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    Merge tag 'xfs-rmap-for-linus-4.8-rc1' of... · 0cbbc422
    Linus Torvalds authored
    Merge tag 'xfs-rmap-for-linus-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs
    
    Pull more xfs updates from Dave Chinner:
     "This is the second part of the XFS updates for this merge cycle, and
      contains the new reverse block mapping feature for XFS.
    
      Reverse mapping allows us to track the owner of a specific block on
      disk precisely.  It is implemented as a set of btrees (one per
      allocation group) that track the owners of allocated extents.
      Effectively it is a "used space tree" that is updated when we allocate
      or free extents.  i.e. it is coherent with the free space btrees we
      already maintain and never overlaps with them.
    
      This reverse mapping infrastructure is the building block of several
      upcoming features - reflink, copy-on-write data, dedupe, online
      metadata and data scrubbing, highly accurate bad sector/data loss
      reporting to users, and significantly improved reconstruction of
      damaged and corrupted filesystems.  There's a lot of new stuff coming
      along in the next couple of cycles,a nd it all builds in the rmap
      infrastructure.
    
      As such, it's a huge chunk of new code with new on-disk format
      features and internal infrastructure.  It warns at mount time as an
      experimental feature and that it may eat data (as we do with all new
      on-disk features until they stabilise).  We have not released
      userspace suport for it yet - userspace support currently requires
      download from Darrick's xfsprogs repo and build from source, so the
      access to this feature is really developer/tester only at this point.
      Initial userspace support will be released at the same time kernel
      with this code in it is released.
    
      The new rmap enabled code regresses 3 xfstests - all are ENOSPC
      related corner cases, one of which Darrick posted a fix for a few
      hours ago.  The other two are fixed by infrastructure that is part of
      the upcoming reflink patchset.  This new ENOSPC infrastructure
      requires a on-disk format tweak required to keep mount times in
      check - we need to keep an on-disk count of allocated rmapbt blocks so
      we don't have to scan the entire btrees at mount time to count them.
    
      This is currently being tested and will be part of the fixes sent in
      the next week or two so users will not be exposed to this change"
    
    * tag 'xfs-rmap-for-linus-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (52 commits)
      xfs: move (and rename) the deferred bmap-free tracepoints
      xfs: collapse single use static functions
      xfs: remove unnecessary parentheses from log redo item recovery functions
      xfs: remove the extents array from the rmap update done log item
      xfs: in btree_lshift, only allocate temporary cursor when needed
      xfs: remove unnecesary lshift/rshift key initialization
      xfs: remove the get*keys and update_keys btree ops pointers
      xfs: enable the rmap btree functionality
      xfs: don't update rmapbt when fixing agfl
      xfs: disable XFS_IOC_SWAPEXT when rmap btree is enabled
      xfs: add rmap btree block detection to log recovery
      xfs: add rmap btree geometry feature flag
      xfs: propagate bmap updates to rmapbt
      xfs: enable the xfs_defer mechanism to process rmaps to update
      xfs: log rmap intent items
      xfs: create rmap update intent log items
      xfs: add rmap btree insert and delete helpers
      xfs: convert unwritten status of reverse mappings
      xfs: remove an extent from the rmap btree
      xfs: add an extent to the rmap btree
      ...
    0cbbc422