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2020-01-08btrfs: do not delete mismatched root refsJosef Bacik
btrfs_del_root_ref() will simply WARN_ON() if the ref doesn't match in any way, and then continue to delete the reference. This shouldn't happen, we have these values because there's more to the reference than the original root and the sub root. If any of these checks fail, return -ENOENT. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-08btrfs: fix invalid removal of root refJosef Bacik
If we have the following sequence of events btrfs sub create A btrfs sub create A/B btrfs sub snap A C mkdir C/foo mv A/B C/foo rm -rf * We will end up with a transaction abort. The reason for this is because we create a root ref for B pointing to A. When we create a snapshot of C we still have B in our tree, but because the root ref points to A and not C we will make it appear to be empty. The problem happens when we move B into C. This removes the root ref for B pointing to A and adds a ref of B pointing to C. When we rmdir C we'll see that we have a ref to our root and remove the root ref, despite not actually matching our reference name. Now btrfs_del_root_ref() allowing this to work is a bug as well, however we know that this inode does not actually point to a root ref in the first place, so we shouldn't be calling btrfs_del_root_ref() in the first place and instead simply look up our dir index for this item and do the rest of the removal. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-08btrfs: rework arguments of btrfs_unlink_subvolJosef Bacik
btrfs_unlink_subvol takes the name of the dentry and the root objectid based on what kind of inode this is, either a real subvolume link or a empty one that we inherited as a snapshot. We need to fix how we unlink in the case for BTRFS_EMPTY_SUBVOL_DIR_OBJECTID in the future, so rework btrfs_unlink_subvol to just take the dentry and handle getting the right objectid given the type of inode this is. There is no functional change here, simply pushing the work into btrfs_unlink_subvol() proper. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-30Btrfs: fix infinite loop during nocow writeback due to raceFilipe Manana
When starting writeback for a range that covers part of a preallocated extent, due to a race with writeback for another range that also covers another part of the same preallocated extent, we can end up in an infinite loop. Consider the following example where for inode 280 we have two dirty ranges: range A, from 294912 to 303103, 8192 bytes range B, from 348160 to 438271, 90112 bytes and we have the following file extent item layout for our inode: leaf 38895616 gen 24544 total ptrs 29 free space 13820 owner 5 (...) item 27 key (280 108 200704) itemoff 14598 itemsize 53 extent data disk bytenr 0 nr 0 type 1 (regular) extent data offset 0 nr 94208 ram 94208 item 28 key (280 108 294912) itemoff 14545 itemsize 53 extent data disk bytenr 10433052672 nr 81920 type 2 (prealloc) extent data offset 0 nr 81920 ram 81920 Then the following happens: 1) Writeback starts for range B (from 348160 to 438271), execution of run_delalloc_nocow() starts; 2) The first iteration of run_delalloc_nocow()'s whil loop leaves us at the extent item at slot 28, pointing to the prealloc extent item covering the range from 294912 to 376831. This extent covers part of our range; 3) An ordered extent is created against that extent, covering the file range from 348160 to 376831 (28672 bytes); 4) We adjust 'cur_offset' to 376832 and move on to the next iteration of the while loop; 5) The call to btrfs_lookup_file_extent() leaves us at the same leaf, pointing to slot 29, 1 slot after the last item (the extent item we processed in the previous iteration); 6) Because we are a slot beyond the last item, we call btrfs_next_leaf(), which releases the search path before doing a another search for the last key of the leaf (280 108 294912); 7) Right after btrfs_next_leaf() released the path, and before it did another search for the last key of the leaf, writeback for the range A (from 294912 to 303103) completes (it was previously started at some point); 8) Upon completion of the ordered extent for range A, the prealloc extent we previously found got split into two extent items, one covering the range from 294912 to 303103 (8192 bytes), with a type of regular extent (and no longer prealloc) and another covering the range from 303104 to 376831 (73728 bytes), with a type of prealloc and an offset of 8192 bytes. So our leaf now has the following layout: leaf 38895616 gen 24544 total ptrs 31 free space 13664 owner 5 (...) item 27 key (280 108 200704) itemoff 14598 itemsize 53 extent data disk bytenr 0 nr 0 type 1 extent data offset 0 nr 8192 ram 94208 item 28 key (280 108 208896) itemoff 14545 itemsize 53 extent data disk bytenr 10433142784 nr 86016 type 1 extent data offset 0 nr 86016 ram 86016 item 29 key (280 108 294912) itemoff 14492 itemsize 53 extent data disk bytenr 10433052672 nr 81920 type 1 extent data offset 0 nr 8192 ram 81920 item 30 key (280 108 303104) itemoff 14439 itemsize 53 extent data disk bytenr 10433052672 nr 81920 type 2 extent data offset 8192 nr 73728 ram 81920 9) After btrfs_next_leaf() returns, we have our path pointing to that same leaf and at slot 30, since it has a key we didn't have before and it's the first key greater then the key that was previously the last key of the leaf (key (280 108 294912)); 10) The extent item at slot 30 covers the range from 303104 to 376831 which is in our target range, so we process it, despite having already created an ordered extent against this extent for the file range from 348160 to 376831. This is because we skip to the next extent item only if its end is less than or equals to the start of our delalloc range, and not less than or equals to the current offset ('cur_offset'); 11) As a result we compute 'num_bytes' as: num_bytes = min(end + 1, extent_end) - cur_offset; = min(438271 + 1, 376832) - 376832 = 0 12) We then call create_io_em() for a 0 bytes range starting at offset 376832; 13) Then create_io_em() enters an infinite loop because its calls to btrfs_drop_extent_cache() do nothing due to the 0 length range passed to it. So no existing extent maps that cover the offset 376832 get removed, and therefore calls to add_extent_mapping() return -EEXIST, resulting in an infinite loop. This loop from create_io_em() is the following: do { btrfs_drop_extent_cache(BTRFS_I(inode), em->start, em->start + em->len - 1, 0); write_lock(&em_tree->lock); ret = add_extent_mapping(em_tree, em, 1); write_unlock(&em_tree->lock); /* * The caller has taken lock_extent(), who could race with us * to add em? */ } while (ret == -EEXIST); Also, each call to btrfs_drop_extent_cache() triggers a warning because the start offset passed to it (376832) is smaller then the end offset (376832 - 1) passed to it by -1, due to the 0 length: [258532.052621] ------------[ cut here ]------------ [258532.052643] WARNING: CPU: 0 PID: 9987 at fs/btrfs/file.c:602 btrfs_drop_extent_cache+0x3f4/0x590 [btrfs] (...) [258532.052672] CPU: 0 PID: 9987 Comm: fsx Tainted: G W 5.4.0-rc7-btrfs-next-64 #1 [258532.052673] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014 [258532.052691] RIP: 0010:btrfs_drop_extent_cache+0x3f4/0x590 [btrfs] (...) [258532.052695] RSP: 0018:ffffb4be0153f860 EFLAGS: 00010287 [258532.052700] RAX: ffff975b445ee360 RBX: ffff975b44eb3e08 RCX: 0000000000000000 [258532.052700] RDX: 0000000000038fff RSI: 0000000000039000 RDI: ffff975b445ee308 [258532.052700] RBP: 0000000000038fff R08: 0000000000000000 R09: 0000000000000001 [258532.052701] R10: ffff975b513c5c10 R11: 00000000e3c0cfa9 R12: 0000000000039000 [258532.052703] R13: ffff975b445ee360 R14: 00000000ffffffef R15: ffff975b445ee308 [258532.052705] FS: 00007f86a821de80(0000) GS:ffff975b76a00000(0000) knlGS:0000000000000000 [258532.052707] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [258532.052708] CR2: 00007fdacf0f3ab4 CR3: 00000001f9d26002 CR4: 00000000003606f0 [258532.052712] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [258532.052717] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [258532.052717] Call Trace: [258532.052718] ? preempt_schedule_common+0x32/0x70 [258532.052722] ? ___preempt_schedule+0x16/0x20 [258532.052741] create_io_em+0xff/0x180 [btrfs] [258532.052767] run_delalloc_nocow+0x942/0xb10 [btrfs] [258532.052791] btrfs_run_delalloc_range+0x30b/0x520 [btrfs] [258532.052812] ? find_lock_delalloc_range+0x221/0x250 [btrfs] [258532.052834] writepage_delalloc+0xe4/0x140 [btrfs] [258532.052855] __extent_writepage+0x110/0x4e0 [btrfs] [258532.052876] extent_write_cache_pages+0x21c/0x480 [btrfs] [258532.052906] extent_writepages+0x52/0xb0 [btrfs] [258532.052911] do_writepages+0x23/0x80 [258532.052915] __filemap_fdatawrite_range+0xd2/0x110 [258532.052938] btrfs_fdatawrite_range+0x1b/0x50 [btrfs] [258532.052954] start_ordered_ops+0x57/0xa0 [btrfs] [258532.052973] ? btrfs_sync_file+0x225/0x490 [btrfs] [258532.052988] btrfs_sync_file+0x225/0x490 [btrfs] [258532.052997] __x64_sys_msync+0x199/0x200 [258532.053004] do_syscall_64+0x5c/0x250 [258532.053007] entry_SYSCALL_64_after_hwframe+0x49/0xbe [258532.053010] RIP: 0033:0x7f86a7dfd760 (...) [258532.053014] RSP: 002b:00007ffd99af0368 EFLAGS: 00000246 ORIG_RAX: 000000000000001a [258532.053016] RAX: ffffffffffffffda RBX: 0000000000000ec9 RCX: 00007f86a7dfd760 [258532.053017] RDX: 0000000000000004 RSI: 000000000000836c RDI: 00007f86a8221000 [258532.053019] RBP: 0000000000021ec9 R08: 0000000000000003 R09: 00007f86a812037c [258532.053020] R10: 0000000000000001 R11: 0000000000000246 R12: 00000000000074a3 [258532.053021] R13: 00007f86a8221000 R14: 000000000000836c R15: 0000000000000001 [258532.053032] irq event stamp: 1653450494 [258532.053035] hardirqs last enabled at (1653450493): [<ffffffff9dec69f9>] _raw_spin_unlock_irq+0x29/0x50 [258532.053037] hardirqs last disabled at (1653450494): [<ffffffff9d4048ea>] trace_hardirqs_off_thunk+0x1a/0x20 [258532.053039] softirqs last enabled at (1653449852): [<ffffffff9e200466>] __do_softirq+0x466/0x6bd [258532.053042] softirqs last disabled at (1653449845): [<ffffffff9d4c8a0c>] irq_exit+0xec/0x120 [258532.053043] ---[ end trace 8476fce13d9ce20a ]--- Which results in flooding dmesg/syslog since btrfs_drop_extent_cache() uses WARN_ON() and not WARN_ON_ONCE(). So fix this issue by changing run_delalloc_nocow()'s loop to move to the next extent item when the current extent item ends at at offset less than or equals to the current offset instead of the start offset. Fixes: 80ff385665b7fc ("Btrfs: update nodatacow code v2") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-30btrfs: fix compressed write bio blkcg attributionDennis Zhou
Bio attribution is handled at bio_set_dev() as once we have a device, we have a corresponding request_queue and then can derive the current css. In special cases, we want to attribute to bio to someone else. This can be done by calling bio_associate_blkg_from_css() or kthread_associate_blkcg() depending on the scenario. Btrfs does this for compressed writeback as they are handled by kworkers, so the latter can be done here. Commit 1a41802701ec ("btrfs: drop bio_set_dev where not needed") removes early bio_set_dev() calls prior to submit_stripe_bio(). This breaks the above assumption that we'll have a request_queue when we are doing association. To fix this, switch to using kthread_associate_blkcg(). Without this, we crash in btrfs/024: [ 3052.093088] BUG: kernel NULL pointer dereference, address: 0000000000000510 [ 3052.107013] #PF: supervisor read access in kernel mode [ 3052.107014] #PF: error_code(0x0000) - not-present page [ 3052.107015] PGD 0 P4D 0 [ 3052.107021] Oops: 0000 [#1] SMP [ 3052.138904] CPU: 42 PID: 201270 Comm: kworker/u161:0 Kdump: loaded Not tainted 5.5.0-rc1-00062-g4852d8ac90a9 #712 [ 3052.138905] Hardware name: Quanta Tioga Pass Single Side 01-0032211004/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 [ 3052.138912] Workqueue: btrfs-delalloc btrfs_work_helper [ 3052.191375] RIP: 0010:bio_associate_blkg_from_css+0x1e/0x3c0 [ 3052.191379] RSP: 0018:ffffc900210cfc90 EFLAGS: 00010282 [ 3052.191380] RAX: 0000000000000000 RBX: ffff88bfe5573c00 RCX: 0000000000000000 [ 3052.191382] RDX: ffff889db48ec2f0 RSI: ffff88bfe5573c00 RDI: ffff889db48ec2f0 [ 3052.191386] RBP: 0000000000000800 R08: 0000000000203bb0 R09: ffff889db16b2400 [ 3052.293364] R10: 0000000000000000 R11: ffff88a07fffde80 R12: ffff889db48ec2f0 [ 3052.293365] R13: 0000000000001000 R14: ffff889de82bc000 R15: ffff889e2b7bdcc8 [ 3052.293367] FS: 0000000000000000(0000) GS:ffff889ffba00000(0000) knlGS:0000000000000000 [ 3052.293368] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3052.293369] CR2: 0000000000000510 CR3: 0000000002611001 CR4: 00000000007606e0 [ 3052.293370] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 3052.293371] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 3052.293372] PKRU: 55555554 [ 3052.293376] Call Trace: [ 3052.402552] btrfs_submit_compressed_write+0x137/0x390 [ 3052.402558] submit_compressed_extents+0x40f/0x4c0 [ 3052.422401] btrfs_work_helper+0x246/0x5a0 [ 3052.422408] process_one_work+0x200/0x570 [ 3052.438601] ? process_one_work+0x180/0x570 [ 3052.438605] worker_thread+0x4c/0x3e0 [ 3052.438614] kthread+0x103/0x140 [ 3052.460735] ? process_one_work+0x570/0x570 [ 3052.460737] ? kthread_mod_delayed_work+0xc0/0xc0 [ 3052.460744] ret_from_fork+0x24/0x30 Fixes: 1a41802701ec ("btrfs: drop bio_set_dev where not needed") Reported-by: Chris Murphy <chris@colorremedies.com> Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-30btrfs: punt all bios created in btrfs_submit_compressed_write()Dennis Zhou
