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path: root/fs/btrfs/ctree.c
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2020-10-07btrfs: cleanup cow block on errorJosef Bacik
In fstest btrfs/064 a transaction abort in __btrfs_cow_block could lead to a system lockup. It gets stuck trying to write back inodes, and the write back thread was trying to lock an extent buffer: $ cat /proc/2143497/stack [<0>] __btrfs_tree_lock+0x108/0x250 [<0>] lock_extent_buffer_for_io+0x35e/0x3a0 [<0>] btree_write_cache_pages+0x15a/0x3b0 [<0>] do_writepages+0x28/0xb0 [<0>] __writeback_single_inode+0x54/0x5c0 [<0>] writeback_sb_inodes+0x1e8/0x510 [<0>] wb_writeback+0xcc/0x440 [<0>] wb_workfn+0xd7/0x650 [<0>] process_one_work+0x236/0x560 [<0>] worker_thread+0x55/0x3c0 [<0>] kthread+0x13a/0x150 [<0>] ret_from_fork+0x1f/0x30 This is because we got an error while COWing a block, specifically here if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) { ret = btrfs_reloc_cow_block(trans, root, buf, cow); if (ret) { btrfs_abort_transaction(trans, ret); return ret; } } [16402.241552] BTRFS: Transaction aborted (error -2) [16402.242362] WARNING: CPU: 1 PID: 2563188 at fs/btrfs/ctree.c:1074 __btrfs_cow_block+0x376/0x540 [16402.249469] CPU: 1 PID: 2563188 Comm: fsstress Not tainted 5.9.0-rc6+ #8 [16402.249936] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 [16402.250525] RIP: 0010:__btrfs_cow_block+0x376/0x540 [16402.252417] RSP: 0018:ffff9cca40e578b0 EFLAGS: 00010282 [16402.252787] RAX: 0000000000000025 RBX: 0000000000000002 RCX: ffff9132bbd19388 [16402.253278] RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff9132bbd19380 [16402.254063] RBP: ffff9132b41a49c0 R08: 0000000000000000 R09: 0000000000000000 [16402.254887] R10: 0000000000000000 R11: ffff91324758b080 R12: ffff91326ef17ce0 [16402.255694] R13: ffff91325fc0f000 R14: ffff91326ef176b0 R15: ffff9132815e2000 [16402.256321] FS: 00007f542c6d7b80(0000) GS:ffff9132bbd00000(0000) knlGS:0000000000000000 [16402.256973] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [16402.257374] CR2: 00007f127b83f250 CR3: 0000000133480002 CR4: 0000000000370ee0 [16402.257867] Call Trace: [16402.258072] btrfs_cow_block+0x109/0x230 [16402.258356] btrfs_search_slot+0x530/0x9d0 [16402.258655] btrfs_lookup_file_extent+0x37/0x40 [16402.259155] __btrfs_drop_extents+0x13c/0xd60 [16402.259628] ? btrfs_block_rsv_migrate+0x4f/0xb0 [16402.259949] btrfs_replace_file_extents+0x190/0x820 [16402.260873] btrfs_clone+0x9ae/0xc00 [16402.261139] btrfs_extent_same_range+0x66/0x90 [16402.261771] btrfs_remap_file_range+0x353/0x3b1 [16402.262333] vfs_dedupe_file_range_one.part.0+0xd5/0x140 [16402.262821] vfs_dedupe_file_range+0x189/0x220 [16402.263150] do_vfs_ioctl+0x552/0x700 [16402.263662] __x64_sys_ioctl+0x62/0xb0 [16402.264023] do_syscall_64+0x33/0x40 [16402.264364] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [16402.264862] RIP: 0033:0x7f542c7d15cb [16402.266901] RSP: 002b:00007ffd35944ea8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [16402.267627] RAX: ffffffffffffffda RBX: 00000000009d1968 RCX: 00007f542c7d15cb [16402.268298] RDX: 00000000009d2490 RSI: 00000000c0189436 RDI: 0000000000000003 [16402.268958] RBP: 00000000009d2520 R08: 0000000000000036 R09: 00000000009d2e64 [16402.269726] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 [16402.270659] R13: 000000000001f000 R14: 00000000009d1970 R15: 00000000009d2e80 [16402.271498] irq event stamp: 0 [16402.271846] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [16402.272497] hardirqs last disabled at (0): [<ffffffff910dbf59>] copy_process+0x6b9/0x1ba0 [16402.273343] softirqs last enabled at (0): [<ffffffff910dbf59>] copy_process+0x6b9/0x1ba0 [16402.273905] softirqs last disabled at (0): [<0000000000000000>] 0x0 [16402.274338] ---[ end trace 737874a5a41a8236 ]--- [16402.274669] BTRFS: error (device dm-9) in __btrfs_cow_block:1074: errno=-2 No such entry [16402.276179] BTRFS info (device dm-9): forced readonly [16402.277046] BTRFS: error (device dm-9) in btrfs_replace_file_extents:2723: errno=-2 No such entry [16402.278744] BTRFS: error (device dm-9) in __btrfs_cow_block:1074: errno=-2 No such entry [16402.279968] BTRFS: error (device dm-9) in __btrfs_cow_block:1074: errno=-2 No such entry [16402.280582] BTRFS info (device dm-9): balance: ended with status: -30 The problem here is that as soon as we allocate the new block it is locked and marked dirty in the btree inode. This means that we could attempt to writeback this block and need to lock the extent buffer. However we're not unlocking it here and thus we deadlock. Fix this by unlocking the cow block if we have any errors inside of __btrfs_cow_block, and also free it so we do not leak it. 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> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: improve error message in setup_items_for_insertNikolay Borisov
