Make the necessary alterations to the extended attribute log intent item
ondisk format so that we can log parent pointer operations.  This
requires the creation of new opcodes specific to parent pointers, and a
new four-argument replace operation to handle renames.  At this point
this part of the patchset has changed so much from what Allison original
wrote that I no longer think her SoB applies.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Move this feature check down to the per-op checks so that we can ensure
that we never see parent pointer attr items on non-pptr filesystems, and
that logged xattrs are turned on for non-pptr attr items.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

If a file is hardlinked with the same name but from multiple parents,
the parent pointers will all have the same dirent name (== attr name)
but with different parent_ino/parent_gen values.  To disambiguate, we
need to be able to match on both the attr name and the attr value.  This
is in contrast to regular xattrs, which are matchtg edit
d only on name.

Therefore, plumb in the ability to match shortform and local attrs on
name and value in the XFS_ATTR_PARENT namespace.  Parent pointer attr
values are never large enough to be stored in a remote attr, so we need
can reject these cases as corruption.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

We need to define the parent pointer attribute format before we start
adding support for it into all the code that needs to use it. The EA
format we will use encodes the following information:

        name={dirent name}
        value={parent inumber, parent inode generation}
        hash=xfs_dir2_hashname(dirent name) ^ (parent_inumber)

The inode/gen gives all the information we need to reliably identify the
parent without requiring child->parent lock ordering, and allows
userspace to do pathname component level reconstruction without the
kernel ever needing to verify the parent itself as part of ioctl calls.

By using the name-value lookup mode in the extended attribute code to
match parent pointers using both the xattr name and value, we can
identify the exact parent pointer EA we need to modify/remove in
rename/unlink operations without searching the entire EA space.

By storing the dirent name, we have enough information to be able to
validate and reconstruct damaged directory trees.  Earlier iterations of
this patchset encoded the directory offset in the parent pointer key,
but this format required repair to keep that in sync across directory
rebuilds, which is unnecessary complexity.
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Add the new parent attribute type. XFS_ATTR_PARENT is used only for parent pointer
entries; it uses reserved blocks like XFS_ATTR_ROOT.
Signed-off-by: Mark Tinguely <mark.tinguely@oracle.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Create a separate function to compute name hashvalues for extended
attributes.  When we get to parent pointers we'll be altering the rules
so that metadump obfuscation doesn't turn heinous.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Move the code that adds the incore xfs_attr_item deferred work data to a
transaction live with the ATTRI log item code.  This means that the
upper level extended attribute code no longer has to know about the
inner workings of the ATTRI log items.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Checking the flags match is much cheaper than a memcmp, so do it early
on in xfs_attr_match, and also add a little helper to calculate the
match mask right under the comment explaining the logic for it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

Rearrange the parameters to this function so that they match the order
of attr listent: attr_flags -> name -> namelen -> value -> valuelen.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Create a standardized helper function to enforce one namespace bit per
extended attribute, and refactor all the open-coded hweight logic.  This
function is not a static inline to avoid porting hassles in userspace.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Hoist the code that checks the attr name and value iovecs into separate
helpers so that we can add more callsites for the new parent pointer
attr intent items.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Move the name and length checks into the attr op switch statement so
that we can perform more specific checks of the value length.  Over the
next few patches we're going to add new attr op flags with different
validation requirements.

While we're at it, remove the incorrect comment.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

We're about to start using tagged unions in the xattr log format, so
create a bunch of local variables in the recovery function so we only
have to decode the log item fields once.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Always set args->value to the recovered value buffer.  This reduces the
amount of code in the switch statement, and hence the amount of thinking
that I have to do.  We validated the recovered buffers, supposedly.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Strengthen the xattri log item recovery code by checking that we
actually have the required name and newname buffers for whatever
operation we're replaying.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Create helper functions to extract the xattr op from the ondisk xattri
log item and the incore attr intent item.  These will get more use in
the patches that follow.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Eliminate the local variable from this function so that we can
streamline things a bit later when we add the PPTR_REPLACE op code.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

While reviewing flag checking in the attr scrub functions, we noticed
that the shortform attr scanner didn't catch entries that have the LOCAL
or INCOMPLETE bits set.  Neither of these flags can ever be set on a
shortform attr, so we need to check this narrower set of valid flags.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

The xattr scrubber doesn't check for undefined flags in shortform attr
entries.  Therefore, define a mask XFS_ATTR_ONDISK_MASK that has all
possible XFS_ATTR_* flags in it, and use that to check for unknown bits
in xchk_xattr_actor.

