Move the xrep_extent_list code into a separate file. Logically, this
data structure is really just a clumsy bitmap, and in the next patch
we'll make this more obvious. No functional changes.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
New verification functions like xfs_verify_fsbno() and
xfs_verify_agino() are spread across multiple files and different
header files. They really don't fit cleanly into the places they've
been put, and have wider scope than the current header includes.
Move the type verifiers to a new file in libxfs (xfs-types.c) and
the prototypes to xfs_types.h where they will be visible to all the
code that uses the types.
Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-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>
Remove the verbose license text from XFS files and replace them
with SPDX tags. This does not change the license of any of the code,
merely refers to the common, up-to-date license files in LICENSES/
This change was mostly scripted. fs/xfs/Makefile and
fs/xfs/libxfs/xfs_fs.h were modified by hand, the rest were detected
and modified by the following command:
for f in `git grep -l "GNU General" fs/xfs/` ; do
echo $f
cat $f | awk -f hdr.awk > $f.new
mv -f $f.new $f
done
And the hdr.awk script that did the modification (including
detecting the difference between GPL-2.0 and GPL-2.0+ licenses)
is as follows:
$ cat hdr.awk
BEGIN {
hdr = 1.0
tag = "GPL-2.0"
str = ""
}
/^ \* This program is free software/ {
hdr = 2.0;
next
}
/any later version./ {
tag = "GPL-2.0+"
next
}
/^ \*\// {
if (hdr > 0.0) {
print "// SPDX-License-Identifier: " tag
print str
print $0
str=""
hdr = 0.0
next
}
print $0
next
}
/^ \* / {
if (hdr > 1.0)
next
if (hdr > 0.0) {
if (str != "")
str = str "\n"
str = str $0
next
}
print $0
next
}
/^ \*/ {
if (hdr > 0.0)
next
print $0
next
}
// {
if (hdr > 0.0) {
if (str != "")
str = str "\n"
str = str $0
next
}
print $0
}
END { }
$
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>
If one of the backup superblocks is found to differ seriously from
superblock 0, write out a fresh copy from the in-core sb.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
So it can be shared with userspace (e.g. mkfs) easily.
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>
Plumb in the pieces necessary to make the "scrub" subfunction of
the scrub ioctl actually work. This means that we make the IFLAG_REPAIR
flag to the scrub ioctl actually do something, and we add an errortag
knob so that xfstests can force the kernel to rebuild a metadata
structure even if there's nothing wrong with it.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.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>
Perform some quick sanity testing of the disk quota information.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Perform simple tests of the realtime bitmap and summary.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Scrub parent pointers, sort of. For directories, we can ride the
'..' entry up to the parent to confirm that there's at most one
dentry that points back to this directory.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Create the infrastructure to scrub symbolic link data.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Scrub the hash tree, keys, and values in an extended attribute structure.
Refactor the attribute code to use the transaction if the caller supplied
one to avoid buffer deadocks.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Scrub the hash tree and all the entries in a directory.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Provide a way to check the shape and scrub the hashes and records
in a directory or extended attribute btree. These are helper functions
for the directory & attribute scrubbers in subsequent patches.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
[fengguang: remove unneeded variable to store return value]
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Dave Chinner <dchinner@redhat.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>
Plumb in the pieces necessary to check the refcount btree. If rmap is
available, check the reference count by performing an interval query
against the rmapbt.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Check the reverse mapping records to make sure that the contents
make sense.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Check the records of the inode btrees to make sure that the values
make sense given the inode records themselves.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Check the extent records free space btrees to ensure that the values
look sane.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Ensure that the geometry presented in the backup superblocks matches
the primary superblock so that repair can recover the filesystem if
that primary gets corrupted.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Create helper functions and tracepoints to deal with errors while
scrubbing a metadata btree.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Create a probe scrubber with id 0. This will be used by xfs_scrub to
probe the kernel's abilities to scrub (and repair) the metadata. We do
this by validating the ioctl inputs from userspace, preparing the
filesystem for a scrub (or a repair) operation, and immediately
returning to userspace. Userspace can use the returned errno and
structure state to decide (in broad terms) if scrub/repair are
supported by the running kernel.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Create an ioctl that can be used to scrub internal filesystem metadata.
