Add a tracepoint in xfs_zero_eof() to facilitate tracking and debugging
EOF zeroing events. This has proven useful in the context of other
direct I/O tracepoints to ensure EOF zeroing occurs within appropriate
file ranges.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

Use DAX to provide support for huge pages.
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Various log items have recovery tracepoints to identify whether a
particular log item is recovered or cancelled. Add the equivalent
tracepoints for the icreate transaction.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Chinner <david@fromorbit.com>

xfs_ialloc_ag_alloc() makes several attempts to allocate a full inode
chunk. If all else fails, reduce the allocation to the sparse length and
alignment and attempt to allocate a sparse inode chunk.

If sparse chunk allocation succeeds, check whether an inobt record
already exists that can track the chunk. If so, inherit and update the
existing record. Otherwise, insert a new record for the sparse chunk.

Create helpers to align sparse chunk inode records and insert or update
existing records in the inode btrees. The xfs_inobt_insert_sprec()
helper implements the merge or update semantics required for sparse
inode records with respect to both the inobt and finobt. To update the
inobt, either insert a new record or merge with an existing record. To
update the finobt, use the updated inobt record to either insert or
replace an existing record.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

DIO writes that lie entirely within EOF have nothing to do in IO
completion. In this case, we don't need no steekin' ioend, and so we
can avoid allocating an ioend until we have a mapping that spans
EOF.

This means that IO completion has two contexts - deferred completion
to the dio workqueue that uses an ioend, and interrupt completion
that does nothing because there is nothing that can be done in this
context.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

Currently a DIO overwrite that extends the EOF (e.g sub-block IO or
write into allocated blocks beyond EOF) requires a transaction for
the EOF update. Thi is done in IO completion context, but we aren't
explicitly handling this situation properly and so it can run in
interrupt context. Ensure that we defer IO that spans EOF correctly
to the DIO completion workqueue, and now that we have an ioend in IO
completion we can use the common ioend completion path to do all the
work.

Note: we do not preallocate the append transaction as we can have
multiple mapping and allocation calls per direct IO. hence
preallocating can still leave us with nested transactions by
attempting to map and allocate more blocks after we've preallocated
an append transaction.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

Currently we can only tell DIO completion that an IO requires
unwritten extent completion. This is done by a hacky non-null
private pointer passed to Io completion, but the private pointer
does not actually contain any information that is used.

We also need to pass to IO completion the fact that the IO may be
beyond EOF and so a size update transaction needs to be done. This
is currently determined by checks in the io completion, but we need
to determine if this is necessary at block mapping time as we need
to defer the size update transactions to a completion workqueue,
just like unwritten extent conversion.

To do this, first we need to allocate and pass an ioend to to IO
completion. Add this for unwritten extent conversion; we'll do the
EOF updates in the next commit.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

This patch implements fallocate's FALLOC_FL_INSERT_RANGE for XFS.

1) Make sure that both offset and len are block size aligned.
2) Update the i_size of inode by len bytes.
3) Compute the file's logical block number against offset. If the computed
   block number is not the starting block of the extent, split the extent
   such that the block number is the starting block of the extent.
4) Shift all the extents which are lying bewteen [offset, last allocated extent]
   towards right by len bytes. This step will make a hole of len bytes
   at offset.
Signed-off-by: NNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: NAshish Sangwan <a.sangwan@samsung.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

Use %pS for actual addresses, otherwise you'll get bad output
on arches like ppc64 where %pF expects a function descriptor.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

Take the i_mmaplock over write page faults. These come through the
->page_mkwrite callout, so we need to wrap that calls with the
i_mmaplock.

This gives us a lock order of mmap_sem -> i_mmaplock -> page_lock
-> i_lock.

Also, move the page_mkwrite wrapper to the same region of xfs_file.c
as the read fault wrappers and add a tracepoint.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

Take the i_mmaplock over read page faults. These come through the
->fault callout, so we need to wrap the generic implementation
with the i_mmaplock. While there, add tracepoints for the read
fault as it passes through XFS.

