XFS_ERROR was designed long ago to trap return values, but it's not
runtime configurable, it's not consistently used, and we can do
similar error trapping with ftrace scripts and triggers from
userspace.
Just nuke XFS_ERROR and associated bits.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Most of the callers are just calling ASSERT(!xfs_buf_geterror())
which means they are checking for bp->b_error == 0. If bp is null in
this case, we will assert fail, and hence it's no different in
result to oopsing because of a null bp. In some cases, errors have
already been checked for or the function returning the buffer can't
return a buffer with an error, so it's just a redundant assert.
Either way, the assert can either be removed.
The other two non-assert callers can just test for a buffer and
error properly.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reports of a shutdown hang when fsyncing a directory have surfaced,
such as this:
[ 3663.394472] Call Trace:
[ 3663.397199] [<ffffffff815f1889>] schedule+0x29/0x70
[ 3663.402743] [<ffffffffa01feda5>] xlog_cil_force_lsn+0x185/0x1a0 [xfs]
[ 3663.416249] [<ffffffffa01fd3af>] _xfs_log_force_lsn+0x6f/0x2f0 [xfs]
[ 3663.429271] [<ffffffffa01a339d>] xfs_dir_fsync+0x7d/0xe0 [xfs]
[ 3663.435873] [<ffffffff811df8c5>] do_fsync+0x65/0xa0
[ 3663.441408] [<ffffffff811dfbc0>] SyS_fsync+0x10/0x20
[ 3663.447043] [<ffffffff815fc7d9>] system_call_fastpath+0x16/0x1b
If we trigger a shutdown in xlog_cil_push() from xlog_write(), we
will never wake waiters on the current push sequence number, so
anything waiting in xlog_cil_force_lsn() for that push sequence
number to come up will not get woken and hence stall the shutdown.
Fix this by ensuring we call wake_up_all(&cil->xc_commit_wait) in
the push abort handling, in the log shutdown code when waking all
waiters, and adding a shutdown check in the sequence completion wait
loops to ensure they abort when a wakeup due to a shutdown occurs.
Reported-by: Boris Ranto <branto@redhat.com>
Reported-by: Eric Sandeen <esandeen@redhat.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
We have had this code in the kernel for over a year now and have
shaken all the known issues out of the code over the past few
releases. It's now time to remove the experimental warnings during
mount and fully support the new filesystem format in production
systems.
Remove the experimental warning, and add a version number to the
initial "mounting filesystem" message to tell use what type of
filesystem is being mounted. Also, remove the temporary inode
cluster size output at mount time now we know that this code works
fine.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
And interesting situation can occur if a log IO error occurs during
the unmount of a filesystem. The cases reported have the same
signature - the update of the superblock counters fails due to a log
write IO error:
XFS (dm-16): xfs_do_force_shutdown(0x2) called from line 1170 of file fs/xfs/xfs_log.c. Return address = 0xffffffffa08a44a1
XFS (dm-16): Log I/O Error Detected. Shutting down filesystem
XFS (dm-16): Unable to update superblock counters. Freespace may not be correct on next mount.
XFS (dm-16): xfs_log_force: error 5 returned.
XFS (¿-¿¿¿): Please umount the filesystem and rectify the problem(s)
It can be seen that the last line of output contains a corrupt
device name - this is because the log and xfs_mount structures have
already been freed by the time this message is printed. A kernel
oops closely follows.
The issue is that the shutdown is occurring in a separate IO
completion thread to the unmount. Once the shutdown processing has
started and all the iclogs are marked with XLOG_STATE_IOERROR, the
log shutdown code wakes anyone waiting on a log force so they can
process the shutdown error. This wakes up the unmount code that
is doing a synchronous transaction to update the superblock
counters.
