We can't use the same algorithm for replacing an existing attribute
when logging attributes. The existing algorithm is essentially:

1. create new attr w/ INCOMPLETE
2. atomically flip INCOMPLETE flags between old + new attribute
3. remove old attr which is marked w/ INCOMPLETE

This algorithm guarantees that we see either the old or new
attribute, and if we fail after the atomic flag flip, we don't have
to recover the removal of the old attr because we never see
INCOMPLETE attributes in lookups.

For logged attributes, however, this does not work. The logged
attribute intents do not track the work that has been done as the
transaction rolls, and hence the only recovery mechanism we have is
"run the replace operation from scratch".

This is further exacerbated by the attempt to avoid needing the
INCOMPLETE flag to create an atomic swap. This means we can create
a second active attribute of the same name before we remove the
original. If we fail at any point after the create but before the
removal has completed, we end up with duplicate attributes in
the attr btree and recovery only tries to replace one of them.

There are several other failure modes where we can leave partially
allocated remote attributes that expose stale data, partially free
remote attributes that enable UAF based stale data exposure, etc.

TO fix this, we need a different algorithm for replace operations
when LARP is enabled. Luckily, it's not that complex if we take the
right first step. That is, the first thing we log is the attri
intent with the new name/value pair and mark the old attr as
INCOMPLETE in the same transaction.

From there, we then remove the old attr and keep relogging the
new name/value in the intent, such that we always know that we have
to create the new attr in recovery. Once the old attr is removed,
we then run a normal ATTR_CREATE operation relogging the intent as
we go. If the new attr is local, then it gets created in a single
atomic transaction that also logs the final intent done. If the new
attr is remote, the we set INCOMPLETE on the new attr while we
allocate and set the remote value, and then we clear the INCOMPLETE
flag at in the last transaction taht logs the final intent done.

If we fail at any point in this algorithm, log recovery will always
see the same state on disk: the new name/value in the intent, and
either an INCOMPLETE attr or no attr in the attr btree. If we find
an INCOMPLETE attr, we run the full replace starting with removing
the INCOMPLETE attr. If we don't find it, then we simply create the
new attr.

Notably, recovery of a failed create that has an INCOMPLETE flag set
is now the same - we start with the lookup of the INCOMPLETE attr,
and if that exists then we do the full replace recovery process,
otherwise we just create the new attr.

Hence changing the way we do the replace operation when LARP is
enabled allows us to use the same log recovery algorithm for both
the ATTR_CREATE and ATTR_REPLACE operations. This is also the same
algorithm we use for runtime ATTR_REPLACE operations (except for the
step setting up the initial conditions).

The result is that:

- ATTR_CREATE uses the same algorithm regardless of whether LARP is
  enabled or not
- ATTR_REPLACE with larp=0 is identical to the old algorithm
- ATTR_REPLACE with larp=1 runs an unmodified attr removal algorithm
  from the larp=0 code and then runs the unmodified ATTR_CREATE
  code.
- log recovery when larp=1 runs the same ATTR_REPLACE algorithm as
  it uses at runtime.

Because the state machine is now quite clean, changing the algorithm
is really just a case of changing the initial state and how the
states link together for the ATTR_REPLACE case. Hence it's not a
huge amount of code for what is a fairly substantial rework
of the attr logging and recovery algorithm....
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

We currently store the high level attr operation in
args->attr_flags. This field contains what the VFS is telling us to
do, but don't necessarily match what we are doing in the low level
modification state machine. e.g. XATTR_REPLACE implies both
XFS_DA_OP_ADDNAME and XFS_DA_OP_RENAME because it is doing both a
remove and adding a new attr.

However, deep in the individual state machine operations, we check
errors against this high level VFS op flags, not the low level
XFS_DA_OP flags. Indeed, we don't even have a low level flag for
a REMOVE operation, so the only way we know we are doing a remove
is the complete absence of XATTR_REPLACE, XATTR_CREATE,
XFS_DA_OP_ADDNAME and XFS_DA_OP_RENAME. And because there are other
flags in these fields, this is a pain to check if we need to.

