1. 10 Apr, 2015 2 commits
    • Josef Bacik's avatar
      Btrfs: account for crcs in delayed ref processing · 1262133b
      Josef Bacik authored
      
      
      As we delete large extents, we end up doing huge amounts of COW in order
      to delete the corresponding crcs.  This adds accounting so that we keep
      track of that space and flushing of delayed refs so that we don't build
      up too much delayed crc work.
      
      This helps limit the delayed work that must be done at commit time and
      tries to avoid ENOSPC aborts because the crcs eat all the global
      reserves.
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      1262133b
    • Chris Mason's avatar
      btrfs: actively run the delayed refs while deleting large files · 28ed1345
      Chris Mason authored
      
      
      When we are deleting large files with large extents, we are building up
      a huge set of delayed refs for processing.  Truncate isn't checking
      often enough to see if we need to back off and process those, or let
      a commit proceed.
      
      The end result is long stalls after the rm, and very long commit times.
      During the commits, other processes back up waiting to start new
      transactions and we get into trouble.
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      28ed1345
  2. 17 Mar, 2015 1 commit
    • Josef Bacik's avatar
      Btrfs: prepare block group cache before writing · dcdf7f6d
      Josef Bacik authored
      
      
      Writing the block group cache will modify the extent tree quite a bit because it
      truncates the old space cache and pre-allocates new stuff.  To try and cut down
      on the churn lets do the setup dance first, then later on hopefully we can avoid
      looping with newly dirtied roots.  Thanks,
      Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
      dcdf7f6d
  3. 13 Mar, 2015 2 commits
    • Josef Bacik's avatar
      Btrfs: fix ASSERT(list_empty(&cur_trans->dirty_bgs_list) · ea526d18
      Josef Bacik authored
      
      
      Dave could hit this assert consistently running btrfs/078.  This is because
      when we update the block groups we could truncate the free space, which would
      try to delete the csums for that range and dirty the csum root.  For this to
      happen we have to have already written out the csum root so it's kind of hard to
      hit this case.  This patch fixes this by changing the logic to only write the
      dirty block groups if the dirty_cowonly_roots list is empty.  This will get us
      the same effect as before since we add the extent root last, and will cover the
      case that we dirty some other root again but not the extent root.  Thanks,
      Reported-by: default avatarDavid Sterba <dsterba@suse.cz>
      Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      ea526d18
    • Liu Bo's avatar
      Btrfs: catch transaction abortion after waiting for it · b4924a0f
      Liu Bo authored
      This problem is uncovered by a test case: http://patchwork.ozlabs.org/patch/244297
      
      .
      
      Fsync() can report success when it actually doesn't.  When we
      have several threads running fsync() at the same tiem and in one fsync() we
      get a transaction abortion due to some problems(in the test case it's disk
      failures), and other fsync()s may return successfully which makes userspace
      programs think that data is now safely flushed into disk.
      
      It's because that after fsyncs() fail btrfs_sync_log() due to disk failures,
      they get to try btrfs_commit_transaction() where it finds that there is
      already a transaction being committed, and they'll just call wait_for_commit()
      and return.  Note that we actually check "trans->aborted" in btrfs_end_transaction,
      but it's likely that the error message is still not yet throwed out and only after
      wait_for_commit() we're sure whether the transaction is committed successfully.
      
      This add the necessary check and it now passes the test.
      Signed-off-by: default avatarLiu Bo <bo.li.liu@oracle.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      b4924a0f
  4. 05 Mar, 2015 1 commit
  5. 03 Mar, 2015 1 commit
  6. 16 Feb, 2015 1 commit
  7. 14 Feb, 2015 1 commit
    • Zhao Lei's avatar
      btrfs: Fix out-of-space bug · 13212b54
      Zhao Lei authored
      Btrfs will report NO_SPACE when we create and remove files for several times,
      and we can't write to filesystem until mount it again.
      
