5034388342
639 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
David Sterba
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43dd529abe |
btrfs: update function comments
Update, reformat or reword function comments. This also removes the kdoc marker so we don't get reports when the function name is missing. Changes made: - remove kdoc markers - reformat the brief description to be a proper sentence - reword to imperative voice - align parameter list - fix typos Signed-off-by: David Sterba <dsterba@suse.com> |
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Josef Bacik
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45c40c8f95 |
btrfs: move root tree prototypes to their own header
Move all the root-tree.c prototypes to root-tree.h, and then update all the necessary files to include the new header. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Josef Bacik
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a0231804af |
btrfs: move extent-tree helpers into their own header file
Move all the extent tree related prototypes to extent-tree.h out of ctree.h, and then go include it everywhere needed so everything compiles. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Omar Sandoval
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94a48aef49 |
btrfs: extend btrfs_dir_item type to store encryption status
For directories with encrypted files/filenames, we need to store a flag indicating this fact. There's no room in other fields, so we'll need to borrow a bit from dir_type. Since it's now a combination of type and flags, we rename it to dir_flags to reflect its new usage. The new flag, FT_ENCRYPTED, indicates a directory containing encrypted data, which is orthogonal to file type; therefore, add the new flag, and make conversion from directory type to file type strip the flag. As the file types almost never change we can afford to use the bits. Actual usage will be guarded behind an incompat bit, this patch only adds the support for later use by fscrypt. Signed-off-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Sweet Tea Dorminy
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6db7531882 |
btrfs: use struct fscrypt_str instead of struct qstr
While struct qstr is more natural without fscrypt, since it's provided by dentries, struct fscrypt_str is provided by the fscrypt handlers processing dentries, and is thus more natural in the fscrypt world. Replace all of the struct qstr uses with struct fscrypt_str. Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Sweet Tea Dorminy
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ab3c5c18e8 |
btrfs: setup qstr from dentrys using fscrypt helper
Most places where we get a struct qstr, we are doing so from a dentry. With fscrypt, the dentry's name may be encrypted on-disk, so fscrypt provides a helper to convert a dentry name to the appropriate disk name if necessary. Convert each of the dentry name accesses to use fscrypt_setup_filename(), then convert the resulting fscrypt_name back to an unencrypted qstr. This does not work for nokey names, but the specific locations that could spawn nokey names are noted. At present, since there are no encrypted directories, nothing goes down the filename encryption paths. Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Sweet Tea Dorminy
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e43eec81c5 |
btrfs: use struct qstr instead of name and namelen pairs
Many functions throughout btrfs take name buffer and name length arguments. Most of these functions at the highest level are usually called with these arguments extracted from a supplied dentry's name. But the entire name can be passed instead, making each function a little more elegant. Each function whose arguments are currently the name and length extracted from a dentry is herein converted to instead take a pointer to the name in the dentry. The couple of calls to these calls without a struct dentry are converted to create an appropriate qstr to pass in. Additionally, every function which is only called with a name/len extracted directly from a qstr is also converted. This change has positive effect on stack consumption, frame of many functions is reduced but this will be used in the future for fscrypt related structures. Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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David Sterba
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e2896e7910 |
btrfs: sink gfp_t parameter to btrfs_qgroup_trace_extent
All callers pass GFP_NOFS, we can drop the parameter and use it directly. Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Josef Bacik
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ad1ac5012c |
btrfs: move btrfs_map_token to accessors
This is specific to the item-accessor code, move it out of ctree.h into accessor.h/.c and then update the users to include the new header file. This un-inlines btrfs_init_map_token, however this is only called once per function so it's not critical to be inlined. This also saves 904 bytes of code on a release build. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Josef Bacik
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c7f13d428e |
btrfs: move fs wide helpers out of ctree.h
We have several fs wide related helpers in ctree.h. The bulk of these are the incompat flag test helpers, but there are things such as btrfs_fs_closing() and the read only helpers that also aren't directly related to the ctree code. Move these into a fs.h header, which will serve as the location for file system wide related helpers. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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796787c978 |
btrfs: do not modify log tree while holding a leaf from fs tree locked
When logging an inode in full mode, or when logging xattrs or when logging the dir index items of a directory, we are modifying the log tree while holding a read lock on a leaf from the fs/subvolume tree. This can lead to a deadlock in rare circumstances, but it is a real possibility, and it was recently reported by syzbot with the following trace from lockdep: WARNING: possible circular locking dependency detected 6.1.0-rc5-next-20221116-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/16154 is trying to acquire lock: ffff88807e3084a0 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0xa1/0xf30 fs/btrfs/delayed-inode.c:256 but task is already holding lock: ffff88807df33078 (btrfs-log-00){++++}-{3:3}, at: __btrfs_tree_lock+0x32/0x3d0 fs/btrfs/locking.c:197 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (btrfs-log-00){++++}-{3:3}: down_read_nested+0x9e/0x450 kernel/locking/rwsem.c:1634 __btrfs_tree_read_lock+0x32/0x350 fs/btrfs/locking.c:135 btrfs_tree_read_lock fs/btrfs/locking.c:141 [inline] btrfs_read_lock_root_node+0x82/0x3a0 fs/btrfs/locking.c:280 btrfs_search_slot_get_root fs/btrfs/ctree.c:1678 [inline] btrfs_search_slot+0x3ca/0x2c70 fs/btrfs/ctree.c:1998 btrfs_lookup_csum+0x116/0x3f0 fs/btrfs/file-item.c:209 btrfs_csum_file_blocks+0x40e/0x1370 fs/btrfs/file-item.c:1021 log_csums.isra.0+0x244/0x2d0 fs/btrfs/tree-log.c:4258 copy_items.isra.0+0xbfb/0xed0 fs/btrfs/tree-log.c:4403 copy_inode_items_to_log+0x13d6/0x1d90 fs/btrfs/tree-log.c:5873 btrfs_log_inode+0xb19/0x4680 fs/btrfs/tree-log.c:6495 btrfs_log_inode_parent+0x890/0x2a20 fs/btrfs/tree-log.c:6982 btrfs_log_dentry_safe+0x59/0x80 fs/btrfs/tree-log.c:7083 btrfs_sync_file+0xa41/0x13c0 fs/btrfs/file.c:1921 vfs_fsync_range+0x13e/0x230 fs/sync.c:188 generic_write_sync include/linux/fs.h:2856 [inline] iomap_dio_complete+0x73a/0x920 fs/iomap/direct-io.c:128 btrfs_direct_write fs/btrfs/file.c:1536 [inline] btrfs_do_write_iter+0xba2/0x1470 fs/btrfs/file.c:1668 call_write_iter include/linux/fs.h:2160 [inline] do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735 do_iter_write+0x182/0x700 fs/read_write.c:861 vfs_iter_write+0x74/0xa0 fs/read_write.c:902 iter_file_splice_write+0x745/0xc90 fs/splice.c:686 do_splice_from fs/splice.c:764 [inline] direct_splice_actor+0x114/0x180 fs/splice.c:931 splice_direct_to_actor+0x335/0x8a0 fs/splice.c:886 do_splice_direct+0x1ab/0x280 fs/splice.c:974 do_sendfile+0xb19/0x1270 fs/read_write.c:1255 __do_sys_sendfile64 fs/read_write.c:1323 [inline] __se_sys_sendfile64 fs/read_write.c:1309 [inline] __x64_sys_sendfile64+0x259/0x2c0 fs/read_write.c:1309 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #1 (btrfs-tree-00){++++}-{3:3}: __lock_release kernel/locking/lockdep.c:5382 [inline] lock_release+0x371/0x810 kernel/locking/lockdep.c:5688 up_write+0x2a/0x520 kernel/locking/rwsem.c:1614 btrfs_tree_unlock_rw fs/btrfs/locking.h:189 [inline] btrfs_unlock_up_safe+0x1e3/0x290 fs/btrfs/locking.c:238 search_leaf fs/btrfs/ctree.c:1832 [inline] btrfs_search_slot+0x265e/0x2c70 fs/btrfs/ctree.c:2074 btrfs_insert_empty_items+0xbd/0x1c0 fs/btrfs/ctree.c:4133 btrfs_insert_delayed_item+0x826/0xfa0 fs/btrfs/delayed-inode.c:746 btrfs_insert_delayed_items fs/btrfs/delayed-inode.c:824 [inline] __btrfs_commit_inode_delayed_items fs/btrfs/delayed-inode.c:1111 [inline] __btrfs_run_delayed_items+0x280/0x590 fs/btrfs/delayed-inode.c:1153 flush_space+0x147/0xe90 fs/btrfs/space-info.c:728 btrfs_async_reclaim_metadata_space+0x541/0xc10 fs/btrfs/space-info.c:1086 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289 worker_thread+0x669/0x1090 kernel/workqueue.c:2436 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 -> #0 (&delayed_node->mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747 __btrfs_release_delayed_node.part.0+0xa1/0xf30 fs/btrfs/delayed-inode.c:256 __btrfs_release_delayed_node fs/btrfs/delayed-inode.c:251 [inline] btrfs_release_delayed_node fs/btrfs/delayed-inode.c:281 [inline] btrfs_remove_delayed_node+0x52/0x60 fs/btrfs/delayed-inode.c:1285 btrfs_evict_inode+0x511/0xf30 fs/btrfs/inode.c:5554 evict+0x2ed/0x6b0 fs/inode.c:664 dispose_list+0x117/0x1e0 fs/inode.c:697 prune_icache_sb+0xeb/0x150 fs/inode.c:896 super_cache_scan+0x391/0x590 fs/super.c:106 do_shrink_slab+0x464/0xce0 mm/vmscan.c:843 shrink_slab_memcg mm/vmscan.c:912 [inline] shrink_slab+0x388/0x660 mm/vmscan.c:991 shrink_node_memcgs mm/vmscan.c:6088 [inline] shrink_node+0x93d/0x1f30 mm/vmscan.c:6117 shrink_zones mm/vmscan.c:6355 [inline] do_try_to_free_pages+0x3b4/0x17a0 mm/vmscan.c:6417 try_to_free_mem_cgroup_pages+0x3a4/0xa70 mm/vmscan.c:6732 reclaim_high.constprop.0+0x182/0x230 mm/memcontrol.c:2393 mem_cgroup_handle_over_high+0x190/0x520 mm/memcontrol.c:2578 try_charge_memcg+0xe0c/0x12f0 mm/memcontrol.c:2816 try_charge mm/memcontrol.c:2827 [inline] charge_memcg+0x90/0x3b0 mm/memcontrol.c:6889 __mem_cgroup_charge+0x2b/0x90 mm/memcontrol.c:6910 mem_cgroup_charge include/linux/memcontrol.h:667 [inline] __filemap_add_folio+0x615/0xf80 mm/filemap.c:852 filemap_add_folio+0xaf/0x1e0 mm/filemap.c:934 __filemap_get_folio+0x389/0xd80 mm/filemap.c:1976 pagecache_get_page+0x2e/0x280 mm/folio-compat.c:104 find_or_create_page include/linux/pagemap.h:612 [inline] alloc_extent_buffer+0x2b9/0x1580 fs/btrfs/extent_io.c:4588 btrfs_init_new_buffer fs/btrfs/extent-tree.c:4869 [inline] btrfs_alloc_tree_block+0x2e1/0x1320 fs/btrfs/extent-tree.c:4988 __btrfs_cow_block+0x3b2/0x1420 fs/btrfs/ctree.c:440 btrfs_cow_block+0x2fa/0x950 fs/btrfs/ctree.c:595 btrfs_search_slot+0x11b0/0x2c70 fs/btrfs/ctree.c:2038 btrfs_update_root+0xdb/0x630 fs/btrfs/root-tree.c:137 update_log_root fs/btrfs/tree-log.c:2841 [inline] btrfs_sync_log+0xbfb/0x2870 fs/btrfs/tree-log.c:3064 btrfs_sync_file+0xdb9/0x13c0 fs/btrfs/file.c:1947 vfs_fsync_range+0x13e/0x230 fs/sync.c:188 generic_write_sync include/linux/fs.h:2856 [inline] iomap_dio_complete+0x73a/0x920 fs/iomap/direct-io.c:128 btrfs_direct_write fs/btrfs/file.c:1536 [inline] btrfs_do_write_iter+0xba2/0x1470 fs/btrfs/file.c:1668 call_write_iter include/linux/fs.h:2160 [inline] do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735 do_iter_write+0x182/0x700 fs/read_write.c:861 vfs_iter_write+0x74/0xa0 fs/read_write.c:902 iter_file_splice_write+0x745/0xc90 fs/splice.c:686 do_splice_from fs/splice.c:764 [inline] direct_splice_actor+0x114/0x180 fs/splice.c:931 splice_direct_to_actor+0x335/0x8a0 fs/splice.c:886 do_splice_direct+0x1ab/0x280 fs/splice.c:974 do_sendfile+0xb19/0x1270 fs/read_write.c:1255 __do_sys_sendfile64 fs/read_write.c:1323 [inline] __se_sys_sendfile64 fs/read_write.c:1309 [inline] __x64_sys_sendfile64+0x259/0x2c0 fs/read_write.c:1309 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Chain exists of: &delayed_node->mutex --> btrfs-tree-00 --> btrfs-log-00 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-log-00); lock(btrfs-tree-00); lock(btrfs-log-00); lock(&delayed_node->mutex); Holding a read lock on a leaf from a fs/subvolume tree creates a nasty lock dependency when we are COWing extent buffers for the log tree and we have two tasks modifying the log tree, with each one in one of the following 2 scenarios: 1) Modifying the log tree triggers an extent buffer allocation while holding a write lock on a parent extent buffer from the log tree. Allocating the pages for an extent buffer, or the extent buffer struct, can trigger inode eviction and finally the inode eviction will trigger a release/remove of a delayed node, which requires taking the delayed node's mutex; 2) Allocating a metadata extent for a log tree can trigger the async reclaim thread and make us wait for it to release enough space and unblock our reservation ticket. The reclaim thread can start flushing delayed items, and that in turn results in the need to lock delayed node mutexes and in the need to write lock extent buffers of a subvolume tree - all this while holding a write lock on the parent extent buffer in the log tree. So one task in scenario 1) running in parallel with another task in scenario 2) could lead to a deadlock, one wanting to lock a delayed node mutex while having a read lock on a leaf from the subvolume, while the other is holding the delayed node's mutex and wants to write lock the same subvolume leaf for flushing delayed items. Fix this by cloning the leaf of the fs/subvolume tree, release/unlock the fs/subvolume leaf and use the clone leaf instead. Reported-by: syzbot+9b7c21f486f5e7f8d029@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/000000000000ccc93c05edc4d8cf@google.com/ CC: stable@vger.kernel.org # 6.0+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Josef Bacik
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26ce911446 |
btrfs: make can_nocow_extent nowait compatible
If we have NOWAIT specified on our IOCB and we're writing into a PREALLOC or NOCOW extent then we need to be able to tell can_nocow_extent that we don't want to wait on any locks or metadata IO. Fix can_nocow_extent to allow for NOWAIT. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Stefan Roesch <shr@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Josef Bacik
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570eb97bac |
btrfs: unify the lock/unlock extent variants
We have two variants of lock/unlock extent, one set that takes a cached state, another that does not. This is slightly annoying, and generally speaking there are only a few places where we don't have a cached state. Simplify this by making lock_extent/unlock_extent the only variant and make it take a cached state, then convert all the callers appropriately. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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7059c65831 |
btrfs: simplify adding and replacing references during log replay
During log replay, when adding/replacing inode references, there are two special cases that have special code for them: 1) When we have an inode with two or more hardlinks in the same directory, therefore two or more names encoded in the same inode reference item, and one of the hard links gets renamed to the old name of another hard link - that is, the index number for a name changes. This was added in commit |
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Filipe Manana
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30b80f3ce0 |
btrfs: use delayed items when logging a directory
When logging a directory we start by flushing all its delayed items. That results in adding dir index items to the subvolume btree, for new dentries, and removing dir index items from the subvolume btree for any dentries that were deleted. This makes it straightforward to log a directory simply by iterating over all the modified subvolume btree leaves, especially when we used to log both dir index keys and dir item keys (before commit |
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Filipe Manana
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5557a069f3 |
btrfs: skip logging parent dir when conflicting inode is not a dir
