trip the WARN_ON(cache->reserved) check when free'ing the block groups on umount. This is because sometimes we don't commit the transaction because of IO errors and thus do not cleanup the tree logs until at umount time. These blocks are still reserved until they are cleaned up, but they aren't cleaned up until _after_ we do the free block groups work. Fix this by moving the free after free'ing the fs roots, that way all of the tree logs are cleaned up and we have a properly cleaned fs. A bunch of loops of generic/475 confirmed this fixes the problem. CC: stable@vger.kernel.org # 4.9+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: Fix split-brain handling when changing FSID to metadata uuidNikolay Borisov1-4/+38
Current code doesn't correctly handle the situation which arises when a file system that has METADATA_UUID_INCOMPAT flag set and has its FSID changed to the one in metadata uuid. This causes the incompat flag to disappear. In case of a power failure we could end up in a situation where part of the disks in a multi-disk filesystem are correctly reverted to METADATA_UUID_INCOMPAT flag unset state, while others have METADATA_UUID_INCOMPAT set and CHANGING_FSID_V2_IN_PROGRESS. This patch corrects the behavior required to handle the case where a disk of the second type is scanned first, creating the necessary btrfs_fs_devices. Subsequently, when a disk which has already completed the transition is scanned it should overwrite the data in btrfs_fs_devices. Reported-by: Su Yue <Damenly_Su@gmx.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: Handle another split brain scenario with metadata uuid featureNikolay Borisov1-3/+14
There is one more cases which isn't handled by the original metadata uuid work. Namely, when a filesystem has METADATA_UUID incompat bit and the user decides to change the FSID to the original one e.g. have metadata_uuid and fsid match. In case of power failure while this operation is in progress we could end up in a situation where some of the disks have the incompat bit removed and the other half have both METADATA_UUID_INCOMPAT and FSID_CHANGING_IN_PROGRESS flags. This patch handles the case where a disk that has successfully changed its FSID such that it equals METADATA_UUID is scanned first. Subsequently when a disk with both METADATA_UUID_INCOMPAT/FSID_CHANGING_IN_PROGRESS flags is scanned find_fsid_changed won't be able to find an appropriate btrfs_fs_devices. This is done by extending find_fsid_changed to correctly find btrfs_fs_devices whose metadata_uuid/fsid are the same and they match the metadata_uuid of the currently scanned device. Fixes: cc5de4e70256 ("btrfs: Handle final split-brain possibility during fsid change") Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reported-by: Su Yue <Damenly_Su@gmx.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: Factor out metadata_uuid code from find_fsid.Su Yue1-35/+42
find_fsid became rather hairy with the introduction of metadata uuid changing feature. Alleviate this by factoring out the metadata uuid specific code in a dedicated function which deals with finding correct fsid for a device with changed uuid. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Su Yue <Damenly_Su@gmx.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: Call find_fsid from find_fsid_inprogressSu Yue1-13/+6
Since find_fsid_inprogress should also handle the case in which an fs didn't change its FSID make it call find_fsid directly. This makes the code in device_list_add simpler by eliminating a conditional call of find_fsid. No functional changes. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Su Yue <Damenly_Su@gmx.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23Btrfs: fix infinite loop during fsync after rename operationsFilipe Manana1-0/+44
Recently fsstress (from fstests) sporadically started to trigger an infinite loop during fsync operations. This turned out to be because support for the rename exchange and whiteout operations was added to fsstress in fstests. These operations, unlike any others in fsstress, cause file names to be reused, whence triggering this issue. However it's not necessary to use rename exchange and rename whiteout operations trigger this issue, simple rename operations and file creations are enough to trigger the issue. The issue boils down to when we are logging inodes that conflict (that had the name of any inode we need to log during the fsync operation), we keep logging them even if they were already logged before, and after that we check if there's any other inode that conflicts with them and then add it again to the list of inodes to log. Skipping already logged inodes fixes the issue. Consider the following example: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ mkdir /mnt/testdir # inode 257 $ touch /mnt/testdir/zz # inode 258 $ ln /mnt/testdir/zz /mnt/testdir/zz_link $ touch /mnt/testdir/a # inode 259 $ sync # The following 3 renames achieve the same result as