Compressed writes happen in the background via kworkers. However, this causes bios to be attributed to root bypassing any cgroup limits from the actual writer. We tag the first bio with REQ_CGROUP_PUNT, which will punt the bio to an appropriate cgroup specific workqueue and attribute the IO properly. However, if btrfs_submit_compressed_write() creates a new bio, we don't tag it the same way. Add the appropriate tagging for subsequent bios. Fixes: ec39f7696ccfa ("Btrfs: use REQ_CGROUP_PUNT for worker thread submitted bios") Reviewed-by: Chris Mason <clm@fb.com> Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: send: remove WARN_ON for readonly mountAnand Jain
We log warning if root::orphan_cleanup_state is not set to ORPHAN_CLEANUP_DONE in btrfs_ioctl_send(). However if the filesystem is mounted as readonly we skip the orphan item cleanup during the lookup and root::orphan_cleanup_state remains at the init state 0 instead of ORPHAN_CLEANUP_DONE (2). So during send in btrfs_ioctl_send() we hit the warning as below. WARN_ON(send_root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE); WARNING: CPU: 0 PID: 2616 at /Volumes/ws/btrfs-devel/fs/btrfs/send.c:7090 btrfs_ioctl_send+0xb2f/0x18c0 [btrfs] :: RIP: 0010:btrfs_ioctl_send+0xb2f/0x18c0 [btrfs] :: Call Trace: :: _btrfs_ioctl_send+0x7b/0x110 [btrfs] btrfs_ioctl+0x150a/0x2b00 [btrfs] :: do_vfs_ioctl+0xa9/0x620 ? __fget+0xac/0xe0 ksys_ioctl+0x60/0x90 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x49/0x130 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reproducer: mkfs.btrfs -fq /dev/sdb mount /dev/sdb /btrfs btrfs subvolume create /btrfs/sv1 btrfs subvolume snapshot -r /btrfs/sv1 /btrfs/ss1 umount /btrfs mount -o ro /dev/sdb /btrfs btrfs send /btrfs/ss1 -f /tmp/f The warning exists because having orphan inodes could confuse send and cause it to fail or produce incorrect streams. The two cases that would cause such send failures, which are already fixed are: 1) Inodes that were unlinked - these are orphanized and remain with a link count of 0. These caused send operations to fail because it expected to always find at least one path for an inode. However this is no longer a problem since send is now able to deal with such inodes since commit 46b2f4590aab ("Btrfs: fix send failure when root has deleted files still open") and treats them as having been completely removed (the state after an orphan cleanup is performed). 2) Inodes that were in the process of being truncated. These resulted in send not knowing about the truncation and potentially issue write operations full of zeroes for the range from the new file size to the old file size. This is no longer a problem because we no longer create orphan items for truncation since commit f7e9e8fc792f ("Btrfs: stop creating orphan items for truncate"). As such before these commits, the WARN_ON here provided a clue in case something went wrong. Instead of being a warning against the root::orphan_cleanup_state value, it could have been more accurate by checking if there were actually any orphan items, and then issue a warning only if any exists, but that would be more expensive to check. Since orphanized inodes no longer cause problems for send, just remove the warning. Reported-by: Christoph Anton Mitterer <calestyo@scientia.net> Link: https://lore.kernel.org/linux-btrfs/21cb5e8d059f6e1496a903fa7bfc0a297e2f5370.camel@scientia.net/ CC: stable@vger.kernel.org # 4.19+ Suggested-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: do not leak reloc root if we fail to read the fs rootJosef Bacik
If we fail to read the fs root corresponding with a reloc root we'll just break out and free the reloc roots. But we remove our current reloc_root from this list higher up, which means we'll leak this reloc_root. Fix this by adding ourselves back to the reloc_roots list so we are properly cleaned up. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: skip log replay on orphaned rootsJosef Bacik
My fsstress modifications coupled with generic/475 uncovered a failure to mount and replay the log if we hit a orphaned root. We do not want to replay the log for an orphan root, but it's completely legitimate to have an orphaned root with a log attached. Fix this by simply skipping replaying the log. We still need to pin it's root node so that we do not overwrite it while replaying other logs, as we re-read the log root at every stage of the replay. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: handle ENOENT in btrfs_uuid_tree_iterateJosef Bacik
If we get an -ENOENT back from btrfs_uuid_iter_rem when iterating the uuid tree we'll just continue and do btrfs_next_item(). However we've done a btrfs_release_path() at this point and no longer have a valid path. So increment the key and go back and do a normal search. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: abort transaction after failed inode updates in create_subvolJosef Bacik
We can just abort the transaction here, and in fact do that for every other failure in this function except these two cases. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13Btrfs: fix hole extent items with a zero size after range cloningFilipe Manana
Normally when cloning a file range if we find an implicit hole at the end of the range we assume it is because the NO_HOLES feature is enabled. However that is not always the case. One well known case [1] is when we have a power failure after mixing buffered and direct IO writes against the same file. In such cases we need to punch a hole in the destination file, and if the NO_HOLES feature is not enabled, we need to insert explicit file extent items to represent the hole. After commit 690a5dbfc51315 ("Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents"), we started to insert file extent items representing the hole with an item size of 0, which is invalid and should be 53 bytes (the size of a btrfs_file_extent_item structure), resulting in all sorts of corruptions and invalid memory accesses. This is detected by the tree checker when we attempt to write a leaf to disk. The problem can be sporadically triggered by test case generic/561 from fstests. That test case does not exercise power failure and creates a new filesystem when it starts, so it does not use a filesystem created by any previous test that tests power failure. However the test does both buffered and direct IO writes (through fsstress) and it's precisely that which is creating the implicit holes in files. That happens even before the commit mentioned earlier. I need to investigate why we get those implicit holes to check if there is a real problem or not. For now this change fixes the regression of introducing file extent items with an item size of 0 bytes. Fix the issue by calling btrfs_punch_hole_range() without passing a btrfs_clone_extent_info structure, which ensures file extent items are inserted to represent the hole with a correct item size. We were passing a btrfs_clone_extent_info with a value of 0 for its 'item_size' field, which was causing the insertion of file extent items with an item size of 0. [1] https://www.spinics.net/lists/linux-btrfs/msg75350.html Reported-by: David Sterba <dsterba@suse.com> Fixes: 690a5dbfc51315 ("Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents") Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Josef Bacik <josef@toxicpanda.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>