The unmount path now sees all the iclogs are marked with
XLOG_STATE_IOERROR and so never waits on them again, knowing that if
it does, there will not be a wakeup trigger for it and we will hang
the unmount if we do. Hence the unmount runs through all the
remaining code and frees all the filesystem structures while the
xlog_iodone() is still processing the shutdown. When the log
shutdown processing completes, xfs_do_force_shutdown() emits the
"Please umount the filesystem and rectify the problem(s)" message,
and xlog_iodone() then aborts all the objects attached to the iclog.
An iclog that has already been freed....
The real issue here is that there is no serialisation point between
the log IO and the unmount. We have serialisations points for log
writes, log forces, reservations, etc, but we don't actually have
any code that wakes for log IO to fully complete. We do that for all
other types of object, so why not iclogbufs?
Well, it turns out that we can easily do this. We've got xfs_buf
handles, and that's what everyone else uses for IO serialisation.
i.e. bp->b_sema. So, lets hold iclogbufs locked over IO, and only
release the lock in xlog_iodone() when we are finished with the
buffer. That way before we tear down the iclog, we can lock and
unlock the buffer to ensure IO completion has finished completely
before we tear it down.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Tested-by: Mike Snitzer <snitzer@redhat.com>
Tested-by: Bob Mastors <bob.mastors@solidfire.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.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: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
In xlog_verify_iclog a debug check of the incore log buffers prints an
error if icptr is null and then goes on to dereference the pointer
regardless. Convert this to an assert so that the intention is clear.
This was reported by Coverty.
Signed-off-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Currently the xfs_inode.h header has a dependency on the definition
of the BMAP btree records as the inode fork includes an array of
xfs_bmbt_rec_host_t objects in it's definition.
Move all the btree format definitions from xfs_btree.h,
xfs_bmap_btree.h, xfs_alloc_btree.h and xfs_ialloc_btree.h to
xfs_format.h to continue the process of centralising the on-disk
format definitions. With this done, the xfs inode definitions are no
longer dependent on btree header files.
The enables a massive culling of unnecessary includes, with close to
200 #include directives removed from the XFS kernel code base.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs_trans.h has a dependency on xfs_log.h for a couple of
structures. Most code that does transactions doesn't need to know
anything about the log, but this dependency means that they have to
include xfs_log.h. Decouple the xfs_trans.h and xfs_log.h header
files and clean up the includes to be in dependency order.
In doing this, remove the direct include of xfs_trans_reserve.h from
xfs_trans.h so that we remove the dependency between xfs_trans.h and
xfs_mount.h. Hence the xfs_trans.h include can be moved to the
indicate the actual dependencies other header files have on it.
Note that these are kernel only header files, so this does not
translate to any userspace changes at all.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
All of the buffer operations structures are needed to be exported
for xfs_db, so move them all to a common location rather than
spreading them all over the place. They are verifying the on-disk
format, so while xfs_format.h might be a good place, it is not part
of the on disk format.
Hence we need to create a new header file that we centralise these
related definitions. Start by moving the bffer operations
structures, and then also move all the other definitions that have
crept into xfs_log_format.h and xfs_format.h as there was no other
shared header file to put them in.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
__xfs_printk adds its own "\n". Having it in the original string
leads to unintentional blank lines from these messages.
Most format strings have no newline, but a few do, leading to
i.e.:
[ 7347.119911] XFS (sdb2): Access to block zero in inode 132 start_block: 0 start_off: 0 blkcnt: 0 extent-state: 0 lastx: 1a05
[ 7347.119911]
[ 7347.119919] XFS (sdb2): Access to block zero in inode 132 start_block: 0 start_off: 0 blkcnt: 0 extent-state: 0 lastx: 1a05
[ 7347.119919]
Fix them all.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Recent analysis of a deadlocked XFS filesystem from a kernel
crash dump indicated that the filesystem was stuck waiting for log
space. The short story of the hang on the RHEL6 kernel is this:
- the tail of the log is pinned by an inode
- the inode has been pushed by the xfsaild
- the inode has been flushed to it's backing buffer and is
currently flush locked and hence waiting for backing
buffer IO to complete and remove it from the AIL
- the backing buffer is marked for write - it is on the
delayed write queue
- the inode buffer has been modified directly and logged
recently due to unlinked inode list modification
- the backing buffer is pinned in memory as it is in the
active CIL context.