Reword and update formats to match variable types. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update formats ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: add kerneldoc for setup_items_for_insertNikolay Borisov
Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: sink total_data parameter in setup_items_for_insertNikolay Borisov
That parameter can easily be derived based on the "data_size" and "nr" parameters exploit this fact to simply the function's signature. No functional changes. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: eliminate total_size parameter from setup_items_for_insertNikolay Borisov
The value of this argument can be derived from the total_data as it's simply the value of the data size + size of btrfs_items being touched. Move the parameter calculation inside the function. This results in a simpler interface and also a minor size reduction: ./scripts/bloat-o-meter ctree.original fs/btrfs/ctree.o add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-34 (-34) Function old new delta btrfs_duplicate_item 260 259 -1 setup_items_for_insert 1200 1190 -10 btrfs_insert_empty_items 177 154 -23 Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: re-arrange statements in setup_items_for_insertNikolay Borisov
Rearrange statements calculating the offset of the newly added items so that the calculation has to be done only once. No functional change. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: use BTRFS_NESTED_NEW_ROOT for double splitsJosef Bacik
I've made this change separate since it requires both of the newly added NESTED flags and I didn't want to slip it into one of those changes. If we do a double split of a node we can end up doing a BTRFS_NESTED_SPLIT on level 0, which throws lockdep off because it appears as a double lock. Since we're maxed out on subclasses, use BTRFS_NESTED_NEW_ROOT if we had to do a double split. This is OK because we won't have to do a double split if we had to insert a new root, and the new root would be at a higher level anyway. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: introduce BTRFS_NESTING_NEW_ROOT for adding new rootsJosef Bacik
The way we add new roots is confusing from a locking perspective for lockdep. We generally have the rule that we lock things in order from highest level to lowest, but in the case of adding a new level to the tree we actually allocate a new block for the root, which makes the locking go in reverse. A similar issue exists for snapshotting, we cow the original root for the root of a new tree, however they're at the same level. Address this by using BTRFS_NESTING_NEW_ROOT for these operations. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: introduce BTRFS_NESTING_SPLIT for split blocksJosef Bacik
If we are splitting a leaf/node, we could do something like the following lock(leaf) BTRFS_NESTING_NORMAL lock(left) BTRFS_NESTING_LEFT + BTRFS_NESTING_COW push from leaf -> left reset path to point to left split left allocate new block, lock block BTRFS_NESTING_SPLIT at the new block point we need to have a different nesting level, because we have already used either BTRFS_NESTING_LEFT or BTRFS_NESTING_RIGHT when pushing items from the original leaf into the adjacent leaves. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: introduce BTRFS_NESTING_LEFT/RIGHT_COWJosef Bacik
For similar reasons as BTRFS_NESTING_COW, we need BTRFS_NESTING_LEFT/RIGHT_COW. The pattern is this lock leaf -> BTRFS_NESTING_NORMAL cow leaf -> BTRFS_NESTING_COW split leaf lock left -> BTRFS_NESTING_LEFT cow left -> BTRFS_NESTING_LEFT_COW We need this in order to indicate to lockdep that these locks are discrete and are being taken in a safe order. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: introduce BTRFS_NESTING_LEFT/BTRFS_NESTING_RIGHTJosef Bacik
Our lockdep maps are based on rootid+level, however in some cases we will lock adjacent blocks on the same level, namely in searching forward or in split/balance. Because of this lockdep will complain, so we need a separate subclass to indicate to lockdep that these are different locks. lock leaf -> BTRFS_NESTING_NORMAL cow leaf -> BTRFS_NESTING_COW split leaf lock left -> BTRFS_NESTING_LEFT lock right -> BTRFS_NESTING_RIGHT The above graph illustrates the need for this new nesting subclass. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: introduce BTRFS_NESTING_COW for cow'ing blocksJosef Bacik