a rename exchange # operation (<rename_exchange> /mnt/testdir/zz_link to /mnt/testdir/a). $ mv /mnt/testdir/a /mnt/testdir/a/tmp $ mv /mnt/testdir/zz_link /mnt/testdir/a $ mv /mnt/testdir/a/tmp /mnt/testdir/zz_link # The following rename and file creation give the same result as a # rename whiteout operation (<rename_whiteout> zz to a2). $ mv /mnt/testdir/zz /mnt/testdir/a2 $ touch /mnt/testdir/zz # inode 260 $ xfs_io -c fsync /mnt/testdir/zz --> results in the infinite loop The following steps happen: 1) When logging inode 260, we find that its reference named "zz" was used by inode 258 in the previous transaction (through the commit root), so inode 258 is added to the list of conflicting indoes that need to be logged; 2) After logging inode 258, we find that its reference named "a" was used by inode 259 in the previous transaction, and therefore we add inode 259 to the list of conflicting inodes to be logged; 3) After logging inode 259, we find that its reference named "zz_link" was used by inode 258 in the previous transaction - we add inode 258 to the list of conflicting inodes to log, again - we had already logged it before at step 3. After logging it again, we find again that inode 259 conflicts with him, and we add again 259 to the list, etc - we end up repeating all the previous steps. So fix this by skipping logging of conflicting inodes that were already logged. Fixes: 6b5fc433a7ad67 ("Btrfs: fix fsync after succession of renames of different files") CC: stable@vger.kernel.org # 5.1+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: set trans->drity in btrfs_commit_transactionJosef Bacik1-0/+8
If we abort a transaction we have the following sequence if (!trans->dirty && list_empty(&trans->new_bgs)) return; WRITE_ONCE(trans->transaction->aborted, err); The idea being if we didn't modify anything with our trans handle then we don't really need to abort the whole transaction, maybe the other trans handles are fine and we can carry on. However in the case of create_snapshot we add a pending_snapshot object to our transaction and then commit the transaction. We don't actually modify anything. sync() behaves the same way, attach to an existing transaction and commit it. This means that if we have an IO error in the right places we could abort the committing transaction with our trans->dirty being not set and thus not set transaction->aborted. This is a problem because in the create_snapshot() case we depend on pending->error being set to something, or btrfs_commit_transaction returning an error. If we are not the trans handle that gets to commit the transaction, and we're waiting on the commit to happen we get our return value from cur_trans->aborted. If this was not set to anything because sync() hit an error in the transaction commit before it could modify anything then cur_trans->aborted would be 0. Thus we'd return 0 from btrfs_commit_transaction() in create_snapshot. This is a problem because we then try to do things with pending_snapshot->snap, which will be NULL because we didn't create the snapshot, and then we'll get a NULL pointer dereference like the following "BUG: kernel NULL pointer dereference, address: 00000000000001f0" RIP: 0010:btrfs_orphan_cleanup+0x2d/0x330 Call Trace: ? btrfs_mksubvol.isra.31+0x3f2/0x510 btrfs_mksubvol.isra.31+0x4bc/0x510 ? __sb_start_write+0xfa/0x200 ? mnt_want_write_file+0x24/0x50 btrfs_ioctl_snap_create_transid+0x16c/0x1a0 btrfs_ioctl_snap_create_v2+0x11e/0x1a0 btrfs_ioctl+0x1534/0x2c10 ? free_debug_processing+0x262/0x2a3 do_vfs_ioctl+0xa6/0x6b0 ? do_sys_open+0x188/0x220 ? syscall_trace_enter+0x1f8/0x330 ksys_ioctl+0x60/0x90 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x4a/0x1b0 In order to fix this we need to make sure anybody who calls commit_transaction has trans->dirty set so that they properly set the trans->transaction->aborted value properly so any waiters know bad things happened. This was found while I was running generic/475 with my modified fsstress, it reproduced within a few runs. I ran with this patch all night and didn't see the problem again. 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>
2020-01-23btrfs: drop log root for dropped rootsJosef Bacik1-10/+12
If we fsync on a subvolume and create a log root for that volume, and then later delete that subvolume we'll never clean up its log root. Fix this by making switch_commit_roots free the log for any dropped roots we encounter. The extra churn is because we need a btrfs_trans_handle, not the btrfs_transaction. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: sysfs, add devid/dev_state kobject and device attributesAnand Jain4-23/+138