As the XFS_DA_OP flags are only needed once the deferred operations
are set up, set these flags appropriately when we set the initial
operation state. We also introduce a XFS_DA_OP_REMOVE flag to make
it easy to know that we are doing a remove operation.

With these, we can remove the use of XATTR_REPLACE and XATTR_CREATE
in low level lookup operations, and manipulate the low level flags
according to the low level context that is operating. e.g. log
recovery does not have a VFS xattr operation state to copy into
args->attr_flags, and the low level state machine ops we do for
recovery do not match the high level VFS operations that were in
progress when the system failed...
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs_attri_remove_iter is not used anymore, so remove it and all the
infrastructure it uses and is needed to drive it. THe
xfs_attr_refillstate() function now throws an unused warning, so
isolate the xfs_attr_fillstate()/xfs_attr_refillstate() code pair
with an #if 0 and a comment explaining why we want to keep this code
and restore the optimisation it provides in the near future.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Now that xfs_attri_set_iter() has initial states for removing
attributes, switch the pure attribute removal code over to using it.
This requires attrs being removed to always be marked as INCOMPLETE
before we start the removal due to the fact we look up the attr to
remove again in xfs_attr_node_remove_attr().

Note: this drops the fillstate/refillstate optimisations from
the remove path that avoid having to look up the path again after
setting the incomplete flag and removing remote attrs. Restoring
that optimisation to this path is future Dave's problem.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

We need to merge the add and remove code paths to enable safe
recovery of replace operations. Hoist the initial remove states from
xfs_attr_remove_iter into xfs_attr_set_iter. We will make use of
them in the next patches.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Now that the full xfs_attr_set_iter() state machine always
terminates with either the state being XFS_DAS_DONE on success or
an error on failure, we can get rid of the need for it to return
-EAGAIN whenever it needs to roll the transaction before running
the next state.

That is, we don't need to spray -EAGAIN return states everywhere,
the caller just check the state machine state for completion to
determine what action should be taken next. This greatly simplifies
the code within the state machine implementation as it now only has
to handle 0 for success or -errno for error and it doesn't need to
tell the caller to retry.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Clean up the final leaf/node states in xfs_attr_set_iter() to
further simplify the high level state machine and to set the
completion state correctly. As we are adding a separate state
for node format removal, we need to ensure that node formats
are collapsed back to shortform or empty correctly.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

We may not have a remote value for the old xattr we have to remove,
so skip over the remote value removal states and go straight to
the xattr name removal in the leaf/node block.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

We can skip the REPLACE state when LARP is enabled, but that means
the XFS_DAS_FLIP_LFLAG state is now poorly named - it indicates
something that has been done rather than what the state is going to
do. Rename it to "REMOVE_OLD" to indicate that we are now going to
perform removal of the old attr.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

When we set a new xattr, we have three exit paths:

	1. nothing else to do
	2. allocate and set the remote xattr value
	3. perform the rest of a replace operation

Currently we push both 2 and 3 into the same state, regardless of
whether we just set a remote attribute or not. Once we've set the
remote xattr, we have two exit states:

	1. nothing else to do
	2. perform the rest of a replace operation

Hence we can split the remote xattr allocation and setting into
their own states and factor it out of xfs_attr_set_iter() to further
clean up the state machine and the implementation of the state
machine.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

The operations performed from XFS_DAS_FOUND_LBLK through to
XFS_DAS_RM_LBLK are now identical to XFS_DAS_FOUND_NBLK through to
XFS_DAS_RM_NBLK. We can collapse these down into a single set of
code.

To do this, define the states that leaf and node run through as
separate sets of sequential states. Then as we move to the next
state, we can use increments rather than specific state assignments
to move through the states. This means the state progression is set
by the initial state that enters the series and we don't need to
duplicate the code anymore.

At the exit point of the series we need to select the correct leaf
or node state, but that can also be done by state increment rather
than assignment.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

We re-enter the XFS_DAS_FOUND_LBLK state when we have to allocate
multiple extents for a remote xattr. We currently have a flag
called XFS_DAC_LEAF_ADDNAME_INIT to avoid running the remote attr
hole finding code more than once.

However, for the node format tree, we have a separate state for this
so we never reenter the state machine at XFS_DAS_FOUND_NBLK and so
it does not need a special flag to skip over the remote attr hold
finding code.