When we COW a block we are holding a lock on the original block, and then we lock the new COW block. Because our lockdep maps are based on root + level, this will make lockdep complain. We need a way to indicate a subclass for locking the COW'ed block, so plumb through our btrfs_lock_nesting from btrfs_cow_block down to the btrfs_init_buffer, and then introduce BTRFS_NESTING_COW to be used for cow'ing blocks. The reason I've added all this extra infrastructure is because there will be need of different nesting classes in follow up patches. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: add nesting tags to the locking helpersJosef Bacik
We will need these when we switch to an rwsem, so plumb in the infrastructure here to use later on. I violate the 80 character limit some here because it'll be cleaned up later. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: introduce btrfs_path::recurseJosef Bacik
Our current tree locking stuff allows us to recurse with read locks if we're already holding the write lock. This is necessary for the space cache inode, as we could be holding a lock on the root_tree root when we need to cache a block group, and thus need to be able to read down the root_tree to read in the inode cache. We can get away with this in our current locking, but we won't be able to with a rwsem. Handle this by purposefully annotating the places where we require recursion, so that in the future we can maybe come up with a way to avoid the recursion. In the case of the free space inode, this will be superseded by the free space tree. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: ctree: check key order before merging tree blocksQu Wenruo
[BUG] With a crafted image, btrfs can panic at btrfs_del_csums(): kernel BUG at fs/btrfs/ctree.c:3188! invalid opcode: 0000 [#1] SMP PTI CPU: 0 PID: 1156 Comm: btrfs-transacti Not tainted 5.0.0-rc8+ #9 RIP: 0010:btrfs_set_item_key_safe+0x16c/0x180 RSP: 0018:ffff976141257ab8 EFLAGS: 00010202 RAX: 0000000000000001 RBX: ffff898a6b890930 RCX: 0000000004b70000 RDX: 0000000000000000 RSI: ffff976141257bae RDI: ffff976141257acf RBP: ffff976141257b10 R08: 0000000000001000 R09: ffff9761412579a8 R10: 0000000000000000 R11: 0000000000000000 R12: ffff976141257abe R13: 0000000000000003 R14: ffff898a6a8be578 R15: ffff976141257bae FS: 0000000000000000(0000) GS:ffff898a77a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f779d9cd624 CR3: 000000022b2b4006 CR4: 00000000000206f0 Call Trace: truncate_one_csum+0xac/0xf0 btrfs_del_csums+0x24f/0x3a0 __btrfs_free_extent.isra.72+0x5a7/0xbe0 __btrfs_run_delayed_refs+0x539/0x1120 btrfs_run_delayed_refs+0xdb/0x1b0 btrfs_commit_transaction+0x52/0x950 ? start_transaction+0x94/0x450 transaction_kthread+0x163/0x190 kthread+0x105/0x140 ? btrfs_cleanup_transaction+0x560/0x560 ? kthread_destroy_worker+0x50/0x50 ret_from_fork+0x35/0x40 Modules linked in: ---[ end trace 93bf9db00e6c374e ]--- [CAUSE] This crafted image has a tricky key order corruption: checksum tree key (CSUM_TREE ROOT_ITEM 0) node 29741056 level 1 items 14 free 107 generation 19 owner CSUM_TREE ... key (EXTENT_CSUM EXTENT_CSUM 73785344) block 29757440 gen 19 key (EXTENT_CSUM EXTENT_CSUM 77594624) block 29753344 gen 19 ... leaf 29757440 items 5 free space 150 generation 19 owner CSUM_TREE item 0 key (EXTENT_CSUM EXTENT_CSUM 73785344) itemoff 2323 itemsize 1672 range start 73785344 end 75497472 length 1712128 item 1 key (EXTENT_CSUM EXTENT_CSUM 75497472) itemoff 2319 itemsize 4 range start 75497472 end 75501568 length 4096 item 2 key (EXTENT_CSUM EXTENT_CSUM 75501568) itemoff 579 itemsize 1740 range start 75501568 end 77283328 length 1781760 item 3 key (EXTENT_CSUM EXTENT_CSUM 77283328) itemoff 575 itemsize 4 range start 77283328 end 77287424 length 4096 item 4 key (EXTENT_CSUM EXTENT_CSUM 4120596480) itemoff 275 itemsize 300 <<< range start 4120596480 end 4120903680 length 307200 leaf 29753344 items 3 free space 1936 generation 19 owner CSUM_TREE item 0 key (18446744073457893366 EXTENT_CSUM 77594624) itemoff 2323 itemsize 1672 range start 77594624 end 79306752 length 1712128 ... Note the item 4 key of leaf 29757440, which is obviously too large, and even larger than the first key of the next leaf. However it still follows the key order in that tree block, thus tree checker is unable to detect it at read time, since tree checker can only work inside one leaf, thus such complex corruption can't be detected in advance. [FIX] The next time to detect such problem is at tree block merge time, which is in push_node_left(), balance_node_right(), push_leaf_left() or push_leaf_right(). Now we check if the key order of the right-most key of the left node is larger than the left-most key of the right node. By this we don't need to call the full tree-checker, while still keeping the key order correct as key order in each node is already checked by tree checker thus we only need to check the above two slots. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202833 Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: delete duplicated words + other fixes in commentsRandy Dunlap
