1. 30 Jun, 2015 5 commits
    • Filipe Manana's avatar
      Btrfs: use kmem_cache_free when freeing entry in inode cache · c3f4a168
      Filipe Manana authored
      The free space entries are allocated using kmem_cache_zalloc(),
      through __btrfs_add_free_space(), therefore we should use
      kmem_cache_free() and not kfree() to avoid any confusion and
      any potential problem. Looking at the kfree() definition at
      mm/slab.c it has the following comment:
      
        /*
         * (...)
         *
         * Don't free memory not originally allocated by kmalloc()
         * or you will run into trouble.
         */
      
      So better be safe and use kmem_cache_free().
      
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.cz>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      c3f4a168
    • Filipe Manana's avatar
      Btrfs: fix race between balance and unused block group deletion · 67c5e7d4
      Filipe Manana authored
      We have a race between deleting an unused block group and balancing the
      same block group that leads to an assertion failure/BUG(), producing the
      following trace:
      
      [181631.208236] BTRFS: assertion failed: 0, file: fs/btrfs/volumes.c, line: 2622
      [181631.220591] ------------[ cut here ]------------
      [181631.222959] kernel BUG at fs/btrfs/ctree.h:4062!
      [181631.223932] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
      [181631.224566] Modules linked in: btrfs dm_flakey dm_mod crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse acpi_cpufreq parpor$
      [181631.224566] CPU: 8 PID: 17451 Comm: btrfs Tainted: G        W       4.1.0-rc5-btrfs-next-10+ #1
      [181631.224566] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
      [181631.224566] task: ffff880127e09590 ti: ffff8800b5824000 task.ti: ffff8800b5824000
      [181631.224566] RIP: 0010:[<ffffffffa03f19f6>]  [<ffffffffa03f19f6>] assfail.constprop.50+0x1e/0x20 [btrfs]
      [181631.224566] RSP: 0018:ffff8800b5827ae8  EFLAGS: 00010246
      [181631.224566] RAX: 0000000000000040 RBX: ffff8800109fc218 RCX: ffffffff81095dce
      [181631.224566] RDX: 0000000000005124 RSI: ffffffff81464819 RDI: 00000000ffffffff
      [181631.224566] RBP: ffff8800b5827ae8 R08: 0000000000000001 R09: 0000000000000000
      [181631.224566] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800109fc200
      [181631.224566] R13: ffff880020095000 R14: ffff8800b1a13f38 R15: ffff880020095000
      [181631.224566] FS:  00007f70ca0b0c80(0000) GS:ffff88013ec00000(0000) knlGS:0000000000000000
      [181631.224566] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
      [181631.224566] CR2: 00007f2872ab6e68 CR3: 00000000a717c000 CR4: 00000000000006e0
      [181631.224566] Stack:
      [181631.224566]  ffff8800b5827ba8 ffffffffa03f3916 ffff8800b5827b38 ffffffffa03d080e
      [181631.224566]  ffffffffa03d1423 ffff880020095000 ffff88001233c000 0000000000000001
      [181631.224566]  ffff880020095000 ffff8800b1a13f38 0000000a69c00000 0000000000000000
      [181631.224566] Call Trace:
      [181631.224566]  [<ffffffffa03f3916>] btrfs_remove_chunk+0xa4/0x6bb [btrfs]
      [181631.224566]  [<ffffffffa03d080e>] ? join_transaction.isra.8+0xb9/0x3ba [btrfs]
      [181631.224566]  [<ffffffffa03d1423>] ? wait_current_trans.isra.13+0x22/0xfc [btrfs]
      [181631.224566]  [<ffffffffa03f3fbc>] btrfs_relocate_chunk.isra.29+0x8f/0xa7 [btrfs]
      [181631.224566]  [<ffffffffa03f54df>] btrfs_balance+0xaa4/0xc52 [btrfs]
      [181631.224566]  [<ffffffffa03fd388>] btrfs_ioctl_balance+0x23f/0x2b0 [btrfs]
      [181631.224566]  [<ffffffff810872f9>] ? trace_hardirqs_on+0xd/0xf
      [181631.224566]  [<ffffffffa04019a3>] btrfs_ioctl+0xfe2/0x2220 [btrfs]
      [181631.224566]  [<ffffffff812603ed>] ? __this_cpu_preempt_check+0x13/0x15
      [181631.224566]  [<ffffffff81084669>] ? arch_local_irq_save+0x9/0xc
      [181631.224566]  [<ffffffff81138def>] ? handle_mm_fault+0x834/0xcd2
      [181631.224566]  [<ffffffff81138def>] ? handle_mm_fault+0x834/0xcd2
      [181631.224566]  [<ffffffff8103e48c>] ? __do_page_fault+0x211/0x424
      [181631.224566]  [<ffffffff811755e6>] do_vfs_ioctl+0x3c6/0x479
      (...)
      
