These only made a difference when quotaoff supported disabling quota
accounting on a mounted file system, so we can switch everyone to use
a single set of flags and helpers now. Note that the *QUOTA_ON naming
for the helpers is kept as it was the much more commonly used one.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NCarlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

Disabling quota accounting is hairy, racy code with all kinds of pitfalls.
And it has a very strange mind set, as quota accounting (unlike
enforcement) really is a propery of the on-disk format.  There is no good
use case for supporting this.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NCarlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

When we log an inode, we format the "log inode" core and set an LSN
in that inode core. We do that via xfs_inode_item_format_core(),
which calls:

	xfs_inode_to_log_dinode(ip, dic, ip->i_itemp->ili_item.li_lsn);

to format the log inode. It writes the LSN from the inode item into
the log inode, and if recovery decides the inode item needs to be
replayed, it recovers the log inode LSN field and writes it into the
on disk inode LSN field.

Now this might seem like a reasonable thing to do, but it is wrong
on multiple levels. Firstly, if the item is not yet in the AIL,
item->li_lsn is zero. i.e. the first time the inode it is logged and
formatted, the LSN we write into the log inode will be zero. If we
only log it once, recovery will run and can write this zero LSN into
the inode.

This means that the next time the inode is logged and log recovery
runs, it will *always* replay changes to the inode regardless of
whether the inode is newer on disk than the version in the log and
that violates the entire purpose of recording the LSN in the inode
at writeback time (i.e. to stop it going backwards in time on disk
during recovery).

Secondly, if we commit the CIL to the journal so the inode item
moves to the AIL, and then relog the inode, the LSN that gets
stamped into the log inode will be the LSN of the inode's current
location in the AIL, not it's age on disk. And it's not the LSN that
will be associated with the current change. That means when log
recovery replays this inode item, the LSN that ends up on disk is
the LSN for the previous changes in the log, not the current
changes being replayed. IOWs, after recovery the LSN on disk is not
in sync with the LSN of the modifications that were replayed into
the inode. This, again, violates the recovery ordering semantics
that on-disk writeback LSNs provide.

Hence the inode LSN in the log dinode is -always- invalid.

Thirdly, recovery actually has the LSN of the log transaction it is
replaying right at hand - it uses it to determine if it should
replay the inode by comparing it to the on-disk inode's LSN. But it
doesn't use that LSN to stamp the LSN into the inode which will be
written back when the transaction is fully replayed. It uses the one
in the log dinode, which we know is always going to be incorrect.

Looking back at the change history, the inode logging was broken by
commit 93f958f9 ("xfs: cull unnecessary icdinode fields") way
back in 2016 by a stupid idiot who thought he knew how this code
worked. i.e. me. That commit replaced an in memory di_lsn field that
was updated only at inode writeback time from the inode item.li_lsn
value - and hence always contained the same LSN that appeared in the
on-disk inode - with a read of the inode item LSN at inode format
time. CLearly these are not the same thing.

Before 93f958f9, the log recovery behaviour was irrelevant,
because the LSN in the log inode always matched the on-disk LSN at
the time the inode was logged, hence recovery of the transaction
would never make the on-disk LSN in the inode go backwards or get
out of sync.

A symptom of the problem is this, caught from a failure of
generic/482. Before log recovery, the inode has been allocated but
never used:

xfs_db> inode 393388
xfs_db> p
core.magic = 0x494e
core.mode = 0
....
v3.crc = 0x99126961 (correct)
v3.change_count = 0
v3.lsn = 0
v3.flags2 = 0
v3.cowextsize = 0
v3.crtime.sec = Thu Jan  1 10:00:00 1970
v3.crtime.nsec = 0

After log recovery:

xfs_db> p
core.magic = 0x494e
core.mode = 020444
....
v3.crc = 0x23e68f23 (correct)
v3.change_count = 2
v3.lsn = 0
v3.flags2 = 0
v3.cowextsize = 0
v3.crtime.sec = Thu Jul 22 17:03:03 2021
v3.crtime.nsec = 751000000
...

You can see that the LSN of the on-disk inode is 0, even though it
clearly has been written to disk. I point out this inode, because
the generic/482 failure occurred because several adjacent inodes in
this specific inode cluster were not replayed correctly and still
appeared to be zero on disk when all the other metadata (inobt,
finobt, directories, etc) indicated they should be allocated and
written back.

