With quotaoff not allowing disabling of accounting there is no need
for untagged lookups in this code, so remove the dead leftovers.
Repoted-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
[djwong: convert to for_each_perag_tag]
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

Now that we defer inode inactivation, we've decoupled the process of
unlinking or closing an inode from the process of inactivating it.  In
theory this should lead to better throughput since we now inactivate the
queued inodes in batches instead of one at a time.

Unfortunately, one of the primary risks with this decoupling is the loss
of rate control feedback between the frontend and background threads.
In other words, a rm -rf /* thread can run the system out of memory if
it can queue inodes for inactivation and jump to a new CPU faster than
the background threads can actually clear the deferred work.  The
workers can get scheduled off the CPU if they have to do IO, etc.

To solve this problem, we configure a shrinker so that it will activate
the /second/ time the shrinkers are called.  The custom shrinker will
queue all percpu deferred inactivation workers immediately and set a
flag to force frontend callers who are releasing a vfs inode to wait for
the inactivation workers.

On my test VM with 560M of RAM and a 2TB filesystem, this seems to solve
most of the OOMing problem when deleting 10 million inodes.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

In xfs_trans_alloc, if the block reservation call returns ENOSPC, we
call xfs_blockgc_free_space with a NULL icwalk structure to try to free
space.  Each frontend thread that encounters this situation starts its
own walk of the inode cache to see if it can find anything, which is
wasteful since we don't have any additional selection criteria.  For
this one common case, create a function that reschedules all pending
background work immediately and flushes the workqueue so that the scan
can run in parallel.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Now that we have the infrastructure to switch background workers on and
off at will, fix the block gc worker code so that we don't actually run
the worker when the filesystem is frozen, same as we do for deferred
inactivation.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Other parts of XFS have learned to call xfs_blockgc_free_{space,quota}
to try to free speculative preallocations when space is tight.  This
means that file writes, transaction reservation failures, quota limit
enforcement, and the EOFBLOCKS ioctl all call this function to free
space when things are tight.

Since inode inactivation is now a background task, this means that the
filesystem can be hanging on to unlinked but not yet freed space.  Add
this to the list of things that xfs_blockgc_free_* makes writer threads
scan for when they cannot reserve space.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Now that we have made the inactivation of unlinked inodes a background
task to increase the throughput of file deletions, we need to be a
little more careful about how long of a delay we can tolerate.

Similar to the patch doing this for free space on the data device, if
the file being inactivated is a realtime file and the realtime volume is
running low on free extents, we want to run the worker ASAP so that the
realtime allocator can make better decisions.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Now that we have made the inactivation of unlinked inodes a background
task to increase the throughput of file deletions, we need to be a
little more careful about how long of a delay we can tolerate.

Specifically, if the dquots attached to the inode being inactivated are
nearing any kind of enforcement boundary, we want to queue that
inactivation work immediately so that users don't get EDQUOT/ENOSPC
errors even after they deleted a bunch of files to stay within quota.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Now that we have made the inactivation of unlinked inodes a background
task to increase the throughput of file deletions, we need to be a
little more careful about how long of a delay we can tolerate.

On a mostly empty filesystem, the risk of the allocator making poor
decisions due to fragmentation of the free space on account a lengthy
delay in background updates is minimal because there's plenty of space.
However, if free space is tight, we want to deallocate unlinked inodes
as quickly as possible to avoid fallocate ENOSPC and to give the
allocator the best shot at optimal allocations for new writes.

Therefore, queue the percpu worker immediately if the filesystem is more
than 95% full.  This follows the same principle that XFS becomes less
aggressive about speculative allocations and lazy cleanup (and more
precise about accounting) when nearing full.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Move inode inactivation to background work contexts so that it no
longer runs in the context that releases the final reference to an
inode. This will allow process work that ends up blocking on
inactivation to continue doing work while the filesytem processes
the inactivation in the background.

A typical demonstration of this is unlinking an inode with lots of
extents. The extents are removed during inactivation, so this blocks
the process that unlinked the inode from the directory structure. By
moving the inactivation to the background process, the userspace
applicaiton can keep working (e.g. unlinking the next inode in the
directory) while the inactivation work on the previous inode is
done by a different CPU.

The implementation of the queue is relatively simple. We use a
per-cpu lockless linked list (llist) to queue inodes for
inactivation without requiring serialisation mechanisms, and a work
item to allow the queue to be processed by a CPU bound worker
thread. We also keep a count of the queue depth so that we can
trigger work after a number of deferred inactivations have been
queued.

The use of a bound workqueue with a single work depth allows the
workqueue to run one work item per CPU. We queue the work item on
the CPU we are currently running on, and so this essentially gives
us affine per-cpu worker threads for the per-cpu queues. THis
maintains the effective CPU affinity that occurs within XFS at the
AG level due to all objects in a directory being local to an AG.
Hence inactivation work tends to run on the same CPU that last
accessed all the objects that inactivation accesses and this
maintains hot CPU caches for unlink workloads.