When we find a conflicting inode (an inode that had the same name and parent directory as the inode we are logging now) that was deleted in the current transaction, we always end up logging its parent directory. This is to deal with the case where the conflicting inode corresponds to a deleted subvolume/snapshot or a directory that had subvolumes/snapshots (or some subdirectory inside it had subvolumes/snapshots, etc), because we can't deal with dropping subvolumes/snapshots during log replay. So if we log the parent directory, and if we are dealing with these special cases, then we fallback to a transaction commit when logging the parent, because its last_unlink_trans will match the current transaction (which gets set and propagated when a subvolume/snapshot is deleted). This change skips the logging of the parent directory when the conflicting inode is not a directory (or a subvolume/snapshot). This is ok because in this case logging the current inode is enough to trigger an unlink of the conflicting inode during log replay. So for a case like this: $ mkdir /mnt/dir $ echo -n "first foo data" > /mnt/dir/foo $ sync $ rm -f /mnt/dir/foo $ echo -n "second foo data" > /mnt/dir/foo $ xfs_io -c "fsync" /mnt/dir/foo We avoid logging parent directory "dir" when logging the new file "foo". In other cases it avoids falling back to a transaction commit, when the parent directory has a last_unlink_trans value that matches the current transaction, due to moving a file from it to some other directory. This is a case that happens frequently with dbench for example, where a new file that has the name/parent of another file that was deleted in the current transaction, is fsynced. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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e09d94c9e4 |
btrfs: log conflicting inodes without holding log mutex of the initial inode
When logging an inode, if we detect the inode has a reference that conflicts with some other inode that got renamed, we log that other inode while holding the log mutex of the current inode. We then find out if there are other inodes that conflict with the first conflicting inode, and log them while under the log mutex of the original inode. This is fine because the recursion can only happen once. For the upcoming work where we directly log delayed items without flushing them first to the subvolume tree, this recursion adds a lot of complexity and it's hard to keep lockdep happy about it. So collect a list of conflicting inodes and then log the inodes after unlocking the log mutex of the inode we started with. Also limit the maximum number of conflict inodes we log to 10, to avoid spending too much time logging (and maybe allocating too many list elements too), as typically we don't have more than 1 or 2 conflicting inodes - if we go over the limit, simply fallback to a transaction commit. It is possible to have a very long list of conflicting inodes to be intentionally created by a user if he/she creates a very long succession of renames like this: (...) rename E to F rename D to E rename C to D rename B to C rename A to B touch A (create a new file named A) fsync A If that happened for a sequence of hundreds or thousands of renames, it could massively slow down the logging and cause other secondary effects like for example blocking other fsync operations and transaction commits for a very long time (assuming it wouldn't run into -ENOSPC or -ENOMEM first). However such cases are very uncommon to happen in practice, nevertheless it's better to be prepared for them and avoid chaos. Such long sequence of conflicting inodes could be created before this change. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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f6d86dbeba |
btrfs: move log_new_dir_dentries() above btrfs_log_inode()
The static function log_new_dir_dentries() is currently defined below btrfs_log_inode(), but in an upcoming patch a new function is introduced that is called by btrfs_log_inode() and this new function needs to call log_new_dir_dentries(). So move log_new_dir_dentries() to a location between btrfs_log_inode() and need_log_inode() (the later is called by log_new_dir_dentries()). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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a375102426 |
btrfs: move need_log_inode() to above log_conflicting_inodes()
The static function need_log_inode() is defined below btrfs_log_inode() and log_conflicting_inodes(), but in the next patches in the series we will need to call need_log_inode() in a couple new functions that will be used by btrfs_log_inode(). So move its definition to a location above log_conflicting_inodes(). Also make its arguments 'const', since they are not supposed to be modified. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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193df62457 |
btrfs: search for last logged dir index if it's not cached in the inode
The key offset of the last dir index item that was logged is stored in the inode's last_dir_index_offset field. However that field is not persisted in the inode item or elsewhere, so if the inode gets evicted and reloaded, it gets a value of (u64)-1, so that when we are logging dir index items we check if they were logged before, to avoid attempts to insert duplicated keys and fallback to a transaction commit. Improve on this by searching for the last dir index that was logged when we start logging a directory if the inode's last_dir_index_offset is not set (has a value of (u64)-1) and it was logged before. This avoids checking if each dir index item we find was already logged before, and simplifies the logging of dir index items (process_dir_items_leaf()). This will also be needed for an incoming change where we start logging delayed items directly, without flushing them first. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Filipe Manana
|
009d9bea49 |
btrfs: avoid memory allocation at log_new_dir_dentries() for common case
At log_new_dir_dentries() we always start by allocating a list element for the starting inode and then do a while loop with the condition being a list emptiness check. This however is not needed, we can avoid allocating this initial list element and then just check for the list emptiness at the end of the loop's body. So just do that to save one memory allocation from the kmalloc-32 slab. This allows for not doing any memory allocation when we don't have any subdirectory to log, which is a very common case. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Filipe Manana
|
4008481343 |
btrfs: free list element sooner at log_new_dir_dentries()
At log_new_dir_dentries(), there's no need to keep the current list element allocated while processing the leaves with directory items for the current directory, and while logging other inodes. Plus in case we find a subdirectory, we also end up allocating a new list element while the current one is still allocated, temporarily using more memory than necessary. So free the current list element early on, before processing leaves. Also make the removal and release of all list elements in case of an error more simple by eliminating the label and goto, adding an explicit loop to release all list elements in case an error happens. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Filipe Manana
|
b96c552b99 |
btrfs: update stale comment for log_new_dir_dentries()
The comment refers to the function log_dir_items() in order to check why
the inodes of new directory entries need to be logged, but the relevant
comments are no longer at log_dir_items(), they were moved to the function
process_dir_items_leaf() in commit
|
||
|
Filipe Manana
|
8786a6d740 |
btrfs: remove the root argument from log_new_dir_dentries()
There's no point in passing a root argument to log_new_dir_dentries() because it always corresponds to the root of the given inode. So remove it and extract the root from the given inode. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Filipe Manana
|
04fc7d5123 |
btrfs: don't drop dir index range items when logging a directory
When logging a directory that was previously logged in the current
transaction, we drop all the range items (BTRFS_DIR_LOG_INDEX_KEY key
type). This is because we will process all leaves in the subvolume's tree
that were changed in the current transaction and then add range items for
covering new dir index items and deleted dir index items, which could
cover now a larger range than before.
