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path: root/fs/btrfs/relocation.c (follow)
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2017-09-26btrfs: fix NULL pointer dereference from free_reloc_roots()Naohiro Aota1-1/+1
__del_reloc_root should be called before freeing up reloc_root->node. If not, calling __del_reloc_root() dereference reloc_root->node, causing the system BUG. Fixes: 6bdf131fac23 ("Btrfs: don't leak reloc root nodes on error") Cc: <stable@vger.kernel.org> # 4.9 Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-21Btrfs: remove BUG_ON in __add_tree_blockLiu Bo1-1/+11
The BUG_ON() can be triggered when the caller is processing an invalid extent inline ref, e.g. a shared data ref is offered instead of an extent data ref, such that it tries to find a non-existent tree block and then btrfs_search_slot returns 1 for no such item. This replaces the BUG_ON() with a WARN() followed by calling btrfs_print_leaf() to show more details about what's going on and returning -EINVAL to upper callers. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-21Btrfs: remove BUG() in add_data_referenceLiu Bo1-1/+4
Now that we have a helper to report invalid value of extent inline ref type, we need to quit gracefully instead of throwing out a kernel panic. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-21Btrfs: convert to use btrfs_get_extent_inline_ref_typeLiu Bo1-2/+11
Since we have a helper which can do sanity check, this converts all btrfs_extent_inline_ref_type to it. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Remove never reached error handling code in __add_reloc_rootNikolay Borisov1-2/+0
One of the error handling paths in __add_reloc_root contains btrfs_panic() followed by some other code. As the name implies what it does is print some error message and call BUG, naturally what follow afterwards is not invoked. So remove this extra code. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-06-29btrfs: fix integer overflow in calc_reclaim_items_nrChris Mason1-1/+1
Dave Jones hit a WARN_ON(nr < 0) in btrfs_wait_ordered_roots() with v4.12-rc6. This was because commit 70e7af244 made it possible for calc_reclaim_items_nr() to return a negative number. It's not really a bug in that commit, it just didn't go far enough down the stack to find all the possible 64->32 bit overflows. This switches calc_reclaim_items_nr() to return a u64 and changes everyone that uses the results of that math to u64 as well. Reported-by: Dave Jones <davej@codemonkey.org.uk> Fixes: 70e7af2 ("Btrfs: fix delalloc accounting leak caused by u32 overflow") Signed-off-by: Chris Mason <clm@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-06-29btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved rangesQu Wenruo1-4/+4
[BUG] For the following case, btrfs can underflow qgroup reserved space at an error path: (Page size 4K, function name without "btrfs_" prefix) Task A | Task B ---------------------------------------------------------------------- Buffered_write [0, 2K) | |- check_data_free_space() | | |- qgroup_reserve_data() | | Range aligned to page | | range [0, 4K) <<< | | 4K bytes reserved <<< | |- copy pages to page cache | | Buffered_write [2K, 4K) | |- check_data_free_space() | | |- qgroup_reserved_data() | | Range alinged to page | | range [0, 4K) | | Already reserved by A <<< | | 0 bytes reserved <<< | |- delalloc_reserve_metadata() | | And it *FAILED* (Maybe EQUOTA) | |- free_reserved_data_space() |- qgroup_free_data() Range aligned to page range [0, 4K) Freeing 4K (Special thanks to Chandan for the detailed report and analyse) [CAUSE] Above Task B is freeing reserved data range [0, 4K) which is actually reserved by Task A. And at writeback time, page dirty by Task A will go through writeback routine, which will free 4K reserved data space at file extent insert time, causing the qgroup underflow. [FIX] For btrfs_qgroup_free_data(), add @reserved parameter to only free data ranges reserved by previous btrfs_qgroup_reserve_data(). So in above case, Task B will try to free 0 byte, so no underflow. Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-06-29btrfs: qgroup: Introduce extent changeset for qgroup reserve functionsQu Wenruo1-1/+3
Introduce a new parameter, struct extent_changeset for btrfs_qgroup_reserved_data() and its callers. Such extent_changeset was used in btrfs_qgroup_reserve_data() to record which range it reserved in current reserve, so it can free it in error paths. The reason we need to export it to callers is, at buffered write error path, without knowing what exactly which range we reserved in current allocation, we can free space which is not reserved by us. This will lead to qgroup reserved space underflow. Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-06-19Btrfs: replace tree->mapping with tree->private_dataJosef Bacik1-2/+1
For extent_io tree's we have carried the address_mapping of the inode around in the io tree in order to pull the inode back out for calling into various tree ops hooks. This works fine when everything that has an extent_io_tree has an inode. But we are going to remove the btree_inode, so we need to change this. Instead just have a generic void * for private data that we can initialize with, and have all the tree ops use that instead. This had a lot of cascading changes but should be relatively straightforward. Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Reviewed-by: David Sterba <dsterba@suse.com> [ minor reordering of the callback prototypes ] Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-28btrfs: Make btrfs_orphan_add take btrfs_inodeNikolay Borisov1-1/+1
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-28btrfs: Make btrfs_drop_extent_cache take btrfs_inodeNikolay Borisov1-4/+4
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-28btrfs: all btrfs_delalloc_release_metadata take btrfs_inodeNikolay Borisov1-2/+2
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-28btrfs: Make btrfs_delalloc_reserve_metadata take btrfs_inodeNikolay Borisov1-1/+2
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-17btrfs: free-space-cache, clean up unnecessary root argumentsJeff Mahoney1-3/+2