Refactor the check in the dabtree scanner function to use the new mask
as well.  The redundant checks need to be in place because the dabtree
check examines the hash mappings and therefore needs to decode the attr
leaf entries to compute the namehash.  This happens before the walk of
the xattr entries themselves.

Fixes: ae0506eb ("xfs: check used space of shortform xattr structures")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Check that the number of recovered log iovecs is what is expected for
the xattri opcode is expecting.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Per reviewer request, use an OPSTATE flag (+ helpers) to decide if
logged xattrs are enabled, instead of querying the xfs_sb.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

The XFS_SB_FEAT_INCOMPAT_LOG_XATTRS feature bit protects a filesystem
from old kernels that do not know how to recover extended attribute log
intent items.  Make this check mandatory instead of a debugging assert.

Fixes: fd920008 ("xfs: Set up infrastructure for log attribute replay")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Christoph noticed that the xfs_attr_is_leaf in xfs_attr_get_ilocked can
access the incore extent tree of the attr fork, but nothing in the
xfs_attr_get path guarantees that the incore tree is actually loaded.

Most of the time it is, but seeing as xfs_attr_is_leaf ignores the
return value of xfs_iext_get_extent I guess we've been making choices
based on random stack contents and nobody's complained?
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

A few notes about struct xfs_da_args:

The XFS_ATTR_* flags only go up as far as XFS_ATTR_INCOMPLETE, which
means that attr_filter could be a u8 field.

I've reduced the number of XFS_DA_OP_* flags down to the point where
op_flags would also fit into a u8.

filetype has 7 bytes of slack after it, which is wasteful.

namelen will never be greater than MAXNAMELEN, which is 256.  This field
could be reduced to a short.

Rearrange the fields in xfs_da_args to waste less space.  This reduces
the structure size from 136 bytes to 128.  Later when we add extra
fields to support parent pointer replacement, this will only bloat the
structure to 144 bytes, instead of 168.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Parent pointers match attrs on name+value, unlike everything else which
matches on only the name.  Therefore, we cannot keep using the heuristic
that !value means remove.  Make this an explicit operation code.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

This field only ever contains XATTR_{CREATE,REPLACE}, and it only goes
as deep as xfs_attr_set.  Remove the field from the structure and
replace it with an enum specifying exactly what kind of change we want
to make to the xattr structure.  Upsert is the name that we'll give to
the flags==0 operation, because we're either updating an existing value
or inserting it, and the caller doesn't care.

Note: The "UPSERTR" name created here is to make userspace porting
easier.  It will be removed in the next patch.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

The only user of this flag sets it prior to an xfs_attr_get_ilocked
call, which doesn't update anything.  Get rid of the flag.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Nobody checks this flag, so get rid of it.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Commit aff3a9ed ("xfs: Use preallocation for inodes with extsz
hints") disabled delayed allocation for all inodes with extent size
hints due a data exposure problem.  It turns out we fixed this data
exposure problem since by always creating unwritten extents for
delalloc conversions due to more data exposure problems, but the
writeback path doesn't actually support extent size hints when
converting delalloc these days, which probably isn't a problem given
that people using the hints know what they get.

However due to the way how xfs_get_extsz_hint is implemented, it
always claims an extent size hint for RT inodes even if the RT
extent size is a single FSB.  Due to that the above commit effectively
disabled delalloc support for RT inodes.

Switch xfs_get_extsz_hint to return 0 for this case and work around
that in a few places to reinstate delalloc support for RT inodes on
file systems with an sb_rextsize of 1.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

When xfs_bmap_del_extent_delay has to split an indirect block it tries
to steal blocks from the the part that gets unmapped to increase the
indirect block reservation that now needs to cover for two extents
instead of one.

This works perfectly fine on the data device, where the data and
indirect blocks come from the same pool.  It has no chance of working
when the inode sits on the RT device.  To support re-enabling delalloc
for inodes on the RT device, make this behavior conditional on not
being for rt extents.