      The sequence of steps leading to this are:
      
                 CPU 0                                         CPU 1
      
        btrfs_balance()
          btrfs_relocate_chunk()
      
            btrfs_relocate_block_group(bg X)
              btrfs_lookup_block_group(bg X)
      
                                                     cleaner_kthread
                                                        locks fs_info->cleaner_mutex
      
                                                        btrfs_delete_unused_bgs()
                                                          finds bg X, which became
                                                          unused in the previous
                                                          transaction
      
                                                          checks bg X ->ro == 0,
                                                          so it proceeds
              sets bg X ->ro to 1
              (btrfs_set_block_group_ro(bg X))
      
              blocks on fs_info->cleaner_mutex
                                                          btrfs_remove_chunk(bg X)
                                                        unlocks fs_info->cleaner_mutex
      
              acquires fs_info->cleaner_mutex
              relocate_block_group()
                --> does nothing, no extents found in
                    the extent tree from bg X
              unlocks fs_info->cleaner_mutex
      
            btrfs_relocate_block_group(bg X) returns
      
          btrfs_remove_chunk(bg X)
             extent map not found
                --> ASSERT(0)
      
      Fix this by using a new mutex to make sure these 2 operations, block
      group relocation and removal, are serialized.
      
      This issue is reproducible by running fstests generic/038 (which stresses
      chunk allocation and automatic removal of unused block groups) together
      with the following balance loop:
      
          while true; do btrfs balance start -dusage=0 <mountpoint> ; done
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      67c5e7d4
    • Zhao Lei's avatar
      btrfs: add error handling for scrub_workers_get() · e82afc52
      Zhao Lei authored
      Although it is a rare case, we'd better free previous allocated
      memory on error.
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      e82afc52
    • Zhao Lei's avatar
      btrfs: cleanup noused initialization of dev in btrfs_end_bio() · 65f53338
      Zhao Lei authored
      It is introduced by:
       c404e0dc
       Btrfs: fix use-after-free in the finishing procedure of the device replace
      
      But seems no relationship with that bug, this patch revirt these
      code block for cleanup.
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      65f53338
    • Yang Dongsheng's avatar
      btrfs: qgroup: allow user to clear the limitation on qgroup · fe759907
      Yang Dongsheng authored
      Currently, we can only set a limitation on a qgroup, but we
      can not clear it.
      
      This patch provide a choice to user to clear a limitation on
      qgroup by passing a value of CLEAR_VALUE(-1) to kernel.
      Reported-by: default avatarTsutomu Itoh <t-itoh@jp.fujitsu.com>
      Signed-off-by: default avatarDongsheng Yang <yangds.fnst@cn.fujitsu.com>
      Tested-by: default avatarTsutomu Itoh <t-itoh@jp.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      fe759907
  2. 24 Jun, 2015 1 commit
  3. 23 Jun, 2015 1 commit
  4. 22 Jun, 2015 1 commit
  5. 19 Jun, 2015 3 commits
  6. 12 Jun, 2015 2 commits
  7. 10 Jun, 2015 27 commits
    • Zhao Lei's avatar
      btrfs: wait for delayed iputs on no space · 9a4e7276
      Zhao Lei authored
      btrfs will report no_space when we run following write and delete
      file loop:
       # FILE_SIZE_M=[ 75% of fs space ]
       # DEV=[ some dev ]
       # MNT=[ some dir ]
       #
       # mkfs.btrfs -f "$DEV"
       # mount -o nodatacow "$DEV" "$MNT"
       # for ((i = 0; i < 100; i++)); do dd if=/dev/zero of="$MNT"/file0 bs=1M count="$FILE_SIZE_M"; rm -f "$MNT"/file0; done
       #
      