      Steps to reproduce:
       1: Create a single-dev btrfs fs with default option
       2: Write a file into it to take up most fs space
       3: Delete above file
       4: Wait about 100s to let chunk removed
       5: goto 2
      
      Script is like following:
       #!/bin/bash
      
       # Recommend 1.2G space, too large disk will make test slow
       DEV="/dev/sda16"
       MNT="/mnt/tmp"
      
       dev_size="$(lsblk -bn -o SIZE "$DEV")" || exit 2
       file_size_m=$((dev_size * 75 / 100 / 1024 / 1024))
      
       echo "Loop write ${file_size_m}M file on $((dev_size / 1024 / 1024))M dev"
      
       for ((i = 0; i < 10; i++)); do umount "$MNT" 2>/dev/null; done
       echo "mkfs $DEV"
       mkfs.btrfs -f "$DEV" >/dev/null || exit 2
       echo "mount $DEV $MNT"
       mount "$DEV" "$MNT" || exit 2
      
       for ((loop_i = 0; loop_i < 20; loop_i++)); do
           echo
           echo "loop $loop_i"
      
           echo "dd file..."
           cmd=(dd if=/dev/zero of="$MNT"/file0 bs=1M count="$file_size_m")
           "${cmd[@]}" 2>/dev/null || {
               # NO_SPACE error triggered
               echo "dd failed: ${cmd[*]}"
               exit 1
           }
      
           echo "rm file..."
           rm -f "$MNT"/file0 || exit 2
      
           for ((i = 0; i < 10; i++)); do
               df "$MNT" | tail -1
               sleep 10
           done
       done
      
      Reason:
       It is triggered by commit: 47ab2a6c
      
      
       which is used to remove empty block groups automatically, but the
       reason is not in that patch. Code before works well because btrfs
       don't need to create and delete chunks so many times with high
       complexity.
       Above bug is caused by many reason, any of them can trigger it.
      
      Reason1:
       When we remove some continuous chunks but leave other chunks after,
       these disk space should be used by chunk-recreating, but in current
       code, only first create will successed.
       Fixed by Forrest Liu <forrestl@synology.com> in:
       Btrfs: fix find_free_dev_extent() malfunction in case device tree has hole
      
      Reason2:
       contains_pending_extent() return wrong value in calculation.
       Fixed by Forrest Liu <forrestl@synology.com> in:
       Btrfs: fix find_free_dev_extent() malfunction in case device tree has hole
      
      Reason3:
       btrfs_check_data_free_space() try to commit transaction and retry
       allocating chunk when the first allocating failed, but space_info->full
       is set in first allocating, and prevent second allocating in retry.
       Fixed in this patch by clear space_info->full in commit transaction.
      
       Tested for severial times by above script.
      
      Changelog v3->v4:
       use light weight int instead of atomic_t to record have_remove_bgs in
       transaction, suggested by:
       Josef Bacik <jbacik@fb.com>
      
      Changelog v2->v3:
       v2 fixed the bug by adding more commit-transaction, but we
       only need to reclaim space when we are really have no space for
       new chunk, noticed by:
       Filipe David Manana <fdmanana@gmail.com>
      
       Actually, our code already have this type of commit-and-retry,
       we only need to make it working with removed-bgs.
       v3 fixed the bug with above way.
      
      Changelog v1->v2:
       v1 will introduce a new bug when delete and create chunk in same disk
       space in same transaction, noticed by:
       Filipe David Manana <fdmanana@gmail.com>
       V2 fix this bug by commit transaction after remove block grops.
      Reported-by: default avatarTsutomu Itoh <t-itoh@jp.fujitsu.com>
      Suggested-by: default avatarFilipe David Manana <fdmanana@gmail.com>
      Suggested-by: default avatarJosef Bacik <jbacik@fb.com>
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      13212b54
  8. 21 Jan, 2015 2 commits
    • Josef Bacik's avatar
      Btrfs: track dirty block groups on their own list · ce93ec54
      Josef Bacik authored
      
      
      Currently any time we try to update the block groups on disk we will walk _all_
      block groups and check for the ->dirty flag to see if it is set.  This function
      can get called several times during a commit.  So if you have several terabytes
      of data you will be a very sad panda as we will loop through _all_ of the block
      groups several times, which makes the commit take a while which slows down the
      rest of the file system operations.
      