- the xfsbufd won't start buffer writeback because it is
pinned
- xfssyncd won't force the log because it sees the log as
needing to be covered and hence wants to issue a dummy
transaction to move the log covering state machine along.
Hence there is no trigger to force the CIL to the log and hence
unpin the inode buffer and therefore complete the inode IO, remove
it from the AIL and hence move the tail of the log along, allowing
transactions to start again.
Mainline kernels also have the same deadlock, though the signature
is slightly different - the inode buffer never reaches the delayed
write lists because xfs_buf_item_push() sees that it is pinned and
hence never adds it to the delayed write list that the xfsaild
flushes.
There are two possible solutions here. The first is to simply force
the log before trying to cover the log and so ensure that the CIL is
emptied before we try to reserve space for the dummy transaction in
the xfs_log_worker(). While this might work most of the time, it is
still racy and is no guarantee that we don't get stuck in
xfs_trans_reserve waiting for log space to come free. Hence it's not
the best way to solve the problem.
The second solution is to modify xfs_log_need_covered() to be aware
of the CIL. We only should be attempting to cover the log if there
is no current activity in the log - covering the log is the process
of ensuring that the head and tail in the log on disk are identical
(i.e. the log is clean and at idle). Hence, by definition, if there
are items in the CIL then the log is not at idle and so we don't
need to attempt to cover it.
When we don't need to cover the log because it is active or idle, we
issue a log force from xfs_log_worker() - if the log is idle, then
this does nothing. However, if the log is active due to there being
items in the CIL, it will force the items in the CIL to the log and
unpin them.
In the case of the above deadlock scenario, instead of
xfs_log_worker() getting stuck in xfs_trans_reserve() attempting to
cover the log, it will instead force the log, thereby unpinning the
inode buffer, allowing IO to be issued and complete and hence
removing the inode that was pinning the tail of the log from the
AIL. At that point, everything will start moving along again. i.e.
the xfs_log_worker turns back into a watchdog that can alleviate
deadlocks based around pinned items that prevent the tail of the log
from being moved...
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
A couple of simple locking annotations and 0 vs NULL warnings.
Nothing that changes any code behaviour, just removes build noise.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
Validate log space during log mount stage, the underlying function
will drop a warning message via syslog in critical level if the log
space is too small or too large.
[ dchinner: For CRC enable filesystems, abort the mounting of the
filesystem as mkfs should never make a log too small for the given
filesystem configuration. ]
[ dchinner: make a note of the fact that the log size limits in
block counts are in units of filesystem blocks, not basic blocks. ]
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Refactor xlog_ticket_alloc() to extract a new helper, i.e.
xfs_log_calc_unit_res().
This helper would be used to calculate the total log reservation
size by adding extra log operation/transation headers for a new
log ticket.
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
While testing and rearranging pquota/gquota code, I stumbled
on a xfs_shutdown() during a mount. But the mount just hung.
Debugged and found that there is a deadlock involving
&log->l_cilp->xc_ctx_lock.
It is in a code path where &log->l_cilp->xc_ctx_lock is first
acquired in read mode and some levels down the same semaphore
is being acquired in write mode causing a deadlock.
This is the stack:
xfs_log_commit_cil -> acquires &log->l_cilp->xc_ctx_lock in read mode
xlog_print_tic_res
xfs_force_shutdown
xfs_log_force_umount
xlog_cil_force
xlog_cil_force_lsn
xlog_cil_push_foreground
xlog_cil_push - tries to acquire same semaphore in write mode
This patch fixes the deadlock by changing the reason code for
xfs_force_shutdown in xlog_print_tic_res() to SHUTDOWN_LOG_IO_ERROR.