      Reason:
       iput() and evict() is run after write pages to block device, if
       write pages work is not finished before next write, the "rm"ed space
       is not freed, and caused above bug.
      
      Fix:
       We can add "-o flushoncommit" mount option to avoid above bug, but
       it have performance problem. Actually, we can to wait for on-the-fly
       writes only when no-space happened, it is which this patch do.
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      9a4e7276
    • Qu Wenruo's avatar
      btrfs: qgroup: Make snapshot accounting work with new extent-oriented · d6726335
      Qu Wenruo authored
      qgroup.
      
      Make snapshot accounting work with new extent-oriented mechanism by
      skipping given root in new/old_roots in create_pending_snapshot().
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      d6726335
    • Qu Wenruo's avatar
      btrfs: qgroup: Add the ability to skip given qgroup for old/new_roots. · 9086db86
      Qu Wenruo authored
      This is used by later qgroup fix patches for snapshot.
      
      As current snapshot accounting is done by btrfs_qgroup_inherit(), but
      new extent oriented quota mechanism will account extent from
      btrfs_copy_root() and other snapshot things, causing wrong result.
      
      So add this ability to handle snapshot accounting.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      9086db86
    • Qu Wenruo's avatar
      btrfs: ulist: Add ulist_del() function. · d4b80404
      Qu Wenruo authored
      This function will delete unode with given (val,aux) pair.
      And with this patch, seqnum for debug usage doesn't have any meaning
      now, so remove them.
      
      This is used by later patches to skip snapshot root.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      d4b80404
    • Qu Wenruo's avatar
      btrfs: qgroup: Cleanup the old ref_node-oriented mechanism. · e69bcee3
      Qu Wenruo authored
      Goodbye, the old mechanisim.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      e69bcee3
    • Qu Wenruo's avatar
      btrfs: qgroup: Switch self test to extent-oriented qgroup mechanism. · 442244c9
      Qu Wenruo authored
      Since the self test transaction don't have delayed_ref_roots, so use
      find_all_roots() and export btrfs_qgroup_account_extent() to simulate it
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      442244c9
    • Qu Wenruo's avatar
      btrfs: qgroup: Switch to new extent-oriented qgroup mechanism. · 0ed4792a
      Qu Wenruo authored
      Switch from old ref_node based qgroup to extent based qgroup mechanism
      for normal operations.
      
      The new mechanism should hugely reduce the overhead of btrfs quota
      system, and further more, the codes and logic should be more clean and
      easier to maintain.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      0ed4792a
    • Qu Wenruo's avatar
      btrfs: qgroup: Switch rescan to new mechanism. · 9d220c95
      Qu Wenruo authored
      Switch rescan to use the new new extent oriented mechanism.
      
      As rescan is also based on extent, new mechanism is just a perfect match
      for rescan.
      
      With re-designed internal functions, rescan is quite easy, just call
      btrfs_find_all_roots() and then btrfs_qgroup_account_one_extent().
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      9d220c95
    • Qu Wenruo's avatar
      btrfs: qgroup: Add new qgroup calculation function · 550d7a2e
      Qu Wenruo authored
      btrfs_qgroup_account_extents().
      
      The new btrfs_qgroup_account_extents() function should be called in
      btrfs_commit_transaction() and it will update all the qgroup according
      to delayed_ref_root->dirty_extent_root.
      