Note that split of delalloc extents should only happen on writeback
failure, as for other kinds of hole punching we first write back all
data and thus convert the delalloc reservations covering the hole to
a real allocation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

Move the check if we have enough indirect blocks and the stealing of
the deleted extent blocks out of xfs_bmap_split_indlen and into the
caller to prepare for handling delayed allocation of RT extents that
can't easily be stolen.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

Add a check for files on the RT subvolume and use m_frextents instead
of m_fdblocks to adjust the preallocation size.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

To prepare for re-enabling delalloc on RT devices, track the data blocks
(which use the RT device when the inode sits on it) and the indirect
blocks (which don't) separately to xfs_mod_delalloc, and add a new
percpu counter to also track the RT delalloc blocks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

The code to account fdblocks and frextents in xfs_bmap_del_extent_delay
is a bit weird in that it accounts frextents before the iext tree
manipulations and fdblocks after it.  Given that the iext tree
manipulations cannot fail currently that's not really a problem, but
still odd.  Move the frextent manipulation to the end, and use a
fdblocks variable to account of the unconditional indirect blocks and
the data blocks only freed for !RT.  This prepares for following
updates in the area and already makes the code more readable.

Also remove the !isrt assert given that this code clearly handles
rt extents correctly, and we'll soon reinstate delalloc support for
RT inodes.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

Allocate data blocks for RT inodes using xfs_dec_frextents.  While at
it optimize the data device case by doing only a single xfs_dec_fdblocks
call for the extent itself and the indirect blocks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

xfs_mod_freecounter has two entirely separate code paths for adding or
subtracting from the free counters.  Only the subtract case looks at the
rsvd flag and can return an error.

Split xfs_mod_freecounter into separate helpers for subtracting or
adding the freecounter, and remove all the impossible to reach error
handling for the addition case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

And to make that more clear, rearrange the code a bit and add asserts
and a comment.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

__xfs_bunmapi is a bit of an odd place to lock the rtbitmap and rtsummary
inodes given that it is very high level code.  While this only looks ugly
right now, it will become a problem when supporting delayed allocations
for RT inodes as __xfs_bunmapi might end up deleting only delalloc extents
and thus never unlock the rt inodes.

Move the locking into xfs_bmap_del_extent_real just before the call to
xfs_rtfree_blocks instead and use a new flag in the transaction to ensure
that the locking happens only once.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

Currently xfs_bmap_del_extent_real frees RT extents before updating
the bmap btree, while it frees regular blocks after performing the bmap
btree update for convoluted historic reasons.  Switch to free the RT
blocks in the same place as the regular data blocks instead to simply
the code and fix a very theoretical bug.

A short history of this code researched by Dave Chiner below:

The truncate for data device extents was originally a two-phase
operation. First it removed the bmapbt record, but because this can
free BMBT extents, it can use up all the free space tree reservation
space. So the transaction gets rolled to commit the BMBT change and
the xfs_bmap_finish() call that frees the data extent runs with a
new transaction reservation that allows different free space btrees
to be logged without overrun.

However, on crash, this could lose the free space because there was
nothing to tell recovery about the extents removed from the BMBT,
hence EFIs were introduced. They tie the extent free operation to the
bmapbt record removal commit for recovery of the second phase of the
extent removal process.

Then RT extents came along. RT extent freeing does not require a
free space btree reservation because the free space metadata is
static and transaction size is bound. Hence we don't need to care if
the BMBT record removal modifies the per-ag free space trees and we
don't need a two-phase extent remove transaction. The only thing we
have to care about is not losing space on crash.

Hence instead of recording the extent for freeing in the bmap list
for xfs_bmap_finish() to process in a new transaction, it simply
freed the rtextent directly. So the original code (from 1994) simply
replaced the "free AG extent later" queueing with a direct free.

This code was originally at the start of xfs_dmap_del_extent(), but
the xfs_bmap_add_free() got moved to the end of the function via the
"do_fx" flag (the current code logic) in 1997 (commit c4fac74eaa58
in the historic xfs-import tree) because there was a shutdown occurring
because of a case where splitting the extent record failed because the
BMBT split and the filesystem didn't have enough space for the split to
be done. (FWIW, I'm not sure this can happen anymore.)

The commit backed out the BMBT change on ENOSPC error, and in doing
so I think this actually breaks RT free space tracking. However, it
then returns an ENOSPC error, and we have a dirty transaction in the
RT case so this will shut down the filesysetm when the transaction
is cancelled. Hence the corrupted "bmbt now points at freed rt dev
space" condition never make it to disk, but it's still the wrong way
to handle the issue.

IOWs, this proposed change fixes that "shutdown at ENOSPC on rt
devices" situation that was introduced by the above commit back in
1997.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

Create helper functions to deal with locking realtime metadata inodes.
This enables us to maintain correct locking order once we start adding
the realtime rmap and refcount btree inodes.
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>