SHUTDOWN_LOG_IO_ERROR is the right reason code to be set since
we are in the log path.
Thanks to Dave for suggesting this solution.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
And "ordered log vector" is a log vector that is used for
tracking a log item through the CIL and into the AIL as part of the
log checkpointing. These ordered log vectors are special in that
they are not written to to journal in any way, and are not accounted
to the checkpoint being written.
The reason for this behaviour is to allow operations to attach items
to transactions and have them follow the normal transactional
lifecycle without actually having to write them to the journal. This
allows logging of items that track high level logical changes and
writing them to the log, while the physical items being modified
pass through into the AIL and pin the tail of the log (and therefore
the logical item in the log) until all the modified items are
physically written to disk.
IOWs, it allows us to write metadata without physically logging
every individual change but still maintain the full transactional
integrity guarantees we currently have w.r.t. crash recovery.
This change modifies some of the CIL item insertion loops, as
ordered log vectors introduce some new constraints as they don't
track any data. One advantage of this change is that it combines
two log vector chain walks into a single pass, so there is less
overhead in the transaction commit pass as well. It also kills some
unused code in the log vector walk loop when committing the CIL.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Use more preferable function name which implies using a pseudo-random
number generator.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: <bpm@sgi.com>
Cc: Ben Myers <bpm@sgi.com>
Cc: Alex Elder <elder@kernel.org>
Cc: xfs@oss.sgi.com
Signed-off-by: Ben Myers <bpm@sgi.com>
Since we are using C99 we have one builtin defined in include/linux/types.h,
use that instead.
v2: you missed one in fs/xfs/xfs_qm_bhv.c, cleaned up. -bpm
Signed-off-by: Thiago Farina <tfarina@chromium.org>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Not a bug as such, just warning noise from the xlog_cksum()
returning a __be32 type when it should be returning a __le32 type.
On Wed, Nov 28, 2012 at 08:30:59AM -0500, Christoph Hellwig wrote:
> But why are we storing the crc field little endian while all other on
> disk formats are big endian? (And yes I realize it might as well have
> been me who did that back in the idea, but I still have no idea why)
Because the CRC always returns the calcuation LE format, even on BE
systems. So rather than always having to byte swap it everywhere and
have all the force casts and anootations for sparse, it seems simpler to
just make it a __le32 everywhere....
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The direct IO path can do a nested transaction reservation when
writing past the EOF. The first transaction is the append
transaction for setting the filesize at IO completion, but we can
also need a transaction for allocation of blocks. If the log is low
on space due to reservations and small log, the append transaction
can be granted after wating for space as the only active transaction
in the system. This then attempts a reservation for an allocation,
which there isn't space in the log for, and the reservation sleeps.
The result is that there is nothing left in the system to wake up
all the processes waiting for log space to come free.
The stack trace that shows this deadlock is relatively innocuous:
xlog_grant_head_wait
xlog_grant_head_check
xfs_log_reserve
xfs_trans_reserve
xfs_iomap_write_direct
__xfs_get_blocks
xfs_get_blocks_direct
do_blockdev_direct_IO
__blockdev_direct_IO
xfs_vm_direct_IO
generic_file_direct_write
xfs_file_dio_aio_writ
xfs_file_aio_write
do_sync_write
vfs_write
This was discovered on a filesystem with a log of only 10MB, and a
log stripe unit of 256k whih increased the base reservations by
512k. Hence a allocation transaction requires 1.2MB of log space to
be available instead of only 260k, and so greatly increased the
chance that there wouldn't be enough log space available for the
nested transaction to succeed. The key to reproducing it is this
mkfs command:
mkfs.xfs -f -d agcount=16,su=256k,sw=12 -l su=256k,size=2560b $SCRATCH_DEV
The test case was a 1000 fsstress processes running with random
freeze and unfreezes every few seconds. Thanks to Eryu Guan
(eguan@redhat.com) for writing the test that found this on a system
with a somewhat unique default configuration....
cc: <stable@vger.kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andrew Dahl <adahl@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Implement CRCs for the log buffers. We re-use a field in
struct xlog_rec_header that was used for a weak checksum of the
log buffer payload in debug builds before.