The fix for this is two-fold. The first is that we need to either
revert the LSN changes in 93f958f9 or stop logging the inode LSN
altogether. If we do the former, log recovery does not need to
change but we add 8 bytes of memory per inode to store what is
largely a write-only inode field. If we do the latter, log recovery
needs to stamp the on-disk inode in the same manner that inode
writeback does.

I prefer the latter, because we shouldn't really be trying to log
and replay changes to the on disk LSN as the on-disk value is the
canonical source of the on-disk version of the inode. It also
matches the way we recover buffer items - we create a buf_log_item
that carries the current recovery transaction LSN that gets stamped
into the buffer by the write verifier when it gets written back
when the transaction is fully recovered.

However, this might break log recovery on older kernels even more,
so I'm going to simply ignore the logged value in recovery and stamp
the on-disk inode with the LSN of the transaction being recovered
that will trigger writeback on transaction recovery completion. This
will ensure that the on-disk inode LSN always reflects the LSN of
the last change that was written to disk, regardless of whether it
comes from log recovery or runtime writeback.

Fixes: 93f958f9 ("xfs: cull unnecessary icdinode fields")
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

While auditing the realtime growfs code, I realized that the GROWFSRT
ioctl (and by extension xfs_growfs) has always allowed sysadmins to
change the realtime extent size when adding a realtime section to the
filesystem.  Since we also have always allowed sysadmins to set
RTINHERIT and EXTSZINHERIT on directories even if there is no realtime
device, this invalidates the premise laid out in the comments added in
commit 603f000b.

In other words, this is not a case of inadequate metadata validation.
This is a case of nearly forgotten (and apparently untested) but
supported functionality.  Update the comments to reflect what we've
learned, and remove the log message about correcting the misalignment.

Fixes: 603f000b ("xfs: validate extsz hints against rt extent size when rtinherit is set")
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NCarlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

While running xfs/168, I noticed occasional write verifier shutdowns
involving inodes at the very end of the filesystem.  Existing inode
btree validation code checks that all inode clusters are fully contained
within the filesystem.

However, due to inadequate checking in the fs shrink code, it's possible
that there could be a sparse inode cluster at the end of the filesystem
where the upper inodes of the cluster are marked as holes and the
corresponding blocks are free.  In this case, the last blocks in the AG
are listed in the bnobt.  This enables the shrink to proceed but results
in a filesystem that trips the inode verifiers.  Fix this by disallowing
the shrink.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NGao Xiang <hsiangkao@linux.alibaba.com>

In preparation to enable -Wimplicit-fallthrough for Clang, fix
the following warnings by replacing /* fallthrough */ comments,
and its variants, with the new pseudo-keyword macro fallthrough:

fs/xfs/libxfs/xfs_attr.c:487:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_attr.c:500:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_attr.c:532:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_attr.c:594:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_attr.c:607:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_attr.c:1410:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_attr.c:1445:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
fs/xfs/libxfs/xfs_attr.c:1473:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]

Notice that Clang doesn't recognize /* fallthrough */ comments as
implicit fall-through markings, so in order to globally enable
-Wimplicit-fallthrough for Clang, these comments need to be
replaced with fallthrough; in the whole codebase.

Link: https://github.com/KSPP/linux/issues/115Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>

A recent bug report generated a warning that a code path in
xfs_attr_remove_iter could potentially return error uninitialized in the
case of XFS_DAS_RM_SHRINK state.  Fix this by initializing error.
Signed-off-by: NAllison Henderson <allison.henderson@oracle.com>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NBill O'Donnell <bodonnel@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

The AGI buffer is in big-endian format, so we must convert the
endianness to CPU format to do any comparisons.

Fixes: 46141dc8 ("xfs: introduce xfs_ag_shrink_space()")
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NGao Xiang <hsiangkao@linux.alibaba.com>

In doing an investigation into AIL push stalls, I was looking at the
log force code to see if an async CIL push could be done instead.
This lead me to xfs_log_force_lsn() and looking at how it works.

xfs_log_force_lsn() is only called from inode synchronisation
contexts such as fsync(), and it takes the ip->i_itemp->ili_last_lsn
value as the LSN to sync the log to. This gets passed to
xlog_cil_force_lsn() via xfs_log_force_lsn() to flush the CIL to the
journal, and then used by xfs_log_force_lsn() to flush the iclogs to
the journal.