The free space cache APIs accept a root but always use the tree root. Also, btrfs_truncate_free_space_cache accepts a root AND an inode but the inode always points to the root anyway, so let's just pass the inode. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-17btrfs: convert btrfs_inc_block_group_ro to accept fs_infoJeff Mahoney1-1/+1
btrfs_inc_block_group_ro is either passed the extent root or the dev root, but it doesn't do anything with the dev tree. Let's convert to passing an fs_info and using the extent root. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-14btrfs: fix over-80 lines introduced by previous cleanupsDavid Sterba1-2/+2
This goes as a separate patch because fixing that inside the patches caused too many many conflicts. Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-14btrfs: Make btrfs_ino take a struct btrfs_inodeNikolay Borisov1-8/+8
Currently btrfs_ino takes a struct inode and this causes a lot of internal btrfs functions which consume this ino to take a VFS inode, rather than btrfs' own struct btrfs_inode. In order to fix this "leak" of VFS structs into the internals of btrfs first it's necessary to eliminate all uses of struct inode for the purpose of inode. This patch does that by using BTRFS_I to convert an inode to btrfs_inode. With this problem eliminated subsequent patches will start eliminating the passing of struct inode altogether, eventually resulting in a lot cleaner code. Signed-off-by: Nikolay Borisov <n.borisov.lkml@gmail.com> [ fix btrfs_get_extent tracepoint prototype ] Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-13Merge branch 'for-chris-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/fdmanana/linux into for-linus-4.10Chris Mason1-22/+12
Patches queued up by Filipe: The most important change is still the fix for the extent tree corruption that happens due to balance when qgroups are enabled (a regression introduced in 4.7 by a fix for a regression from the last qgroups rework). This has been hitting SLE and openSUSE users and QA very badly, where transactions keep getting aborted when running delayed references leaving the root filesystem in RO mode and nearly unusable. There are fixes here that allow us to run xfstests again with the integrity checker enabled, which has been impossible since 4.8 (apparently I'm the only one running xfstests with the integrity checker enabled, which is useful to validate dirtied leafs, like checking if there are keys out of order, etc). The rest are just some trivial fixes, most of them tagged for stable, and two cleanups. Signed-off-by: Chris Mason <clm@fb.com>
2016-12-06btrfs: remove root parameter from transaction commit/end routinesJeff Mahoney1-15/+15
Now we only use the root parameter to print the root objectid in a tracepoint. We can use the root parameter from the transaction handle for that. It's also used to join the transaction with async commits, so we remove the comment that it's just for checking. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-06btrfs: take an fs_info directly when the root is not used otherwiseJeff Mahoney1-37/+41
There are loads of functions in btrfs that accept a root parameter but only use it to obtain an fs_info pointer. Let's convert those to just accept an fs_info pointer directly. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-06btrfs: root->fs_info cleanup, add fs_info convenience variablesJeff Mahoney1-57/+71
In routines where someptr->fs_info is referenced multiple times, we introduce a convenience variable. This makes the code considerably more readable. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-06btrfs: pull node/sector/stripe sizes out of root and into fs_infoJeff Mahoney1-19/+20
We track the node sizes per-root, but they never vary from the values in the superblock. This patch messes with the 80-column style a bit, but subsequent patches to factor out root->fs_info into a convenience variable fix it up again. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-06btrfs: call functions that always use the same root with fs_info insteadJeff Mahoney1-2/+2
There are many functions that are always called with the same root argument. Rather than passing the same root every time, we can pass an fs_info pointer instead and have the function get the root pointer itself. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-11-30btrfs: qgroup: Fix qgroup data leaking by using subtree tracingQu Wenruo1-96/+23
Commit 62b99540a1d91e464 (btrfs: relocation: Fix leaking qgroups numbers on data extents) only fixes the problem partly. The previous fix is to trace all new data extents at transaction commit time when balance finishes. However balance is not done in a large transaction, every path replacement can happen in its own transaction. This makes the fix useless if transaction commits during relocation. For example: relocate_block_group() |-merge_reloc_roots() | |- merge_reloc_root() | |- btrfs_start_transaction() <- Trans X | |- replace_path() <- Cause leak | |- btrfs_end_transaction_throttle() <- Trans X commits here | | Leak not fixed | | | |- btrfs_start_transaction() <- Trans Y | |- replace_path() <- Cause leak | |- btrfs_end_transaction_throttle() <- Trans Y ends | but not committed |-btrfs_join_transaction() <- Still trans Y |-qgroup_fix() <- Only fixes data leak | in trans Y |-btrfs_commit_transaction() <- Trans Y commits In that case, qgroup fixup can only fix data leak in trans Y, data leak in trans X is out of fix. So the correct fix should happen in the same transaction of replace_path(). This patch fixes it by tracing both subtrees of tree block swap, so it can fix the problem and ensure all leaking and fix are in the same transaction, so no leak again. Reported-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-and-Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-11-30btrfs: qgroup: Rename functions to make it follow reserve,trace,account stepsQu Wenruo1-1/+1