The new checksumming uses the crc32c checksum we will use elsewhere
in XFS, and also protects the record header and addition cycle data.
Due to this there are some interesting changes in xlog_sync, as we
need to do the cycle wrapping for the split buffer case much earlier,
as we would touch the buffer after generating the checksum otherwise.
The CRC calculation is always enabled, even for non-CRC filesystems,
as adding this CRC does not change the log format. On non-CRC
filesystems, only issue an alert if a CRC mismatch is found and
allow recovery to continue - this will act as an indicator that
log recovery problems are a result of log corruption. On CRC enabled
filesystems, however, log recovery will fail.
Note that existing debug kernels will write a simple checksum value
to the log, so the first time this is run on a filesystem taht was
last used on a debug kernel it will through CRC mismatch warning
errors. These can be ignored.
Initially based on a patch from Dave Chinner, then modified
significantly by Christoph Hellwig. Modified again by Dave Chinner
to get to this version.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Add a verifier function callback capability to the buffer read
interfaces. This will be used by the callers to supply a function
that verifies the contents of the buffer when it is read from disk.
This patch does not provide callback functions, but simply modifies
the interfaces to allow them to be called.
The reason for adding this to the read interfaces is that it is very
difficult to tell fom the outside is a buffer was just read from
disk or whether we just pulled it out of cache. Supplying a callbck
allows the buffer cache to use it's internal knowledge of the buffer
to execute it only when the buffer is read from disk.
It is intended that the verifier functions will mark the buffer with
an EFSCORRUPTED error when verification fails. This allows the
reading context to distinguish a verification error from an IO
error, and potentially take further actions on the buffer (e.g.
attempt repair) based on the error reported.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The log write code stamps each iclog with the current tail LSN in
the iclog header so that recovery knows where to find the tail of
thelog once it has found the head. Normally this is taken from the
first item on the AIL - the log item that corresponds to the oldest
active item in the log.
The problem is that when the AIL is empty, the tail lsn is dervied
from the the l_last_sync_lsn, which is the LSN of the last iclog to
be written to the log. In most cases this doesn't happen, because
the AIL is rarely empty on an active filesystem. However, when it
does, it opens up an interesting case when the transaction being
committed to the iclog spans multiple iclogs.
That is, the first iclog is stamped with the l_last_sync_lsn, and IO
is issued. Then the next iclog is setup, the changes copied into the
iclog (takes some time), and then the l_last_sync_lsn is stamped
into the header and IO is issued. This is still the same
transaction, so the tail lsn of both iclogs must be the same for log
recovery to find the entire transaction to be able to replay it.
The problem arises in that the iclog buffer IO completion updates
the l_last_sync_lsn with it's own LSN. Therefore, If the first iclog
completes it's IO before the second iclog is filled and has the tail
lsn stamped in it, it will stamp the LSN of the first iclog into
it's tail lsn field. If the system fails at this point, log recovery
will not see a complete transaction, so the transaction will no be
replayed.
The fix is simple - the l_last_sync_lsn is updated when a iclog
buffer IO completes, and this is incorrect. The l_last_sync_lsn
shoul dbe updated when a transaction is completed by a iclog buffer
IO. That is, only iclog buffers that have transaction commit
callbacks attached to them should update the l_last_sync_lsn. This
means that the last_sync_lsn will only move forward when a commit
record it written, not in the middle of a large transaction that is
rolling through multiple iclog buffers.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
xfs_quiesce_attr() is supposed to leave the log empty with an
unmount record written. Right now it does not wait for the AIL to be
emptied before writing the unmount record, not does it wait for
metadata IO completion, either. Fix it to use the same method and
code as xfs_log_unmount().
