For repairs, we need to reserve at least as many blocks as we think
we're going to need to rebuild the data structure, and we're going to
need some helpers to roll transactions while maintaining locks on the AG
headers so that other threads cannot wander into the middle of a repair.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
If we've already decided that something is corrupt, we might as well
abort all the loops and exit as quickly as possible.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Don't bother looking for cross-referencing problems if the metadata is
already corrupt or we've already found a cross-referencing problem.
Since we added a helper function for flags testing, convert existing
users to use it.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Since the transaction allocation helper is about to become more complex,
move it to common.c and remove the redundant parameters.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Now that we no longer do raw inode buffer scrubbing, the bp parameter is
no longer used anywhere we're dealing with an inode, so remove it and
all the useless NULL parameters that go with it.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
When we're scanning an extent mapping inode fork, ensure that every rmap
record for this ifork has a corresponding bmbt record too. This
(mostly) provides the ability to cross-reference rmap records with bmap
data. The rmap scrubber cannot do the xref on its own because that
requires taking an ilock with the agf lock held, which violates our
locking order rules (inode, then agf).
Note that we only do this for forks that are in btree format due to the
increased complexity; or forks that should have data but suspiciously
have zero extents because the inode could have just had its iforks
zapped by the inode repair code and now we need to reclaim the old
extents.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
xfs_bmbt_irec.br_blockcount is declared as xfs_filblks_t, which is an
unsigned 64-bit integer. Though the bmbt helpers will never set a value
larger than 2^21 (since the underlying on-disk extent record has a
length field that is only 21 bits wide), we should be a little defensive
about checking that a bmbt record doesn't exceed what we're expecting or
overflow into the next AG.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
While we're scrubbing various btrees, cross-reference the records
with the other metadata.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
During metadata btree scrub, we should cross-reference with the
reference counts.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
When scrubbing various btrees, we should cross-reference the records
with the reverse mapping btree and ensure that traversing the btree
finds the same number of blocks that the rmapbt thinks are owned by
that btree.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Cross-reference the inode btrees with the other metadata when we
scrub the filesystem.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
When we're scrubbing various btrees, cross-reference the records with
the bnobt to ensure that we don't also think the space is free.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Create some stubs that will be used to cross-reference metadata records.
The actual cross-referencing will be filled in by subsequent patches.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Refactor xfs_scrub_bmap to use for_each_xfs_iext now that it exists.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
[darrick: fix broken initializer in xfs_scrub_xattr]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Replace the current linear list and the indirection array for the in-core
extent list with a b+tree to avoid the need for larger memory allocations
for the indirection array when lots of extents are present. The current
extent list implementations leads to heavy pressure on the memory
allocator when modifying files with a high extent count, and can lead
to high latencies because of that.
The replacement is a b+tree with a few quirks. The leaf nodes directly
store the extent record in two u64 values. The encoding is a little bit
different from the existing in-core extent records so that the start
offset and length which are required for lookups can be retreived with
simple mask operations. The inner nodes store a 64-bit key containing
the start offset in the first half of the node, and the pointers to the
next lower level in the second half. In either case we walk the node
from the beginninig to the end and do a linear search, as that is more
efficient for the low number of cache lines touched during a search
(2 for the inner nodes, 4 for the leaf nodes) than a binary search.
We store termination markers (zero length for the leaf nodes, an
otherwise impossible high bit for the inner nodes) to terminate the key
list / records instead of storing a count to use the available cache
lines as efficiently as possible.
One quirk of the algorithm is that while we normally split a node half and
half like usual btree implementations we just spill over entries added at
the very end of the list to a new node on its own. This means we get a
100% fill grade for the common cases of bulk insertion when reading an
inode into memory, and when only sequentially appending to a file. The
downside is a slightly higher chance of splits on the first random
insertions.
Both insert and removal manually recurse into the lower levels, but
the bulk deletion of the whole tree is still implemented as a recursive
function call, although one limited by the overall depth and with very
little stack usage in every iteration.
For the first few extents we dynamically grow the list from a single
extent to the next powers of two until we have a first full leaf block
and that building the actual tree.
The code started out based on the generic lib/btree.c code from Joern
Engel based on earlier work from Peter Zijlstra, but has since been
rewritten beyond recognition.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Add a new xfs_iext_cursor structure to hide the direct extent map
index manipulations. In addition to the existing lookup/get/insert/
remove and update routines new primitives to get the first and last
extent cursor, as well as moving up and down by one extent are
provided. Also new are convenience to increment/decrement the
cursor and retreive the new extent, as well as to peek into the
previous/next extent without updating the cursor and last but not
least a macro to iterate over all extents in a fork.
[darrick: rename for_each_iext to for_each_xfs_iext]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Scrub an individual inode's block mappings to make sure they make sense.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