Convert the leaf block code to use the same state machine as the
node blocks and kill the  XFS_DAC_LEAF_ADDNAME_INIT flag.

This further points out that this "ALLOC" state is only traversed
if we have remote xattrs or we are doing a rename operation. Rename
both the leaf and node alloc states to _ALLOC_RMT to indicate they
are iterating to do allocation of remote xattr blocks.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

We current use XFS_DAS_UNINIT for several steps in the attr_set
state machine. We use it for setting shortform xattrs, converting
from shortform to leaf, leaf add, leaf-to-node and leaf add. All of
these things are essentially known before we start the state machine
iterating, so we really should separate them out:

XFS_DAS_SF_ADD:
	- tries to do a shortform add
	- on success -> done
	- on ENOSPC converts to leaf, -> XFS_DAS_LEAF_ADD
	- on error, dies.

XFS_DAS_LEAF_ADD:
	- tries to do leaf add
	- on success:
		- inline attr -> done
		- remote xattr || REPLACE -> XFS_DAS_FOUND_LBLK
	- on ENOSPC converts to node, -> XFS_DAS_NODE_ADD
	- on error, dies

XFS_DAS_NODE_ADD:
	- tries to do node add
	- on success:
		- inline attr -> done
		- remote xattr || REPLACE -> XFS_DAS_FOUND_NBLK
	- on error, dies

This makes it easier to understand how the state machine starts
up and sets us up on the path to further state machine
simplifications.

This also converts the DAS state tracepoints to use strings rather
than numbers, as converting between enums and numbers requires
manual counting rather than just reading the name.

This also introduces a XFS_DAS_DONE state so that we can trace
successful operation completions easily.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Logged attribute intents only have set and remove types - there is
no separate intent type for a replace operation. We should have a
separate type for a replace operation, as it needs to perform
operations that neither SET or REMOVE can perform.

Add this type to the intent items and rearrange the deferred
operation setup to reflect the different operations we are
performing.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

We currently set it and hold it when converting from short to leaf
form, then release it only to immediately look it back up again
to do the leaf insert.

Do a bit of refactoring to xfs_attr_leaf_try_add() to avoid this
messy handling of the newly allocated leaf buffer.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

On the first allocation of a attrd item, xfs_trans_add_item() fires
an assert like so:

 XFS (pmem0): EXPERIMENTAL logged extended attributes feature added. Use at your own risk!
 XFS: Assertion failed: !test_bit(XFS_LI_DIRTY, &lip->li_flags), file: fs/xfs/xfs_trans.c, line: 683
 ------------[ cut here ]------------
 kernel BUG at fs/xfs/xfs_message.c:102!
 Call Trace:
  <TASK>
  xfs_trans_add_item+0x17e/0x190
  xfs_trans_get_attrd+0x67/0x90
  xfs_attr_create_done+0x13/0x20
  xfs_defer_finish_noroll+0x100/0x690
  __xfs_trans_commit+0x144/0x330
  xfs_trans_commit+0x10/0x20
  xfs_attr_set+0x3e2/0x4c0
  xfs_initxattrs+0xaa/0xe0
  security_inode_init_security+0xb0/0x130
  xfs_init_security+0x18/0x20
  xfs_generic_create+0x13a/0x340
  xfs_vn_create+0x17/0x20
  path_openat+0xff3/0x12f0
  do_filp_open+0xb2/0x150

The attrd log item is allocated via kmem_cache_alloc, and
xfs_log_item_init() does not zero the entire log item structure - it
assumes that the structure is already all zeros as it only
initialises non-zero fields. Fix the attr items to be allocated
via the *zalloc methods.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

generic/642 triggered a reproducable assert failure in
xlog_cil_commit() that resulted from a xfs_attr_set() committing
an empty but dirty transaction. When the CIL is empty and this
occurs, xlog_cil_commit() tries a background push and this triggers
a "pushing an empty CIL" assert.