2019-12-13Btrfs: make tree checker detect checksum items with overlapping rangesFilipe Manana
Having checksum items, either on the checksums tree or in a log tree, that represent ranges that overlap each other is a sign of a corruption. Such case confuses the checksum lookup code and can result in not being able to find checksums or find stale checksums. So add a check for such case. This is motivated by a recent fix for a case where a log tree had checksum items covering ranges that overlap each other due to extent cloning, and resulted in missing checksums after replaying the log tree. It also helps detect past issues such as stale and outdated checksums due to overlapping, commit 27b9a8122ff71a ("Btrfs: fix csum tree corruption, duplicate and outdated checksums"). CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13Btrfs: fix missing data checksums after replaying a log treeFilipe Manana
When logging a file that has shared extents (reflinked with other files or with itself), we can end up logging multiple checksum items that cover overlapping ranges. This confuses the search for checksums at log replay time causing some checksums to never be added to the fs/subvolume tree. Consider the following example of a file that shares the same extent at offsets 0 and 256Kb: [ bytenr 13893632, offset 64Kb, len 64Kb ] 0 64Kb [ bytenr 13631488, offset 64Kb, len 192Kb ] 64Kb 256Kb [ bytenr 13893632, offset 0, len 256Kb ] 256Kb 512Kb When logging the inode, at tree-log.c:copy_items(), when processing the file extent item at offset 0, we log a checksum item covering the range 13959168 to 14024704, which corresponds to 13893632 + 64Kb and 13893632 + 64Kb + 64Kb, respectively. Later when processing the extent item at offset 256K, we log the checksums for the range from 13893632 to 14155776 (which corresponds to 13893632 + 256Kb). These checksums get merged with the checksum item for the range from 13631488 to 13893632 (13631488 + 256Kb), logged by a previous fsync. So after this we get the two following checksum items in the log tree: (...) item 6 key (EXTENT_CSUM EXTENT_CSUM 13631488) itemoff 3095 itemsize 512 range start 13631488 end 14155776 length 524288 item 7 key (EXTENT_CSUM EXTENT_CSUM 13959168) itemoff 3031 itemsize 64 range start 13959168 end 14024704 length 65536 The first one covers the range from the second one, they overlap. So far this does not cause a problem after replaying the log, because when replaying the file extent item for offset 256K, we copy all the checksums for the extent 13893632 from the log tree to the fs/subvolume tree, since searching for an checksum item for bytenr 13893632 leaves us at the first checksum item, which covers the whole range of the extent. However if we write 64Kb to file offset 256Kb for example, we will not be able to find and copy the checksums for the last 128Kb of the extent at bytenr 13893632, referenced by the file range 384Kb to 512Kb. After writing 64Kb into file offset 256Kb we get the following extent layout for our file: [ bytenr 13893632, offset 64K, len 64Kb ] 0 64Kb [ bytenr 13631488, offset 64Kb, len 192Kb ] 64Kb 256Kb [ bytenr 14155776, offset 0, len 64Kb ] 256Kb 320Kb [ bytenr 13893632, offset 64Kb, len 192Kb ] 320Kb 512Kb After fsync'ing the file, if we have a power failure and then mount the filesystem to replay the log, the following happens: 1) When replaying the file extent item for file offset 320Kb, we lookup for the checksums for the extent range from 13959168 (13893632 + 64Kb) to 14155776 (13893632 + 256Kb), through a call to btrfs_lookup_csums_range(); 2) btrfs_lookup_csums_range() finds the checksum item that starts precisely at offset 13959168 (item 7 in the log tree, shown before); 3) However that checksum item only covers 64Kb of data, and not 192Kb of data; 4) As a result only the checksums for the first 64Kb of data referenced by the file extent item are found and copied to the fs/subvolume tree. The remaining 128Kb of data, file range 384Kb to 512Kb, doesn't get the corresponding data checksums found and copied to the fs/subvolume tree. 5) After replaying the log userspace will not be able to read the file range from 384Kb to 512Kb, because the checksums are missing and resulting in an -EIO error. The following steps reproduce this scenario: $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt/sdc $ xfs_io -f -c "pwrite -S 0xa3 0 256K" /mnt/sdc/foobar $ xfs_io -c "fsync" /mnt/sdc/foobar $ xfs_io -c "pwrite -S 0xc7 256K 256K" /mnt/sdc/foobar $ xfs_io -c "reflink /mnt/sdc/foobar 320K 0 64K" /mnt/sdc/foobar $ xfs_io -c "fsync" /mnt/sdc/foobar $ xfs_io -c "pwrite -S 0xe5 256K 64K" /mnt/sdc/foobar $ xfs_io -c "fsync" /mnt/sdc/foobar <power failure> $ mount /dev/sdc /mnt/sdc $ md5sum /mnt/sdc/foobar md5sum: /mnt/sdc/foobar: Input/output error $ dmesg | tail [165305.003464] BTRFS info (device sdc): no csum found for inode 257 start 401408 [165305.004014] BTRFS info (device sdc): no csum found for inode 257 start 405504 [165305.004559] BTRFS info (device sdc): no csum found for inode 257 start 409600 [165305.005101] BTRFS info (device sdc): no csum found for inode 257 start 413696 [165305.005627] BTRFS info (device sdc): no csum found for inode 257 start 417792 [165305.006134] BTRFS info (device sdc): no csum found for inode 257 start 421888 [165305.006625] BTRFS info (device sdc): no csum found for inode 257 start 425984 [165305.007278] BTRFS info (device sdc): no csum found for inode 257 start 430080 [165305.008248] BTRFS warning (device sdc): csum failed root 5 ino 257 off 393216 csum 0x1337385e expected csum 0x00000000 mirror 1 [165305.009550] BTRFS warning (device sdc): csum failed root 5 ino 257 off 393216 csum 0x1337385e expected csum 0x00000000 mirror 1 Fix this simply by deleting first any checksums, from the log tree, for the range of the extent we are logging at copy_items(). This ensures we do not get checksum items in the log tree that have overlapping ranges. This is a long time issue that has been present since we have the clone (and deduplication) ioctl, and can happen both when an extent is shared between different files and within the same file. A test case for fstests follows soon. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: return error pointer from alloc_test_extent_bufferDan Carpenter
Callers of alloc_test_extent_buffer have not correctly interpreted the return value as error pointer, as alloc_test_extent_buffer should behave as alloc_extent_buffer. The self-tests were unaffected but btrfs_find_create_tree_block could call both functions and that would cause problems up in the call chain. Fixes: faa2dbf004e8 ("Btrfs: add sanity tests for new qgroup accounting code") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: fix devs_max constraints for raid1c3 and raid1c4David Sterba