We used to fail if we tried to insert a range item key that already
exists, so we dropped all range items to avoid failing. However nowadays,
since commit
|
||
|
Omar Sandoval
|
d1f68ba069 |
btrfs: rename btrfs_insert_file_extent() to btrfs_insert_hole_extent()
btrfs_insert_file_extent() is only ever used to insert holes, so rename it and remove the redundant parameters. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Filipe Manana
|
769030e118 |
btrfs: fix warning during log replay when bumping inode link count
During log replay, at add_link(), we may increment the link count of
another inode that has a reference that conflicts with a new reference
for the inode currently being processed.
During log replay, at add_link(), we may drop (unlink) a reference from
some inode in the subvolume tree if that reference conflicts with a new
reference found in the log for the inode we are currently processing.
After the unlink, If the link count has decreased from 1 to 0, then we
increment the link count to prevent the inode from being deleted if it's
evicted by an iput() call, because we may have references to add to that
inode later on (and we will fixup its link count later during log replay).
However incrementing the link count from 0 to 1 triggers a warning:
$ cat fs/inode.c
(...)
void inc_nlink(struct inode *inode)
{
if (unlikely(inode->i_nlink == 0)) {
WARN_ON(!(inode->i_state & I_LINKABLE));
atomic_long_dec(&inode->i_sb->s_remove_count);
}
(...)
The I_LINKABLE flag is only set when creating an O_TMPFILE file, so it's
never set during log replay.
Most of the time, the warning isn't triggered even if we dropped the last
reference of the conflicting inode, and this is because:
1) The conflicting inode was previously marked for fixup, through a call
to link_to_fixup_dir(), which increments the inode's link count;
2) And the last iput() on the inode has not triggered eviction of the
inode, nor was eviction triggered after the iput(). So at add_link(),
even if we unlink the last reference of the inode, its link count ends
up being 1 and not 0.
So this means that if eviction is triggered after link_to_fixup_dir() is
called, at add_link() we will read the inode back from the subvolume tree
and have it with a correct link count, matching the number of references
it has on the subvolume tree. So if when we are at add_link() the inode
has exactly one reference only, its link count is 1, and after the unlink
its link count becomes 0.
So fix this by using set_nlink() instead of inc_nlink(), as the former
accepts a transition from 0 to 1 and it's what we use in other similar
contexts (like at link_to_fixup_dir().
Also make add_inode_ref() use set_nlink() instead of inc_nlink() to
bump the link count from 0 to 1.
The warning is actually harmless, but it may scare users. Josef also ran
into it recently.
CC: stable@vger.kernel.org # 5.1+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
||
|
Filipe Manana
|
7a6b75b799 |
btrfs: fix lost error handling when looking up extended ref on log replay
During log replay, when processing inode references, if we get an error
when looking up for an extended reference at __add_inode_ref(), we ignore
it and proceed, returning success (0) if no other error happens after the
lookup. This is obviously wrong because in case an extended reference
exists and it encodes some name not in the log, we need to unlink it,
otherwise the filesystem state will not match the state it had after the
last fsync.
So just make __add_inode_ref() return an error it gets from the extended
reference lookup.
Fixes:
|
||
|
Filipe Manana
|
723df2bcc9 |
btrfs: join running log transaction when logging new name
When logging a new name, in case of a rename, we pin the log before changing it. We then either delete a directory entry from the log or insert a key range item to mark the old name for deletion on log replay. However when doing one of those log changes we may have another task that started writing out the log (at btrfs_sync_log()) and it started before we pinned the log root. So we may end up changing a log tree while its writeback is being started by another task syncing the log. This can lead to inconsistencies in a log tree and other unexpected results during log replay, because we can get some committed node pointing to a node/leaf that ends up not getting written to disk before the next log commit. The problem, conceptually, started to happen in commit |
||
|
Josef Bacik
|
f31f09f6be |
btrfs: tree-log: make the return value for log syncing consistent
Currently we will return 1 or -EAGAIN if we decide we need to commit the transaction rather than sync the log. In practice this doesn't really matter, we interpret any !0 and !BTRFS_NO_LOG_SYNC as needing to commit the transaction. However this makes it hard to figure out what the correct thing to do is. Fix this up by defining BTRFS_LOG_FORCE_COMMIT and using this in all the places where we want to force the transaction to be committed. CC: stable@vger.kernel.org # 5.15+ 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> |
||
|
David Sterba
|
143823cf4d |
btrfs: fix typos in comments
Codespell has found a few typos. Signed-off-by: David Sterba <dsterba@suse.com> |
||
Lv Ruyi
|
8aa1e49ea1 |
btrfs: remove unnecessary check of iput argument
iput() already handles NULL and non-NULL parameter, so it is not needed to check that. This unifies all iput calls. Reported-by: Zeal Robot <zealci@zte.com.cn> Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Filipe Manana
|
6a2e9dc46f |
btrfs: remove trivial wrapper btrfs_read_buffer()
The function btrfs_read_buffer() is useless, it just calls btree_read_extent_buffer_pages() with exactly the same arguments. So remove it and rename btree_read_extent_buffer_pages() to btrfs_read_extent_buffer(), which is a shorter name, has the "btrfs_" prefix (since it's used outside disk-io.c) and the name is clear enough about what it does. 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> |
||
|
Filipe Manana
|
750ee45490 |
btrfs: fix assertion failure when logging directory key range item
When inserting a key range item (BTRFS_DIR_LOG_INDEX_KEY) while logging
a directory, we don't expect the insertion to fail with -EEXIST, because
we are holding the directory's log_mutex and we have dropped all existing
BTRFS_DIR_LOG_INDEX_KEY keys from the log tree before we started to log
the directory. However it's possible that during the logging we attempt
to insert the same BTRFS_DIR_LOG_INDEX_KEY key twice, but for this to
happen we need to race with insertions of items from other inodes in the
subvolume's tree while we are logging a directory. Here's how this can
happen:
1) We are logging a directory with inode number 1000 that has its items
spread across 3 leaves in the subvolume's tree:
leaf A - has index keys from the range 2 to 20 for example. The last
item in the leaf corresponds to a dir item for index number 20. All
these dir items were created in a past transaction.
leaf B - has index keys from the range 22 to 100 for example. It has
no keys from other inodes, all its keys are dir index keys for our
directory inode number 1000. Its first key is for the dir item with
a sequence number of 22. All these dir items were also created in a
past transaction.
leaf C - has index keys for our directory for the range 101 to 120 for
example. This leaf also has items from other inodes, and its first
item corresponds to the dir item for index number 101 for our directory
with inode number 1000;
2) When we finish processing the items from leaf A at log_dir_items(),
we log a BTRFS_DIR_LOG_INDEX_KEY key with an offset of 21 and a last
offset of 21, meaning the log is authoritative for the index range
from 21 to 21 (a single sequence number). At this point leaf B was
not yet modified in the current transaction;
3) When we return from log_dir_items() we have released our read lock on
leaf B, and have set *last_offset_ret to 21 (index number of the first
item on leaf B minus 1);
4) Some other task inserts an item for other inode (inode number 1001 for
example) into leaf C. That resulted in pushing some items from leaf C
into leaf B, in order to make room for the new item, so now leaf B
has dir index keys for the sequence number range from 22 to 102 and
leaf C has the dir items for the sequence number range 103 to 120;
5) At log_directory_changes() we call log_dir_items() again, passing it
a 'min_offset' / 'min_key' value of 22 (*last_offset_ret from step 3
plus 1, so 21 + 1). Then btrfs_search_forward() leaves us at slot 0
of leaf B, since leaf B was modified in the current transaction.