Rename btrfs_qgroup_insert_dirty_extent(_nolock) to btrfs_qgroup_trace_extent(_nolock), according to the new reserve/trace/account naming schema. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-and-Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-11-30btrfs: remove constant parameter to memset_extent_buffer and rename itDavid Sterba1-1/+1
The only memset we do is to 0, so sink the parameter to the function and simplify all calls. Rename the function to reflect the behaviour. Signed-off-by: David Sterba <dsterba@suse.com>
2016-11-30btrfs: make block group flags in balance printks human-readableAdam Borowski1-3/+40
They're not even documented anywhere, letting users with no recourse but to RTFS. It's no big burden to output the bitfield as words. Also, display unknown flags as hex. Signed-off-by: Adam Borowski <kilobyte@angband.pl> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-11-19Btrfs: remove unused code when creating and merging reloc treesFilipe Manana1-19/+0
In commit 5bc7247ac47c (Btrfs: fix broken nocow after balance) we started abusing the rtransid and otransid fields of root items from relocation trees to fix some issues with nodatacow mode. However later in commit ba8b0289333a (Btrfs: do not reset last_snapshot after relocation) we dropped the code that made use of those fields but did not remove the code that sets those fields. So just remove them to avoid confusion. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Josef Bacik <jbacik@fb.com>
2016-11-19Btrfs: fix relocation incorrectly dropping data referencesFilipe Manana1-3/+12
During relocation of a data block group we create a relocation tree for each fs/subvol tree by making a snapshot of each tree using btrfs_copy_root() and the tree's commit root, and then setting the last snapshot field for the fs/subvol tree's root to the value of the current transaction id minus 1. However this can lead to relocation later dropping references that it did not create if we have qgroups enabled, leaving the filesystem in an inconsistent state that keeps aborting transactions. Lets consider the following example to explain the problem, which requires qgroups to be enabled. We are relocating data block group Y, we have a subvolume with id 258 that has a root at level 1, that subvolume is used to store directory entries for snapshots and we are currently at transaction 3404. When committing transaction 3404, we have a pending snapshot and therefore we call btrfs_run_delayed_items() at transaction.c:create_pending_snapshot() in order to create its dentry at subvolume 258. This results in COWing leaf A from root 258 in order to add the dentry. Note that leaf A also contains file extent items referring to extents from some other block group X (we are currently relocating block group Y). Later on, still at create_pending_snapshot() we call qgroup_account_snapshot(), which switches the commit root for root 258 when it calls switch_commit_roots(), so now the COWed version of leaf A, lets call it leaf A', is accessible from the commit root of tree 258. At the end of qgroup_account_snapshot(), we call record_root_in_trans() with 258 as its argument, which results in btrfs_init_reloc_root() being called, which in turn calls relocation.c:create_reloc_root() in order to create a relocation tree associated to root 258, which results in assigning the value of 3403 (which is the current transaction id minus 1 = 3404 - 1) to the last_snapshot field of root 258. When creating the relocation tree root at ctree.c:btrfs_copy_root() we add a shared reference for leaf A', corresponding to the relocation tree's root, when we call btrfs_inc_ref() against the COWed root (a copy of the commit root from tree 258), which is at level 1. So at this point leaf A' has 2 references, one normal reference corresponding to root 258 and one shared reference corresponding to the root of the relocation tree. Transaction 3404 finishes its commit and transaction 3405 is started by relocation when calling merge_reloc_root() for the relocation tree associated to root 258. In the meanwhile leaf A' is COWed again, in response to some filesystem operation, when we are still at transaction 3405. However when we COW leaf A', at ctree.c:update_ref_for_cow(), we call btrfs_block_can_be_shared() in order to figure out if other trees refer to the leaf and if any such trees exists, add a full back reference to leaf A' - but btrfs_block_can_be_shared() incorrectly returns false because the following condition is false: btrfs_header_generation(buf) <= btrfs_root_last_snapshot(&root->root_item) which evaluates to 3404 <= 3403. So after leaf A' is COWed, it stays with only one reference, corresponding to the shared reference we created when we called btrfs_copy_root() to create the relocation tree's root and btrfs_inc_ref() ends up not being called for leaf A' nor we end up setting the flag BTRFS_BLOCK_FLAG_FULL_BACKREF in leaf A'. This results in not adding shared references for the extents from block group X that leaf A' refers to with its file extent items. Later, after merging the relocation root we do a call to to btrfs_drop_snapshot() in order to delete the relocation tree. This ends up calling do_walk_down() when path->slots[1] points to leaf A', which results in calling btrfs_lookup_extent_info() to get the number of references for leaf A', which is 1 at this time (only the shared reference exists) and this value is stored at wc->refs[0]. After this walk_up_proc() is called when wc->level is 0 and path->nodes[0] corresponds to leaf A'. Because the current level is 0 and wc->refs[0] is 1, it does call btrfs_dec_ref() against leaf A', which results in removing the single references that the extents from block group X have which are associated to root 258 - the expectation was to have each of these extents with 2 references - one reference for root 258 and one shared reference related to the root of the relocation tree, and so we would drop only the shared reference (because leaf A' was supposed to have the flag BTRFS_BLOCK_FLAG_FULL_BACKREF set). This leaves the filesystem in an inconsistent state as we now have file extent items in a subvolume tree that point to extents from block group X without references in the extent tree. So