      The new function can handle both normal operation during
      commit_transaction() or in rescan in a unified method with clearer
      logic.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      550d7a2e
    • Qu Wenruo's avatar
      btrfs: backref: Add special time_seq == (u64)-1 case for · 21633fc6
      Qu Wenruo authored
      btrfs_find_all_roots().
      
      Allow btrfs_find_all_roots() to skip all delayed_ref_head lock and tree
      lock to do tree search.
      
      This is important for later qgroup implement which will call
      find_all_roots() after fs trees are committed.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      21633fc6
    • Qu Wenruo's avatar
      btrfs: qgroup: Add new function to record old_roots. · 3b7d00f9
      Qu Wenruo authored
      Add function btrfs_qgroup_prepare_account_extents() to get old_roots
      which are needed for qgroup.
      
      We do it in commit_transaction() and before switch_roots(), and only
      search commit_root, so it gives a quite accurate view for previous
      transaction.
      
      With old_roots from previous transaction, we can use it to do accurate
      account with current transaction.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      3b7d00f9
    • Qu Wenruo's avatar
      btrfs: qgroup: Record possible quota-related extent for qgroup. · 3368d001
      Qu Wenruo authored
      Add hook in add_delayed_ref_head() to record quota-related extent record
      into delayed_ref_root->dirty_extent_record rb-tree for later qgroup
      accounting.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      3368d001
    • Qu Wenruo's avatar
      btrfs: qgroup: Add function qgroup_update_counters(). · 823ae5b8
      Qu Wenruo authored
      Add function qgroup_update_counters(), which will update related
      qgroups' rfer/excl according to old/new_roots.
      
      This is one of the two core functions for the new qgroup implement.
      
      This is based on btrfs_adjust_coutners() but with clearer logic and
      comment.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      823ae5b8
    • Qu Wenruo's avatar
      btrfs: qgroup: Add function qgroup_update_refcnt(). · d810ef2b
      Qu Wenruo authored
      This function is used to update refcnt for qgroups.
      And is one of the two core functions used in the new qgroup implement.
      
      This is based on the old update_old/new_refcnt, but provides a unified
      logic and behavior.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      d810ef2b
    • Qu Wenruo's avatar
      btrfs: extent-tree: Use ref_node to replace unneeded parameters in... · c682f9b3
      Qu Wenruo authored
      btrfs: extent-tree: Use ref_node to replace unneeded parameters in __inc_extent_ref() and __free_extent()
      
      __btrfs_inc_extent_ref() and __btrfs_free_extent() have already had too
      many parameters, but three of them can be extracted from
      btrfs_delayed_ref_node struct.
      
      So use btrfs_delayed_ref_node struct as a single parameter to replace
      the bytenr/num_byte/no_quota parameters.
      
      The real objective of this patch is to allow btrfs_qgroup_record_ref()
      get the delayed_ref_node in incoming qgroup patches.
      
      Other functions calling btrfs_qgroup_record_ref() are not affected since
      the rest will only add/sub exclusive extents, where node is not used.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      c682f9b3
    • Qu Wenruo's avatar
      btrfs: qgroup: Cleanup open-coded old/new_refcnt update and read. · 9c542136
      Qu Wenruo authored
      Use inline functions to do such things, to improve readability.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Acked-by: default avatarDavid Sterba <dsterba@suse.cz>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      9c542136
    • Qu Wenruo's avatar
      btrfs: delayed-ref: Cleanup the unneeded functions. · c43d160f
      Qu Wenruo authored
      Cleanup the rb_tree merge/insert/update functions, since now we use list
      instead of rb_tree now.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      c43d160f
    • Qu Wenruo's avatar
      btrfs: delayed-ref: Use list to replace the ref_root in ref_head. · c6fc2454
      Qu Wenruo authored
      This patch replace the rbtree used in ref_head to list.
      This has the following advantage:
      1) Easier merge logic.
      With the new list implement, we only need to care merging the tail
      ref_node with the new ref_node.
      And this can be done quite easy at insert time, no need to do a
      indicated merge at run_delayed_refs().
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      c6fc2454
    • Qu Wenruo's avatar
      btrfs: backref: Don't merge refs which are not for same block. · 00db646d
      Qu Wenruo authored
      Old __merge_refs() in backref.c will even merge refs whose root_id are
      different, which makes qgroup gives wrong result.
      