We have also initialized 'last_old_dentry_offset' to 20 after calling
btrfs_previous_item() at log_dir_items(), as it left us at the last
item of leaf A, which refers to the dir item with sequence number 20;
6) We then call process_dir_items_leaf() to process the dir items of
leaf B, and when we process the first item, corresponding to slot 0,
sequence number 22, we notice the dir item was created in a past
transaction and its sequence number is greater than the value of
*last_old_dentry_offset + 1 (20 + 1), so we decide to log again a
BTRFS_DIR_LOG_INDEX_KEY key with an offset of 21 and an end range
of 21 (key.offset - 1 == 22 - 1 == 21), which results in an -EEXIST
error from insert_dir_log_key(), as we have already inserted that
key at step 2, triggering the assertion at process_dir_items_leaf().
The trace produced in dmesg is like the following:
assertion failed: ret != -EEXIST, in fs/btrfs/tree-log.c:3857
[198255.980839][ T7460] ------------[ cut here ]------------
[198255.981666][ T7460] kernel BUG at fs/btrfs/ctree.h:3617!
[198255.983141][ T7460] invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
[198255.984080][ T7460] CPU: 0 PID: 7460 Comm: repro-ghost-dir Not tainted 5.18.0-5314c78ac373-misc-next+
[198255.986027][ T7460] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
[198255.988600][ T7460] RIP: 0010:assertfail.constprop.0+0x1c/0x1e
[198255.989465][ T7460] Code: 8b 4c 89 (...)
[198255.992599][ T7460] RSP: 0018:ffffc90007387188 EFLAGS: 00010282
[198255.993414][ T7460] RAX: 000000000000003d RBX: 0000000000000065 RCX: 0000000000000000
[198255.996056][ T7460] RDX: 0000000000000001 RSI: ffffffff8b62b180 RDI: fffff52000e70e24
[198255.997668][ T7460] RBP: ffffc90007387188 R08: 000000000000003d R09: ffff8881f0e16507
[198255.999199][ T7460] R10: ffffed103e1c2ca0 R11: 0000000000000001 R12: 00000000ffffffef
[198256.000683][ T7460] R13: ffff88813befc630 R14: ffff888116c16e70 R15: ffffc90007387358
[198256.007082][ T7460] FS: 00007fc7f7c24640(0000) GS:ffff8881f0c00000(0000) knlGS:0000000000000000
[198256.009939][ T7460] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[198256.014133][ T7460] CR2: 0000560bb16d0b78 CR3: 0000000140b34005 CR4: 0000000000170ef0
[198256.015239][ T7460] Call Trace:
[198256.015674][ T7460] <TASK>
[198256.016313][ T7460] log_dir_items.cold+0x16/0x2c
[198256.018858][ T7460] ? replay_one_extent+0xbf0/0xbf0
[198256.025932][ T7460] ? release_extent_buffer+0x1d2/0x270
[198256.029658][ T7460] ? rcu_read_lock_sched_held+0x16/0x80
[198256.031114][ T7460] ? lock_acquired+0xbe/0x660
[198256.032633][ T7460] ? rcu_read_lock_sched_held+0x16/0x80
[198256.034386][ T7460] ? lock_release+0xcf/0x8a0
[198256.036152][ T7460] log_directory_changes+0xf9/0x170
[198256.036993][ T7460] ? log_dir_items+0xba0/0xba0
[198256.037661][ T7460] ? do_raw_write_unlock+0x7d/0xe0
[198256.038680][ T7460] btrfs_log_inode+0x233b/0x26d0
[198256.041294][ T7460] ? log_directory_changes+0x170/0x170
[198256.042864][ T7460] ? btrfs_attach_transaction_barrier+0x60/0x60
[198256.045130][ T7460] ? rcu_read_lock_sched_held+0x16/0x80
[198256.046568][ T7460] ? lock_release+0xcf/0x8a0
[198256.047504][ T7460] ? lock_downgrade+0x420/0x420
[198256.048712][ T7460] ? ilookup5_nowait+0x81/0xa0
[198256.049747][ T7460] ? lock_downgrade+0x420/0x420
[198256.050652][ T7460] ? do_raw_spin_unlock+0xa9/0x100
[198256.051618][ T7460] ? __might_resched+0x128/0x1c0
[198256.052511][ T7460] ? __might_sleep+0x66/0xc0
[198256.053442][ T7460] ? __kasan_check_read+0x11/0x20
[198256.054251][ T7460] ? iget5_locked+0xbd/0x150
[198256.054986][ T7460] ? run_delayed_iput_locked+0x110/0x110
[198256.055929][ T7460] ? btrfs_iget+0xc7/0x150
[198256.056630][ T7460] ? btrfs_orphan_cleanup+0x4a0/0x4a0
[198256.057502][ T7460] ? free_extent_buffer+0x13/0x20
[198256.058322][ T7460] btrfs_log_inode+0x2654/0x26d0
[198256.059137][ T7460] ? log_directory_changes+0x170/0x170
[198256.060020][ T7460] ? rcu_read_lock_sched_held+0x16/0x80
[198256.060930][ T7460] ? rcu_read_lock_sched_held+0x16/0x80
[198256.061905][ T7460] ? lock_contended+0x770/0x770
[198256.062682][ T7460] ? btrfs_log_inode_parent+0xd04/0x1750
[198256.063582][ T7460] ? lock_downgrade+0x420/0x420
[198256.064432][ T7460] ? preempt_count_sub+0x18/0xc0
[198256.065550][ T7460] ? __mutex_lock+0x580/0xdc0
[198256.066654][ T7460] ? stack_trace_save+0x94/0xc0
[198256.068008][ T7460] ? __kasan_check_write+0x14/0x20
[198256.072149][ T7460] ? __mutex_unlock_slowpath+0x12a/0x430
[198256.073145][ T7460] ? mutex_lock_io_nested+0xcd0/0xcd0
[198256.074341][ T7460] ? wait_for_completion_io_timeout+0x20/0x20
[198256.075345][ T7460] ? lock_downgrade+0x420/0x420
[198256.076142][ T7460] ? lock_contended+0x770/0x770
[198256.076939][ T7460] ? do_raw_spin_lock+0x1c0/0x1c0
[198256.078401][ T7460] ? btrfs_sync_file+0x5e6/0xa40
[198256.080598][ T7460] btrfs_log_inode_parent+0x523/0x1750
[198256.081991][ T7460] ? wait_current_trans+0xc8/0x240
[198256.083320][ T7460] ? lock_downgrade+0x420/0x420
[198256.085450][ T7460] ? btrfs_end_log_trans+0x70/0x70
[198256.086362][ T7460] ? rcu_read_lock_sched_held+0x16/0x80
[198256.087544][ T7460] ? lock_release+0xcf/0x8a0
[198256.088305][ T7460] ? lock_downgrade+0x420/0x420
[198256.090375][ T7460] ? dget_parent+0x8e/0x300
[198256.093538][ T7460] ? do_raw_spin_lock+0x1c0/0x1c0
[198256.094918][ T7460] ? lock_downgrade+0x420/0x420
[198256.097815][ T7460] ? do_raw_spin_unlock+0xa9/0x100
[198256.101822][ T7460] ? dget_parent+0xb7/0x300
[198256.103345][ T7460] btrfs_log_dentry_safe+0x48/0x60
[198256.105052][ T7460] btrfs_sync_file+0x629/0xa40
[198256.106829][ T7460] ? start_ordered_ops.constprop.0+0x120/0x120
[198256.109655][ T7460] ? __fget_files+0x161/0x230
[198256.110760][ T7460] vfs_fsync_range+0x6d/0x110
[198256.111923][ T7460] ? start_ordered_ops.constprop.0+0x120/0x120
[198256.113556][ T7460] __x64_sys_fsync+0x45/0x70
[198256.114323][ T7460] do_syscall_64+0x5c/0xc0
[198256.115084][ T7460] ? syscall_exit_to_user_mode+0x3b/0x50
[198256.116030][ T7460] ? do_syscall_64+0x69/0xc0
[198256.116768][ T7460] ? do_syscall_64+0x69/0xc0
[198256.117555][ T7460] ? do_syscall_64+0x69/0xc0
[198256.118324][ T7460] ? sysvec_call_function_single+0x57/0xc0
[198256.119308][ T7460] ? asm_sysvec_call_function_single+0xa/0x20
[198256.120363][ T7460] entry_SYSCALL_64_after_hwframe+0x44/0xae
[198256.121334][ T7460] RIP: 0033:0x7fc7fe97b6ab
[198256.122067][ T7460] Code: 0f 05 48 (...)