The problem is that ip->i_itemp->ili_last_lsn does not store a
log sequence number. What it stores is passed to it from the
->iop_committing method, which is called by xfs_log_commit_cil().
The value this passes to the iop_committing method is the CIL
context sequence number that the item was committed to.

As it turns out, xlog_cil_force_lsn() converts the sequence to an
actual commit LSN for the related context and returns that to
xfs_log_force_lsn(). xfs_log_force_lsn() overwrites it's "lsn"
variable that contained a sequence with an actual LSN and then uses
that to sync the iclogs.

This caused me some confusion for a while, even though I originally
wrote all this code a decade ago. ->iop_committing is only used by
a couple of log item types, and only inode items use the sequence
number it is passed.

Let's clean up the API, CIL structures and inode log item to call it
a sequence number, and make it clear that the high level code is
using CIL sequence numbers and not on-disk LSNs for integrity
synchronisation purposes.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NAllison Henderson <allison.henderson@oracle.com>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

We don't need to look at the xfs_mount and superblock every time we
need to do an iclog roundoff calculation. The property is fixed for
the life of the log, so store the roundoff in the log at mount time
and use that everywhere.

On a debug build:

$ size fs/xfs/xfs_log.o.*
   text	   data	    bss	    dec	    hex	filename
  27360	    560	      8	  27928	   6d18	fs/xfs/xfs_log.o.orig
  27219	    560	      8	  27787	   6c8b	fs/xfs/xfs_log.o.patched
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NAllison Henderson <allison.henderson@oracle.com>

Dan Carpenter's static checker reported:

The patch 7b13c515: "xfs: use perag for ialloc btree cursors"
from Jun 2, 2021, leads to the following Smatch complaint:

    fs/xfs/libxfs/xfs_ialloc.c:2403 xfs_imap()
    error: we previously assumed 'pag' could be null (see line 2294)

And it's right. Fix it.

Fixes: 7b13c515 ("xfs: use perag for ialloc btree cursors")
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NAllison Henderson <allison.henderson@oracle.com>

This patch renames the following functions to make the nameing scheme more consistent:
xfs_attr_shortform_remove -> xfs_attr_sf_removename
xfs_attr_node_remove_name -> xfs_attr_node_removename
xfs_attr_set_fmt -> xfs_attr_sf_addname
Suggested-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NAllison Henderson <allison.henderson@oracle.com>
Reviewed-by: NChandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

This ASSERT checks for the state value of RM_SHRINK in the set path
which should never happen.  Change to ASSERT(0);
Suggested-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NAllison Henderson <allison.henderson@oracle.com>
Reviewed-by: NChandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

From: Dave Chinner <dchinner@redhat.com>

Stephen Rothwell reported this compiler warning from linux-next:

fs/xfs/libxfs/xfs_ialloc.c: In function 'xfs_difree_finobt':
fs/xfs/libxfs/xfs_ialloc.c:2032:20: warning: unused variable 'agi' [-Wunused-variable]
 2032 |  struct xfs_agi   *agi = agbp->b_addr;

Which is fallout from agno -> perag conversions that were done in
this function. xfs_check_agi_freecount() is the only user of "agi"
in xfs_difree_finobt() now, and it only uses the agi to get the
current free inode count. We hold that in the perag structure, so
there's not need to directly reference the raw AGI to get this
information.

The btree cursor being passed to xfs_check_agi_freecount() has a
reference to the perag being operated on, so use that directly in
xfs_check_agi_freecount() rather than passing an AGI.

Fixes: 7b13c515 ("xfs: use perag for ialloc btree cursors")
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NCarlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

Radix tree tags are supposed to be unsigned ints, so fix the callers.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

xfs_bmap_set_attrforkoff is only used inside of xfs_bmap.c, so mark it
static.
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>

Variable busy is set to false, but this value is never read as it is
overwritten or not used later on, hence it is a redundant assignment
and can be removed.

