| Age | Commit message (Collapse) | Author | Files | Lines |
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The only user of the ->data_dot_entry_p and ->data_dotdot_entry_p
methods is the xfs_dir2_sf_to_block function that builds block format
directorys from a short form directory. It already uses pointer
arithmetics with a offset variable to do so for the real entries in
the directory, so switch the generation of the . and .. entries to
the same scheme, and clean up some of the later pointer arithmetics
to use bp->b_addr directly as well and avoid some casts.
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>
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The data_dotdot_offset value is always equal to data_entry_offset plus
the fixed size of the "." entry. Right now calculating that fixed size
requires an indirect call, but by the end of this series it will be
an inline function that can be constant folded.
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>
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The data_dot_offset value is always equal to data_entry_offset given
that "." is always the first entry in the directory.
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>
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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>
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Replace the ->sf_get_ftype and ->sf_put_ftype dir ops methods with
directly called xfs_dir2_sf_get_ftype and xfs_dir2_sf_put_ftype helpers
that takes care of the differences between the directory format with and
without the file type field.
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>
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Replace the ->sf_get_ino and ->sf_put_ino dir ops methods with directly
called xfs_dir2_sf_get_ino and xfs_dir2_sf_put_ino helpers that take care
of the difference between the directory format with and without the file
type field. Also move xfs_dir2_sf_get_parent_ino and
xfs_dir2_sf_put_parent_ino to xfs_dir2_sf.c with the rest of the
low-level short form entry handling and use XFS_MAXINUMBER istead of
opencoded constants.
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>
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Just check for file-type enabled directories directly.
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>
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The parent inode handling is the same for all directory format variants,
just use direct calls instead of going through a pointless indirect
call.
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>
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Now that the max bests value is in struct xfs_da_geometry both instances
of ->db_to_fdb and ->db_to_fdindex are identical. Replace them with
local xfs_dir2_db_to_fdb and xfs_dir2_db_to_fdindex functions in
xfs_dir2_node.c.
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>
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Move the max free bests count towards our structure for dir/attr
geometry parameters.
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>
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Move the free header size towards our structure for dir/attr geometry
parameters.
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>
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All but two callers of the ->free_bests_p dir operation already have a
struct xfs_dir3_icfree_hdr from a previous call to
xfs_dir2_free_hdr_from_disk at hand. Add a pointer to the bests to
struct xfs_dir3_icfree_hdr to clean up this pattern. To optimize this
pattern, pass the struct xfs_dir3_icfree_hdr to xfs_dir2_free_log_bests
instead of recalculating the pointer there.
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>
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Return the xfs_dir3_icfree_hdr used by the helpers called from
xfs_dir2_node_addname_int to the main function to prepare for the
next round of changes where we'll use the ichdr in xfs_dir3_icfree_hdr
to avoid extra operations to find the bests pointers.
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>
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Replace the ->free_hdr_to_disk dir ops method with a directly called
xfs_dir2_free_hdr_to_disk helper that takes care of the differences
between the v4 and v5 on-disk format.
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>
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Replace the ->free_hdr_from_disk dir ops method with a directly called
xfs_dir_free_hdr_from_disk helper that takes care of the differences
between the v4 and v5 on-disk format.
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>
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Move the max leaf entries count towards our structure for dir/attr
geometry parameters.
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>
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Move the leaf header size towards our structure for dir/attr geometry
parameters.
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>
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All callers of the ->node_tree_p dir operation already have a struct
xfs_dir3_icleaf_hdr from a previous call to xfs_da_leaf_hdr_from_disk at
hand, or just need slight changes to the calling conventions to do so.
Add a pointer to the entries to struct xfs_dir3_icleaf_hdr to clean up
this pattern. To make this possible the xfs_dir3_leaf_log_ents function
grow a new argument to pass the xfs_dir3_icleaf_hdr that call callers
already have, and xfs_dir2_leaf_lookup_int returns the
xfs_dir3_icleaf_hdr to the callers so that they can later use it.
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>
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Replace the ->leaf_hdr_to_disk dir ops method with a directly called
xfs_dir_leaf_hdr_to_disk helper that takes care of the differences
between the v4 and v5 on-disk format.
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>
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Replace the ->leaf_hdr_from_disk dir ops method with a directly called
xfs_dir2_leaf_hdr_from_disk helper that takes care of the differences
between the v4 and v5 on-disk format.
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>
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Move the node header size field to struct xfs_da_geometry, and remove
the now unused non-directory dir ops infrastructure.