Delete repeated words in fs/btrfs/. {to, the, a, and old} and change "into 2 part" to "into 2 parts". Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27btrfs: set the lockdep class for log tree extent buffersJosef Bacik
These are special extent buffers that get rewound in order to lookup the state of the tree at a specific point in time. As such they do not go through the normal initialization paths that set their lockdep class, so handle them appropriately when they are created and before they are locked. 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> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19btrfs: use the correct const function attribute for btrfs_get_num_csumsDavid Sterba
The build robot reports compiler: h8300-linux-gcc (GCC) 9.3.0 In file included from fs/btrfs/tests/extent-map-tests.c:8: >> fs/btrfs/tests/../ctree.h:2166:8: warning: type qualifiers ignored on function return type [-Wignored-qualifiers] 2166 | size_t __const btrfs_get_num_csums(void); | ^~~~~~~ The function attribute for const does not follow the expected scheme and in this case is confused with a const type qualifier. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27btrfs: add little-endian optimized key helpersDavid Sterba
The CPU and on-disk keys are mapped to two different structures because of the endianness. There's an intermediate buffer used to do the conversion, but this is not necessary when CPU and on-disk endianness match. Add optimized versions of helpers that take disk_key and use the buffer directly for CPU keys or drop the intermediate buffer and conversion. This saves a lot of stack space accross many functions and removes about 6K of generated binary code: text data bss dec hex filename 1090439 17468 14912 1122819 112203 pre/btrfs.ko 1084613 17456 14912 1116981 110b35 post/btrfs.ko Delta: -5826 Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-02btrfs: convert comments to fallthrough annotationsMarcos Paulo de Souza
Convert fall through comments to the pseudo-keyword which is now the preferred way. Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-28btrfs: remove redundant local variable in read_block_for_searchNikolay Borisov
The local 'b' variable is only used to directly read values from passed extent buffer. So eliminate it and directly use the input parameter. Furthermore this shrinks the size of the following functions: ./scripts/bloat-o-meter ctree.orig fs/btrfs/ctree.o add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-73 (-73) Function old new delta read_block_for_search.isra 876 871 -5 push_node_left 1112 1044 -68 Total: Before=50348, After=50275, chg -0.14% Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-28btrfs: open code key_searchNikolay Borisov
This function wraps the optimisation implemented by d7396f07358a ("Btrfs: optimize key searches in btrfs_search_slot") however this optimisation is really used in only one place - btrfs_search_slot. Just open code the optimisation and also add a comment explaining how it works since it's not clear just by looking at the code - the key point here is it depends on an internal invariant that BTRFS' btree provides, namely intermediate pointers always contain the key at slot0 at the child node. So in the case of exact match we can safely assume that the given key will always be in slot 0 on lower levels. Furthermore this results in a reduction of btrfs_search_slot's size: ./scripts/bloat-o-meter ctree.orig fs/btrfs/ctree.o add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-75 (-75) Function old new delta btrfs_search_slot 2783 2708 -75 Total: Before=50423, After=50348, chg -0.15% Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25btrfs: rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLEQu Wenruo
