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
...
projects / kernel.git / commitdiff