The value 0 for devs_max means to spread the allocated chunks over all available devices, eg. stripe for RAID0 or RAID5. This got mistakenly copied to the RAID1C3/4 profiles. The intention is to have exactly 3 and 4 copies respectively. Fixes: 47e6f7423b91 ("btrfs: add support for 3-copy replication (raid1c3)") Fixes: 8d6fac0087e5 ("btrfs: add support for 4-copy replication (raid1c4)") Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: tree-checker: Fix error format string for size_tAndreas Färber
Argument BTRFS_FILE_EXTENT_INLINE_DATA_START is defined as offsetof(), which returns type size_t, so we need %zu instead of %lu. This fixes a build warning on 32-bit ARM: ../fs/btrfs/tree-checker.c: In function 'check_extent_data_item': ../fs/btrfs/tree-checker.c:230:43: warning: format '%lu' expects argument of type 'long unsigned int', but argument 5 has type 'unsigned int' [-Wformat=] 230 | "invalid item size, have %u expect [%lu, %u)", | ~~^ | long unsigned int | %u Fixes: 153a6d299956 ("btrfs: tree-checker: Check item size before reading file extent type") Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andreas Färber <afaerber@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: don't double lock the subvol_sem for rename exchangeJosef Bacik
If we're rename exchanging two subvols we'll try to lock this lock twice, which is bad. Just lock once if either of the ino's are subvols. Fixes: cdd1fedf8261 ("btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: handle error in btrfs_cache_block_groupJosef Bacik
We have a BUG_ON(ret < 0) in find_free_extent from btrfs_cache_block_group. If we fail to allocate our ctl we'll just panic, which is not good. Instead just go on to another block group. If we fail to find a block group we don't want to return ENOSPC, because really we got a ENOMEM and that's the root of the problem. Save our return from btrfs_cache_block_group(), and then if we still fail to make our allocation return that ret so we get the right error back. Tested with inject-error.py from bcc. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: do not call synchronize_srcu() in inode_tree_delJosef Bacik
Testing with the new fsstress uncovered a pretty nasty deadlock with lookup and snapshot deletion. Process A unlink -> final iput -> inode_tree_del -> synchronize_srcu(subvol_srcu) Process B btrfs_lookup <- srcu_read_lock() acquired here -> btrfs_iget -> find inode that has I_FREEING set -> __wait_on_freeing_inode() We're holding the srcu_read_lock() while doing the iget in order to make sure our fs root doesn't go away, and then we are waiting for the inode to finish freeing. However because the free'ing process is doing a synchronize_srcu() we deadlock. Fix this by dropping the synchronize_srcu() in inode_tree_del(). We don't need people to stop accessing the fs root at this point, we're only adding our empty root to the dead roots list. A larger much more invasive fix is forthcoming to address how we deal with fs roots, but this fixes the immediate problem. Fixes: 76dda93c6ae2 ("Btrfs: add snapshot/subvolume destroy ioctl") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13Btrfs: fix cloning range with a hole when using the NO_HOLES featureFilipe Manana
When using the NO_HOLES feature if we clone a range that contains a hole and a temporary ENOSPC happens while dropping extents from the target inode's range, we can end up failing and aborting the transaction with -EEXIST or with a corrupt file extent item, that has a length greater than it should and overlaps with other extents. For example when cloning the following range from inode A to inode B: Inode A: extent A1 extent A2 [ ----------- ] [ hole, implicit, 4MB length ] [ ------------- ] 0 1MB 5MB 6MB Range to clone: [1MB, 6MB) Inode B: extent B1 extent B2 extent B3 extent B4 [ ---------- ] [ --------- ] [ ---------- ] [ ---------- ] 0 1MB 1MB 2MB 2MB 5MB 5MB 6MB Target range: [1MB, 6MB) (same as source, to make it easier to explain) The following can happen: 1) btrfs_punch_hole_range() gets -ENOSPC from __btrfs_drop_extents(); 2) At that point, 'cur_offset' is set to 1MB and __btrfs_drop_extents() set 'drop_end' to 2MB, meaning it was able to drop only extent B2; 3) We then compute 'clone_len' as 'drop_end' - 'cur_offset' = 2MB - 1MB = 1MB; 4) We then attempt to insert a file extent item at inode B with a file offset of 5MB, which is the value of clone_info->file_offset. This fails with error -EEXIST because there's already an extent at that offset (extent B4); 5) We abort the current transaction with -EEXIST and return that error to user space as well. Another example, for extent corruption: Inode A: extent A1 extent A2 [ ----------- ] [ hole, implicit, 10MB length ] [ ------------- ] 0 1MB 11MB 12MB Inode B: extent B1 extent B2 [ ----------- ] [ --------- ] [ ----------------------------- ] 0 1MB 1MB 5MB 5MB 12MB Target range: [1MB, 12MB) (same as source, to make it easier to explain) 1) btrfs_punch_hole_range() gets -ENOSPC from __btrfs_drop_extents(); 2) At that point, 'cur_offset' is set to 1MB and __btrfs_drop_extents() set 'drop_end' to 5MB, meaning it was able to drop only extent B2; 3) We then compute 'clone_len' as 'drop_end' - 'cur_offset' = 5MB - 1MB = 4MB; 4) We then insert a file extent item at inode B with a file offset of 11MB which is the value of clone_info->file_offset, and a length of 4MB (the value of 'clone_len'). So we get 2 extents items with ranges that overlap and an extent length of 4MB, larger then the extent A2 from inode A (1MB length); 5) After that we end the transaction, balance the btree dirty pages and then start another or join the previous transaction. It might happen that the transaction which inserted the incorrect extent was committed by another task so we end up with extent corruption if a power failure happens. So fix this by making sure we attempt to insert the extent to clone at the destination inode only if we are past dropping the sub-range that corresponds to a hole. Fixes: 690a5dbfc51315 ("Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-13btrfs: Fix error messages in qgroup_rescan_initNikolay Borisov
The branch of qgroup_rescan_init which is executed from the mount path prints wrong errors messages. The textual print out in case BTRFS_QGROUP_STATUS_FLAG_RESCAN/BTRFS_QGROUP_STATUS_FLAG_ON are not set are transposed. Fix it by exchanging their place. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: drop bdev argument from submit_extent_pageDavid Sterba
After previous patches removing bdev being passed around to set it to bio, it has become unused in submit_extent_page. So it now has "only" 13 parameters. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: remove extent_map::bdevDavid Sterba