New sysfs attributes that track the filesystem status of devices, stored in the per-filesystem directory in /sys/fs/btrfs/FSID/devinfo . There's a directory for each device, with name corresponding to the numerical device id. in_fs_metadata - device is in the list of fs metadata missing - device is missing (no device node or block device) replace_target - device is target of replace writeable - writes from fs are allowed These attributes reflect the state of the device::dev_state and created at mount time. Sample output: $ pwd /sys/fs/btrfs/6e1961f1-5918-4ecc-a22f-948897b409f7/devinfo/1/ $ ls in_fs_metadata missing replace_target writeable $ cat missing 0 The output from these attributes are 0 or 1. 0 indicates unset and 1 indicates set. These attributes are readonly. It is observed that the device delete thread and sysfs read thread will not race because the delete thread calls sysfs kobject_put() which in turn waits for existing sysfs read to complete. Note for device replace devid swap: During the replace the target device temporarily assumes devid 0 before assigning the devid of the soruce device. In btrfs_dev_replace_finishing() we remove source sysfs devid using the function btrfs_sysfs_remove_devices_attr(), so after that call kobject_rename() to update the devid in the sysfs. This adds and calls btrfs_sysfs_update_devid() helper function to update the device id. Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update changelog ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: Refactor btrfs_rmap_block to improve readabilityNikolay Borisov1-22/+33
Move variables to appropriate scope. Remove last BUG_ON in the function and rework error handling accordingly. Make the duplicate detection code more straightforward. Use in_range macro. And give variables more descriptive name by explicitly distinguishing between IO stripe size (size recorded in the chunk item) and data stripe size (the size of an actual stripe, constituting a logical chunk/block group). Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: Add self-tests for btrfs_rmap_blockNikolay Borisov1-1/+153
Add RAID1 and single testcases to verify that data stripes are excluded from super block locations and that the address mapping is valid. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update changelog ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: selftests: Add support for dummy devicesNikolay Borisov2-0/+30
Add basic infrastructure to create and link dummy btrfs_devices. This will be used in the pending btrfs_rmap_block test which deals with the block groups. Calling btrfs_alloc_dummy_device will link the newly created device to the passed fs_info and the test framework will free them once the test is finished. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: Move and unexport btrfs_rmap_blockNikolay Borisov4-71/+91
It's used only during initial block group reading to map physical address of super block to a list of logical ones. Make it private to block-group.c, add proper kernel doc and ensure it's exported only for tests. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23btrfs: separate definition of assertion failure handlersDavid Sterba1-8/+12
There's a report where objtool detects unreachable instructions, eg.: fs/btrfs/ctree.o: warning: objtool: btrfs_search_slot()+0x2d4: unreachable instruction This seems to be a false positive due to compiler version. The cause is in the ASSERT macro implementation that does the conditional check as IS_DEFINED(CONFIG_BTRFS_ASSERT) and not an #ifdef. To avoid that, use the ifdefs directly. There are still 2 reports that aren't fixed: fs/btrfs/extent_io.o: warning: objtool: __set_extent_bit()+0x71f: unreachable instruction fs/btrfs/relocation.o: warning: objtool: find_data_references()+0x4e0: unreachable instruction Co-developed-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: device stats, log when stats are zeroedAnand Jain1-0/+2
We had a report indicating that some read errors aren't reported by the device stats in the userland. It is important to have the errors reported in the device stat as user land scripts might depend on it to take the reasonable corrective actions. But to debug these issue we need to be really sure that request to reset the device stat did not come from the userland itself. So log an info message when device error reset happens. For example: BTRFS info (device sdc): device stats zeroed by btrfs(9223) Reported-by: philip@philip-seeger.de Link: https://www.spinics.net/lists/linux-btrfs/msg96528.html Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: fix improper setting of scanned for range cyclic write cache pagesJosef Bacik1-2/+10