later on when we try to decrement the references for these extents, for example due to a file unlink operation, truncate operation or overwriting ranges of a file, we fail because the expected references do not exist in the extent tree. This leads to warnings and transaction aborts like the following: [ 588.965795] ------------[ cut here ]------------ [ 588.965815] WARNING: CPU: 2 PID: 2479 at fs/btrfs/extent-tree.c:1625 lookup_inline_extent_backref+0x432/0x5b0 [btrfs] [ 588.965816] Modules linked in: af_packet iscsi_ibft iscsi_boot_sysfs xfs libcrc32c ppdev acpi_cpufreq button tpm_tis e1000 i2c_piix4 pcspkr parport_pc parport tpm qemu_fw_cfg joydev btrfs xor raid6_pq sr_mod cdrom ata_generic virtio_scsi ata_piix virtio_pci bochs_drm virtio_ring drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops virtio ttm serio_raw drm floppy sg [ 588.965831] CPU: 2 PID: 2479 Comm: kworker/u8:7 Not tainted 4.7.3-3-default-fdm+ #1 [ 588.965832] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014 [ 588.965844] Workqueue: btrfs-extent-refs btrfs_extent_refs_helper [btrfs] [ 588.965845] 0000000000000000 ffff8802263bfa28 ffffffff813af542 0000000000000000 [ 588.965847] 0000000000000000 ffff8802263bfa68 ffffffff81081e8b 0000065900000000 [ 588.965848] ffff8801db2af000 000000012bbe2000 0000000000000000 ffff880215703b48 [ 588.965849] Call Trace: [ 588.965852] [<ffffffff813af542>] dump_stack+0x63/0x81 [ 588.965854] [<ffffffff81081e8b>] __warn+0xcb/0xf0 [ 588.965855] [<ffffffff81081f7d>] warn_slowpath_null+0x1d/0x20 [ 588.965863] [<ffffffffa0175042>] lookup_inline_extent_backref+0x432/0x5b0 [btrfs] [ 588.965865] [<ffffffff81143220>] ? trace_clock_local+0x10/0x30 [ 588.965867] [<ffffffff8114c5df>] ? rb_reserve_next_event+0x6f/0x460 [ 588.965875] [<ffffffffa0175215>] insert_inline_extent_backref+0x55/0xd0 [btrfs] [ 588.965882] [<ffffffffa017531f>] __btrfs_inc_extent_ref.isra.55+0x8f/0x240 [btrfs] [ 588.965890] [<ffffffffa017acea>] __btrfs_run_delayed_refs+0x74a/0x1260 [btrfs] [ 588.965892] [<ffffffff810cb046>] ? cpuacct_charge+0x86/0xa0 [ 588.965900] [<ffffffffa017e74f>] btrfs_run_delayed_refs+0x9f/0x2c0 [btrfs] [ 588.965908] [<ffffffffa017ea04>] delayed_ref_async_start+0x94/0xb0 [btrfs] [ 588.965918] [<ffffffffa01c799a>] btrfs_scrubparity_helper+0xca/0x350 [btrfs] [ 588.965928] [<ffffffffa01c7c5e>] btrfs_extent_refs_helper+0xe/0x10 [btrfs] [ 588.965930] [<ffffffff8109b323>] process_one_work+0x1f3/0x4e0 [ 588.965931] [<ffffffff8109b658>] worker_thread+0x48/0x4e0 [ 588.965932] [<ffffffff8109b610>] ? process_one_work+0x4e0/0x4e0 [ 588.965934] [<ffffffff810a1659>] kthread+0xc9/0xe0 [ 588.965936] [<ffffffff816f2f1f>] ret_from_fork+0x1f/0x40 [ 588.965937] [<ffffffff810a1590>] ? kthread_worker_fn+0x170/0x170 [ 588.965938] ---[ end trace 34e5232c933a1749 ]--- [ 588.966187] ------------[ cut here ]------------ [ 588.966196] WARNING: CPU: 2 PID: 2479 at fs/btrfs/extent-tree.c:2966 btrfs_run_delayed_refs+0x28c/0x2c0 [btrfs] [ 588.966196] BTRFS: Transaction aborted (error -5) [ 588.966197] Modules linked in: af_packet iscsi_ibft iscsi_boot_sysfs xfs libcrc32c ppdev acpi_cpufreq button tpm_tis e1000 i2c_piix4 pcspkr parport_pc parport tpm qemu_fw_cfg joydev btrfs xor raid6_pq sr_mod cdrom ata_generic virtio_scsi ata_piix virtio_pci bochs_drm virtio_ring drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops virtio ttm serio_raw drm floppy sg [ 588.966206] CPU: 2 PID: 2479 Comm: kworker/u8:7 Tainted: G W 4.7.3-3-default-fdm+ #1 [ 588.966207] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014 [ 588.966217] Workqueue: btrfs-extent-refs btrfs_extent_refs_helper [btrfs] [ 588.966217] 0000000000000000 ffff8802263bfc98 ffffffff813af542 ffff8802263bfce8 [ 588.966219] 0000000000000000 ffff8802263bfcd8 ffffffff81081e8b 00000b96345ee000 [ 588.966220] ffffffffa021ae1c ffff880215703b48 00000000000005fe ffff8802345ee000 [ 588.966221] Call Trace: [ 588.966223] [<ffffffff813af542>] dump_stack+0x63/0x81 [ 588.966224] [<ffffffff81081e8b>] __warn+0xcb/0xf0 [ 588.966225] [<ffffffff81081eff>] warn_slowpath_fmt+0x4f/0x60 [ 588.966233] [<ffffffffa017e93c>] btrfs_run_delayed_refs+0x28c/0x2c0 [btrfs] [ 588.966241] [<ffffffffa017ea04>] delayed_ref_async_start+0x94/0xb0 [btrfs] [ 588.966250] [<ffffffffa01c799a>] btrfs_scrubparity_helper+0xca/0x350 [btrfs] [ 588.966259] [<ffffffffa01c7c5e>] btrfs_extent_refs_helper+0xe/0x10 [btrfs] [ 588.966260] [<ffffffff8109b323>] process_one_work+0x1f3/0x4e0 [ 588.966261] [<ffffffff8109b658>] worker_thread+0x48/0x4e0 [ 588.966263] [<ffffffff8109b610>] ? process_one_work+0x4e0/0x4e0 [ 588.966264] [<ffffffff810a1659>] kthread+0xc9/0xe0 [ 588.966265] [<ffffffff816f2f1f>] ret_from_fork+0x1f/0x40 [ 588.966267] [<ffffffff810a1590>] ? kthread_worker_fn+0x170/0x170 [ 588.966268] ---[ end trace 34e5232c933a174a ]--- [ 588.966269] BTRFS: error (device sda2) in btrfs_run_delayed_refs:2966: errno=-5 IO failure [ 588.966270] BTRFS info (device sda2): forced readonly This was happening often on openSUSE and SLE systems using btrfs as the root filesystem (with its default layout where multiple subvolumes are used) where balance happens in the background triggered by a cron job and snapshots are automatically created before/after package installations, upgrades and removals. The issue could be triggered simply by running the following loop on the first system boot post installation: while true; do zypper -n in nfs-kernel-server zypper -n rm nfs-kernel-server done (If we were fast enough and made that loop before the cron job triggered a balance operation and the balance finished) So fix by setting the last_snapshot field of the root to the value of the generation of its commit root. Like this btrfs_block_can_be_shared() behaves correctly for the case where the relocation root is created during a transaction commit and for the case where it's created before a transaction commit. Fixes: 6426c7ad697d (btrfs: qgroup: Fix qgroup accounting when creating snapshot) Cc: stable@vger.kernel.org # 4.7+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Josef Bacik <jbacik@fb.com>
2016-10-17Btrfs: kill BUG_ON in do_relocationLiu Bo1-1/+8