This gives us a lock order of mmap_sem -> i_mmaplock -> page_lock
-> i_lock.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

There is a lot of cookie-cutter code that looks like:

	if (shutdown)
		handle buffer error
	xfs_buf_iorequest(bp)
	error = xfs_buf_iowait(bp)
	if (error)
		handle buffer error

spread through XFS. There's significant complexity now in
xfs_buf_iorequest() to specifically handle this sort of synchronous
IO pattern, but there's all sorts of nasty surprises in different
error handling code dependent on who owns the buffer references and
the locks.

Pull this pattern into a single helper, where we can hide all the
synchronous IO warts and hence make the error handling for all the
callers much saner. This removes the need for a special extra
reference to protect IO completion processing, as we can now hold a
single reference across dispatch and waiting, simplifying the sync
IO smeantics and error handling.

In doing this, also rename xfs_buf_iorequest to xfs_buf_submit and
make it explicitly handle on asynchronous IO. This forces all users
to be switched specifically to one interface or the other and
removes any ambiguity between how the interfaces are to be used. It
also means that xfs_buf_iowait() goes away.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Chinner <david@fromorbit.com>

iter_file_splice_write() - a ->splice_write() instance that gathers the
pipe buffers, builds a bio_vec-based iov_iter covering those and feeds
it to ->write_iter().  A bunch of simple cases coverted to that...

[AV: fixed the braino spotted by Cyrill]
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

When we are zeroing space andit is covered by a delalloc range, we
need to punch the delalloc range out before we truncate the page
cache. Failing to do so leaves and inconsistency between the page
cache and the extent tree, which we later trip over when doing
direct IO over the same range.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Tested-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Chinner <david@fromorbit.com>

This patch implements fallocate's FALLOC_FL_COLLAPSE_RANGE for XFS.

The semantics of this flag are following:
1) It collapses the range lying between offset and length by removing any data
   blocks which are present in this range and than updates all the logical
   offsets of extents beyond "offset + len" to nullify the hole created by
   removing blocks. In short, it does not leave a hole.
2) It should be used exclusively. No other fallocate flag in combination.
3) Offset and length supplied to fallocate should be fs block size aligned
   in case of xfs and ext4.
4) Collaspe range does not work beyond i_size.
Signed-off-by: NNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: NAshish Sangwan <a.sangwan@samsung.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

To help track down AGI/AGF lock ordering issues, I added these
tracepoints to tell us when an AGI or AGF is read and locked.  With
these we can now determine if the lock ordering goes wrong from
tracing captures.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBen Myers <bpm@sgi.com>

I debugging a log tail issue on a RHEL6 kernel, I added these trace
points to trace log items being added, moved and removed in the AIL
and how that affected the log tail LSN that was written to the log.
They were very helpful in that they immediately identified the cause
of the problem being seen. Hence I'd like to always have them
available for use.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBen Myers <bpm@sgi.com>

If we have a buffer that we have modified but we do not wish to
physically log in a transaction (e.g. we've logged a logical
change), we still need to ensure that transactional integrity is
maintained. Hence we must not move the tail of the log past the
transaction that the buffer is associated with before the buffer is
written to disk.

This means these special buffers still need to be included in the
transaction and added to the AIL just like a normal buffer, but we
do not want the modifications to the buffer written into the
transaction. IOWs, what we want is an "ordered buffer" that
maintains the same transactional life cycle as a physically logged
buffer, just without the transcribing of the modifications to the
log.

Hence we need to flag the buffer as an "ordered buffer" to avoid
including it in vector size calculations or formatting during the
transaction. Once the transaction is committed, the buffer appears
for all intents to be the same as a physically logged buffer as it
transitions through the log and AIL.