A depth of 32 inodes was chosen to match the number of inodes in an
inode cluster buffer. This hopefully allows sequential
allocation/unlink behaviours to defering inactivation of all the
inodes in a single cluster buffer at a time, further helping
maintain hot CPU and buffer cache accesses while running
inactivations.

A hard per-cpu queue throttle of 256 inode has been set to avoid
runaway queuing when inodes that take a long to time inactivate are
being processed. For example, when unlinking inodes with large
numbers of extents that can take a lot of processing to free.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
[djwong: tweak comments and tracepoints, convert opflags to state bits]
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

If we don't need to inactivate an inode, we can detach the dquots and
move on to reclamation.  This isn't strictly required here; it's a
preparation patch for deferred inactivation per reviewer request[1] to
move the creation of xfs_inode_needs_inactivation into a separate
change.  Eventually this !need_inactive chunk will turn into the code
path for inodes that skip xfs_inactive and go straight to memory
reclaim.

[1] https://lore.kernel.org/linux-xfs/20210609012838.GW2945738@locust/T/#mca6d958521cb88bbc1bfe1a30767203328d410b5Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Move the xfs_inactive call and all the other debugging checks and stats
updates into xfs_inode_mark_reclaimable because most of that are
implementation details about the inode cache.  This is preparation for
deferred inactivation that is coming up.  We also move it around
xfs_icache.c in preparation for deferred inactivation.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

xfs_dqrele_all_inodes is unused now, remove it and all supporting code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

It's currently unlikely that we will ever end up with more than 4
billion inodes waiting for reclamation, but the fs object code uses long
int for object counts and we're certainly capable of generating that
many.  Instead of truncating the internal counters, widen them and
report the object counts correctly.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

During review of the v6 deferred inode inactivation patchset[1], Dave
commented that _cache_hit should have a clear separation between inode
selection criteria and actions performed on a selected inode.  Move a
hunk to make this true, and compact the shrink cases in the function.

[1] https://lore.kernel.org/linux-xfs/162310469340.3465262.504398465311182657.stgit@locust/T/#mca6d958521cb88bbc1bfe1a30767203328d410b5Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

Hoist the code in xfs_iget_cache_hit that restores the VFS inode state
to an xfs_inode that was previously vfs-destroyed.  The next patch will
add a new set of state flags, so we need the helper to avoid
duplication.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

The xfs_eofblocks structure is no longer well-named -- nowadays it
provides optional filtering criteria to any walk of the incore inode
cache.  Only one of the cache walk goals has anything to do with
clearing of speculative post-EOF preallocations, so change the name to
be more appropriate.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

It's important that the filesystem retain its memory of sick inodes for
a little while after problems are found so that reports can be collected
about what was wrong.  Don't let inode reclamation free sick inodes
unless we're unmounting or the fs already went down.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NCarlos Maiolino <cmaiolino@redhat.com>

In preparation for renaming struct xfs_eofblocks to struct xfs_icwalk,
change the prefix of the existing XFS_EOF_FLAGS_* flags to
XFS_ICWALK_FLAG_ and convert all the existing users.  This adds a degree
of interface separation between the ioctl definitions and the incore
parameters.  Since FLAGS_UNION is only used in xfs_icache.c, move it
there as a private flag.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NCarlos Maiolino <cmaiolino@redhat.com>

While running some fuzz tests on inode metadata, I noticed that the
filesystem health report (as provided by xfs_spaceman) failed to report
the file corruption even when spaceman was run immediately after running
xfs_scrub to detect the corruption.  That isn't the intended behavior;
one ought to be able to run scrub to detect errors in the ondisk
metadata and be able to access to those reports for some time after the
scrub.

After running the same sequence through an instrumented kernel, I
discovered the reason why -- scrub igets the file, scans it, marks it
sick, and ireleases the inode.  When the VFS lets go of the incore
inode, it moves to RECLAIMABLE state.  If spaceman igets the incore
inode before it moves to RECLAIM state, iget reinitializes the VFS
state, clears the sick and checked masks, and hands back the inode.  At
this point, the caller has the exact same incore inode, but with all the
health state erased.

In other words, we're erasing the incore inode's health state flags when
we've decided NOT to sever the link between the incore inode and the
ondisk inode.  This is wrong, so we need to remove the lines that zero
the fields from xfs_iget_cache_hit.

As a precaution, we add the same lines into xfs_reclaim_inode just after
we sever the link between incore and ondisk inode.  Strictly speaking
this isn't necessary because once an inode has gone through reclaim it
must go through xfs_inode_alloc (which also zeroes the state) and
xfs_iget is careful to check for mismatches between the inode it pulls
out of the radix tree and the one it wants.