The name BTRFS_ROOT_REF_COWS is not very clear about the meaning. In fact, that bit can only be set to those trees: - Subvolume roots - Data reloc root - Reloc roots for above roots All other trees won't get this bit set. So just by the result, it is obvious that, roots with this bit set can have tree blocks shared with other trees. Either shared by snapshots, or by reloc roots (an special snapshot created by relocation). This patch will rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLE to make it easier to understand, and update all comment mentioning "reference counted" to follow the rename. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25btrfs: speed up and simplify generic_bin_searchDavid Sterba
The bin search jumps over the extent buffer item keys, comparing directly the bytes if the key is in one page, or storing it in a temporary buffer in case it spans two pages. The mapping start and length are obtained from map_private_extent_buffer, which is heavy weight compared to what we need. We know the key size and can find out the eb page in a simple way. For keys spanning two pages the fallback read_extent_buffer is used. The temporary variables are reduced and moved to the scope of use. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25btrfs: don't use set/get token in leaf_space_usedDavid Sterba
The token is supposed to cache the last page used by the set/get helpers. In leaf_space_used the first and last items are accessed, it's not likely they'd be on the same page so there's some overhead caused updating the token address but not using it. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25btrfs: drop eb parameter from set/get token helpersDavid Sterba
Now that all set/get helpers use the eb from the token, we don't need to pass it to many btrfs_token_*/btrfs_set_token_* helpers, saving some stack space. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25btrfs: remove the redundant parameter level in btrfs_bin_search()Qu Wenruo
All callers pass the eb::level so we can get read it directly inside the btrfs_bin_search and key_search. This is inspired by the work of Marek in U-boot. CC: Marek Behun <marek.behun@nic.cz> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23btrfs: inline checksum name and driver definitionsDavid Sterba
There's an unnecessary indirection in the checksum definition table, pointer and the string itself. The strings are short and the overall size of one entry is now 24 bytes. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23btrfs: simplify parameters of btrfs_set_disk_extent_flagsDavid Sterba
All callers pass extent buffer start and length so the extent buffer itself should work fine. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23btrfs: move root node locking helpers to locking.cDavid Sterba
The helpers are related to locking so move them there, update comments. Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23Btrfs: don't iterate mod seq list when putting a tree mod seqFilipe Manana
Each new element added to the mod seq list is always appended to the list, and each one gets a sequence number coming from a counter which gets incremented everytime a new element is added to the list (or a new node is added to the tree mod log rbtree). Therefore the element with the lowest sequence number is always the first element in the list. So just remove the list iteration at btrfs_put_tree_mod_seq() that computes the minimum sequence number in the list and replace it with a check for the first element's sequence number. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-31Btrfs: fix race between adding and putting tree mod seq elements and nodesFilipe Manana
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>
2019-12-13Btrfs: fix removal logic of the tree mod log that leads to use-after-free issuesFilipe Manana
When a tree mod log user no longer needs to use the tree it calls btrfs_put_tree_mod_seq() to remove itself from the list of users and delete all no longer used elements of the tree's red black tree, which should be all elements with a sequence number less then our equals to the caller's sequence number. However the logic is broken because it can delete and free elements from the red black tree that have a sequence number greater then the caller's sequence number: 1) At a point in time we have sequence numbers 1, 2, 3 and 4 in the tree mod log; 2) The task which got assigned the sequence number 1 calls btrfs_put_tree_mod_seq(); 3) Sequence number 1 is deleted from the list of sequence numbers; 4) The current minimum sequence number is computed to be the sequence number 2; 5) A task using sequence number 2 is at tree_mod_log_rewind() and gets a pointer to one of its elements from the red black tree through a call to tree_mod_log_search(); 6) The task with sequence number 1 iterates the red black tree of tree modification elements and deletes (and