XFS: Assertion failed: !list_empty(&cil->xc_cil), file: fs/xfs/xfs_log_cil.c, line: 1274
Call Trace:
 <TASK>
 xlog_cil_commit+0xa5a/0xad0
 __xfs_trans_commit+0xb8/0x330
 xfs_trans_commit+0x10/0x20
 xfs_attr_set+0x3e2/0x4c0
 xfs_xattr_set+0x8d/0xe0
 __vfs_setxattr+0x6b/0x90
 __vfs_setxattr_noperm+0x76/0x220
 __vfs_setxattr_locked+0xdf/0x100
 vfs_setxattr+0x94/0x170
 setxattr+0x110/0x200
 path_setxattr+0xbf/0xe0
 __x64_sys_setxattr+0x2b/0x30
 do_syscall_64+0x35/0x80

The problem is related to the breakdown of attribute addition in
xfs_attr_set_iter() and how it is called from deferred operations.
When we have a pure leaf xattr insert, we add the xattr to the leaf
and set the next state to XFS_DAS_FOUND_LBLK and return -EAGAIN.
This requeues the xattr defered work, rolls the transaction and
runs xfs_attr_set_iter() again. This then checks the xattr for
being remote (it's not) and whether a replace op is being done (this
is a create op) and if neither are true it returns without having
done anything.

xfs_xattri_finish_update() then unconditionally sets the transaction
dirty, and the deferops finishes and returns to __xfs_trans_commit()
which sees the transaction dirty and tries to commit it by calling
xlog_cil_commit(). The transaction is empty, and then the assert
fires if this happens when the CIL is empty.

This patch addresses the structure of xfs_attr_set_iter() that
requires re-entry on leaf add even when nothing will be done. This
gets rid of the trailing empty transaction and so doesn't trigger
the XFS_TRANS_DIRTY assignment in xfs_xattri_finish_update()
incorrectly. Addressing that is for a different patch.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Add an error tag on xfs_attr3_leaf_to_node to test log attribute
recovery and replay.
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Add an error tag on xfs_da3_split to test log attribute recovery
and replay.
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Quick helper function to collapse duplicate code to initialize
transactions for attributes
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Suggested-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

This patch adds a helper function xfs_attr_leaf_addname.  While this
does help to break down xfs_attr_set_iter, it does also hoist out some
of the state management.  This patch has been moved to the end of the
clean up series for further discussion.
Suggested-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

This is a clean up patch that merges xfs_delattr_context into
xfs_attr_item.  Now that the refactoring is complete and the delayed
operation infrastructure is in place, we can combine these to eliminate
the extra struct
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

This patch adds a debug option to enable log attribute replay. Eventually
this can be removed when delayed attrs becomes permanent.
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

This patch adds an error tag that we can use to test log attribute
recovery and replay
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Remove xfs_attr_set_args, xfs_attr_remove_args, and xfs_attr_trans_roll.
These high level loops are now driven by the delayed operations code,
and can be removed.

Additionally collapse in the leaf_bp parameter of xfs_attr_set_iter
since we only have one caller that passes dac->leaf_bp
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

These routines set up and queue a new deferred attribute operations.
These functions are meant to be called by any routine needing to
initiate a deferred attribute operation as opposed to the existing
inline operations. New helper function xfs_attr_item_init also added.

Finally enable delayed attributes in xfs_attr_set and xfs_attr_remove.
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

This is a clean up patch that skips the flip flag logic for delayed attr
renames.  Since the log replay keeps the inode locked, we do not need to
worry about race windows with attr lookups.  So we can skip over
flipping the flag and the extra transaction roll for it
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

This patch adds the needed routines to create, log and recover logged
extended attribute intents.
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Currently attributes are modified directly across one or more
transactions. But they are not logged or replayed in the event of an
error. The goal of log attr replay is to enable logging and replaying
of attribute operations using the existing delayed operations
infrastructure.  This will later enable the attributes to become part of
larger multi part operations that also must first be recorded to the
log.  This is mostly of interest in the scheme of parent pointers which
would need to maintain an attribute containing parent inode information
any time an inode is moved, created, or removed.  Parent pointers would
then be of interest to any feature that would need to quickly derive an
inode path from the mount point. Online scrub, nfs lookups and fs grow
or shrink operations are all features that could take advantage of this.