Relogging will also work just fine for such an ordered buffer - the
logical transaction will be replayed before the subsequent
modifications that relog the buffer, so everything will be
reconstructed correctly by recovery.
Signed-off-by: NDave Chinner <david@fromorbit.com>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

Adding an extended attribute to a symbolic link can force that
link to an remote extent. xfs_inactive() incorrectly assumes
that any symbolic link small enough to be in the inode core
is incore, resulting in the remote extent to not be removed.
xfs_ifree() will assert on presence of this leaked remote extent.
Signed-off-by: NMark Tinguely <tinguely@sgi.com>
Reviewed-by: NBen Myers <bpm@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

->invalidatepage() aop now accepts range to invalidate so we can make
use of it in xfs_vm_invalidatepage()
Signed-off-by: NLukas Czerner <lczerner@redhat.com>
Acked-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBen Myers <bpm@sgi.com>
Cc: xfs@oss.sgi.com

Add a tracepoint to provide some feedback on preallocation size
calculation.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

When the new inode verify in xfs_iread() fails, the create
transaction is aborted and a shutdown occurs. The subsequent unmount
then hangs in xfs_wait_buftarg() on a buffer that has an elevated
hold count. Debug showed that it was an AGI buffer getting stuck:

[   22.576147] XFS (vdb): buffer 0x2/0x1, hold 0x2 stuck
[   22.976213] XFS (vdb): buffer 0x2/0x1, hold 0x2 stuck
[   23.376206] XFS (vdb): buffer 0x2/0x1, hold 0x2 stuck
[   23.776325] XFS (vdb): buffer 0x2/0x1, hold 0x2 stuck

The trace of this buffer leading up to the shutdown (trimmed for
brevity) looks like:

xfs_buf_init:        bno 0x2 nblks 0x1 hold 1 caller xfs_buf_get_map
xfs_buf_get:         bno 0x2 len 0x200 hold 1 caller xfs_buf_read_map
xfs_buf_read:        bno 0x2 len 0x200 hold 1 caller xfs_trans_read_buf_map
xfs_buf_iorequest:   bno 0x2 nblks 0x1 hold 1 caller _xfs_buf_read
xfs_buf_hold:        bno 0x2 nblks 0x1 hold 1 caller xfs_buf_iorequest
xfs_buf_rele:        bno 0x2 nblks 0x1 hold 2 caller xfs_buf_iorequest
xfs_buf_iowait:      bno 0x2 nblks 0x1 hold 1 caller _xfs_buf_read
xfs_buf_ioerror:     bno 0x2 len 0x200 hold 1 caller xfs_buf_bio_end_io
xfs_buf_iodone:      bno 0x2 nblks 0x1 hold 1 caller _xfs_buf_ioend
xfs_buf_iowait_done: bno 0x2 nblks 0x1 hold 1 caller _xfs_buf_read
xfs_buf_hold:        bno 0x2 nblks 0x1 hold 1 caller xfs_buf_item_init
xfs_trans_read_buf:  bno 0x2 len 0x200 hold 2 recur 0 refcount 1
xfs_trans_brelse:    bno 0x2 len 0x200 hold 2 recur 0 refcount 1
xfs_buf_item_relse:  bno 0x2 nblks 0x1 hold 2 caller xfs_trans_brelse
xfs_buf_rele:        bno 0x2 nblks 0x1 hold 2 caller xfs_buf_item_relse
xfs_buf_unlock:      bno 0x2 nblks 0x1 hold 1 caller xfs_trans_brelse
xfs_buf_rele:        bno 0x2 nblks 0x1 hold 1 caller xfs_trans_brelse
xfs_buf_trylock:     bno 0x2 nblks 0x1 hold 2 caller _xfs_buf_find
xfs_buf_find:        bno 0x2 len 0x200 hold 2 caller xfs_buf_get_map
xfs_buf_get:         bno 0x2 len 0x200 hold 2 caller xfs_buf_read_map
xfs_buf_read:        bno 0x2 len 0x200 hold 2 caller xfs_trans_read_buf_map
xfs_buf_hold:        bno 0x2 nblks 0x1 hold 2 caller xfs_buf_item_init
xfs_trans_read_buf:  bno 0x2 len 0x200 hold 3 recur 0 refcount 1
xfs_trans_log_buf:   bno 0x2 len 0x200 hold 3 recur 0 refcount 1
xfs_buf_item_unlock: bno 0x2 len 0x200 hold 3 flags DIRTY liflags ABORTED
xfs_buf_unlock:      bno 0x2 nblks 0x1 hold 3 caller xfs_buf_item_unlock
xfs_buf_rele:        bno 0x2 nblks 0x1 hold 3 caller xfs_buf_item_unlock

And that is the AGI buffer from cold cache read into memory to
transaction abort. You can see at transaction abort the bli is dirty
and only has a single reference. The item is not pinned, and it's
not in the AIL. Hence the only reference to it is this transaction.