We noticed that we were having regular CG OOM kills in cases where there was still enough dirty pages to avoid OOM'ing. It turned out there's this corner case in btrfs's handling of range_cyclic where files that were being redirtied were not getting fully written out because of how we do range_cyclic writeback. We unconditionally were setting scanned = 1; the first time we found any pages in the inode. This isn't actually what we want, we want it to be set if we've scanned the entire file. For range_cyclic we could be starting in the middle or towards the end of the file, so we could write one page and then not write any of the other dirty pages in the file because we set scanned = 1. Fix this by not setting scanned = 1 if we find pages. The rules for setting scanned should be 1) !range_cyclic. In this case we have a specified range to write out. 2) range_cyclic && index == 0. In this case we've started at the beginning and there is no need to loop around a second time. 3) range_cyclic && we started at index > 0 and we've reached the end of the file without satisfying our nr_to_write. This patch fixes both of our writepages implementations to make sure these rules hold true. This fixed our over zealous CG OOMs in production. Fixes: d1310b2e0cd9 ("Btrfs: Split the extent_map code into two parts") Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add comment ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: safely advance counter when looking up bio csumsDavid Sterba1-1/+2
Dan's smatch tool reports fs/btrfs/file-item.c:295 btrfs_lookup_bio_sums() warn: should this be 'count == -1' which points to the while (count--) loop. With count == 0 the check itself could decrement it to -1. There's a WARN_ON a few lines below that has never been seen in practice though. It turns out that the value of page_bytes_left matches the count (by sectorsize multiples). The loop never reaches the state where count would go to -1, because page_bytes_left == 0 is found first and this breaks out. For clarity, use only plain check on count (and only for positive value), decrement safely inside the loop. Any other discrepancy after the whole bio list processing should be reported by the exising WARN_ON_ONCE as well. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: remove unused member btrfs_device::workDavid Sterba1-2/+0
This is a leftover from recently removed bio scheduling framework. Fixes: ba8a9d079543 ("Btrfs: delete the entire async bio submission framework") Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: remove unnecessary wrapper get_alloc_profileJohannes Thumshirn1-6/+1
btrfs_get_alloc_profile() is a simple wrapper over get_alloc_profile(). The only difference is btrfs_get_alloc_profile() is visible to other functions in btrfs while get_alloc_profile() is static and thus only visible to functions in block-group.c. Let's just fold get_alloc_profile() into btrfs_get_alloc_profile() to get rid of the unnecessary second function. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Johannes Thumshirn <jth@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: add correction to handle -1 edge case in async discardDennis Zhou1-0/+22
From Dave's testing described below, it's possible to drive a file system to have bogus values of discardable_extents and _bytes. As btrfs_discard_calc_delay() is the only user of discardable_extents, we can correct here for any negative discardable_extents/discardable_bytes. The problem is not reliably reproducible. The workload that created it was based on linux git tree, switching between release tags, then everytihng deleted followed by a full rebalance. At this state the values of discardable_bytes was 16K and discardable_extents was -1, expected values 0 and 0. Repeating the workload again did not correct the bogus values so the offset seems to be stable once it happens. Reported-by: David Sterba <dsterba@suse.com> Signed-off-by: Dennis Zhou <dennis@kernel.org> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: ensure removal of discardable_* in free_bitmap()Dennis Zhou1-0/+14
Most callers of free_bitmap() only call it if bitmap_info->bytes is 0. However, there are certain cases where we may free the free space cache via __btrfs_remove_free_space_cache(). This exposes a path where free_bitmap() is called regardless. This may result in a bad accounting situation for discardable_bytes and discardable_extents. So, remove the stats and call btrfs_discard_update_discardable(). Signed-off-by: Dennis Zhou <dennis@kernel.org> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: make smaller extents more likely to go into bitmapsDennis Zhou1-2/+2
It's less than ideal for small extents to eat into our extent budget, so force extents <= 32KB into the bitmaps save for the first handful. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Dennis Zhou <dennis@kernel.org> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: increase the metadata allowance for the free_space_cacheDennis Zhou1-15/+11
Currently, there is no way for the free space cache to recover from being serviced by purely bitmaps because the extent threshold is set to 0 in recalculate_thresholds() when we surpass the metadata allowance. This adds a recovery mechanism by keeping large extents out of the bitmaps and increases the metadata upper bound to 64KB. The recovery mechanism bypasses this upper bound, thus making it a soft upper bound. But, with the bypass being 1MB or greater, it shouldn't add unbounded overhead. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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