      This patch introduces a dirty list for the block groups that we get added to
      when we dirty the block group for the first time.  Then we simply update any
      block groups that have been dirtied since the last time we called
      btrfs_write_dirty_block_groups.  This allows us to clean up how we write the
      free space cache out so it is much cleaner.  Thanks,
      Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      ce93ec54
    • Josef Bacik's avatar
      Btrfs: change how we track dirty roots · e7070be1
      Josef Bacik authored
      
      
      I've been overloading root->dirty_list to keep track of dirty roots and which
      roots need to have their commit roots switched at transaction commit time.  This
      could cause us to lose an update to the root which could corrupt the file
      system.  To fix this use a state bit to know if the root is dirty, and if it
      isn't set we go ahead and move the root to the dirty list.  This way if we
      re-dirty the root after adding it to the switch_commit list we make sure to
      update it.  This also makes it so that the extent root is always the last root
      on the dirty list to try and keep the amount of churn down at this point in the
      commit.  Thanks,
      Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      e7070be1
  9. 20 Jan, 2015 1 commit
  10. 21 Nov, 2014 1 commit
    • Josef Bacik's avatar
      Btrfs: make sure logged extents complete in the current transaction V3 · 50d9aa99
      Josef Bacik authored
      
      
      Liu Bo pointed out that my previous fix would lose the generation update in the
      scenario I described.  It is actually much worse than that, we could lose the
      entire extent if we lose power right after the transaction commits.  Consider
      the following
      
      write extent 0-4k
      log extent in log tree
      commit transaction
      	< power fail happens here
      ordered extent completes
      
      We would lose the 0-4k extent because it hasn't updated the actual fs tree, and
      the transaction commit will reset the log so it isn't replayed.  If we lose
      power before the transaction commit we are save, otherwise we are not.
      
      Fix this by keeping track of all extents we logged in this transaction.  Then
      when we go to commit the transaction make sure we wait for all of those ordered
      extents to complete before proceeding.  This will make sure that if we lose
      power after the transaction commit we still have our data.  This also fixes the
      problem of the improperly updated extent generation.  Thanks,
      
      cc: stable@vger.kernel.org
      Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      50d9aa99
  11. 20 Nov, 2014 2 commits
    • Filipe Manana's avatar
      Btrfs: make find_first_extent_bit be able to cache any state · e38e2ed7
      Filipe Manana authored
      
      
      Right now the only caller of find_first_extent_bit() that is interested
      in caching extent states (transaction or log commit), never gets an extent
      state cached. This is because find_first_extent_bit() only caches states
      that have at least one of the flags EXTENT_IOBITS or EXTENT_BOUNDARY, and
      the transaction/log commit caller always passes a tree that doesn't have
      ever extent states with any of those flags (they can only have one of the
      following flags: EXTENT_DIRTY, EXTENT_NEW or EXTENT_NEED_WAIT).
      
      This change together with the following one in the patch series (titled
      "Btrfs: avoid returning -ENOMEM in convert_extent_bit() too early") will
      help reduce significantly the chances of calls to convert_extent_bit()
      fail with -ENOMEM when called from the transaction/log commit code.
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      e38e2ed7
    • Filipe Manana's avatar
      Btrfs: deal with convert_extent_bit errors to avoid fs corruption · 663dfbb0
      Filipe Manana authored
      
      
      When committing a transaction or a log, we look for btree extents that
      need to be durably persisted by searching for ranges in a io tree that
      have some bits set (EXTENT_DIRTY or EXTENT_NEW). We then attempt to clear
      those bits and set the EXTENT_NEED_WAIT bit, with calls to the function
      convert_extent_bit, and then start writeback for the extents.
      