We can now remove the bdev from extent_map. Previous patches made sure that bio_set_dev is correctly in all places and that we don't need to grab it from latest_bdev or pass it around inside the extent map. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: drop bio_set_dev where not neededDavid Sterba
bio_set_dev sets a bdev to a bio and is not only setting a pointer bug also changing some state bits if there was a different bdev set before. This is one thing that's not needed. Another thing is that setting a bdev at bio allocation time is too early and actually does not work with plain redundancy profiles, where each time we submit a bio to a device, the bdev is set correctly. In many places the bio bdev is set to latest_bdev that seems to serve as a stub pointer "just to put something to bio". But we don't have to do that. Where do we know which bdev to set: * for regular IO: submit_stripe_bio that's called by btrfs_map_bio * repair IO: repair_io_failure, read or write from specific device * super block write (using buffer_heads but uses raw bdev) and barriers * scrub: this does not use all regular IO paths as it needs to reach all copies, verify and fixup eventually, and for that all bdev management is independent * raid56: rbio_add_io_page, for the RMW write * integrity-checker: does it's own low-level block tracking Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: get bdev directly from fs_devices in submit_extent_pageDavid Sterba
This is preparatory patch to remove @bdev parameter from submit_extent_page. It can't be removed completely, because the cgroups need it for wbc when initializing the bio wbc_init_bio bio_associate_blkg_from_css dereference bdev->bi_disk->queue The bdev pointer is the same as latest_bdev, thus no functional change. We can retrieve it from fs_devices that's reachable through several dereferences. The local variable shadows the parameter, but that's only temporary. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: record all roots for rename exchange on a subvolJosef Bacik
Testing with the new fsstress support for subvolumes uncovered a pretty bad problem with rename exchange on subvolumes. We're modifying two different subvolumes, but we only start the transaction on one of them, so the other one is not added to the dirty root list. This is caught by btrfs_cow_block() with a warning because the root has not been updated, however if we do not modify this root again we'll end up pointing at an invalid root because the root item is never updated. Fix this by making sure we add the destination root to the trans list, the same as we do with normal renames. This fixes the corruption. Fixes: cdd1fedf8261 ("btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT") CC: stable@vger.kernel.org # 4.9+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18Btrfs: fix block group remaining RO forever after error during device replaceFilipe Manana
When doing a device replace, while at scrub.c:scrub_enumerate_chunks(), we set the block group to RO mode and then wait for any ongoing writes into extents of the block group to complete. While doing that wait we overwrite the value of the variable 'ret' and can break out of the loop if an error happens without turning the block group back into RW mode. So what happens is the following: 1) btrfs_inc_block_group_ro() returns 0, meaning it set the block group to RO mode (its ->ro field set to 1 or incremented to some value > 1); 2) Then btrfs_wait_ordered_roots() returns a value > 0; 3) Then if either joining or committing the transaction fails, we break out of the loop wihtout calling btrfs_dec_block_group_ro(), leaving the block group in RO mode forever. To fix this, just remove the code that waits for ongoing writes to extents of the block group, since it's not needed because in the initial setup phase of a device replace operation, before starting to find all chunks and their extents, we set the target device for replace while holding fs_info->dev_replace->rwsem, which ensures that after releasing that semaphore, any writes into the source device are made to the target device as well (__btrfs_map_block() guarantees that). So while at scrub_enumerate_chunks() we only need to worry about finding and copying extents (from the source device to the target device) that were written before we started the device replace operation. Fixes: f0e9b7d6401959 ("Btrfs: fix race setting block group readonly during device replace") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: scrub: Don't check free space before marking a block group ROQu Wenruo
[BUG] When running btrfs/072 with only one online CPU, it has a pretty high chance to fail: btrfs/072 12s ... _check_dmesg: something found in dmesg (see xfstests-dev/results//btrfs/072.dmesg) - output mismatch (see xfstests-dev/results//btrfs/072.out.bad) --- tests/btrfs/072.out 2019-10-22 15:18:14.008965340 +0800 +++ /xfstests-dev/results//btrfs/072.out.bad 2019-11-14 15:56:45.877152240 +0800 @@ -1,2 +1,3 @@ QA output created by 072 Silence is golden +Scrub find errors in "-m dup -d single" test ... And with the following call trace: BTRFS info (device dm-5): scrub: started on devid 1 ------------[ cut here ]------------ BTRFS: Transaction aborted (error -27) WARNING: CPU: 0 PID: 55087 at fs/btrfs/block-group.c:1890 btrfs_create_pending_block_groups+0x3e6/0x470 [btrfs] CPU: 0 PID: 55087 Comm: btrfs Tainted: G W O 5.4.0-rc1-custom+ #13 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:btrfs_create_pending_block_groups+0x3e6/0x470 [btrfs] Call Trace: __btrfs_end_transaction+0xdb/0x310 [btrfs] btrfs_end_transaction+0x10/0x20 [btrfs] btrfs_inc_block_group_ro+0x1c9/0x210 [btrfs] scrub_enumerate_chunks+0x264/0x940 [btrfs] btrfs_scrub_dev+0x45c/0x8f0 [btrfs] btrfs_ioctl+0x31a1/0x3fb0 [btrfs] do_vfs_ioctl+0x636/0xaa0 ksys_ioctl+0x67/0x90 __x64_sys_ioctl+0x43/0x50 do_syscall_64+0x79/0xe0 entry_SYSCALL_64_after_hwframe+0x49/0xbe ---[ end trace 166c865cec7688e7 ]--- [CAUSE] The error number -27 is -EFBIG, returned from the following call chain: btrfs_end_transaction() |- __btrfs_end_transaction() |- btrfs_create_pending_block_groups() |- btrfs_finish_chunk_alloc() |- btrfs_add_system_chunk() This happens because we have used up all space of btrfs_super_block::sys_chunk_array. The root cause is, we have the following bad loop of creating tons of system chunks: 1. The only SYSTEM chunk is being scrubbed It's very common to have only one SYSTEM chunk. 2. New SYSTEM bg will be allocated As btrfs_inc_block_group_ro() will check if we have enough space after marking current bg RO. If not, then allocate a new chunk. 3. New SYSTEM bg is still empty, will be reclaimed During the reclaim, we will mark it RO again. 4. That newly allocated empty SYSTEM bg get scrubbed We go back to step 2, as the bg is already mark RO but still not cleaned up yet. If the cleaner kthread doesn't get executed fast enough (e.g. only one CPU), then we will get more and more empty SYSTEM chunks, using up all the space of btrfs_super_block::sys_chunk_array. [FIX] Since scrub/dev-replace doesn't always need to allocate new extent, especially chunk tree extent, so we don't really need to do chunk pre-allocation. To break above spiral, here we introduce a new parameter to btrfs_inc_block_group(), @do_chunk_alloc, which indicates whether we need extra chunk pre-allocation. For relocation, we pass @do_chunk_alloc=true, while for scrub, we pass @do_chunk_alloc=false. This should keep unnecessary empty chunks from popping up for scrub. Also, since there are two parameters for btrfs_inc_block_group_ro(), add more comment for it. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: change btrfs_fs_devices::rotating to boolJohannes Thumshirn