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>
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All but two callers of the ->node_tree_p dir operation already have a
xfs_da3_icnode_hdr from a previous call to xfs_da3_node_hdr_from_disk at
hand. Add a pointer to the btree entries to struct xfs_da3_icnode_hdr
to clean up this pattern. The two remaining callers now expand the
whole header as well, but that isn't very expensive and not in a super
hot path anyway.
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>
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Replace the ->node_hdr_to_disk dir ops method with a directly called
xfs_da_node_hdr_to_disk helper that takes care of the v4 vs v5
difference.
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>
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Replace the ->node_hdr_from_disk dir ops method with a directly called
xfs_da_node_hdr_from_disk helper that takes care of the v4 vs v5
difference.
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>
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None of these can ever be negative, so use unsigned types.
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>
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Move the abstract in-memory version of various btree block headers
out of xfs_da_format.h as they aren't on-disk formats.
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>
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Replace the open-coded checks for whether or not an inode fork maps
blocks with a macro that will implant the code for us. This helps us
declutter the bmap code a bit.
Note that I had to use a macro instead of a static inline function
because of C header dependency problems between xfs_inode.h and
xfs_inode_fork.h.
Conversion was performed with the following Coccinelle script:
@@
expression ip, w;
@@
- XFS_IFORK_FORMAT(ip, w) == XFS_DINODE_FMT_EXTENTS || XFS_IFORK_FORMAT(ip, w) == XFS_DINODE_FMT_BTREE
+ xfs_ifork_has_extents(ip, w)
@@
expression ip, w;
@@
- XFS_IFORK_FORMAT(ip, w) != XFS_DINODE_FMT_EXTENTS && XFS_IFORK_FORMAT(ip, w) != XFS_DINODE_FMT_BTREE
+ !xfs_ifork_has_extents(ip, w)
@@
expression ip, w;
@@
- XFS_IFORK_FORMAT(ip, w) == XFS_DINODE_FMT_BTREE || XFS_IFORK_FORMAT(ip, w) == XFS_DINODE_FMT_EXTENTS
+ xfs_ifork_has_extents(ip, w)
@@
expression ip, w;
@@
- XFS_IFORK_FORMAT(ip, w) != XFS_DINODE_FMT_BTREE && XFS_IFORK_FORMAT(ip, w) != XFS_DINODE_FMT_EXTENTS
+ !xfs_ifork_has_extents(ip, w)
@@
expression ip, w;
@@
- (xfs_ifork_has_extents(ip, w))
+ xfs_ifork_has_extents(ip, w)
@@
expression ip, w;
@@
- (!xfs_ifork_has_extents(ip, w))
+ !xfs_ifork_has_extents(ip, w)
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Refactor the weird while loop out of existence.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Just fix the typos checkpatch notices...
Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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Coverity complains that we don't check the return value of
xfs_iext_peek_prev_extent like we do nearly all of the time. If there
is no previous extent then just null out bma->prev like we do elsewhere
in the bmap code.
Coverity-id: 1424057
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Some of the xfs source files are missing header includes, so add them
back. Sparse complains about non-static functions that don't have a
forward declaration anywhere.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Refactor the code that complains when a dir/attr mapping doesn't exist
but the caller requires a mapping. This small restructuring helps us to
reduce the indenting level.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Make sure we log something to dmesg whenever we return -EFSCORRUPTED up
the call stack.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Each of the four functions that operate on shortform directories checks
that the directory's di_size is at least as large as the shortform
directory header. This is now checked by the inode fork verifiers
(di_size is used to allocate if_bytes, and if_bytes is checked against
the header structure size) so we can turn these checks into ASSERTions.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Always set XFS_ALLOC_USERDATA for data fork allocations, and check it
in xfs_alloc_is_userdata instead of the current obsfucated check.
Also remove the xfs_alloc_is_userdata and xfs_alloc_allow_busy_reuse
helpers to make the code a little easier to understand.
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>
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Move the extent zeroing case there for the XFS_BMAPI_ZERO flag outside
the low-level allocator and into xfs_bmapi_allocate, where is still
is in transaction context, but outside the very lowlevel code where
it doesn't belong.
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>
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Avoid duplicate userdata and data fork checks by restructuring the code
so we only have a helper for userdata allocations that combines these
checks in a straight foward way. That also helps to obsoletes the
comments explaining what the code does as it is now clearly obvious.