      That function however can return an error (at the moment only -ENOMEM
      is possible, specially when it does GFP_ATOMIC allocation requests
      through alloc_extent_state_atomic) - that means the ranges didn't got
      the EXTENT_NEED_WAIT bit set (or at least not for the whole range),
      which in turn means a call to btrfs_wait_marked_extents() won't find
      those ranges for which we started writeback, causing a transaction
      commit or a log commit to persist a new superblock without waiting
      for the writeback of extents in that range to finish first.
      
      Therefore if a crash happens after persisting the new superblock and
      before writeback finishes, we have a superblock pointing to roots that
      weren't fully persisted or roots that point to nodes or leafs that weren't
      fully persisted, causing all sorts of unexpected/bad behaviour as we endup
      reading garbage from disk or the content of some node/leaf from a past
      generation that got cowed or deleted and is no longer valid (for this later
      case we end up getting error messages like "parent transid verify failed on
      X wanted Y found Z" when reading btree nodes/leafs from disk).
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      663dfbb0
  12. 12 Nov, 2014 3 commits
    • David Sterba's avatar
      btrfs: introduce pending action: commit · d51033d0
      David Sterba authored
      
      
      In some contexts, like in sysfs handlers, we don't want to trigger a
      transaction commit. It's a heavy operation, we don't know what external
      locks may be taken. Instead, make it possible to finish the operation
      through sync syscall or SYNC_FS ioctl.
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.cz>
      d51033d0
    • David Sterba's avatar
      btrfs: switch inode_cache option handling to pending changes · 7e1876ac
      David Sterba authored
      
      
      The pending mount option(s) now share namespace and bits with the normal
      options, and the existing one for (inode_cache) is unset unconditionally
      at each transaction commit.
      
      Introduce a separate namespace for pending changes and enhance the
      descriptions of the intended change to use separate bits for each
      action.
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.cz>
      7e1876ac
    • David Sterba's avatar
      btrfs: add support for processing pending changes · 572d9ab7
      David Sterba authored
      
      
      There are some actions that modify global filesystem state but cannot be
      performed at the time of request, but later at the transaction commit
      time when the filesystem is in a known state.
      
      For example enabling new incompat features on-the-fly or issuing
      transaction commit from unsafe contexts (sysfs handlers).
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.cz>
      572d9ab7
  13. 03 Oct, 2014 2 commits
    • Sage Weil's avatar
      Btrfs: fix race in WAIT_SYNC ioctl · 42383020
      Sage Weil authored
      
      
      We check whether transid is already committed via last_trans_committed and
      then search through trans_list for pending transactions.  If
      last_trans_committed is updated by btrfs_commit_transaction after we check
      it (there is no locking), we will fail to find the committed transaction
      and return EINVAL to the caller.  This has been observed occasionally by
      ceph-osd (which uses this ioctl heavily).
      
      Fix by rechecking whether the provided transid <= last_trans_committed
      after the search fails, and if so return 0.
      Signed-off-by: default avatarSage Weil <sage@redhat.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      42383020
    • Filipe Manana's avatar
      Btrfs: be aware of btree inode write errors to avoid fs corruption · 656f30db
      Filipe Manana authored
      
      
      While we have a transaction ongoing, the VM might decide at any time
      to call btree_inode->i_mapping->a_ops->writepages(), which will start
      writeback of dirty pages belonging to btree nodes/leafs. This call
      might return an error or the writeback might finish with an error
      before we attempt to commit the running transaction. If this happens,
      we might have no way of knowing that such error happened when we are
      committing the transaction - because the pages might no longer be
      marked dirty nor tagged for writeback (if a subsequent modification
      to the extent buffer didn't happen before the transaction commit) which
      makes filemap_fdata[write|wait]_range unable to find such pages (even
      if they're marked with SetPageError).
      So if this happens we must abort the transaction, otherwise we commit
      a super block with btree roots that point to btree nodes/leafs whose
      content on disk is invalid - either garbage or the content of some
      node/leaf from a past generation that got cowed or deleted and is no
      longer valid (for this later case we end up getting error messages like
      "parent transid verify failed on 10826481664 wanted 25748 found 29562"
      when reading btree nodes/leafs from disk).
      