frees) all elements with a sequence number less then or equals to 2 (the computed minimum sequence number) - it ends up only leaving elements with sequence numbers of 3 and 4; 7) The task with sequence number 2 now uses the pointer to its element, already freed by the other task, at __tree_mod_log_rewind(), resulting in a use-after-free issue. When CONFIG_DEBUG_PAGEALLOC=y it produces a trace like the following: [16804.546854] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI [16804.547451] CPU: 0 PID: 28257 Comm: pool Tainted: G W 5.4.0-rc8-btrfs-next-51 #1 [16804.548059] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014 [16804.548666] RIP: 0010:rb_next+0x16/0x50 (...) [16804.550581] RSP: 0018:ffffb948418ef9b0 EFLAGS: 00010202 [16804.551227] RAX: 6b6b6b6b6b6b6b6b RBX: ffff90e0247f6600 RCX: 6b6b6b6b6b6b6b6b [16804.551873] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff90e0247f6600 [16804.552504] RBP: ffff90dffe0d4688 R08: 0000000000000001 R09: 0000000000000000 [16804.553136] R10: ffff90dffa4a0040 R11: 0000000000000000 R12: 000000000000002e [16804.553768] R13: ffff90e0247f6600 R14: 0000000000001663 R15: ffff90dff77862b8 [16804.554399] FS: 00007f4b197ae700(0000) GS:ffff90e036a00000(0000) knlGS:0000000000000000 [16804.555039] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [16804.555683] CR2: 00007f4b10022000 CR3: 00000002060e2004 CR4: 00000000003606f0 [16804.556336] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [16804.556968] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [16804.557583] Call Trace: [16804.558207] __tree_mod_log_rewind+0xbf/0x280 [btrfs] [16804.558835] btrfs_search_old_slot+0x105/0xd00 [btrfs] [16804.559468] resolve_indirect_refs+0x1eb/0xc70 [btrfs] [16804.560087] ? free_extent_buffer.part.19+0x5a/0xc0 [btrfs] [16804.560700] find_parent_nodes+0x388/0x1120 [btrfs] [16804.561310] btrfs_check_shared+0x115/0x1c0 [btrfs] [16804.561916] ? extent_fiemap+0x59d/0x6d0 [btrfs] [16804.562518] extent_fiemap+0x59d/0x6d0 [btrfs] [16804.563112] ? __might_fault+0x11/0x90 [16804.563706] do_vfs_ioctl+0x45a/0x700 [16804.564299] ksys_ioctl+0x70/0x80 [16804.564885] ? trace_hardirqs_off_thunk+0x1a/0x20 [16804.565461] __x64_sys_ioctl+0x16/0x20 [16804.566020] do_syscall_64+0x5c/0x250 [16804.566580] entry_SYSCALL_64_after_hwframe+0x49/0xbe [16804.567153] RIP: 0033:0x7f4b1ba2add7 (...) [16804.568907] RSP: 002b:00007f4b197adc88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [16804.569513] RAX: ffffffffffffffda RBX: 00007f4b100210d8 RCX: 00007f4b1ba2add7 [16804.570133] RDX: 00007f4b100210d8 RSI: 00000000c020660b RDI: 0000000000000003 [16804.570726] RBP: 000055de05a6cfe0 R08: 0000000000000000 R09: 00007f4b197add44 [16804.571314] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4b197add48 [16804.571905] R13: 00007f4b197add40 R14: 00007f4b100210d0 R15: 00007f4b197add50 (...) [16804.575623] ---[ end trace 87317359aad4ba50 ]--- Fix this by making btrfs_put_tree_mod_seq() skip deletion of elements that have a sequence number equals to the computed minimum sequence number, and not just elements with a sequence number greater then that minimum. Fixes: bd989ba359f2ac ("Btrfs: add tree modification log functions") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: add blake2b to checksumming algorithmsDavid Sterba
Add blake2b (with 256 bit digest) to the list of possible checksumming algorithms used by BTRFS. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: add member for a specific checksum driverDavid Sterba
Currently all the checksum algorithms generate a fixed size digest size and we use it. The on-disk format can hold up to BTRFS_CSUM_SIZE bytes and BLAKE2b produces digest of 512 bits by default. We can't do that and will use the blake2b-256, this needs to be passed to the crypto API. Separate that from the base algorithm name and add a member to request specific driver, in this case with the digest size. The only place that uses the driver name is the crypto API setup. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: sysfs: export supported checksumsDavid Sterba
Export supported checksum algorithms via sysfs in the list of static features: /sys/fs/btrfs/features/supported_checksums Space spearated list of checksum algorithm names. Co-developed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: add sha256 to checksumming algorithmJohannes Thumshirn
Add sha256 to the list of possible checksumming algorithms used by BTRFS. Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: add xxhash64 to checksumming algorithmsJohannes Thumshirn