struct btrfs_fs_devices::rotating currently is declared as an integer variable but only used as a boolean. Change the variable definition to bool and update to code touching it to set 'true' and 'false'. Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: change btrfs_fs_devices::seeding to boolJohannes Thumshirn
struct btrfs_fs_devices::seeding currently is declared as an integer variable but only used as a boolean. Change the variable definition to bool and update to code touching it to set 'true' and 'false'. Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: rename btrfs_block_group_cacheDavid Sterba
The type name is misleading, a single entry is named 'cache' while this normally means a collection of objects. Rename that everywhere. Also the identifier was quite long, making function prototypes harder to format. Suggested-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: block-group: Reuse the item key from caller of read_one_block_group()Qu Wenruo
For read_one_block_group(), its only caller has already got the item key to search next block group item. So we can use that key directly without doing our own convertion on stack. Also, since that key used in btrfs_read_block_groups() is vital for block group item search, add 'const' keyword for that parameter to prevent read_one_block_group() to modify it. 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: block-group: Refactor btrfs_read_block_groups()Qu Wenruo
Refactor the work inside the loop of btrfs_read_block_groups() into one separate function, read_one_block_group(). This allows read_one_block_group to be reused for later BG_TREE feature. The refactor does the following extra fix: - Use btrfs_fs_incompat() to replace open-coded feature check Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> 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>
2019-11-18btrfs: document extent buffer lockingDavid Sterba
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: access eb::blocking_writers according to ACCESS_ONCE policiesDavid Sterba
A nice writeup of the LKMM (Linux Kernel Memory Model) rules for access once policies can be found here https://lwn.net/Articles/799218/#Access-Marking%20Policies . The locked and unlocked access to eb::blocking_writers should be annotated accordingly, following this: Writes: - locked write must use ONCE, may use plain read - unlocked write must use ONCE Reads: - unlocked read must use ONCE - locked read may use plain read iff not mixed with unlocked read - unlocked read then locked must use ONCE There's one difference on the assembly level, where btrfs_tree_read_lock_atomic and btrfs_try_tree_read_lock used the cached value and did not reevaluate it after taking the lock. This could have missed some opportunities to take the lock in case blocking writers changed between the calls, but the window is just a few instructions long. As this is in try-lock, the callers handle that. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: set blocking_writers directly, no increment or decrementDavid Sterba
The increment and decrement was inherited from previous version that used atomics, switched in commit 06297d8cefca ("btrfs: switch extent_buffer blocking_writers from atomic to int"). The only possible values are 0 and 1 so we can set them directly. The generated assembly (gcc 9.x) did the direct value assignment in btrfs_set_lock_blocking_write (asm diff after change in 06297d8cefca): 5d: test %eax,%eax 5f: je 62 <btrfs_set_lock_blocking_write+0x22> 61: retq - 62: lock incl 0x44(%rdi) - 66: add $0x50,%rdi - 6a: jmpq 6f <btrfs_set_lock_blocking_write+0x2f> + 62: movl $0x1,0x44(%rdi) + 69: add $0x50,%rdi + 6d: jmpq 72 <btrfs_set_lock_blocking_write+0x32> The part in btrfs_tree_unlock did a decrement because BUG_ON(blockers > 1) is probably not a strong hint for the compiler, but otherwise the output looks safe: - lock decl 0x44(%rdi) + sub $0x1,%eax + mov %eax,0x44(%rdi) Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: merge blocking_writers branches in btrfs_tree_read_lockDavid Sterba
There are two ifs that use eb::blocking_writers. As this is a variable modified inside and outside of locks, we could minimize number of accesses to avoid problems with getting different results at different times. The access here is locked so this can only race with btrfs_tree_unlock that sets blocking_writers to 0 without lock and unsets the lock owner. The first branch is taken only if the same thread already holds the lock, the second if checks for blocking writers. Here we'd either unlock and wait, or proceed. Both are valid states of the locking protocol. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: drop incompat bit for raid1c34 after last block group is goneDavid Sterba
When there are no raid1c3 or raid1c4 block groups left after balance (either convert or with other filters applied), remove the incompat bit. This is already done for RAID56, do the same for RAID1C34. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: add incompat for raid1 with 3, 4 copiesDavid Sterba
The new raid1c3 and raid1c4 profiles are backward incompatible and the name shall be 'raid1c34', the status can be found in the global supported features in /sys/fs/btrfs/features or in the per-filesystem directory. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: add support for 4-copy replication (raid1c4)David Sterba
Add new block group profile to store 4 copies in a simliar way that current RAID1 does. The profile attributes and constraints are defined in the raid table and used by the same code that already handles the 2- and 3-copy RAID1. The minimum number of devices is 4, the maximum number of devices/chunks that can be lost/damaged is 3. There is no comparable traditional RAID level, the profile is added for future needs to accompany triple-parity and beyond. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: add support for 3-copy replication (raid1c3)David Sterba