      Note that setting and checking AS_EIO/AS_ENOSPC in the btree inode's
      i_mapping would not be enough because we need to distinguish between
      log tree extents (not fatal) vs non-log tree extents (fatal) and
      because the next call to filemap_fdatawait_range() will catch and clear
      such errors in the mapping - and that call might be from a log sync and
      not from a transaction commit, which means we would not know about the
      error at transaction commit time. Also, checking for the eb flag
      EXTENT_BUFFER_IOERR at transaction commit time isn't done and would
      not be completely reliable, as the eb might be removed from memory and
      read back when trying to get it, which clears that flag right before
      reading the eb's pages from disk, making us not know about the previous
      write error.
      
      Using the new 3 flags for the btree inode also makes us achieve the
      goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
      writeback for all dirty pages and before filemap_fdatawait_range() is
      called, the writeback for all dirty pages had already finished with
      errors - because we were not using AS_EIO/AS_ENOSPC,
      filemap_fdatawait_range() would return success, as it could not know
      that writeback errors happened (the pages were no longer tagged for
      writeback).
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      656f30db
  14. 02 Oct, 2014 2 commits
  15. 17 Sep, 2014 4 commits
  16. 15 Aug, 2014 1 commit
    • Chris Mason's avatar
      btrfs: disable strict file flushes for renames and truncates · 8d875f95
      Chris Mason authored
      
      
      Truncates and renames are often used to replace old versions of a file
      with new versions.  Applications often expect this to be an atomic
      replacement, even if they haven't done anything to make sure the new
      version is fully on disk.
      
      Btrfs has strict flushing in place to make sure that renaming over an
      old file with a new file will fully flush out the new file before
      allowing the transaction commit with the rename to complete.
      
      This ordering means the commit code needs to be able to lock file pages,
      and there are a few paths in the filesystem where we will try to end a
      transaction with the page lock held.  It's rare, but these things can
      deadlock.
      
      This patch removes the ordered flushes and switches to a best effort
      filemap_flush like ext4 uses. It's not perfect, but it should fix the
      deadlocks.
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      8d875f95
  17. 03 Jul, 2014 2 commits
    • Filipe Manana's avatar
      Btrfs: fix crash when starting transaction · abdd2e80
      Filipe Manana authored
      
      
      Often when starting a transaction we commit the currently running transaction,
      which can end up writing block group caches when the current process has its
      journal_info set to NULL (and not to a transaction). This makes our assertion
      at btrfs_check_data_free_space() (current_journal != NULL) fail, resulting
      in a crash/hang. Therefore fix it by setting journal_info.
      
      Two different traces of this issue follow below.
      
      1)
      