Add xxhash64 to the list of possible checksumming algorithms used by BTRFS. Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: opencode extent_buffer_getDavid Sterba
The helper is trivial and we can understand what the atomic_inc on something named refs does. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: add __pure attribute to functionsDavid Sterba
The attribute is more relaxed than const and the functions could dereference pointers, as long as the observable state is not changed. We do have such functions, based on -Wsuggest-attribute=pure . The visible effects of this patch are negligible, there are differences in the assembly but hard to summarize. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: move btrfs_unlock_up_safe to other locking functionsDavid Sterba
The function belongs to the family of locking functions, so move it there. The 'noinline' keyword is dropped as it's now an exported function that does not need it. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: move btrfs_set_path_blocking to other locking functionsDavid Sterba
The function belongs to the family of locking functions, so move it there. The 'noinline' keyword is dropped as it's now an exported function that does not need it. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: ctree: Remove stray comment of setting up path lockQu Wenruo
The following comment shows up in btrfs_search_slot() with out much sense: /* * setup the path here so we can release it under lock * contention with the cow code */ if (cow) { /* code touching path->lock[] is far away from here */ } This comment hasn't been cleaned up after the relevant code has been removed. The original code is introduced in commit 65b51a009e29 ("btrfs_search_slot: reduce lock contention by cowing in two stages"): + + /* + * setup the path here so we can release it under lock + * contention with the cow code + */ + p->nodes[level] = b; + if (!p->skip_locking) + p->locks[level] = 1; + But in current code, we have different timing for modifying path lock, so just remove the comment. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: ctree: Reduce one indent level for btrfs_search_old_slot()Qu Wenruo
Similar to btrfs_search_slot() done in previous patch, make a shortcut for the level 0 case and allow to reduce indentation for the remaining case. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update changelog ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: ctree: Reduce one indent level for btrfs_search_slot()Qu Wenruo
In btrfs_search_slot(), we something like: if (level != 0) { /* Do search inside tree nodes*/ } else { /* Do search inside tree leaves */ goto done; } This caused extra indent for tree node search code. Change it to something like: if (level == 0) { /* Do search inside tree leaves */ goto done' } /* Do search inside tree nodes */ So we have more space to maneuver our code, this is especially useful as the tree nodes search code is more complex than the leaves search code. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: Don't assign retval of ↵Nikolay Borisov
btrfs_try_tree_write_lock/btrfs_tree_read_lock_atomic Those function are simple boolean predicates there is no need to assign their return values to interim variables. Use them directly as predicates. No functional changes. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: create structure to encode checksum type and lengthJohannes Thumshirn
Create a structure to encode the type and length for the known on-disk checksums. This makes it easier to add new checksums later. The structure and helpers are moved from ctree.h so they don't occupy space in all headers including ctree.h. This save some space in the final object. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: tie extent buffer and it's token togetherDavid Sterba
Further simplifaction of the get/set helpers is possible when the token is uniquely tied to an extent buffer. A condition and an assignment can be avoided. The initializations are moved closer to the first use when the extent buffer is valid. There's one exception in __push_leaf_left where the token is reused. Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: move functions for tree compare to send.cDavid Sterba
Send is the only user of tree_compare, we can move it there along with the other helpers and definitions. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: rename and export read_node_slotDavid Sterba
Preparatory work for code that will be moved out of ctree and uses this function. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: David Sterba <dsterba@suse.com>
generated by cgit (git 2.34.1) at 2025-04-07 12:25:15 +0000