This patch adds two new log item types for setting or removing
attributes as deferred operations.  The xfs_attri_log_item will log an
intent to set or remove an attribute.  The corresponding
xfs_attrd_log_item holds a reference to the xfs_attri_log_item and is
freed once the transaction is done.  Both log items use a generic
xfs_attr_log_format structure that contains the attribute name, value,
flags, inode, and an op_flag that indicates if the operations is a set
or remove.

[dchinner: added extra little bits needed for intent whiteouts]
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

During an attr rename operation, blocks are saved for later removal
as rmtblkno2. The rmtblkno is used in the case of needing to alloc
more blocks if not enough were available.  However, in the case
that no further blocks need to be added or removed, we can return as soon
as xfs_attr_node_addname completes, rather than rolling the transaction
with an -EAGAIN return.  This extra loop does not hurt anything right
now, but it will be a problem later when we get into log items because
we end up with an empty log transaction.  So, add a simple check to
cut out the unneeded iteration.
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

The new deferred attr patch set uncovered a double unlock in the
recent port of the defer ops capture and continue code.  During log
recovery, we're allowed to hold buffers to a transaction that's being
used to replay an intent item.  When we capture the resources as part
of scheduling a continuation of an intent chain, we call xfs_buf_hold
to retain our reference to the buffer beyond the transaction commit,
but we do /not/ call xfs_trans_bhold to maintain the buffer lock.
This means that xfs_defer_ops_continue needs to relock the buffers
before xfs_defer_restore_resources joins then tothe new transaction.

Additionally, the buffers should not be passed back via the dres
structure since they need to remain locked unlike the inodes.  So
simply set dr_bufs to zero after populating the dres structure.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Merge tag 'reflink-speedups-5.19_2022-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-5.19-for-next

xfs: fix reflink inefficiencies

As Dave Chinner has complained about on IRC, there are a couple of
things about reflink that are very inefficient.  First of all, we
limited the size of all bunmapi operations to avoid flooding the log
with defer ops in the worst case, but recent changes to the defer
ops code have solved that problem, so get rid of the bunmapi length
clamp.

Second, the log reservations for reflink operations are far far
larger than they need to be.  Shrink them to exactly what we need to
handle each deferred RUI and CUI log item, and no more.  Also reduce
logcount because we don't need 8 rolls per operation.  Introduce a
transaction reservation compatibility layer to avoid changing the
minimum log size calculations.
Signed-off-by: Dave Chinner <david@fromorbit.com>

Merge tag 'rmap-speedups-5.19_2022-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-5.19-for-next

xfs: fix rmap inefficiencies

Reduce the performance impact of the reverse mapping btree when
reflink is enabled by using the much faster non-overlapped btree
lookup functions when we're searching the rmap index with a fully
specified key.  If we find the exact record we're looking for,
great!  We don't have to perform the full overlapped scan.  For
filesystems with high sharing factors this reduces the xfs_scrub
runtime by a good 15%%.

This has been shown to reduce the fstests runtime for realtime rmap
configurations by 30%%, since the lack of AGs severely limits
scalability.
Signed-off-by: Dave Chinner <david@fromorbit.com>

We don't check that the v4 feature flags taht v5 requires to be set
are actually set anywhere. Do this check when we see that the
filesystem is a v5 filesystem.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

While xfs_has_nlink() is not used in kernel, it is used in userspace
(e.g. by xfs_db) so we need to set the XFS_FEAT_NLINK flag correctly
in xfs_sb_version_to_features().
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs_repair catches fork size/format mismatches, but the in-kernel
verifier doesn't, leading to null pointer failures when attempting
to perform operations on the fork. This can occur in the
xfs_dir_is_empty() where the in-memory fork format does not match
the size and so the fork data pointer is accessed incorrectly.

Note: this causes new failures in xfs/348 which is testing mode vs
ftype mismatches. We now detect a regular file that has been changed
to a directory or symlink mode as being corrupt because the data
fork is for a symlink or directory should be in local form when
there are only 3 bytes of data in the data fork. Hence the inode
verify for the regular file now fires w/ -EFSCORRUPTED because
the inode fork format does not match the format the corrupted mode
says it should be in.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

To catch the obvious graph cycle problem and hence potential endless
looping.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>