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
With the syncd functions moved to the log and/or removed, the syncd
workqueue is the only remaining bit left. It is used by the log
covering/ail pushing work, as well as by the inode reclaim work.
Given how cheap workqueues are these days, give the log and inode
reclaim work their own work queues and kill the syncd work queue.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
When unmounting the filesystem, there are lots of operations that
need to be done in a specific order, and they are spread across
across a couple of functions. We have to drain the AIL before we
write the unmount record, and we have to shut down the background
log work before we do either of them.
But this is all split haphazardly across xfs_unmountfs() and
xfs_log_unmount(). Move all the AIL flushing and log manipulations
to xfs_log_unmount() so that the responisbilities of each function
is clear and the operations they perform obvious.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The only thing the periodic sync work does now is flush the AIL and
idle the log. These are really functions of the log code, so move
the work to xfs_log.c and rename it appropriately.
The only wart that this leaves behind is the xfssyncd_centisecs
sysctl, otherwise the xfssyncd is dead. Clean up any comments that
related to xfssyncd to reflect it's passing.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
Remove the xlog_t type definitions.
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben 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: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
Revert commit 1307bbd, which uses the s_umount semaphore to provide
exclusion between xfs_sync_worker and unmount, in favor of shutting down
the sync worker before freeing the log in xfs_log_unmount. This is a
cleaner way of resolving the race between xfs_sync_worker and unmount
than using s_umount.
Signed-off-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.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: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sig.com>
With the removal of xfs_rw.h and other changes over time, xfs_bit.h
is being included in many files that don't actually need it. Clean
up the includes as necessary.
Also move the only-used-once xfs_ialloc_find_free() static inline
function out of a header file that is widely included to reduce
the number of needless dependencies on xfs_bit.h.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The only thing left in xfs_rw.h is a function prototype for an inode
function. Move that to xfs_inode.h, and kill xfs_rw.h.
Also move the function implementing the prototype from xfs_rw.c to
xfs_inode.c so we only have one function left in xfs_rw.c
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
Untangle the header file includes a bit by moving the definition of
xfs_agino_t to xfs_types.h. This removes the dependency that xfs_ag.h has on
xfs_inum.h, meaning we don't need to include xfs_inum.h everywhere we include
xfs_ag.h.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Now that we pass block counts everywhere, and index buffers by block
number and length in units of blocks, convert the desired IO size
into block counts rather than bytes. Convert the code to use block
counts, and those that need byte counts get converted at the time of
use.
Rename the b_desired_count variable to something closer to it's
purpose - b_io_length - as it is only used to specify the length of
an IO for a subset of the buffer. The only time this is used is for
log IO - both writing iclogs and during log recovery. In all other
cases, the b_io_length matches b_length, and hence a lot of code
confuses the two. e.g. the buf item code uses the io count
exclusively when it should be using the buffer length. Fix these
apprpriately as they are found.
Also, remove the XFS_BUF_{SET_}COUNT() macros that are just wrappers
around the desired IO length. They only serve to make the code
shouty loud, don't actually add any real value, and are often used
incorrectly.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben 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: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The xfs_buf_get/read API is not consistent in the units it uses, and
does not use appropriate or consistent units/types for the
variables.
Convert the API to use disk addresses and block counts for all
buffer get and read calls. Use consistent naming for all the
functions and their declarations, and convert the internal functions
to use disk addresses and block counts to avoid need to convert them
from one type to another and back again.
Fix all the callers to use disk addresses and block counts. In many
cases, this removes an additional conversion from the function call
as the callers already have a block count.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Provide a variant of xlog_assign_tail_lsn that has the AIL lock already
held. By doing so we do an additional atomic_read + atomic_set under
the lock, which comes down to two instructions.