While updating btree, we try to push items between sibling nodes/leaves in order to keep height as low as possible. But we don't memset the original places with zero when pushing items so that we could end up leaving stale content in nodes/leaves. One may read the above stale content by increasing btree blocks' @nritems. One case I've come across is that in fs tree, a leaf has two parent nodes, hence running balance ends up with processing this leaf with two parent nodes, but it can only reach the valid parent node through btrfs_search_slot, so it'd be like, do_relocation for P in all parent nodes of block A: if !P->eb: btrfs_search_slot(key); --> get path from P to A. if lowest: BUG_ON(A->bytenr != bytenr of A recorded in P); btrfs_cow_block(P, A); --> change A's bytenr in P. After btrfs_cow_block, P has the new bytenr of A, but with the same @key, we get the same path again, and get panic by BUG_ON. Note that this is only happening in a corrupted fs, for a regular fs in which we have correct @nritems so that we won't read stale content in any case. Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-26btrfs: unsplit printed stringsJeff Mahoney1-7/+9
CodingStyle chapter 2: "[...] never break user-visible strings such as printk messages, because that breaks the ability to grep for them." This patch unsplits user-visible strings. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-26Btrfs: don't leak reloc root nodes on errorJosef Bacik1-0/+4
We don't track the reloc roots in any sort of normal way, so the only way the root/commit_root nodes get free'd is if the relocation finishes successfully and the reloc root is deleted. Fix this by free'ing them in free_reloc_roots. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-26Btrfs: return gracefully from balance if fs tree is corruptedLiu Bo1-6/+17
When relocating tree blocks, we firstly get block information from back references in the extent tree, we then search fs tree to try to find all parents of a block. However, if fs tree is corrupted, eg. if there're some missing items, we could come across these WARN_ONs and BUG_ONs. This makes us print some error messages and return gracefully from balance. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-26Btrfs: add a flags field to btrfs_fs_infoJosef Bacik1-1/+1
We have a lot of random ints in btrfs_fs_info that can be put into flags. This is mostly equivalent with the exception of how we deal with quota going on or off, now instead we set a flag when we are turning it on or off and deal with that appropriately, rather than just having a pending state that the current quota_enabled gets set to. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-26btrfs: extend btrfs_set_extent_delalloc and its friends to support in-band dedupe and subpage size patchsetQu Wenruo1-1/+1
Extend btrfs_set_extent_delalloc() and extent_clear_unlock_delalloc() parameters for both in-band dedupe and subpage sector size patchset. This should reduce conflict of both patchset and the effort to rebase them. Cc: Chandan Rajendra <chandan@linux.vnet.ibm.com> Cc: David Sterba <dsterba@suse.cz> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-01Btrfs: fix endless loop in balancing block groupsLiu Bo1-3/+5
Qgroup function may overwrite the saved error 'err' with 0 in case quota is not enabled, and this ends up with a endless loop in balance because we keep going back to balance the same block group. It really should use 'ret' instead. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-08-25btrfs: update btrfs_space_info's bytes_may_use timelyWang Xiaoguang1-2/+9
This patch can fix some false ENOSPC errors, below test script can reproduce one false ENOSPC error: #!/bin/bash dd if=/dev/zero of=fs.img bs=$((1024*1024)) count=128 dev=$(losetup --show -f fs.img) mkfs.btrfs -f -M $dev mkdir /tmp/mntpoint mount $dev /tmp/mntpoint cd /tmp/mntpoint xfs_io -f -c "falloc 0 $((64*1024*1024))" testfile Above script will fail for ENOSPC reason, but indeed fs still has free space to satisfy this request. Please see call graph: btrfs_fallocate() |-> btrfs_alloc_data_chunk_ondemand() | bytes_may_use += 64M |-> btrfs_prealloc_file_range() |-> btrfs_reserve_extent() |-> btrfs_add_reserved_bytes() | alloc_type is RESERVE_ALLOC_NO_ACCOUNT, so it does not | change bytes_may_use, and bytes_reserved += 64M. Now | bytes_may_use + bytes_reserved == 128M, which is greater | than btrfs_space_info's total_bytes, false enospc occurs. | Note, the bytes_may_use decrease operation will be done in | end of btrfs_fallocate(), which is too late. Here is another simple case for buffered write: CPU 1 | CPU 2 | |-> cow_file_range() |-> __btrfs_buffered_write() |-> btrfs_reserve_extent() | | | | | | | | | ..... | |-> btrfs_check_data_free_space() | | | | |-> extent_clear_unlock_delalloc() | In CPU 1, btrfs_reserve_extent()->find_free_extent()-> btrfs_add_reserved_bytes() do not decrease bytes_may_use, the decrease operation will be delayed to be done in extent_clear_unlock_delalloc(). Assume in this case, btrfs_reserve_extent() reserved 128MB data, CPU2's btrfs_check_data_free_space() tries to reserve 100MB data space. If 100MB > data_sinfo->total_bytes - data_sinfo->bytes_used - data_sinfo->bytes_reserved - data_sinfo->bytes_pinned - data_sinfo->bytes_readonly - data_sinfo->bytes_may_use btrfs_check_data_free_space() will try to allcate new data chunk or call btrfs_start_delalloc_roots(), or commit current transaction in order to reserve some free space, obviously a lot of work. But indeed it's not necessary as long as decreasing bytes_may_use timely, we still have free space, decreasing 128M from bytes_may_use. To fix this issue, this patch chooses to update bytes_may_use for both data and metadata in btrfs_add_reserved_bytes(). For compress path, real extent length may not be equal to file content length, so introduce a ram_bytes argument for btrfs_reserve_extent(), find_free_extent() and btrfs_add_reserved_bytes(), it's becasue bytes_may_use is increased by file content length. Then compress path can update bytes_may_use correctly. Also now we can discard RESERVE_ALLOC_NO_ACCOUNT, RESERVE_ALLOC and RESERVE_FREE. As we know, usually EXTENT_DO_ACCOUNTING is used for error path. In run_delalloc_nocow(), for inode marked as NODATACOW or extent marked as PREALLOC, we also need to update bytes_may_use, but can not pass EXTENT_DO_ACCOUNTING, because it also clears metadata reservation, so here we introduce EXTENT_CLEAR_DATA_RESV flag to indicate btrfs_clear_bit_hook() to update btrfs_space_info's bytes_may_use. Meanwhile __btrfs_prealloc_file_range() will call btrfs_free_reserved_data_space() internally for both sucessful and failed path, btrfs_prealloc_file_range()'s callers does not need to call btrfs_free_reserved_data_space() any more. Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2016-08-25btrfs: use correct offset for reloc_inode in prealloc_file_extent_cluster()Wang Xiaoguang1-4/+6