          [51502.241936] BTRFS: assertion failed: current->journal_info, file: fs/btrfs/extent-tree.c, line: 3670
          [51502.242213] ------------[ cut here ]------------
          [51502.242493] kernel BUG at fs/btrfs/ctree.h:3964!
          [51502.242669] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
          (...)
          [51502.244010] Call Trace:
          [51502.244010]  [<ffffffffa02bc025>] btrfs_check_data_free_space+0x395/0x3a0 [btrfs]
          [51502.244010]  [<ffffffffa02c3bdc>] btrfs_write_dirty_block_groups+0x4ac/0x640 [btrfs]
          [51502.244010]  [<ffffffffa0357a6a>] commit_cowonly_roots+0x164/0x226 [btrfs]
          [51502.244010]  [<ffffffffa02d53cd>] btrfs_commit_transaction+0x4ed/0xab0 [btrfs]
          [51502.244010]  [<ffffffff8168ec7b>] ? _raw_spin_unlock+0x2b/0x40
          [51502.244010]  [<ffffffffa02d6259>] start_transaction+0x459/0x620 [btrfs]
          [51502.244010]  [<ffffffffa02d67ab>] btrfs_start_transaction+0x1b/0x20 [btrfs]
          [51502.244010]  [<ffffffffa02d73e1>] __unlink_start_trans+0x31/0xe0 [btrfs]
          [51502.244010]  [<ffffffffa02dea67>] btrfs_unlink+0x37/0xc0 [btrfs]
          [51502.244010]  [<ffffffff811bb054>] ? do_unlinkat+0x114/0x2a0
          [51502.244010]  [<ffffffff811baebc>] vfs_unlink+0xcc/0x150
          [51502.244010]  [<ffffffff811bb1a0>] do_unlinkat+0x260/0x2a0
          [51502.244010]  [<ffffffff811a9ef4>] ? filp_close+0x64/0x90
          [51502.244010]  [<ffffffff810aaea6>] ? trace_hardirqs_on_caller+0x16/0x1e0
          [51502.244010]  [<ffffffff81349cab>] ? trace_hardirqs_on_thunk+0x3a/0x3f
          [51502.244010]  [<ffffffff811be9eb>] SyS_unlinkat+0x1b/0x40
          [51502.244010]  [<ffffffff81698452>] system_call_fastpath+0x16/0x1b
          [51502.244010] Code: 0b 55 48 89 e5 0f 0b 55 48 89 e5 0f 0b 55 89 f1 48 c7 c2 71 13 36 a0 48 89 fe 31 c0 48 c7 c7 b8 43 36 a0 48 89 e5 e8 5d b0 32 e1 <0f> 0b 0f 1f 44 00 00 55 b9 11 00 00 00 48 89 e5 41 55 49 89 f5
          [51502.244010] RIP  [<ffffffffa03575da>] assfail.constprop.88+0x1e/0x20 [btrfs]
      
      2)
      
          [25405.097230] BTRFS: assertion failed: current->journal_info, file: fs/btrfs/extent-tree.c, line: 3670
          [25405.097488] ------------[ cut here ]------------
          [25405.097767] kernel BUG at fs/btrfs/ctree.h:3964!
          [25405.097940] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
          (...)
          [25405.100008] Call Trace:
          [25405.100008]  [<ffffffffa02bc025>] btrfs_check_data_free_space+0x395/0x3a0 [btrfs]
          [25405.100008]  [<ffffffffa02c3bdc>] btrfs_write_dirty_block_groups+0x4ac/0x640 [btrfs]
          [25405.100008]  [<ffffffffa035755a>] commit_cowonly_roots+0x164/0x226 [btrfs]
          [25405.100008]  [<ffffffffa02d53cd>] btrfs_commit_transaction+0x4ed/0xab0 [btrfs]
          [25405.100008]  [<ffffffff8109c170>] ? bit_waitqueue+0xc0/0xc0
          [25405.100008]  [<ffffffffa02d6259>] start_transaction+0x459/0x620 [btrfs]
          [25405.100008]  [<ffffffffa02d67ab>] btrfs_start_transaction+0x1b/0x20 [btrfs]
          [25405.100008]  [<ffffffffa02e3407>] btrfs_create+0x47/0x210 [btrfs]
          [25405.100008]  [<ffffffffa02d74cc>] ? btrfs_permission+0x3c/0x80 [btrfs]
          [25405.100008]  [<ffffffff811bc63b>] vfs_create+0x9b/0x130
          [25405.100008]  [<ffffffff811bcf19>] do_last+0x849/0xe20
          [25405.100008]  [<ffffffff811b9409>] ? link_path_walk+0x79/0x820
          [25405.100008]  [<ffffffff811bd5b5>] path_openat+0xc5/0x690
          [25405.100008]  [<ffffffff810ab07d>] ? trace_hardirqs_on+0xd/0x10
          [25405.100008]  [<ffffffff811cdcd2>] ? __alloc_fd+0x32/0x1d0
          [25405.100008]  [<ffffffff811be2a3>] do_filp_open+0x43/0xa0
          [25405.100008]  [<ffffffff811cddf1>] ? __alloc_fd+0x151/0x1d0
          [25405.100008]  [<ffffffff811abcfc>] do_sys_open+0x13c/0x230
          [25405.100008]  [<ffffffff810aaea6>] ? trace_hardirqs_on_caller+0x16/0x1e0
          [25405.100008]  [<ffffffff811abe12>] SyS_open+0x22/0x30
          [25405.100008]  [<ffffffff81698452>] system_call_fastpath+0x16/0x1b
          [25405.100008] Code: 0b 55 48 89 e5 0f 0b 55 48 89 e5 0f 0b 55 89 f1 48 c7 c2 51 13 36 a0 48 89 fe 31 c0 48 c7 c7 d0 43 36 a0 48 89 e5 e8 6d b5 32 e1 <0f> 0b 0f 1f 44 00 00 55 b9 11 00 00 00 48 89 e5 41 55 49 89 f5
          [25405.100008] RIP  [<ffffffffa03570ca>] assfail.constprop.88+0x1e/0x20 [btrfs]
      Signed-off-by: default avatarFilipe David Borba Manana <fdmanana@gmail.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      abdd2e80
    • David Sterba's avatar
      btrfs: remove stale comment from btrfs_flush_all_pending_stuffs · 0a4eaea8
      David Sterba authored
      Commit fcebe456
      