      Fix it by checking ref_for_same_block() before any mode specific works.
      Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      00db646d
    • Zhao Lei's avatar
      btrfs: Fix lockdep warning of wr_ctx->wr_lock in scrub_free_wr_ctx() · 20b2e302
      Zhao Lei authored
      lockdep report following warning in test:
       [25176.843958] =================================
       [25176.844519] [ INFO: inconsistent lock state ]
       [25176.845047] 4.1.0-rc3 #22 Tainted: G        W
       [25176.845591] ---------------------------------
       [25176.846153] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
       [25176.846713] fsstress/26661 [HC0[0]:SC1[1]:HE1:SE0] takes:
       [25176.847246]  (&wr_ctx->wr_lock){+.?...}, at: [<ffffffffa04cdc6d>] scrub_free_ctx+0x2d/0xf0 [btrfs]
       [25176.847838] {SOFTIRQ-ON-W} state was registered at:
       [25176.848396]   [<ffffffff810bf460>] __lock_acquire+0x6a0/0xe10
       [25176.848955]   [<ffffffff810bfd1e>] lock_acquire+0xce/0x2c0
       [25176.849491]   [<ffffffff816489af>] mutex_lock_nested+0x7f/0x410
       [25176.850029]   [<ffffffffa04d04ff>] scrub_stripe+0x4df/0x1080 [btrfs]
       [25176.850575]   [<ffffffffa04d11b1>] scrub_chunk.isra.19+0x111/0x130 [btrfs]
       [25176.851110]   [<ffffffffa04d144c>] scrub_enumerate_chunks+0x27c/0x510 [btrfs]
       [25176.851660]   [<ffffffffa04d3b87>] btrfs_scrub_dev+0x1c7/0x6c0 [btrfs]
       [25176.852189]   [<ffffffffa04e918e>] btrfs_dev_replace_start+0x36e/0x450 [btrfs]
       [25176.852771]   [<ffffffffa04a98e0>] btrfs_ioctl+0x1e10/0x2d20 [btrfs]
       [25176.853315]   [<ffffffff8121c5b8>] do_vfs_ioctl+0x318/0x570
       [25176.853868]   [<ffffffff8121c851>] SyS_ioctl+0x41/0x80
       [25176.854406]   [<ffffffff8164da17>] system_call_fastpath+0x12/0x6f
       [25176.854935] irq event stamp: 51506
       [25176.855511] hardirqs last  enabled at (51506): [<ffffffff810d4ce5>] vprintk_emit+0x225/0x5e0
       [25176.856059] hardirqs last disabled at (51505): [<ffffffff810d4b77>] vprintk_emit+0xb7/0x5e0
       [25176.856642] softirqs last  enabled at (50886): [<ffffffff81067a23>] __do_softirq+0x363/0x640
       [25176.857184] softirqs last disabled at (50949): [<ffffffff8106804d>] irq_exit+0x10d/0x120
       [25176.857746]
       other info that might help us debug this:
       [25176.858845]  Possible unsafe locking scenario:
       [25176.859981]        CPU0
       [25176.860537]        ----
       [25176.861059]   lock(&wr_ctx->wr_lock);
       [25176.861705]   <Interrupt>
       [25176.862272]     lock(&wr_ctx->wr_lock);
       [25176.862881]
        *** DEADLOCK ***
      
      Reason:
       Above warning is caused by:
       Interrupt
       -> bio_endio()
       -> ...
       -> scrub_put_ctx()
       -> scrub_free_ctx() *1
       -> ...
       -> mutex_lock(&wr_ctx->wr_lock);
      
       scrub_put_ctx() is allowed to be called in end_bio interrupt, but
       in code design, it will never call scrub_free_ctx(sctx) in interrupe
       context(above *1), because btrfs_scrub_dev() get one additional
       reference of sctx->refs, which makes scrub_free_ctx() only called
       withine btrfs_scrub_dev().
      