Clean up the following clang-analyzer warning:

fs/xfs/libxfs/xfs_alloc.c:1679:2: warning: Value stored to 'busy' is
never read [clang-analyzer-deadcode.DeadStores].
Reported-by: NAbaci Robot <abaci@linux.alibaba.com>
Signed-off-by: NJiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

Variable 'xfs_agf_buf_ops', 'xfs_agi_buf_ops', 'xfs_dquot_buf_ops' and
'xfs_symlink_buf_ops' are declared twice, so sort these variables
alphabetically and remove the repeated declaration.

Cc: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: NShaokun Zhang <zhangshaokun@hisilicon.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>

Almost unused, gets rid of another typedef.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

Unlinked lists are held in the perag, and freeing of inodes needs to
be passed a perag, too, so look up the perag early in the unlink
processing and use it throughout.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

Because it's a mess.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

Now that we've internalised the two-phase inode allocation, we can
now easily make the AG selection and allocation atomic from the
perspective of a single perag context. This will ensure AGs going
offline/away cannot occur between the selection and allocation
steps.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

This is just a simple wrapper around the per-ag inode allocation
that doesn't need to exist. The internal mechanism to select and
allocate within an AG does not need to be exposed outside
xfs_ialloc.c, and it being exposed simply makes it harder to follow
the code and simplify it.

This is simplified by internalising xf_dialloc_select_ag() and
xfs_dialloc_ag() into a single xfs_dialloc() function and then
xfs_dir_ialloc() can go away.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

xfs_dialloc_select_ag() does a lot of repetitive work. It first
calls xfs_ialloc_ag_select() to select the AG to start allocation
attempts in, which can do up to two entire loops across the perags
that inodes can be allocated in. This is simply checking if there is
spce available to allocate inodes in an AG, and it returns when it
finds the first candidate AG.

xfs_dialloc_select_ag() then does it's own iterative walk across
all the perags locking the AGIs and trying to allocate inodes from
the locked AG. It also doesn't limit the search to mp->m_maxagi,
so it will walk all AGs whether they can allocate inodes or not.

Hence if we are really low on inodes, we could do almost 3 entire
walks across the whole perag range before we find an allocation
group we can allocate inodes in or report ENOSPC.

Because xfs_ialloc_ag_select() returns on the first candidate AG it
finds, we can simply do these checks directly in
xfs_dialloc_select_ag() before we lock and try to allocate inodes.
This reduces the inode allocation pass down to 2 perag sweeps at
most - one for aligned inode cluster allocation and if we can't
allocate full, aligned inode clusters anywhere we'll do another pass
trying to do sparse inode cluster allocation.

This also removes a big chunk of duplicate code.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

The only caller of xfs_dialloc_select_ag() will always return
-ENOSPC to it's caller if the agbp returned from
xfs_dialloc_select_ag() is NULL. IOWs, failure to find a candidate
AGI we can allocate inodes from is always an ENOSPC condition, so
move this logic up into xfs_dialloc_select_ag() so we can simplify
the return logic in this function.

xfs_dialloc_select_ag() now only ever returns 0 with a locked
agbp, or an error with no agbp.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

Now that everything passes a perag, the agno is not needed anymore.
Convert all the users to use pag->pag_agno instead and remove the
agno from the cursor. This was largely done as an automated search
and replace.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

Which will eventually completely replace the agno in it.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

Needs a [from, to] ranged AG walk, and the perag to be stuffed into
the info structure for callouts to use.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

We currently pass an agno from the AG reservation functions to the
individual feature accounting functions, which in future may have to
do perag lookups to access per-AG state. Instead, pre-emptively
plumb the perag through from the highest AG reservation layer to the
feature callouts so they won't have to look it up again.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

All of the callers of the busy extent API either have perag
references available to use so we can pass a perag to the busy
extent functions rather than having them have to do unnecessary
lookups.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

Clean up the last external manual AG walk.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

Rather than manually walking the ags and passing agnunbers around,
pass the perag for the AG we are currently working on around in the
iwalk structure.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

Convert the raw walks to an iterator, pulling the current AG out of
pag->pag_agno instead of the loop iterator variable.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <djwong@kernel.org>

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>

Move the xfs_perag infrastructure to the libxfs files that contain
all the per AG infrastructure. This helps set up for passing perags
around all the code instead of bare agnos with minimal extra
includes for existing files.
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>