[198256.125198][ T7460] RSP: 002b:00007fc7f7c23950 EFLAGS: 00000293 ORIG_RAX: 000000000000004a
[198256.126568][ T7460] RAX: ffffffffffffffda RBX: 00007fc7f7c239f0 RCX: 00007fc7fe97b6ab
[198256.127942][ T7460] RDX: 0000000000000002 RSI: 000056167536bcf0 RDI: 0000000000000004
[198256.129302][ T7460] RBP: 0000000000000004 R08: 0000000000000000 R09: 000000007ffffeb8
[198256.130670][ T7460] R10: 00000000000001ff R11: 0000000000000293 R12: 0000000000000001
[198256.132046][ T7460] R13: 0000561674ca8140 R14: 00007fc7f7c239d0 R15: 000056167536dab8
[198256.133403][ T7460] </TASK>
Fix this by treating -EEXIST as expected at insert_dir_log_key() and have
it update the item with an end offset corresponding to the maximum between
the previously logged end offset and the new requested end offset. The end
offsets may be different due to dir index key deletions that happened as
part of unlink operations while we are logging a directory (triggered when
fsyncing some other inode parented by the directory) or during renames
which always attempt to log a single dir index deletion.
Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Link: https://lore.kernel.org/linux-btrfs/YmyefE9mc2xl5ZMz@hungrycats.org/
Fixes:
|
||
|
Filipe Manana
|
d0e64a981f |
btrfs: always log symlinks in full mode
On Linux, empty symlinks are invalid, and attempting to create one with the system call symlink(2) results in an -ENOENT error and this is explicitly documented in the man page. If we rename a symlink that was created in the current transaction and its parent directory was logged before, we actually end up logging the symlink without logging its content, which is stored in an inline extent. That means that after a power failure we can end up with an empty symlink, having no content and an i_size of 0 bytes. It can be easily reproduced like this: $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt $ mkdir /mnt/testdir $ sync # Create a file inside the directory and fsync the directory. $ touch /mnt/testdir/foo $ xfs_io -c "fsync" /mnt/testdir # Create a symlink inside the directory and then rename the symlink. $ ln -s /mnt/testdir/foo /mnt/testdir/bar $ mv /mnt/testdir/bar /mnt/testdir/baz # Now fsync again the directory, this persist the log tree. $ xfs_io -c "fsync" /mnt/testdir <power failure> $ mount /dev/sdc /mnt $ stat -c %s /mnt/testdir/baz 0 $ readlink /mnt/testdir/baz $ Fix this by always logging symlinks in full mode (LOG_INODE_ALL), so that their content is also logged. A test case for fstests will follow. CC: stable@vger.kernel.org # 4.9+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Filipe Manana
|
50ff57888d |
btrfs: fix leaked plug after failure syncing log on zoned filesystems
On a zoned filesystem, if we fail to allocate the root node for the log
root tree while syncing the log, we end up returning without finishing
the IO plug we started before, resulting in leaking resources as we
have started writeback for extent buffers of a log tree before. That
allocation failure, which typically is either -ENOMEM or -ENOSPC, is not
fatal and the fsync can safely fallback to a full transaction commit.
So release the IO plug if we fail to allocate the extent buffer for the
root of the log root tree when syncing the log on a zoned filesystem.
Fixes:
|
||
|
Filipe Manana
|
313ab75399 |
btrfs: add and use helper for unlinking inode during log replay
During log replay there is this pattern of running delayed items after every inode unlink. To avoid repeating this several times, move the logic into an helper function and use it instead of calling btrfs_unlink_inode() followed by btrfs_run_delayed_items(). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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23e3337faf |
btrfs: reset last_reflink_trans after fsyncing inode
When an inode has a last_reflink_trans matching the current transaction, we have to take special care when logging its checksums in order to avoid getting checksum items with overlapping ranges in a log tree, which could result in missing checksums after log replay (more on that in the changelogs of commit |
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Filipe Manana
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96acb3753e |
btrfs: voluntarily relinquish cpu when doing a full fsync
Doing a full fsync may require processing many leaves of metadata, which can take some time and result in a task monopolizing a cpu for too long. So add a cond_resched() after processing a leaf when doing a full fsync, while not holding any locks on any tree (a subvolume or a log tree). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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5b7ce5e287 |
btrfs: hold on to less memory when logging checksums during full fsync
When doing a full fsync, at copy_items(), we iterate over all extents and then collect their checksums into a list. After copying all the extents to the log tree, we then log all the previously collected checksums. Before the previous patch in the series (subject "btrfs: stop copying old file extents when doing a full fsync"), we had to do it this way, because while we were iterating over the items in the leaf of the subvolume tree, we were holding a write lock on a leaf of the log tree, so logging the checksums for an extent right after we collected them could result in a deadlock, in case the checksum items ended up in the same leaf. However after the previous patch in the series we now do a first iteration over all the items in the leaf of the subvolume tree before locking a path in the log tree, so we can now log the checksums right after we have obtained them. This avoids holding in memory all checksums for all extents in the leaf while copying items from the source leaf to the log tree. The amount of memory used to hold all checksums of the extents in a leaf can be significant. For example if a leaf has 200 file extent items referring to 1M extents, using the default crc32c checksums, would result in using over 200K of memory (not accounting for the extra overhead of struct btrfs_ordered_sum), with smaller or less extents it would be less, but it could be much more with more extents per leaf and/or much larger extents. So change copy_items() to log the checksums for an extent after looking them up, and then free their memory, as they are no longer necessary. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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7f30c07288 |
btrfs: stop copying old file extents when doing a full fsync
When logging an inode in full sync mode, we go over every leaf that was modified in the current transaction and has items associated to our inode, and then copy all those items into the log tree. This includes copying file extent items that were created and added to the inode in past transactions, which is useless and only makes use more leaf space in the log tree. It's common to have a file with many file extent items spanning many leaves where only a few file extent items are new and need to be logged, and in such case we log all the file extent items we find in the modified leaves. So change the full sync behaviour to skip over file extent items that are not needed. Those are the ones that match the following criteria: 1) Have a generation older than the current transaction and the inode was not a target of a reflink operation, as that can copy file extent items from a past generation from some other inode into our inode, so we have to log them; 2) Start at an offset within i_size - we must log anything at or beyond i_size, otherwise we would lose prealloc extents after log replay. The following script exercises a scenario where this happens, and it's somehow close enough to what happened often on a SQL Server workload which I had to debug sometime ago to fix an issue where a pattern of writes to prealloc extents and fsync resulted in fsync failing with -EIO (that was commit |
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Filipe Manana
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e1f53ed874 |
btrfs: prepare extents to be logged before locking a log tree path
When we want to log an extent, in the fast fsync path, we obtain a path
to the leaf that will hold the file extent item either through a deletion
search, via btrfs_drop_extents(), or through an insertion search using
btrfs_insert_empty_item(). After that we fill the file extent item's
fields one by one directly on the leaf.