Add new block group profile to store 3 copies in a simliar way that current RAID1 does. The profile attributes and constraints are defined in the raid table and used by the same code that already handles the 2-copy RAID1. The minimum number of devices is 3, the maximum number of devices/chunks that can be lost/damaged is 2. Like RAID6 but with 33% space utilization. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: sink write flags to cow_file_range_asyncDavid Sterba
In commit "Btrfs: use REQ_CGROUP_PUNT for worker thread submitted bios", cow_file_range_async gained wbc as a parameter and this makes passing write flags redundant. Set it inside the function and remove the parameter. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: sink write_flags to __extent_writepage_ioDavid Sterba
__extent_writepage reads write flags from wbc and passes both to __extent_writepage_io. This makes write_flags redundant and we can remove it. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18Btrfs: send, skip backreference walking for extents with many referencesFilipe Manana
Backreference walking, which is used by send to figure if it can issue clone operations instead of write operations, can be very slow and use too much memory when extents have many references. This change simply skips backreference walking when an extent has more than 64 references, in which case we fallback to a write operation instead of a clone operation. This limit is conservative and in practice I observed no signicant slowdown with up to 100 references and still low memory usage up to that limit. This is a temporary workaround until there are speedups in the backref walking code, and as such it does not attempt to add extra interfaces or knobs to tweak the threshold. Reported-by: Atemu <atemu.main@gmail.com> Link: https://lore.kernel.org/linux-btrfs/CAE4GHgkvqVADtS4AzcQJxo0Q1jKQgKaW3JGp3SGdoinVo=C9eQ@mail.gmail.com/T/#me55dc0987f9cc2acaa54372ce0492c65782be3fa CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18Btrfs: send, allow clone operations within the same fileFilipe Manana
For send we currently skip clone operations when the source and destination files are the same. This is so because clone didn't support this case in its early days, but support for it was added back in May 2013 by commit a96fbc72884fcb ("Btrfs: allow file data clone within a file"). This change adds support for it. Example: $ mkfs.btrfs -f /dev/sdd $ mount /dev/sdd /mnt/sdd $ xfs_io -f -c "pwrite -S 0xab -b 64K 0 64K" /mnt/sdd/foobar $ xfs_io -c "reflink /mnt/sdd/foobar 0 64K 64K" /mnt/sdd/foobar $ btrfs subvolume snapshot -r /mnt/sdd /mnt/sdd/snap $ mkfs.btrfs -f /dev/sde $ mount /dev/sde /mnt/sde $ btrfs send /mnt/sdd/snap | btrfs receive /mnt/sde Without this change file foobar at the destination has a single 128Kb extent: $ filefrag -v /mnt/sde/snap/foobar Filesystem type is: 9123683e File size of /mnt/sde/snap/foobar is 131072 (32 blocks of 4096 bytes) ext: logical_offset: physical_offset: length: expected: flags: 0: 0.. 31: 0.. 31: 32: last,unknown_loc,delalloc,eof /mnt/sde/snap/foobar: 1 extent found With this we get a single 64Kb extent that is shared at file offsets 0 and 64K, just like in the source filesystem: $ filefrag -v /mnt/sde/snap/foobar Filesystem type is: 9123683e File size of /mnt/sde/snap/foobar is 131072 (32 blocks of 4096 bytes) ext: logical_offset: physical_offset: length: expected: flags: 0: 0.. 15: 3328.. 3343: 16: shared 1: 16.. 31: 3328.. 3343: 16: 3344: last,shared,eof /mnt/sde/snap/foobar: 2 extents found 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>
2019-11-18btrfs: Ensure we trim ranges across block group boundaryQu Wenruo
[BUG] When deleting large files (which cross block group boundary) with discard mount option, we find some btrfs_discard_extent() calls only trimmed part of its space, not the whole range: btrfs_discard_extent: type=0x1 start=19626196992 len=2144530432 trimmed=1073741824 ratio=50% type: bbio->map_type, in above case, it's SINGLE DATA. start: Logical address of this trim len: Logical length of this trim trimmed: Physically trimmed bytes ratio: trimmed / len Thus leaving some unused space not discarded. [CAUSE] When discard mount option is specified, after a transaction is fully committed (super block written to disk), we begin to cleanup pinned extents in the following call chain: btrfs_commit_transaction() |- btrfs_finish_extent_commit() |- find_first_extent_bit(unpin, 0, &start, &end, EXTENT_DIRTY); |- btrfs_discard_extent() However, pinned extents are recorded in an extent_io_tree, which can merge adjacent extent states. When a large file gets deleted and it has adjacent file extents across block group boundary, we will get a large merged range like this: |<--- BG1 --->|<--- BG2 --->| |//////|<-- Range to discard --->|/////| To discard that range, we have the following calls: btrfs_discard_extent() |- btrfs_map_block() | Returned bbio will end at BG1's end. As btrfs_map_block() | never returns result across block group boundary. |- btrfs_issuse_discard() Issue discard for each stripe. So we will only discard the range in BG1, not the remaining part in BG2. Furthermore, this bug is not that reliably observed, for above case, if there is no other extent in BG2, BG2 will be empty and btrfs will trim all space of BG2, covering up the bug. [FIX] - Allow __btrfs_map_block_for_discard() to modify @length parameter btrfs_map_block() uses its @length paramter to notify the caller how many bytes are mapped in current call. With __btrfs_map_block_for_discard() also modifing the @length, btrfs_discard_extent() now understands when to do extra trim. - Call btrfs_map_block() in a loop until we hit the range end Since we now know how many bytes are mapped each time, we can iterate through each block group boundary and issue correct trim for each range. Reviewed-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: volumes: Use more straightforward way to calculate map lengthQu Wenruo
The old code goes: offset = logical - em->start; length = min_t(u64, em->len - offset, length); Where @length calculation is dependent on offset, it can take reader several more seconds to find it's just the same code as: offset = logical - em->start; length = min_t(u64, em->start + em->len - logical, length); Use above code to make the length calculate independent from other variable, thus slightly increase the readability. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> 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>
2019-11-18btrfs: tree-checker: Check item size before reading file extent typeQu Wenruo
In check_extent_data_item(), we read file extent type without verifying if the item size is valid. Add such check to ensure the file extent type we read is correct. The check is not as accurate as we need to cover both inline and regular extents, so it only checks if the item size is larger or equal to inline header. So the existing size checks on inline/regular extents are still needed. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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