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>
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xfs_iread_extents open-codes everything in xfs_btree_visit_blocks, so
refactor the btree helper to be able to iterate only the records on
level 0, then port iread_extents to use it.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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There are a few places where we return -EIO instead of -EFSCORRUPTED
when we find corrupt metadata. Fix those places.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
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Actually call namecheck on attribute names before we hand them over to
userspace.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
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Add missing structure checks in the attribute leaf verifier.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
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xfs_bmapi_write() takes a total block requirement parameter that is
passed down to the block allocation code and is used to specify the
total block requirement of the associated transaction. This is used
to try and select an AG that can not only satisfy the requested
extent allocation, but can also accommodate subsequent allocations
that might be required to complete the transaction. For example,
additional bmbt block allocations may be required on insertion of
the resulting extent to an inode data fork.
While it's important for callers to calculate and reserve such extra
blocks in the transaction, it is not necessary to pass the total
value to xfs_bmapi_write() in all cases. The latter automatically
sets minleft to ensure that sufficient free blocks remain after the
allocation attempt to expand the format of the associated inode
(i.e., such as extent to btree conversion, btree splits, etc).
Therefore, any callers that pass a total block requirement of the
bmap mapping length plus worst case bmbt expansion essentially
specify the additional reservation requirement twice. These callers
can pass a total of zero to rely on the bmapi minleft policy.
Beyond being superfluous, the primary motivation for this change is
that the total reservation logic in the bmbt code is dubious in
scenarios where minlen < maxlen and a maxlen extent cannot be
allocated (which is more common for data extent allocations where
contiguity is not required). The total value is based on maxlen in
the xfs_bmapi_write() caller. If the bmbt code falls back to an
allocation between minlen and maxlen, that allocation will not
succeed until total is reset to minlen, which essentially throws
away any additional reservation included in total by the caller. In
addition, the total value is not reset until after alignment is
dropped, which means that such callers drop alignment far too
aggressively than necessary.
Update all callers of xfs_bmapi_write() that pass a total block
value of the mapping length plus bmbt reservation to instead pass
zero and rely on xfs_bmapi_minleft() to enforce the bmbt reservation
requirement. This trades off slightly less conservative AG selection
for the ability to preserve alignment in more scenarios.
xfs_bmapi_write() callers that incorporate unrelated or additional
reservations in total beyond what is already included in minleft
must continue to use the former.
Signed-off-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>
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Cap longest extent to the largest we can allocate based on limits
calculated at mount time. Dynamic state (such as finobt blocks)
can result in the longest free extent exceeding the size we can
allocate, and that results in failure to align full AG allocations
when the AG is empty.
Result:
xfs_io-4413 [003] 426.412459: xfs_alloc_vextent_loopfailed: dev 8:96 agno 0 agbno 32 minlen 243968 maxlen 244000 mod 0 prod 1 minleft 1 total 262148 alignment 32 minalignslop 0 len 0 type NEAR_BNO otype START_BNO wasdel 0 wasfromfl 0 resv 0 datatype 0x5 firstblock 0xffffffffffffffff
minlen and maxlen are now separated by the alignment size, and
allocation fails because args.total > free space in the AG.
[bfoster: Added xfs_bmap_btalloc() changes.]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-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>
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[commit message is verbose for discussion purposes - will trim it
down later. Some questions about implementation details at the end.]
Zorro Lang recently ran a new test to stress single inode extent
counts now that they are no longer limited by memory allocation.
The test was simply:
# xfs_io -f -c "falloc 0 40t" /mnt/scratch/big-file
# ~/src/xfstests-dev/punch-alternating /mnt/scratch/big-file
This test uncovered a problem where the hole punching operation
appeared to finish with no error, but apparently only created 268M
extents instead of the 10 billion it was supposed to.
Further, trying to punch out extents that should have been present
resulted in success, but no change in the extent count. It looked
like a silent failure.
While running the test and observing the behaviour in real time,
I observed the extent coutn growing at ~2M extents/minute, and saw
this after about an hour:
# xfs_io -f -c "stat" /mnt/scratch/big-file |grep next ; \
> sleep 60 ; \
> xfs_io -f -c "stat" /mnt/scratch/big-file |grep next
fsxattr.nextents = 127657993
fsxattr.nextents = 129683339
#
And a few minutes later this:
# xfs_io -f -c "stat" /mnt/scratch/big-file |grep next
fsxattr.nextents = 4177861124
#
Ah, what? Where did that 4 billion extra extents suddenly come from?