Instead of doing that, we could prepare the file extent item before
obtaining a btree path, and then copy the prepared extent item with a
single operation once we get the path. This helps avoid some contention
on the log tree, since we are holding write locks for longer than
necessary, especially in the case where the path is obtained via
btrfs_drop_extents() through a deletion search, which always keeps a
write lock on the nodes at levels 1 and 2 (besides the leaf).
This change does that, we prepare the file extent item that is going to
be inserted before acquiring a path, and then copy it into a leaf using
a single copy operation once we get a path.
This change if part of a patchset that is comprised of the following
patches:
1/6 btrfs: remove unnecessary leaf free space checks when pushing items
2/6 btrfs: avoid unnecessary COW of leaves when deleting items from a leaf
3/6 btrfs: avoid unnecessary computation when deleting items from a leaf
4/6 btrfs: remove constraint on number of visited leaves when replacing extents
5/6 btrfs: remove useless path release in the fast fsync path
6/6 btrfs: prepare extents to be logged before locking a log tree path
The following test was run to measure the impact of the whole patchset:
$ cat test.sh
#!/bin/bash
DEV=/dev/sdi
MNT=/mnt/sdi
MOUNT_OPTIONS="-o ssd"
MKFS_OPTIONS="-R free-space-tree -O no-holes"
NUM_JOBS=8
FILE_SIZE=128M
RUN_TIME=200
cat <<EOF > /tmp/fio-job.ini
[writers]
rw=randwrite
fsync=1
fallocate=none
group_reporting=1
direct=0
bssplit=4k/20:8k/20:16k/20:32k/10:64k/10:128k/5:256k/5:512k/5:1m/5
ioengine=sync
filesize=$FILE_SIZE
runtime=$RUN_TIME
time_based
directory=$MNT
numjobs=$NUM_JOBS
thread
EOF
echo "performance" | \
tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
echo
echo "Using config:"
echo
cat /tmp/fio-job.ini
echo
umount $MNT &> /dev/null
mkfs.btrfs -f $MKFS_OPTIONS $DEV
mount $MOUNT_OPTIONS $DEV $MNT
fio /tmp/fio-job.ini
umount $MNT
The test ran inside a VM (8 cores, 32G of RAM) with the target disk
mapping to a raw NVMe device, and using a non-debug kernel config
(Debian's default config).
Before the patchset:
WRITE: bw=116MiB/s (122MB/s), 116MiB/s-116MiB/s (122MB/s-122MB/s), io=22.7GiB (24.4GB), run=200013-200013msec
After the patchset:
WRITE: bw=125MiB/s (131MB/s), 125MiB/s-125MiB/s (131MB/s-131MB/s), io=24.3GiB (26.1GB), run=200007-200007msec
A 7.8% gain on throughput and +7.0% more IO done in the same period of
time (200 seconds).
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Filipe Manana
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d845753170 |
btrfs: remove useless path release in the fast fsync path
There's no point in calling btrfs_release_path() after finishing the loop that logs the modified extents, since log_one_extent() returns with the path released. In case the list of extents is empty, the path is already released, so there's no need for that case as well. So just remove that unnecessary btrfs_release_path() call. This change if part of a patchset that is comprised of the following patches: 1/6 btrfs: remove unnecessary leaf free space checks when pushing items 2/6 btrfs: avoid unnecessary COW of leaves when deleting items from a leaf 3/6 btrfs: avoid unnecessary computation when deleting items from a leaf 4/6 btrfs: remove constraint on number of visited leaves when replacing extents 5/6 btrfs: remove useless path release in the fast fsync path 6/6 btrfs: prepare extents to be logged before locking a log tree path The last patch in the series has some performance test result in its changelog. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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65faced5b9 |
btrfs: use single variable to track return value at btrfs_log_inode()
At btrfs_log_inode(), we have two variables to track errors and the return value of the function, named 'ret' and 'err'. In some places we use 'ret' and if gets a non-zero value we assign its value to 'err' and then jump to the 'out' label, while in other places we use 'err' directly without 'ret' as an intermediary. This is inconsistent, error prone and not necessary. So change that to use only the 'ret' variable, making this consistent with most functions in btrfs. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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0f8ce49821 |
btrfs: avoid inode logging during rename and link when possible
During a rename or link operation, we need to determine if an inode was previously logged or not, and if it was, do some update to the logged inode. We used to rely exclusively on the logged_trans field of struct btrfs_inode to determine that, but that was not reliable because the value of that field is not persisted in the inode item, so it's lost when an inode is evicted and loaded back again. That led to several issues in the past, such as not persisting deletions (such as the case fixed by commit |
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Filipe Manana
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259c4b96d7 |
btrfs: stop doing unnecessary log updates during a rename
During a rename, we call __btrfs_unlink_inode(), which will call
btrfs_del_inode_ref_in_log() and btrfs_del_dir_entries_in_log(), in order
to remove an inode reference and a directory entry from the log. These
are necessary when __btrfs_unlink_inode() is called from the unlink path,
but not necessary when it's called from a rename context, because:
1) For the btrfs_del_inode_ref_in_log() call, it's pointless to delete the
inode reference related to the old name, because later in the rename
path we call btrfs_log_new_name(), which will drop all inode references
from the log and copy all inode references from the subvolume tree to
the log tree. So we are doing one unnecessary btree operation which
adds additional latency and lock contention in case there are other
tasks accessing the log tree;
2) For the btrfs_del_dir_entries_in_log() call, we are now doing the
equivalent at btrfs_log_new_name() since the previous patch in the
series, that has the subject "btrfs: avoid logging all directory
changes during renames". In fact, having __btrfs_unlink_inode() call
this function not only adds additional latency and lock contention due
to the extra btree operation, but also can make btrfs_log_new_name()
unnecessarily log a range item to track the deletion of the old name,
since it has no way to known that the directory entry related to the
old name was previously logged and already deleted by
__btrfs_unlink_inode() through its call to
btrfs_del_dir_entries_in_log().