In prealloc_file_extent_cluster(), btrfs_check_data_free_space() uses wrong file offset for reloc_inode, it uses cluster->start and cluster->end, which indeed are extent's bytenr. The correct value should be cluster->[start|end] minus block group's start bytenr. start bytenr cluster->start | | extent | extent | ...| extent | |----------------------------------------------------------------| | block group reloc_inode | Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2016-08-25btrfs: relocation: Fix leaking qgroups numbers on data extentsQu Wenruo1-6/+103
This patch fixes a REGRESSION introduced in 4.2, caused by the big quota rework. When balancing data extents, qgroup will leak all its numbers for relocated data extents. The relocation is done in the following steps for data extents: 1) Create data reloc tree and inode 2) Copy all data extents to data reloc tree And commit transaction 3) Create tree reloc tree(special snapshot) for any related subvolumes 4) Replace file extent in tree reloc tree with new extents in data reloc tree And commit transaction 5) Merge tree reloc tree with original fs, by swapping tree blocks For 1)~4), since tree reloc tree and data reloc tree doesn't count to qgroup, everything is OK. But for 5), the swapping of tree blocks will only info qgroup to track metadata extents. If metadata extents contain file extents, qgroup number for file extents will get lost, leading to corrupted qgroup accounting. The fix is, before commit transaction of step 5), manually info qgroup to track all file extents in data reloc tree. Since at commit transaction time, the tree swapping is done, and qgroup will account these data extents correctly. Cc: Mark Fasheh <mfasheh@suse.de> Reported-by: Mark Fasheh <mfasheh@suse.de> Reported-by: Filipe Manana <fdmanana@gmail.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2016-07-26btrfs: btrfs_abort_transaction, drop root parameterJeff Mahoney1-2/+2
__btrfs_abort_transaction doesn't use its root parameter except to obtain an fs_info pointer. We can obtain that from trans->root->fs_info for now and from trans->fs_info in a later patch. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-07-26Btrfs: fix panic in balance due to EIOLiu Bo1-0/+4
During build_backref_tree(), if we fail to read a btree node, we can eventually run into BUG_ON(cache->nr_nodes) that we put in backref_cache_cleanup(), meaning we have at least one memory leak. This frees the backref_node that we's allocated at the very beginning of build_backref_tree(). Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-07-26Btrfs: change BUG_ON()'s to ASSERT()'s in backref_cache_cleanup()Liu Bo1-6/+6
Since it is just an in-memory building of the backrefs of several btree blocks, nothing is fatal other than memory leaks, so this changes BUG_ON()'s to ASSERT()'s. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-07-07Btrfs: use FLUSH_LIMIT for relocation in reserve_metadata_bytesJosef Bacik1-17/+20
We used to allow you to set FLUSH_ALL and then just wouldn't do things like commit transactions or wait on ordered extents if we noticed you were in a transaction. However now that all the flushing for FLUSH_ALL is asynchronous we've lost the ability to tell, and we could end up deadlocking. So instead use FLUSH_LIMIT in reserve_metadata_bytes in relocation and then return -EAGAIN if we error out to preserve the previous behavior. I've also added an ASSERT() to catch anybody else who tries to do this. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-07-07Btrfs: fill relocation block rsv after allocationJosef Bacik1-0/+6
Since we set the reloc control before we've reserved our space for relocation we could race with a root being dirtied and not actually have space to do our init reloc root. So once we've allocated it and set it up go ahead and make our reservation before setting the relocate control, that way anybody who tries to do the reloc root init has space to use. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-07-07Btrfs: fix callers of btrfs_block_rsv_migrateJosef Bacik1-1/+1
So btrfs_block_rsv_migrate just unconditionally calls block_rsv_migrate_bytes. Not only this but it unconditionally changes the size of the block_rsv. This isn't a bug strictly speaking, but it makes truncate block rsv's look funny because every time we migrate bytes over its size grows, even though we only want it to be a specific size. So collapse this into one function that takes an update_size argument and make truncate and evict not update the size for consistency sake. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-05-25Merge branch 'cleanups-4.7' into for-chris-4.7-20160525David Sterba1-10/+9
2016-05-25btrfs: fix string and comment grammatical issues and typosNicholas D Steeves1-6/+6
Signed-off-by: Nicholas D Steeves <nsteeves@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-05-17Merge branch 'for-chris-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/fdmanana/linux into for-linus-4.7Chris Mason1-6/+5
Signed-off-by: Chris Mason <clm@fb.com>
2016-05-13Btrfs: fix race between block group relocation and nocow writesFilipe Manana1-0/+1