       Now the code runs out of our wish, because free sequence in
       scrub_pending_bio_dec() have a gap.
      
       Current code:
       -----------------------------------+-----------------------------------
       scrub_pending_bio_dec()            |  btrfs_scrub_dev
       -----------------------------------+-----------------------------------
       atomic_dec(&sctx->bios_in_flight); |
       wake_up(&sctx->list_wait);         |
                                          | scrub_put_ctx()
                                          | -> atomic_dec_and_test(&sctx->refs)
       scrub_put_ctx(sctx);               |
       -> atomic_dec_and_test(&sctx->refs)|
       -> scrub_free_ctx()                |
       -----------------------------------+-----------------------------------
      
       We expected:
       -----------------------------------+-----------------------------------
       scrub_pending_bio_dec()            |  btrfs_scrub_dev
       -----------------------------------+-----------------------------------
       atomic_dec(&sctx->bios_in_flight); |
       wake_up(&sctx->list_wait);         |
       scrub_put_ctx(sctx);               |
       -> atomic_dec_and_test(&sctx->refs)|
                                          | scrub_put_ctx()
                                          | -> atomic_dec_and_test(&sctx->refs)
                                          | -> scrub_free_ctx()
       -----------------------------------+-----------------------------------
      
      Fix:
       Move scrub_pending_bio_dec() to a workqueue, to avoid this function run
       in interrupt context.
       Tested by check tracelog in debug.
      
      Changelog v1->v2:
       Use workqueue instead of adjust function call sequence in v1,
       because v1 will introduce a bug pointed out by:
       Filipe David Manana <fdmanana@gmail.com>
      Reported-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      20b2e302
    • Mark Fasheh's avatar
      btrfs: Handle unaligned length in extent_same · e1d227a4
      Mark Fasheh authored
      The extent-same code rejects requests with an unaligned length. This
      poses a problem when we want to dedupe the tail extent of files as we
      skip cloning the portion between i_size and the extent boundary.
      
      If we don't clone the entire extent, it won't be deleted. So the
      combination of these behaviors winds up giving us worst-case dedupe on
      many files.
      
      We can fix this by allowing a length that extents to i_size and
      internally aligining those to the end of the block. This is what
      btrfs_ioctl_clone() so we can just copy that check over.
      Signed-off-by: default avatarMark Fasheh <mfasheh@suse.de>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      e1d227a4
    • chandan's avatar
      Btrfs: btrfs_defrag_file: Fix calculation of max_to_defrag. · 070034bd
      chandan authored
      max_to_defrag represents the number of pages to defrag rather than the last
      page of the file range to be defragged.
      
      Consider a file having 10 4k blocks (i.e. blocks in the range [0 - 9]). If the
      defrag ioctl was invoked for the block range [3 - 6], then max_to_defrag
      should actually have the value 4. Instead in the current code we end up
      setting it to 6.
      
      Now, this does not (yet) cause an issue since the first part of the while loop
      condition in btrfs_defrag_file() (i.e. "i <= last_index") causes the control
      to flow out of the while loop before any buggy behavior is actually caused. So
      the patch just makes sure that max_to_defrag ends up having the right value
      rather than fixing a bug. I did run the xfstests suite to make sure that the
      code does not regress.
      