The new ioctl takes the metadata type, an (optional) AG number, an
(optional) inode number and generation, and a flags argument. This will
be used by the upcoming XFS online scrub tool.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Use the common helper uuid_is_null() and remove the xfs specific
helper uuid_is_nil().
The common helper does not check for the NULL pointer value as
xfs helper did, but xfs code never calls the helper with a pointer
that can be NULL.
Conform comments and warning strings to use the term 'null uuid'
instead of 'nil uuid', because this is the terminology used by
lib/uuid.c and its users. It is also the terminology used in
userspace by libuuid and xfsprogs.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
[hch: remove now unused uuid.[ch]]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Introduce a new ioctl that uses the reverse mapping btree to return
information about the physical layout of the filesystem.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Introduce a new in-core fork for storing copy-on-write delalloc
reservations and allocated extents that are in the process of being
written out.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Provide a mechanism for higher levels to create BUI/BUD items, submit
them to the log, and a stub function to deal with recovered BUI items.
These parts will be connected to the rmapbt in a later patch.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Create bmbt update intent/done log items to record redo information in
the log. Because we roll transactions multiple times for reflink
operations, we also have to track the status of the metadata updates
that will be recorded in the post-roll transactions in case we crash
before committing the final transaction. This mechanism enables log
recovery to finish what was already started.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Provide a mechanism for higher levels to create CUI/CUD items, submit
them to the log, and a stub function to deal with recovered CUI items.
These parts will be connected to the refcountbt in a later patch.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Create refcount update intent/done log items to record redo
information in the log. Because we need to roll transactions between
updating the bmbt mapping and updating the reverse mapping, we also
have to track the status of the metadata updates that will be recorded
in the post-roll transactions, just in case we crash before committing
the final transaction. This mechanism enables log recovery to finish
what was already started.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Implement the generic btree operations required to manipulate refcount
btree blocks. The implementation is similar to the bmapbt, though it
will only allocate and free blocks from the AG.
Since the refcount root and level fields are separate from the
existing roots and levels array, they need a separate logging flag.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
[hch: fix logging of AGF refcount btree fields]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Start constructing the refcount btree implementation by establishing
the on-disk format and everything needed to read, write, and
manipulate the refcount btree blocks.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
One unfortunate quirk of the reference count and reverse mapping
btrees -- they can expand in size when blocks are written to *other*
allocation groups if, say, one large extent becomes a lot of tiny
extents. Since we don't want to start throwing errors in the middle
of CoWing, we need to reserve some blocks to handle future expansion.
The transaction block reservation counters aren't sufficient here
because we have to have a reserve of blocks in every AG, not just
somewhere in the filesystem.
Therefore, create two per-AG block reservation pools. One feeds the
AGFL so that rmapbt expansion always succeeds, and the other feeds all
other metadata so that refcountbt expansion never fails.
Use the count of how many reserved blocks we need to have on hand to
create a virtual reservation in the AG. Through selective clamping of
the maximum length of allocation requests and of the length of the
longest free extent, we can make it look like there's less free space
in the AG unless the reservation owner is asking for blocks.
In other words, play some accounting tricks in-core to make sure that
we always have blocks available. On the plus side, there's nothing to
clean up if we crash, which is contrast to the strategy that the rough
draft used (actually removing extents from the freespace btrees).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
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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
...
Provide a mechanism for higher levels to create RUI/RUD items, submit
them to the log, and a stub function to deal with recovered RUI items.
These parts will be connected to the rmapbt in a later patch.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Create rmap update intent/done log items to record redo information in
the log. Because we need to roll transactions between updating the
bmbt mapping and updating the reverse mapping, we also have to track
the status of the metadata updates that will be recorded in the
post-roll transactions, just in case we crash before committing the
final transaction. This mechanism enables log recovery to finish what
was already started.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Originally-From: Dave Chinner <dchinner@redhat.com>
Now we have all the surrounding call infrastructure in place, we can
start filling out the rmap btree implementation. Start with the
on-disk btree format; add everything needed to read, write and
manipulate rmap btree blocks. This prepares the way for adding the
btree operations implementation.
[darrick: record owner and offset info in rmap btree]
[darrick: fork, bmbt and unwritten state in rmap btree]
[darrick: flags are a separate field in xfs_rmap_irec]
[darrick: calculate maxlevels separately]
[darrick: move the 'unwritten' bit into unused parts of rm_offset]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Originally-From: Dave Chinner <dchinner@redhat.com>
Add the stubs into the extent allocation and freeing paths that the
rmap btree implementation will hook into. While doing this, add the
trace points that will be used to track rmap btree extent
manipulations.