       (Btrfs: rework qgroup
      accounting) removed the qgroup accounting after delayed refs.
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.cz>
      0a4eaea8
  18. 28 Jun, 2014 1 commit
  19. 13 Jun, 2014 1 commit
  20. 10 Jun, 2014 1 commit
  21. 09 Jun, 2014 4 commits
    • Chris Mason's avatar
      Btrfs: async delayed refs · a79b7d4b
      Chris Mason authored
      
      
      Delayed extent operations are triggered during transaction commits.
      The goal is to queue up a healthly batch of changes to the extent
      allocation tree and run through them in bulk.
      
      This farms them off to async helper threads.  The goal is to have the
      bulk of the delayed operations being done in the background, but this is
      also important to limit our stack footprint.
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      a79b7d4b
    • Josef Bacik's avatar
      Btrfs: rework qgroup accounting · fcebe456
      Josef Bacik authored
      
      
      Currently qgroups account for space by intercepting delayed ref updates to fs
      trees.  It does this by adding sequence numbers to delayed ref updates so that
      it can figure out how the tree looked before the update so we can adjust the
      counters properly.  The problem with this is that it does not allow delayed refs
      to be merged, so if you say are defragging an extent with 5k snapshots pointing
      to it we will thrash the delayed ref lock because we need to go back and
      manually merge these things together.  Instead we want to process quota changes
      when we know they are going to happen, like when we first allocate an extent, we
      free a reference for an extent, we add new references etc.  This patch
      accomplishes this by only adding qgroup operations for real ref changes.  We
      only modify the sequence number when we need to lookup roots for bytenrs, this
      reduces the amount of churn on the sequence number and allows us to merge
      delayed refs as we add them most of the time.  This patch encompasses a bunch of
      architectural changes
      
      1) qgroup ref operations: instead of tracking qgroup operations through the
      delayed refs we simply add new ref operations whenever we notice that we need to
      when we've modified the refs themselves.
      
      2) tree mod seq:  we no longer have this separation of major/minor counters.
      this makes the sequence number stuff much more sane and we can remove some
      locking that was needed to protect the counter.
      
      3) delayed ref seq: we now read the tree mod seq number and use that as our
      sequence.  This means each new delayed ref doesn't have it's own unique sequence
      number, rather whenever we go to lookup backrefs we inc the sequence number so
      we can make sure to keep any new operations from screwing up our world view at
      that given point.  This allows us to merge delayed refs during runtime.
      