Relocation of a block group waits for all existing tasks flushing dellaloc, starting direct IO writes and any ordered extents before starting the relocation process. However for direct IO writes that end up doing nocow (inode either has the flag nodatacow set or the write is against a prealloc extent) we have a short time window that allows for a race that makes relocation proceed without waiting for the direct IO write to complete first, resulting in data loss after the relocation finishes. This is illustrated by the following diagram: CPU 1 CPU 2 btrfs_relocate_block_group(bg X) direct IO write starts against an extent in block group X using nocow mode (inode has the nodatacow flag or the write is for a prealloc extent) btrfs_direct_IO() btrfs_get_blocks_direct() --> can_nocow_extent() returns 1 btrfs_inc_block_group_ro(bg X) --> turns block group into RO mode btrfs_wait_ordered_roots() --> returns and does not know about the DIO write happening at CPU 2 (the task there has not created yet an ordered extent) relocate_block_group(bg X) --> rc->stage == MOVE_DATA_EXTENTS find_next_extent() --> returns extent that the DIO write is going to write to relocate_data_extent() relocate_file_extent_cluster() --> reads the extent from disk into pages belonging to the relocation inode and dirties them --> creates DIO ordered extent btrfs_submit_direct() --> submits bio against a location on disk obtained from an extent map before the relocation started btrfs_wait_ordered_range() --> writes all the pages read before to disk (belonging to the relocation inode) relocation finishes bio completes and wrote new data to the old location of the block group So fix this by tracking the number of nocow writers for a block group and make sure relocation waits for that number to go down to 0 before starting to move the extents. The same race can also happen with buffered writes in nocow mode since the patch I recently made titled "Btrfs: don't do unnecessary delalloc flushes when relocating", because we are no longer flushing all delalloc which served as a synchonization mechanism (due to page locking) and ensured the ordered extents for nocow buffered writes were created before we called btrfs_wait_ordered_roots(). The race with direct IO writes in nocow mode existed before that patch (no pages are locked or used during direct IO) and that fixed only races with direct IO writes that do cow. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Josef Bacik <jbacik@fb.com>
2016-05-13Btrfs: don't do unnecessary delalloc flushes when relocatingFilipe Manana1-5/+1
Before we start the actual relocation process of a block group, we do calls to flush delalloc of all inodes and then wait for ordered extents to complete. However we do these flush calls just to make sure we don't race with concurrent tasks that have actually already started to run delalloc and have allocated an extent from the block group we want to relocate, right before we set it to readonly mode, but have not yet created the respective ordered extents. The flush calls make us wait for such concurrent tasks because they end up calling filemap_fdatawrite_range() (through btrfs_start_delalloc_roots() -> __start_delalloc_inodes() -> btrfs_alloc_delalloc_work() -> btrfs_run_delalloc_work()) which ends up serializing us with those tasks due to attempts to lock the same pages (and the delalloc flush procedure calls the allocator and creates the ordered extents before unlocking the pages). These flushing calls not only make us waste time (cpu, IO) but also reduce the chances of writing larger extents (applications might be writing to contiguous ranges and we flush before they finish dirtying the whole ranges). So make sure we don't flush delalloc and just wait for concurrent tasks that have already started flushing delalloc and have allocated an extent from the block group we are about to relocate. This change also ends up fixing a race with direct IO writes that makes relocation not wait for direct IO ordered extents. This race is illustrated by the following diagram: CPU 1 CPU 2 btrfs_relocate_block_group(bg X) starts direct IO write, target inode currently has no ordered extents ongoing nor dirty pages (delalloc regions), therefore the root for our inode is not in the list fs_info->ordered_roots btrfs_direct_IO() __blockdev_direct_IO() btrfs_get_blocks_direct() btrfs_lock_extent_direct() locks range in the io tree btrfs_new_extent_direct() btrfs_reserve_extent() --> extent allocated from bg X btrfs_inc_block_group_ro(bg X) btrfs_start_delalloc_roots() __start_delalloc_inodes() --> does nothing, no dealloc ranges in the inode's io tree so the inode's root is not in the list fs_info->delalloc_roots btrfs_wait_ordered_roots() --> does not find the inode's root in the list fs_info->ordered_roots --> ends up not waiting for the direct IO write started by the task at CPU 2 relocate_block_group(rc->stage == MOVE_DATA_EXTENTS) prepare_to_relocate() btrfs_commit_transaction() iterates the extent tree, using its commit root and moves extents into new locations btrfs_add_ordered_extent_dio() --> now a ordered extent is created and added to the list root->ordered_extents and the root added to the list fs_info->ordered_roots --> this is too late and the task at CPU 1 already started the relocation btrfs_commit_transaction() btrfs_finish_ordered_io() btrfs_alloc_reserved_file_extent() --> adds delayed data reference for the extent allocated from bg X relocate_block_group(rc->stage == UPDATE_DATA_PTRS) prepare_to_relocate() btrfs_commit_transaction() --> delayed refs are run, so an extent item for the allocated extent from bg X is added to extent tree --> commit roots are switched, so the next scan in the extent tree will see the extent item sees the extent in the extent tree When this happens the relocation produces the following warning when it finishes: [ 7260.832836] ------------[ cut here ]------------ [ 7260.834653] WARNING: CPU: 5 PID: 6765 at fs/btrfs/relocation.c:4318 btrfs_relocate_block_group+0x245/0x2a1 [btrfs]() [ 7260.838268] Modules linked in: btrfs crc32c_generic xor ppdev raid6_pq psmouse sg acpi_cpufreq evdev i2c_piix4 tpm_tis serio_raw tpm i2c_core pcspkr parport_pc [ 7260.850935] CPU: 5 PID: 6765 Comm: btrfs Not tainted 4.5.0-rc6-btrfs-next-28+ #1 [ 