[darrick.wong@oracle.com: Extend the stubs to take full owner info.]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
All the code around struct xfs_bmap_free basically implements a
deferred operation framework through which we can roll transactions
(to unlock buffers and avoid violating lock order rules) while
managing all the necessary log redo items. Previously we only used
this code to free extents after some sort of mapping operation, but
with the advent of rmap and reflink, we suddenly need to do more than
that.
With that in mind, xfs_bmap_free really becomes a deferred ops control
structure. Rename the structure and move the deferred ops into their
own file to avoid further bloating of the bmap code.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Instead of creeping pnfs layout configuration into filesystems, move the
definition of block-based export operations under a more abstract
configuration.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This is a simple extension to the block layout driver to use SCSI
persistent reservations for access control and fencing, as well as
SCSI VPD pages for device identification.
For this we need to pass the nfs4_client to the proc_getdeviceinfo method
to generate the reservation key, and add a new fence_client method
to allow for fence actions in the layout driver.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Split the config symbols into a generic pNFS one, which is invisible
and gets selected by the layout drivers, and one for the block layout
driver.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
So we need to fix the makefile to understand this, otherwise build
errors with CONFIG_PROC_FS=n occur.
Reported-and-tested-by: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The header side of xfs_bit.c is already in libxfs, and the sparse
inode code requires the xfs_next_bit() function so pull in the
xfs_bit.c file so that a sparse inode enabled libxfs compiles
cleanly in userspace.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Add operations to export pNFS block layouts from an XFS filesystem. See
the previous commit adding the operations for an explanation of them.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Embed a base kobject into xfs_mount. This creates a kobject associated
with each XFS mount and a subdirectory in sysfs with the name of the
filesystem. The subdirectory lifecycle matches that of the mount. Also
add the new xfs_sysfs.[c,h] source files with some XFS sysfs
infrastructure to facilitate attribute creation.
Note that there are currently no attributes exported as part of the
xfs_mount kobject. It exists solely to serve as a per-mount container
for child objects.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Move all the source files that are shared with userspace into
libxfs/. This is done as one big chunk simpy to get it done
quickly
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
To minimise the differences between kernel and userspace code,
split the kernel code into the same structure as the userspace code.
That is, the gneric core functionality of XFS is moved to a libxfs/
directory and treat it as a layering barrier in the XFS code.
This patch introduces the libxfs directory, the build infrastructure
and an initial source and header file to build. The libxfs directory
will contain the header files that are needed to build libxfs - most
of userspace does not care about the location of these header files
as they are accessed indirectly. Hence keeping them inside libxfs
makes it easy to track the changes and script the sync process as
the directory structure will be identical.
To allow this changeover to occur in the kernel code, there are some
temporary infrastructure in the makefiles to grab the header
filesystem from both locations. Once all the files are moved,
modifications will be made in the source code that will make the
need for these include directives go away.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Lots of the dir code now goes through switches to determine what is
the correct on-disk format to parse. It generally involves a
"xfs_sbversion_hasfoo" check, deferencing the superblock version and
feature fields and hence touching several cache lines per operation
in the process. Some operations do multiple checks because they nest
conditional operations and they don't pass the information in a
direct fashion between each other.
Hence, add an ops vector to the xfs_inode structure that is
configured when the inode is initialised to point to all the correct
decode and encoding operations. This will significantly reduce the
branchiness and cacheline footprint of the directory object decoding
and encoding.
This is the first patch in a series of conversion patches. It will
introduce the ops structure, the setup of it and add the first
operation to the vector. Subsequent patches will convert directory
ops one at a time to keep the changes simple and obvious.
Just this patch shows the benefit of such an approach on code size.
Just converting the two shortform dir operations as this patch does
decreases the built binary size by ~1500 bytes:
$ size fs/xfs/xfs.o.orig fs/xfs/xfs.o.p1
text data bss dec hex filename
794490 96802 1096 892388 d9de4 fs/xfs/xfs.o.orig
792986 96802 1096 890884 d9804 fs/xfs/xfs.o.p1
$
That's a significant decrease in the instruction cache footprint of
the directory code for such a simple change, and indicates that this
approach is definitely worth pursuing further.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