The problem is that the xfs_buf_item_unlock() call is dropping the
last reference to the xfs_buf_log_item attached to the buffer (which
holds a reference to the buffer), but it is not freeing the
xfs_buf_log_item. Hence nothing will ever release the buffer, and
the unmount hangs waiting for this reference to go away.

The fix is simple - xfs_buf_item_unlock needs to detect the last
reference going away in this case and free the xfs_buf_log_item to
release the reference it holds on the buffer.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBen Myers <bpm@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

When the new inode verify in xfs_iread() fails, the create
transaction is aborted and a shutdown occurs. The subsequent unmount
then hangs in xfs_wait_buftarg() on a buffer that has an elevated
hold count. Debug showed that it was an AGI buffer getting stuck:

[   22.576147] XFS (vdb): buffer 0x2/0x1, hold 0x2 stuck
[   22.976213] XFS (vdb): buffer 0x2/0x1, hold 0x2 stuck
[   23.376206] XFS (vdb): buffer 0x2/0x1, hold 0x2 stuck
[   23.776325] XFS (vdb): buffer 0x2/0x1, hold 0x2 stuck

The trace of this buffer leading up to the shutdown (trimmed for
brevity) looks like:

xfs_buf_init:        bno 0x2 nblks 0x1 hold 1 caller xfs_buf_get_map
xfs_buf_get:         bno 0x2 len 0x200 hold 1 caller xfs_buf_read_map
xfs_buf_read:        bno 0x2 len 0x200 hold 1 caller xfs_trans_read_buf_map
xfs_buf_iorequest:   bno 0x2 nblks 0x1 hold 1 caller _xfs_buf_read
xfs_buf_hold:        bno 0x2 nblks 0x1 hold 1 caller xfs_buf_iorequest
xfs_buf_rele:        bno 0x2 nblks 0x1 hold 2 caller xfs_buf_iorequest
xfs_buf_iowait:      bno 0x2 nblks 0x1 hold 1 caller _xfs_buf_read
xfs_buf_ioerror:     bno 0x2 len 0x200 hold 1 caller xfs_buf_bio_end_io
xfs_buf_iodone:      bno 0x2 nblks 0x1 hold 1 caller _xfs_buf_ioend
xfs_buf_iowait_done: bno 0x2 nblks 0x1 hold 1 caller _xfs_buf_read
xfs_buf_hold:        bno 0x2 nblks 0x1 hold 1 caller xfs_buf_item_init
xfs_trans_read_buf:  bno 0x2 len 0x200 hold 2 recur 0 refcount 1
xfs_trans_brelse:    bno 0x2 len 0x200 hold 2 recur 0 refcount 1
xfs_buf_item_relse:  bno 0x2 nblks 0x1 hold 2 caller xfs_trans_brelse
xfs_buf_rele:        bno 0x2 nblks 0x1 hold 2 caller xfs_buf_item_relse
xfs_buf_unlock:      bno 0x2 nblks 0x1 hold 1 caller xfs_trans_brelse
xfs_buf_rele:        bno 0x2 nblks 0x1 hold 1 caller xfs_trans_brelse
xfs_buf_trylock:     bno 0x2 nblks 0x1 hold 2 caller _xfs_buf_find
xfs_buf_find:        bno 0x2 len 0x200 hold 2 caller xfs_buf_get_map
xfs_buf_get:         bno 0x2 len 0x200 hold 2 caller xfs_buf_read_map
xfs_buf_read:        bno 0x2 len 0x200 hold 2 caller xfs_trans_read_buf_map
xfs_buf_hold:        bno 0x2 nblks 0x1 hold 2 caller xfs_buf_item_init
xfs_trans_read_buf:  bno 0x2 len 0x200 hold 3 recur 0 refcount 1
xfs_trans_log_buf:   bno 0x2 len 0x200 hold 3 recur 0 refcount 1
xfs_buf_item_unlock: bno 0x2 len 0x200 hold 3 flags DIRTY liflags ABORTED
xfs_buf_unlock:      bno 0x2 nblks 0x1 hold 3 caller xfs_buf_item_unlock
xfs_buf_rele:        bno 0x2 nblks 0x1 hold 3 caller xfs_buf_item_unlock

And that is the AGI buffer from cold cache read into memory to
transaction abort. You can see at transaction abort the bli is dirty
and only has a single reference. The item is not pinned, and it's
not in the AIL. Hence the only reference to it is this transaction.