      With all of these changes the delayed ref stuff is a little saner and the qgroup
      accounting stuff no longer goes negative in some cases like it was before.
      Thanks,
      Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      fcebe456
    • Miao Xie's avatar
    • David Sterba's avatar
      btrfs: assert that send is not in progres before root deletion · 61155aa0
      David Sterba authored
      
      
      CC: Miao Xie <miaox@cn.fujitsu.com>
      CC: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.cz>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      61155aa0
  22. 06 Apr, 2014 2 commits
    • Josef Bacik's avatar
      Btrfs: remove transaction from send · 9e351cc8
      Josef Bacik authored
      
      
      Lets try this again.  We can deadlock the box if we send on a box and try to
      write onto the same fs with the app that is trying to listen to the send pipe.
      This is because the writer could get stuck waiting for a transaction commit
      which is being blocked by the send.  So fix this by making sure looking at the
      commit roots is always going to be consistent.  We do this by keeping track of
      which roots need to have their commit roots swapped during commit, and then
      taking the commit_root_sem and swapping them all at once.  Then make sure we
      take a read lock on the commit_root_sem in cases where we search the commit root
      to make sure we're always looking at a consistent view of the commit roots.
      Previously we had problems with this because we would swap a fs tree commit root
      and then swap the extent tree commit root independently which would cause the
      backref walking code to screw up sometimes.  With this patch we no longer
      deadlock and pass all the weird send/receive corner cases.  Thanks,
      Reportedy-by: default avatarHugo Mills <hugo@carfax.org.uk>
      Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      9e351cc8
    • Josef Bacik's avatar
      Btrfs: don't clear uptodate if the eb is under IO · a26e8c9f
      Josef Bacik authored
      
      
      So I have an awful exercise script that will run snapshot, balance and
      send/receive in parallel.  This sometimes would crash spectacularly and when it
      came back up the fs would be completely hosed.  Turns out this is because of a
      bad interaction of balance and send/receive.  Send will hold onto its entire
      path for the whole send, but its blocks could get relocated out from underneath
      it, and because it doesn't old tree locks theres nothing to keep this from
      happening.  So it will go to read in a slot with an old transid, and we could
      have re-allocated this block for something else and it could have a completely
      different transid.  But because we think it is invalid we clear uptodate and
      re-read in the block.  If we do this before we actually write out the new block
      we could write back stale data to the fs, and boom we're screwed.
      
      Now we definitely need to fix this disconnect between send and balance, but we
      really really need to not allow ourselves to accidently read in stale data over
      new data.  So make sure we check if the extent buffer is not under io before
      clearing uptodate, this will kick back EIO to the caller instead of reading in
      stale data and keep us from corrupting the fs.  Thanks,
      Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      a26e8c9f
  23. 20 Mar, 2014 1 commit
    • Josef Bacik's avatar
      Btrfs: fix deadlock with nested trans handles · 3bbb24b2
      Josef Bacik authored
      
      
      Zach found this deadlock that would happen like this
      
      btrfs_end_transaction <- reduce trans->use_count to 0
        btrfs_run_delayed_refs
          btrfs_cow_block
            find_free_extent
      	btrfs_start_transaction <- increase trans->use_count to 1
                allocate chunk
      	btrfs_end_transaction <- decrease trans->use_count to 0
      	  btrfs_run_delayed_refs
      	    lock tree block we are cowing above ^^
      
      We need to only decrease trans->use_count if it is above 1, otherwise leave it
      alone.  This will make nested trans be the only ones who decrease their added
      ref, and will let us get rid of the trans->use_count++ hack if we have to commit
      the transaction.  Thanks,
      
      cc: stable@vger.kernel.org
      Reported-by: default avatarZach Brown <zab@redhat.com>
      Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
      Tested-by: default avatarZach Brown <zab@redhat.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      3bbb24b2
  24. 10 Mar, 2014 1 commit