      Changelog: v1->v2:
      Provide a much descriptive commit message.
      Signed-off-by: default avatarChandan Rajendra <chandan@linux.vnet.ibm.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      070034bd
    • chandan's avatar
      Btrfs: btrfs_defrag_file: Fix ra_index computation. · e4826a5b
      chandan authored
      Read-ahead is done for the pages in the range [ra_index, ra_index + cluster -
      1]. So the next read-ahead should be starting from the page at index 'ra_index
      + cluster' (unless we deemed that the extent at 'ra_index + cluster' as
      non-defraggable) rather than from the page at index 'ra_index +
      max_cluster'. This patch fixes this. I did run the xfstests suite to make sure
      that the code does not regress.
      Signed-off-by: default avatarChandan Rajendra <chandan@linux.vnet.ibm.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      e4826a5b
    • Filipe Manana's avatar
      Btrfs: fix necessary chunk tree space calculation when allocating a chunk · 4617ea3a
      Filipe Manana authored
      When allocating a new chunk or removing one we need to update num_devs
      device items and insert or remove a chunk item in the chunk tree, so
      in the worst case the space needed in the chunk space_info is:
      
        btrfs_calc_trunc_metadata_size(chunk_root, num_devs) +
           btrfs_calc_trans_metadata_size(chunk_root, 1)
      
      That is, in the worst case we need to cow num_devs paths and cow 1 other
      path that can result in splitting every node and leaf, and each path
      consisting of BTRFS_MAX_LEVEL - 1 nodes and 1 leaf. We were requiring
      some additional chunk_root->nodesize * BTRFS_MAX_LEVEL * num_devs bytes,
      which were unnecessary since updating the existing device items does
      not result in splitting the nodes and leaf since after updating them
      they remain with the same size.
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      4617ea3a
    • Filipe Manana's avatar
      Btrfs: don't attach unnecessary extents to transaction on fsync · 7558c8bc
      Filipe Manana authored
      We don't need to attach ordered extents that have completed to the current
      transaction. Doing so only makes us hold memory for longer than necessary
      and delaying the iput of the inode until the transaction is committed (for
      each created ordered extent we do an igrab and then schedule an asynchronous
      iput when the ordered extent's reference count drops to 0), preventing the
      inode from being evictable until the transaction commits.
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      7558c8bc
    • Filipe Manana's avatar
      Btrfs: avoid syncing log in the fast fsync path when not necessary · b659ef02
      Filipe Manana authored
      Commit 3a8b36f3 ("Btrfs: fix data loss in the fast fsync path") added
      a performance regression for that causes an unnecessary sync of the log
      trees (fs/subvol and root log trees) when 2 consecutive fsyncs are done
      against a file, without no writes or any metadata updates to the inode in
      between them and if a transaction is committed before the second fsync is
      called.
      
      Huang Ying reported this to lkml (https://lkml.org/lkml/2015/3/18/99)
      after a test sysbench test that measured a -62% decrease of file io
      requests per second for that tests' workload.
      
      The test is:
      
        echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
        echo performance > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor
        echo performance > /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor
        echo performance > /sys/devices/system/cpu/cpu3/cpufreq/scaling_governor
        mkfs -t btrfs /dev/sda2
        mount -t btrfs /dev/sda2 /fs/sda2
        cd /fs/sda2
        for ((i = 0; i < 1024; i++)); do fallocate -l 67108864 testfile.$i; done
        sysbench --test=fileio --max-requests=0 --num-threads=4 --max-time=600 \
          --file-test-mode=rndwr --file-total-size=68719476736 --file-io-mode=sync \
          --file-num=1024 run
      
      A test on kvm guest, running a debug kernel gave me the following results:
      
      Without 3a8b36f3:             16.01 reqs/sec
      With 3a8b36f3:                 3.39 reqs/sec
      With 3a8b36f3 and this patch: 16.04 reqs/sec
      Reported-by: default avatarHuang Ying <ying.huang@intel.com>
      Tested-by: default avatarHuang, Ying <ying.huang@intel.com>
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      b659ef02
    • Chris Mason's avatar
      Merge branch 'send_fixes_4.2' of... · 1ab818b1
      Chris Mason authored
      Merge branch 'send_fixes_4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/fdmanana/linux into for-linus-4.2
      1ab818b1