Fixes: 6772c1f1 ("xfs: track metadata health status")
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NCarlos Maiolino <cmaiolino@redhat.com>

In preparation for adding another incore inode tree tag, refactor the
code that sets and clears tags from the per-AG inode tree and the tree
of per-AG structures, and remove the open-coded versions used by the
blockgc code.

Note: For reclaim, we now rely on the radix tree tags instead of the
reclaimable inode count more heavily than we used to.  The conversion
should be fine, but the logic isn't 100% identical.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Merge these two inode walk loops together, since they're pretty similar
now.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Pass a pointer to the actual eofb structure around the inode scanner
functions instead of a void pointer, now that none of the functions is
used as a callback.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Soon we're going to be adding two new callers to the incore inode walk
code: reclaim of incore inodes, and (later) inactivation of inodes.
Both states operate on inodes that no longer have any VFS state, so we
need to move the xfs_irele calls into the processing functions.

In other words, icwalk processing functions are responsible for cleaning
up whatever state changes are made by the corresponding icwalk igrab
function that picked the inode for processing.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Clean up the definition of which inode states are not eligible for
speculative preallocation garbage collecting by creating a private
#define.  The deferred inactivation patchset will add two new entries to
the set of flags-to-ignore, so we want the definition not to end up a
cluttered mess.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

It turns out that there is a 1:1 mapping between the execute and goal
parameters that are passed to xfs_inode_walk_ag:

	xfs_blockgc_scan_inode <=> XFS_ICWALK_BLOCKGC
	xfs_dqrele_inode <=> XFS_ICWALK_DQRELE

Because of this exact correspondence, we don't need the execute function
pointer and can replace it with a direct call.

For the price of a forward static declaration, we can eliminate the
indirect function call.  This likely has a negligible impact on
performance (since the execute function runs transactions), but it also
simplifies the function signature.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

The sole iter_flags is XFS_INODE_WALK_INEW_WAIT, and there are no users.
Remove the flag, and the parameter, and all the code that used it.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Move the INEW wait into xfs_dqrele_inode so that we can drop the
iter_flags parameter in the next patch.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Disentangle the dqrele_all inode grab code from the "generic" inode walk
grabbing code, and and use the opportunity to document why the dqrele
grab function does what it does.  Since xfs_inode_walk_ag_grab is now
only used for blockgc, rename it to reflect that.

Ultimately, there will be four reasons to perform a walk of incore
inodes: quotaoff dquote releasing (dqrele), garbage collection of
speculative preallocations (blockgc), reclamation of incore inodes
(reclaim), and deferred inactivation (inodegc).  Each of these four have
their own slightly different criteria for deciding if they want to
handle an inode, so it makes more sense to have four cohesive igrab
functions than one confusing parameteric grab function like we do now.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

As part of removing the indirect calls and radix tag implementation
details from the incore inode walk loop, create an enum to represent the
goal of the inode iteration.  More immediately, this separate removes
the need for the "ICI_NOTAG" define which makes little sense.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Shorten the prefix so that all the incore inode cache walk code has
"xfs_icwalk" in the name somewhere.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Move the inode walk functions further down in the file to limit the
forward declarations to the two walk functions as we add new code that
uses the inode walks.  We'll clean them out later (i.e. after the
deferred inode inactivation series).
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

Once we're done with inactivating an inode, we're finished updating
metadata for that inode.  This means that we can detach the dquots at
the end and not have to wait for reclaim to do it for us.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

The only external caller of xfs_inode_walk* happens in quotaoff, when we
want to walk all the incore inodes to detach the dquots.  Move this code
to xfs_icache.c so that we can hide xfs_inode_walk as the starting step
in more cleanups of inode walks.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

for_each_perag_tag() is defined in xfs_icache.c for local use.
Promote this to xfs_ag.h and define equivalent iteration functions
so that we can use them to iterate AGs instead to replace open coded
perag walks and perag lookups.

We also convert as many of the straight forward open coded AG walks
to use these iterators as possible. Anything that is not a direct
conversion to an iterator is ignored and will be updated in future
commits.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

They are AG functions, not superblock functions, so move them to the
appropriate location.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

In xfs_inode_free_eofblocks, move the xfs_can_free_eofblocks call
further down in the function to the point where we have taken the
IOLOCK.  This is preparation for the next patch, where we will need that
lock (or equivalent) so that we can check if there are any post-eof
blocks to clean out.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

In preparation of removing the historic icinode struct, move the flags2
field into the containing xfs_inode structure.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

In preparation of removing the historic icinode struct, move the
forkoff field into the containing xfs_inode structure.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

In preparation of removing the historic icinode struct, move the
flushiter field into the containing xfs_inode structure.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

In preparation of removing the historic icinode struct, move the nblocks
field into the containing xfs_inode structure.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>