1. 03 Oct, 2008 1 commit
    • Chris Mason's avatar
      Btrfs: O_DIRECT writes via buffered writes + invaldiate · cb843a6f
      Chris Mason authored
      This reworks the btrfs O_DIRECT write code a bit.  It had always fallen
      back to buffered IO and done an invalidate, but needed to be updated
      for the data=ordered code.  The invalidate wasn't actually removing pages
      because they were still inside an ordered extent.
      This also combines the O_DIRECT/O_SYNC paths where possible, and kicks
      off IO in the main btrfs_file_write loop to keep the pipe down the the
      disk full as we process long writes.
      Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
  2. 01 Oct, 2008 4 commits
    • Chris Mason's avatar
      Btrfs: don't read leaf blocks containing only checksums during truncate · 323ac95b
      Chris Mason authored
      Checksum items take up a significant portion of the metadata for large files.
      It is possible to avoid reading them during truncates by checking the keys in
      the higher level nodes.
      If a given leaf is followed by another leaf where the lowest key is a checksum
      item from the same file, we know we can safely delete the leaf without
      reading it.
      For a 32GB file on a 6 drive raid0 array, Btrfs needs 8s to delete
      the file with a cold cache.  It is read bound during the run.
      With this change, Btrfs is able to delete the file in 0.5s
      Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
    • Josef Bacik's avatar
      Btrfs: fix deadlock between alloc_mutex/chunk_mutex · cf749823
      Josef Bacik authored
      This fixes a deadlock that happens between the alloc_mutex and chunk_mutex.
      Process A comes in, decides to do a do_chunk_alloc, which takes the
      chunk_mutex, and is holding the alloc_mutex because the only way you get to
      do_chunk_alloc is by holding the alloc_mutex.  btrfs_alloc_chunk does its thing
      and goes to insert a new item, which results in a cow of the block.
      We get into del_pending_extents from there, where if we need to be rescheduled
      we drop the alloc_mutex and schedule.  At this point process B comes in to do
      an allocation and gets the alloc_mutex, and because process A did not do the
      chunk allocation completely it thinks its a good time to do a chunk allocation
      as well, and hangs on the chunk_mutex.
      Process A wakes up and tries to take the alloc_mutex and cannot.  The way to
      fix this is do a mutex_trylock() on chunk_mutex.  If we return 0 we didn't get
      the lock, and if this is just a "hey it may be a good time to allocate a chunk"
      then we just exit.  If we are trying to force an allocation then we reschedule
      and keep trying to acquire the chunk_mutex.  If once we acquire it the space is
      already full then we can just exit, otherwise we can continue with the chunk
      allocation.  Thank you,
      Signed-off-by: default avatarJosef Bacik <jbacik@redhat.com>
    • Jim Meyering's avatar
    • Jim Meyering's avatar
  3. 30 Sep, 2008 2 commits
    • Chris Mason's avatar
      Btrfs: fix multi-device code to use raid policies set by mkfs · 75ccf47d
      Chris Mason authored
      When reading in block groups, a global mask of the available raid policies
      should be adjusted based on the types of block groups found on disk.  This
      global mask is then used to decide which raid policy to use for new
      block groups.
      The recent allocator changes dropped the call that updated the global
      mask, making all the block groups allocated at run time single striped
      onto a single drive.
      This also fixes the async worker threads to set any thread that uses
      the requeue mechanism as busy.  This allows us to avoid blocking
      on get_request_wait for the async bio submission threads.
      Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
    • Josef Bacik's avatar
      Btrfs: fix seekiness due to finding the wrong block group · 45b8c9a8
      Josef Bacik authored
      This patch fixes a problem where we end up seeking too much when *last_ptr is
      valid.  This happens because btrfs_lookup_first_block_group only returns a
      block group that starts on or after the given search start, so if the
      search_start is in the middle of a block group it will return the block group
      after the given search_start, which is suboptimal.
      This patch fixes that by doing a btrfs_lookup_block_group, which will return
      the block group that contains the given search start.  If we fail to find a
      block group, we fall back on btrfs_lookup_first_block_group so we can find the
      next block group, not sure if this is absolutely needed, but better safe than
      Also if we can't find the block group that we need, or it happens to not be of
      the right type, we need to add empty_cluster since *last_ptr could point to a
      mismatched block group, which means we need to start over with empty_cluster
      added to total needed.  Thank you,
      Signed-off-by: default avatarJosef Bacik <jbacik@redhat.com>
      Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
  4. 29 Sep, 2008 3 commits
    • Chris Mason's avatar
      Btrfs: add and improve comments · d352ac68
      Chris Mason authored
      This improves the comments at the top of many functions.  It didn't
      dive into the guts of functions because I was trying to
      avoid merging problems with the new allocator and back reference work.
      extent-tree.c and volumes.c were both skipped, and there is definitely
      more work todo in cleaning and commenting the code.
      Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
    • Chris Mason's avatar
      Btrfs: drop WARN_ON from btrfs_add_leaf_ref · 9a5e1ea1
      Chris Mason authored
      btrfs_add_leaf_ref was doing checks on the objects it found in the
      rbtree to make sure they were properly linked into the tree.  But, the field
      it was checking can be safely changed outside of the tree spin lock.
      The WARN_ON was for debugging the initial implementation and can be
      safely removed.
      Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
    • Chris Mason's avatar
      Btrfs: Wait for IO on the block device inodes of newly added devices · 8c8bee1d
      Chris Mason authored
      btrfs-vol -a /dev/xxx will zero the first and last two MB of the device.
      The kernel code needs to wait for this IO to finish before it adds
      the device.
      btrfs metadata IO does not happen through the block device inode.  A
      separate address space is used, allowing the zero filled buffer heads in
      the block device inode to be written to disk after FS metadata starts
      going down to the disk via the btrfs metadata inode.
      The end result is zero filled metadata blocks after adding new devices
      into the filesystem.
      The fix is a simple filemap_write_and_wait on the block device inode
      before actually inserting it into the pool of available devices.
      Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
  5. 26 Sep, 2008 4 commits
    • Zheng Yan's avatar
      Btrfs: update space balancing code · 1a40e23b
      Zheng Yan authored
      This patch updates the space balancing code to utilize the new
      backref format.  Before, btrfs-vol -b would break any COW links
      on data blocks or metadata.  This was slow and caused the amount
      of space used to explode if a large number of snapshots were present.
      The new code can keeps the sharing of all data extents and
      most of the tree blocks.
      To maintain the sharing of data extents, the space balance code uses
      a seperate inode hold data extent pointers, then updates the references
      to point to the new location.
      To maintain the sharing of tree blocks, the space balance code uses
      reloc trees to relocate tree blocks in reference counted roots.
      There is one reloc tree for each subvol, and all reloc trees share
      same root key objectid. Reloc trees are snapshots of the latest
      committed roots of subvols (root->commit_root).
      To relocate a tree block referenced by a subvol, there are two steps.
      COW the block through subvol's reloc tree, then update block pointer in
      the subvol to point to the new block. Since all reloc trees share
      same root key objectid, doing special handing for tree blocks
      owned by them is easy. Once a tree block has been COWed in one
      reloc tree, we can use the resulting new block directly when the
      same block is required to COW again through other reloc trees.
      In this way, relocated tree blocks are shared between reloc trees,
      so they are also shared between subvols.
      Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
    • Zheng Yan's avatar
      Btrfs: extent_map and data=ordered fixes for space balancing · 5b21f2ed
      Zheng Yan authored
      * Add an EXTENT_BOUNDARY state bit to keep the writepage code
      from merging data extents that are in the process of being
      relocated.  This allows us to do accounting for them properly.
      * The balancing code relocates data extents indepdent of the underlying
      inode.  The extent_map code was modified to properly account for
      things moving around (invalidating extent_map caches in the inode).
      * Don't take the drop_mutex in the create_subvol ioctl.  It isn't
      * Fix walking of the ordered extent list to avoid races with sys_unlink
      * Change the lock ordering rules.  Transaction start goes outside
      the drop_mutex.  This allows btrfs_commit_transaction to directly
      drop the relocation trees.
      Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
    • Zheng Yan's avatar
      Btrfs: Add shared reference cache · e4657689
      Zheng Yan authored
      Btrfs has a cache of reference counts in leaves, allowing it to
      avoid reading tree leaves while deleting snapshots.  To reduce
      contention with multiple subvolumes, this cache is private to each
      This patch adds shared reference cache support. The new space
      balancing code plays with multiple subvols at the same time, So
      the old per-subvol reference cache is not well suited.
      Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
    • Zheng Yan's avatar
      Btrfs: allocator fixes for space balancing update · e8569813
      Zheng Yan authored
      * Reserved extent accounting:  reserved extents have been
      allocated in the rbtrees that track free space but have not
      been allocated on disk.  They were never properly accounted for
      in the past, making it hard to know how much space was really free.
      * btrfs_find_block_group used to return NULL for block groups that
      had been removed by the space balancing code.  This made it hard
      to account for space during the final stages of a balance run.
      Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
  6. 25 Sep, 2008 26 commits