Stop the workload, unmount, mount:
# xfs_io -f -c "stat" /mnt/scratch/big-file |grep next
fsxattr.nextents = 166044375
#
And it's back at the expected number. i.e. the extent count is
correct on disk, but it's screwed up in memory. I loaded up the
extent list, and immediately:
# xfs_io -f -c "stat" /mnt/scratch/big-file |grep next
fsxattr.nextents = 4192576215
#
It's bad again. So, where does that number come from?
xfs_fill_fsxattr():
if (ip->i_df.if_flags & XFS_IFEXTENTS)
fa->fsx_nextents = xfs_iext_count(&ip->i_df);
else
fa->fsx_nextents = ip->i_d.di_nextents;
And that's the behaviour I just saw in a nutshell. The on disk count
is correct, but once the tree is loaded into memory, it goes whacky.
Clearly there's something wrong with xfs_iext_count():
inline xfs_extnum_t xfs_iext_count(struct xfs_ifork *ifp)
{
return ifp->if_bytes / sizeof(struct xfs_iext_rec);
}
Simple enough, but 134M extents is 2**27, and that's right about
where things went wrong. A struct xfs_iext_rec is 16 bytes in size,
which means 2**27 * 2**4 = 2**31 and we're right on target for an
integer overflow. And, sure enough:
struct xfs_ifork {
int if_bytes; /* bytes in if_u1 */
....
Once we get 2**27 extents in a file, we overflow if_bytes and the
in-core extent count goes wrong. And when we reach 2**28 extents,
if_bytes wraps back to zero and things really start to go wrong
there. This is where the silent failure comes from - only the first
2**28 extents can be looked up directly due to the overflow, all the
extents above this index wrap back to somewhere in the first 2**28
extents. Hence with a regular pattern, trying to punch a hole in the
range that didn't have holes mapped to a hole in the first 2**28
extents and so "succeeded" without changing anything. Hence "silent
failure"...
Fix this by converting if_bytes to a int64_t and converting all the
index variables and size calculations to use int64_t types to avoid
overflows in future. Signed integers are still used to enable easy
detection of extent count underflows. This enables scalability of
extent counts to the limits of the on-disk format - MAXEXTNUM
(2**31) extents.
Current testing is at over 500M extents and still going:
fsxattr.nextents = 517310478
Reported-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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The near mode fallback algorithm consists of a left/right scan of
the bnobt. This algorithm has very poor breakdown characteristics
under worst case free space fragmentation conditions. If a suitable
extent is far enough from the locality hint, each allocation may
scan most or all of the bnobt before it completes. This causes
pathological behavior and extremely high allocation latencies.
While locality is important to near mode allocations, it is not so
important as to incur pathological allocation latency to provide the
asolute best available locality for every allocation. If the
allocation is large enough or far enough away, there is a point of
diminishing returns. As such, we can bound the overall operation by
including an iterative cntbt lookup in the broader search. The cntbt
lookup is optimized to immediately find the extent with best
locality for the given size on each iteration. Since the cntbt is
indexed by extent size, the lookup repeats with a variably
aggressive increasing search key size until it runs off the edge of
the tree.
This approach provides a natural balance between the two algorithms
for various situations. For example, the bnobt scan is able to
satisfy smaller allocations such as for inode chunks or btree blocks
more quickly where the cntbt search may have to search through a
large set of extent sizes when the search key starts off small
relative to the largest extent in the tree. On the other hand, the
cntbt search more deterministically covers the set of suitable
extents for larger data extent allocation requests that the bnobt
scan may have to search the entire tree to locate.
Signed-off-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>
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Lift the btree fixup path into a helper function.
Signed-off-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>
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In preparation to enhance the near mode allocation bnobt scan algorithm, lift
it into a separate function. No functional changes.
Signed-off-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>
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The bnobt "find best" helper implements a simple btree walker
function. This general pattern, or a subset thereof, is reused in
various parts of a near mode allocation operation. For example, the
bnobt left/right scans are each iterative btree walks along with the
cntbt lastblock scan.
Rework this function into a generic btree walker, add a couple
parameters to control termination behavior from various contexts and
reuse it where applicable.
Signed-off-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>
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Both algorithms duplicate the same btree allocation code. Eliminate
the duplication and reuse the fallback algorithm codepath.
Signed-off-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>
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The near mode bnobt scan searches left and right in the bnobt
looking for the closest free extent to the allocation hint that
satisfies minlen. Once such an extent is found, the left/right
search terminates, we search one more time in the opposite direction
and finish the allocation with the best overall extent.
The left/right and find best searches are currently controlled via a
combination of cursor state and local variables. Clean up this code
and prepare for further improvements to the near mode fallback
algorithm by reusing the allocation cursor best extent tracking
mechanism. Update the tracking logic to deactivate bnobt cursors
when out of allocation range and replace open-coded extent checks to
calls to the common helper. In doing so, rename some misnamed local
variables in the top-level near mode allocation function.
Signed-off-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>
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