The problem is that the xfs_buf_item_unlock() call is dropping the
last reference to the xfs_buf_log_item attached to the buffer (which
holds a reference to the buffer), but it is not freeing the
xfs_buf_log_item. Hence nothing will ever release the buffer, and
the unmount hangs waiting for this reference to go away.

The fix is simple - xfs_buf_item_unlock needs to detect the last
reference going away in this case and free the xfs_buf_log_item to
release the reference it holds on the buffer.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBen Myers <bpm@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

Added when debugging recent attribute tree problems to more finely
trace code execution through the maze of twisty passages that makes
up the attr code.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

xfs_inodes_free_eofblocks() implements scanning functionality for
EOFBLOCKS inodes. It uses the AG iterator to walk the tagged inodes
and free post-EOF blocks via the xfs_inode_free_eofblocks() execute
function. The scan can be invoked in best-effort mode or wait
(force) mode.

A best-effort scan (default) handles all inodes that do not have a
dirty cache and we successfully acquire the io lock via trylock. In
wait mode, we continue to cycle through an AG until all inodes are
handled.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

Add the XFS_ICI_EOFBLOCKS_TAG inode tag to identify inodes with
speculatively preallocated blocks beyond EOF. An inode is tagged
when speculative preallocation occurs and untagged either via
truncate down or when post-EOF blocks are freed via release or
reclaim.

The tag management is intentionally not aggressive to prefer
simplicity over the complexity of handling all the corner cases
under which post-EOF blocks could be freed (i.e., forward
truncation, fallocate, write error conditions, etc.). This means
that a tagged inode may or may not have post-EOF blocks after a
period of time. The tag is eventually cleared when the inode is
released or reclaimed.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

I noticed that "struct xfs_mount_args" was still declared in
"fs/xfs/xfs_mount.h".  That struct doesn't even exist any more (and
is obviously not referenced elsewhere in that header file).  While
in there, delete four other unneeded struct declarations in that
file.

Doing so highlights that "fs/xfs/xfs_trace.h" was relying indirectly
on "xfs_mount.h" to be #included in order to declare "struct
xfs_bmbt_irec", so add that declaration to resolve that issue.
Signed-off-by: NAlex Elder <elder@inktank.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

Use this new method to replace our hacky use of ->dirty_inode.  An additional
benefit is that we can now propagate errors up the stack.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

Rename the XFS log structure to xlog to help crash distinquish it from the
other logs in Linux.
Signed-off-by: NMark Tinguely <tinguely@sgi.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBen Myers <bpm@sgi.com>

Rename the XFS log structure to xlog to help crash distinquish it from the
other logs in Linux.
Signed-off-by: NMark Tinguely <tinguely@sgi.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBen Myers <bpm@sgi.com>

To enable easy tracing of the location of log forces and the
frequency of them via perf, add a pair of trace points to the log
force functions.  This will help debug where excessive log forces
are being issued from by simple perf commands like:

# ~/perf/perf top -e xfs:xfs_log_force -G -U

Which gives this sort of output:

Events: 141  xfs:xfs_log_force
-  100.00%  [kernel]  [k] xfs_log_force
   - xfs_log_force
        87.04% xfsaild
           kthread
           kernel_thread_helper
      - 12.87% xfs_buf_lock
           _xfs_buf_find
           xfs_buf_get
           xfs_trans_get_buf
           xfs_da_do_buf
           xfs_da_get_buf
           xfs_dir2_data_init
           xfs_dir2_leaf_addname
           xfs_dir_createname
           xfs_create
           xfs_vn_mknod
           xfs_vn_create
           vfs_create
           do_last.isra.41
           path_openat
           do_filp_open
           do_sys_open
           sys_open
           system_call_fastpath
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sig.com>

Now that the busy extent tracking has been moved out of the
allocation files, clean up the namespace it uses to
"xfs_extent_busy" rather than a mix of "xfs_busy" and
"xfs_alloc_busy".