7260.852998] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014 [ 7260.852998] 0000000000000000 ffff88020bf57bc0 ffffffff812648b3 0000000000000000 [ 7260.852998] 0000000000000009 ffff88020bf57bf8 ffffffff81051608 ffffffffa03c1b2d [ 7260.852998] ffff8800b2bbb800 0000000000000000 ffff8800b17bcc58 ffff8800399dd000 [ 7260.852998] Call Trace: [ 7260.852998] [<ffffffff812648b3>] dump_stack+0x67/0x90 [ 7260.852998] [<ffffffff81051608>] warn_slowpath_common+0x99/0xb2 [ 7260.852998] [<ffffffffa03c1b2d>] ? btrfs_relocate_block_group+0x245/0x2a1 [btrfs] [ 7260.852998] [<ffffffff810516d4>] warn_slowpath_null+0x1a/0x1c [ 7260.852998] [<ffffffffa03c1b2d>] btrfs_relocate_block_group+0x245/0x2a1 [btrfs] [ 7260.852998] [<ffffffffa039d9de>] btrfs_relocate_chunk.isra.29+0x66/0xdb [btrfs] [ 7260.852998] [<ffffffffa039f314>] btrfs_balance+0xde1/0xe4e [btrfs] [ 7260.852998] [<ffffffff8127d671>] ? debug_smp_processor_id+0x17/0x19 [ 7260.852998] [<ffffffffa03a9583>] btrfs_ioctl_balance+0x255/0x2d3 [btrfs] [ 7260.852998] [<ffffffffa03ac96a>] btrfs_ioctl+0x11e0/0x1dff [btrfs] [ 7260.852998] [<ffffffff811451df>] ? handle_mm_fault+0x443/0xd63 [ 7260.852998] [<ffffffff81491817>] ? _raw_spin_unlock+0x31/0x44 [ 7260.852998] [<ffffffff8108b36a>] ? arch_local_irq_save+0x9/0xc [ 7260.852998] [<ffffffff811876ab>] vfs_ioctl+0x18/0x34 [ 7260.852998] [<ffffffff81187cb2>] do_vfs_ioctl+0x550/0x5be [ 7260.852998] [<ffffffff81190c30>] ? __fget_light+0x4d/0x71 [ 7260.852998] [<ffffffff81187d77>] SyS_ioctl+0x57/0x79 [ 7260.852998] [<ffffffff81492017>] entry_SYSCALL_64_fastpath+0x12/0x6b [ 7260.893268] ---[ end trace eb7803b24ebab8ad ]--- This is because at the end of the first stage, in relocate_block_group(), we commit the current transaction, which makes delayed refs run, the commit roots are switched and so the second stage will find the extent item that the ordered extent added to the delayed refs. But this extent was not moved (ordered extent completed after first stage finished), so at the end of the relocation our block group item still has a positive used bytes counter, triggering a warning at the end of btrfs_relocate_block_group(). Later on when trying to read the extent contents from disk we hit a BUG_ON() due to the inability to map a block with a logical address that belongs to the block group we relocated and is no longer valid, resulting in the following trace: [ 7344.885290] BTRFS critical (device sdi): unable to find logical 12845056 len 4096 [ 7344.887518] ------------[ cut here ]------------ [ 7344.888431] kernel BUG at fs/btrfs/inode.c:1833! [ 7344.888431] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 7344.888431] Modules linked in: btrfs crc32c_generic xor ppdev raid6_pq psmouse sg acpi_cpufreq evdev i2c_piix4 tpm_tis serio_raw tpm i2c_core pcspkr parport_pc [ 7344.888431] CPU: 0 PID: 6831 Comm: od Tainted: G W 4.5.0-rc6-btrfs-next-28+ #1 [ 7344.888431] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014 [ 7344.888431] task: ffff880215818600 ti: ffff880204684000 task.ti: ffff880204684000 [ 7344.888431] RIP: 0010:[<ffffffffa037c88c>] [<ffffffffa037c88c>] btrfs_merge_bio_hook+0x54/0x6b [btrfs] [ 7344.888431] RSP: 0018:ffff8802046878f0 EFLAGS: 00010282 [ 7344.888431] RAX: 00000000ffffffea RBX: 0000000000001000 RCX: 0000000000000001 [ 7344.888431] RDX: ffff88023ec0f950 RSI: ffffffff8183b638 RDI: 00000000ffffffff [ 7344.888431] RBP: ffff880204687908 R08: 0000000000000001 R09: 0000000000000000 [ 7344.888431] R10: ffff880204687770 R11: ffffffff82f2d52d R12: 0000000000001000 [ 7344.888431] R13: ffff88021afbfee8 R14: 0000000000006208 R15: ffff88006cd199b0 [ 7344.888431] FS: 00007f1f9e1d6700(0000) GS:ffff88023ec00000(0000) knlGS:0000000000000000 [ 7344.888431] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7344.888431] CR2: 00007f1f9dc8cb60 CR3: 000000023e3b6000 CR4: 00000000000006f0 [ 7344.888431] Stack: [ 7344.888431] 0000000000001000 0000000000001000 ffff880204687b98 ffff880204687950 [ 7344.888431] ffffffffa0395c8f ffffea0004d64d48 0000000000000000 0000000000001000 [ 7344.888431] ffffea0004d64d48 0000000000001000 0000000000000000 0000000000000000 [ 7344.888431] Call Trace: [ 7344.888431] [<ffffffffa0395c8f>] submit_extent_page+0xf5/0x16f [btrfs] [ 7344.888431] [<ffffffffa03970ac>] __do_readpage+0x4a0/0x4f1 [btrfs] [ 7344.888431] [<ffffffffa039680d>] ? btrfs_create_repair_bio+0xcb/0xcb [btrfs] [ 7344.888431] [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs] [ 7344.888431] [<ffffffff8108df55>] ? trace_hardirqs_on+0xd/0xf [ 7344.888431] [<ffffffffa039728c>] __do_contiguous_readpages.constprop.26+0xc2/0xe4 [btrfs] [ 7344.888431] [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs] [ 7344.888431] [<ffffffffa039739b>] __extent_readpages.constprop.25+0xed/0x100 [btrfs] [ 7344.888431] [<ffffffff81129d24>] ? lru_cache_add+0xe/0x10 [ 7344.888431] [<ffffffffa0397ea8>] extent_readpages+0x160/0x1aa [btrfs] [ 7344.888431] [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs] [ 7344.888431] [<ffffffff8115daad>] ? alloc_pages_current+0xa9/0xcd [ 7344.888431] [<ffffffffa037cdc9>] btrfs_readpages+0x1f/0x21 [btrfs] [ 7344.888431] [<ffffffff81128316>] __do_page_cache_readahead+0x168/0x1fc [ 7344.888431] [<ffffffff811285a0>] ondemand_readahead+0x1f6/0x207 [ 7344.888431] [<ffffffff811285a0>] ? ondemand_readahead+0x1f6/0x207 [ 7344.888431] [<ffffffff8111cf34>] ? pagecache_get_page+0x2b/0x154 [ 7344.888431] [<ffffffff8112870e>] page_cache_sync_readahead+0x3d/0x3f [ 7344.888431] [<ffffffff8111dbf7>] generic_file_read_iter+0x197/0x4e1 [ 7344.888431] [<ffffffff8117773a>] __vfs_read+0x79/0x9d [ 7344.888431] [<ffffffff81178050>] vfs_read+0x8f/0xd2 [ 7344.888431] [<ffffffff81178a38>] SyS_read+0x50/0x7e [ 7344.888431] [<ffffffff81492017>] entry_SYSCALL_64_fastpath+0x12/0x6b [ 7344.888431] Code: 8d 4d e8 45 31 c9 45 31 c0 48 8b 00 48 c1 e2 09 48 8b 80 80 fc ff ff 4c 89 65 e8 48 8b b8 f0 01 00 00 e8 1d 42 02 00 85 c0 79 02 <0f> 0b 4c 0 [ 7344.888431] RIP [<ffffffffa037c88c>] btrfs_merge_bio_hook+0x54/0x6b [btrfs] [ 7344.888431] RSP <ffff8802046878f0> [ 7344.970544] ---[ end trace eb7803b24ebab8ae ]--- Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com>