So skip those calls at __btrfs_unlink_inode() when we are doing a rename.
Skipping them also allows us now to reduce the duration of time we are
pinning a log transaction during renames, which is always beneficial as
it's not delaying so much other tasks trying to sync the log tree, in
particular we end up not holding the log transaction pinned while adding
the new name (adding inode ref, directory entry, etc).
This change is part of a patchset comprised of the following patches:
1/5 btrfs: add helper to delete a dir entry from a log tree
2/5 btrfs: pass the dentry to btrfs_log_new_name() instead of the inode
3/5 btrfs: avoid logging all directory changes during renames
4/5 btrfs: stop doing unnecessary log updates during a rename
5/5 btrfs: avoid inode logging during rename and link when possible
Just like the previous patch in the series, "btrfs: avoid logging all
directory changes during renames", the following script mimics part of
what a package installation/upgrade with zypper does, which is basically
renaming a lot of files, in some directory under /usr, to a name with a
suffix of "-RPMDELETE":
$ cat test.sh
#!/bin/bash
DEV=/dev/nvme0n1
MNT=/mnt/nvme0n1
NUM_FILES=10000
mkfs.btrfs -f $DEV
mount $DEV $MNT
mkdir $MNT/testdir
for ((i = 1; i <= $NUM_FILES; i++)); do
echo -n > $MNT/testdir/file_$i
done
sync
# Do some change to testdir and fsync it.
echo -n > $MNT/testdir/file_$((NUM_FILES + 1))
xfs_io -c "fsync" $MNT/testdir
echo "Renaming $NUM_FILES files..."
start=$(date +%s%N)
for ((i = 1; i <= $NUM_FILES; i++)); do
mv $MNT/testdir/file_$i $MNT/testdir/file_$i-RPMDELETE
done
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "Renames took $dur milliseconds"
umount $MNT
Testing this change on box a using a non-debug kernel (Debian's default
kernel config) gave the following results:
NUM_FILES=10000, before patchset: 27399 ms
NUM_FILES=10000, after patches 1/5 to 3/5 applied: 9093 ms (-66.8%)
NUM_FILES=10000, after patches 1/5 to 4/5 applied: 9016 ms (-67.1%)
NUM_FILES=5000, before patchset: 9241 ms
NUM_FILES=5000, after patches 1/5 to 3/5 applied: 4642 ms (-49.8%)
NUM_FILES=5000, after patches 1/5 to 4/5 applied: 4553 ms (-50.7%)
NUM_FILES=2000, before patchset: 2550 ms
NUM_FILES=2000, after patches 1/5 to 3/5 applied: 1788 ms (-29.9%)
NUM_FILES=2000, after patches 1/5 to 4/5 applied: 1767 ms (-30.7%)
NUM_FILES=1000, before patchset: 1088 ms
NUM_FILES=1000, after patches 1/5 to 3/5 applied: 905 ms (-16.9%)
NUM_FILES=1000, after patches 1/5 to 4/5 applied: 883 ms (-18.8%)
The next patch in the series (5/5), also contains dbench results after
applying to whole patchset.
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1193549
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Filipe Manana
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88d2beec7e |
btrfs: avoid logging all directory changes during renames
When doing a rename of a file, if the file or its old parent directory
were logged before, we log the new name of the file and then make sure
we log the old parent directory, to ensure that after a log replay the
old name of the file is deleted and the new name added.
The logging of the old parent directory can take some time, because it
will scan all leaves modified in the current transaction, check which
directory entries were already logged, copy the ones that were not
logged before, etc. In this rename context all we need to do is make
sure that the old name of the file is deleted on log replay, so instead
of triggering a directory log operation, we can just delete the old
directory entry from the log if it's there, or in case it isn't there,
just log a range item to signal log replay that the old name must be
deleted. So change btrfs_log_new_name() to do that.
This scenario is actually not uncommon to trigger, and recently on a
5.15 kernel, an openSUSE Tumbleweed user reported package installations
and upgrades, with the zypper tool, were often taking a long time to
complete, much more than usual. With strace it could be observed that
zypper was spending over 99% of its time on rename operations, and then
with further analysis we checked that directory logging was happening
too frequently and causing high latencies for the rename operations.
Taking into account that installation/upgrade of some of these packages
needed about a few thousand file renames, the slowdown was very noticeable
for the user.
The issue was caused indirectly due to an excessive number of inode
evictions on a 5.15 kernel, about 100x more compared to a 5.13, 5.14
or a 5.16-rc8 kernel. After an inode eviction we can't tell for sure,
in an efficient way, if an inode was previously logged in the current
transaction, so we are pessimistic and assume it was, because in case
it was we need to update the logged inode. More details on that in one
of the patches in the same series (subject "btrfs: avoid inode logging
during rename and link when possible"). Either way, in case the parent
directory was logged before, we currently do more work then necessary
during a rename, and this change minimizes that amount of work.
The following script mimics part of what a package installation/upgrade
with zypper does, which is basically renaming a lot of files, in some
directory under /usr, to a name with a suffix of "-RPMDELETE":
$ cat test.sh
#!/bin/bash
DEV=/dev/nvme0n1
MNT=/mnt/nvme0n1
NUM_FILES=10000
mkfs.btrfs -f $DEV
mount $DEV $MNT
mkdir $MNT/testdir
for ((i = 1; i <= $NUM_FILES; i++)); do
echo -n > $MNT/testdir/file_$i
done
sync
# Do some change to testdir and fsync it.
echo -n > $MNT/testdir/file_$((NUM_FILES + 1))
xfs_io -c "fsync" $MNT/testdir
echo "Renaming $NUM_FILES files..."
start=$(date +%s%N)
for ((i = 1; i <= $NUM_FILES; i++)); do
mv $MNT/testdir/file_$i $MNT/testdir/file_$i-RPMDELETE
done
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "Renames took $dur milliseconds"
umount $MNT
Testing this change on box using a non-debug kernel (Debian's default
kernel config) gave the following results:
NUM_FILES=10000, before this patch: 27399 ms
NUM_FILES=10000, after this patch: 9093 ms (-66.8%)
NUM_FILES=5000, before this patch: 9241 ms
NUM_FILES=5000, after this patch: 4642 ms (-49.8%)
NUM_FILES=2000, before this patch: 2550 ms
NUM_FILES=2000, after this patch: 1788 ms (-29.9%)
NUM_FILES=1000, before this patch: 1088 ms
NUM_FILES=1000, after this patch: 905 ms (-16.9%)
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1193549
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Filipe Manana
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d5f5bd5465 |
btrfs: pass the dentry to btrfs_log_new_name() instead of the inode
In the next patch in the series, there will be the need to access the old name, and its length, of an inode when logging the inode during a rename. So instead of passing the inode to btrfs_log_new_name() pass the dentry, because from the dentry we can get the inode, the name and its length. This will avoid passing 3 new parameters to btrfs_log_new_name() in the next patch - the name, its length and an index number. This way we end up passing only 1 new parameter, the index number. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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839061fe88 |
btrfs: add helper to delete a dir entry from a log tree
Move the code that finds and deletes a logged dir entry out of btrfs_del_dir_entries_in_log() into a helper function. This new helper function will be used by another patch in the same series, and serves to avoid having duplicated logic. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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de6bc7f598 |
btrfs: stop trying to log subdirectories created in past transactions
When logging a directory we are trying to log subdirectories that were
changed in the current transaction and created in a past transaction.
This type of behaviour was introduced by commit
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