Signed-off-by: Dave Chinner<dchinner@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

Now that we pass block counts everywhere, and index buffers by block
number, track the length of the buffer in units of blocks rather
than bytes. Convert the code to use block counts, and those that
need byte counts get converted at the time of use.

Also, remove the XFS_BUF_{SET_}SIZE() macros that are just wrappers
around the buffer length. They only serve to make the code shouty
loud and don't actually add any real value.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

Queue delwri buffers on a local on-stack list instead of a per-buftarg one,
and write back the buffers per-process instead of by waking up xfsbufd.

This is now easily doable given that we have very few places left that write
delwri buffers:

 - log recovery:
	Only done at mount time, and already forcing out the buffers
	synchronously using xfs_flush_buftarg

 - quotacheck:
	Same story.

 - dquot reclaim:
	Writes out dirty dquots on the LRU under memory pressure.  We might
	want to look into doing more of this via xfsaild, but it's already
	more optimal than the synchronous inode reclaim that writes each
	buffer synchronously.

 - xfsaild:
	This is the main beneficiary of the change.  By keeping a local list
	of buffers to write we reduce latency of writing out buffers, and
	more importably we can remove all the delwri list promotions which
	were hitting the buffer cache hard under sustained metadata loads.

The implementation is very straight forward - xfs_buf_delwri_queue now gets
a new list_head pointer that it adds the delwri buffers to, and all callers
need to eventually submit the list using xfs_buf_delwi_submit or
xfs_buf_delwi_submit_nowait.  Buffers that already are on a delwri list are
skipped in xfs_buf_delwri_queue, assuming they already are on another delwri
list.  The biggest change to pass down the buffer list was done to the AIL
pushing. Now that we operate on buffers the trylock, push and pushbuf log
item methods are merged into a single push routine, which tries to lock the
item, and if possible add the buffer that needs writeback to the buffer list.
This leads to much simpler code than the previous split but requires the
individual IOP_PUSH instances to unlock and reacquire the AIL around calls
to blocking routines.

Given that xfsailds now also handle writing out buffers, the conditions for
log forcing and the sleep times needed some small changes.  The most
important one is that we consider an AIL busy as long we still have buffers
to push, and the other one is that we do increment the pushed LSN for
buffers that are under flushing at this moment, but still count them towards
the stuck items for restart purposes.  Without this we could hammer on stuck
items without ever forcing the log and not make progress under heavy random
delete workloads on fast flash storage devices.

[ Dave Chinner:
	- rebase on previous patches.
	- improved comments for XBF_DELWRI_Q handling
	- fix XBF_ASYNC handling in queue submission (test 106 failure)
	- rename delwri submit function buffer list parameters for clarity
	- xfs_efd_item_push() should return XFS_ITEM_PINNED ]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

Signed-off-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

Strings store in an xfs_name structure are often not NUL terminated,
print them using the correct printf specifiers that make use of the
string length store in the xfs_name structure.
Reported-by: NBrian Candler <B.Candler@pobox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBen Myers <bpm@sgi.com>

Replace the global hash tables for looking up in-memory dquot structures
with per-filesystem radix trees to allow scaling to a large number of
in-memory dquot structures.
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBen Myers <bpm@sgi.com>

Timestamps on regular files are the last metadata that XFS does not update
transactionally.  Now that we use the delaylog mode exclusively and made
the log scode scale extremly well there is no need to bypass that code for
timestamp updates.  Logging all updates allows to drop a lot of code, and
will allow for further performance improvements later on.

Note that this patch drops optimized handling of fdatasync - it will be
added back in a separate commit.
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

Split the log regrant case out of xfs_log_reserve into a separate function,
and merge xlog_grant_log_space and xlog_regrant_write_log_space into their
respective callers.  Also replace the XFS_LOG_PERM_RESERV flag, which easily
got misused before the previous cleanups with a simple boolean parameter.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NBen Myers <bpm@sgi.com>