Switch xfs_trans_ail_update_bulk and xfs_trans_ail_delete_bulk to the
new version to reduce the number of lock roundtrips, and prepare for
a new addition that would require a third lock roundtrip in
xfs_trans_ail_delete_bulk. This addition is also the reason for
slightly rearranging the conditionals and relying on xfs_log_space_wake
for checking that the filesystem has been shut down internally.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
There have been a few reports of this warning appearing recently:
XFS (dm-4): xlog_space_left: head behind tail
tail_cycle = 129, tail_bytes = 20163072
GH cycle = 129, GH bytes = 20162880
The common cause appears to be lots of freeze and unfreeze cycles,
and the output from the warnings indicates that we are leaking
around 8 bytes of log space per freeze/unfreeze cycle.
When we freeze the filesystem, we write an unmount record and that
uses xlog_write directly - a special type of transaction,
effectively. What it doesn't do, however, is correctly account for
the log space it uses. The unmount record writes an 8 byte structure
with a special magic number into the log, and the space this
consumes is not accounted for in the log ticket tracking the
operation. Hence we leak 8 bytes every unmount record that is
written.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben 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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Add a new data structure to allow sharing code between the log grant and
regrant code.
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The tic->t_wait waitqueues can never have more than a single waiter
on them, so we can easily replace them with a task_struct pointer
and wake_up_process.
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Remove the now unused opportunistic parameter, and use the the
xlog_writeq_wake and xlog_reserveq_wake helpers now that we don't have
to care about the opportunistic wakeups.
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The only reason that xfs_log_space_wake had to do opportunistic wakeups
was that the old xfs_log_move_tail calling convention didn't allow for
exact wakeups when not updating the log tail LSN. Since this issue has
been fixed we can do exact wakeups now.
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Currently xfs_log_move_tail has a tail_lsn argument that is horribly
overloaded: it may contain either an actual lsn to assign to the log tail,
0 as a special case to use the last sync LSN, or 1 to indicate that no tail
LSN assignment should be performed, and we should opportunisticly wake up
at one task waiting for log space even if we did not move the LSN.
Remove the tail lsn assigned from xfs_log_move_tail and make the two callers
use xlog_assign_tail_lsn instead of the current variant of partially using
the code in xfs_log_move_tail and partially opencoding it. Note that means
we grow an addition lock roundtrip on the AIL lock for each bulk update
or delete, which is still far less than what we had before introducing the
bulk operations. If this proves to be a problem we can still add a variant
of xlog_assign_tail_lsn that expects the lock to be held already.
Also rename the remainder of xfs_log_move_tail to xfs_log_space_wake as
that name describes its functionality much better.
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The delaylog mode has been the default for a long time, and the nodelaylog
option has been scheduled for removal in Linux 3.3. Remove it and code
only used by it now that we have opened the 3.3 window.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Apply the scheme used in log_regrant_write_log_space to wake up any other
threads waiting for log space before the newly added one to
log_regrant_write_log_space as well, and factor the code into readable
helpers. For each of the queues we have add two helpers:
- one to try to wake up all waiting threads. This helper will also be
usable by xfs_log_move_tail once we remove the current opportunistic
wakeups in it.
- one to sleep on t_wait until enough log space is available, loosely
modelled after Linux waitqueues.
And use them to reimplement the guts of log_regrant_write_log_space and
log_regrant_write_log_space. These two function now use one and the same
algorithm for waiting on log space instead of subtly different ones before,
with an option to completely unify them in the near future.
Also move the filesystem shutdown handling to the common caller given
that we had to touch it anyway.
Based on hard debugging and an earlier patch from
Chandra Seetharaman <sekharan@us.ibm.com>.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chandra Seetharaman <sekharan@us.ibm.com>
Tested-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The log item ops aren't nessecarily the biggest exploit vector, but marking
them const is easy enough. Also remove the unused xfs_item_ops_t typedef
while we're at it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Alex Elder <aelder@sgi.com>
Instead of passing the block number and mount structure explicitly
get them off the bp and fix make the argument order more natural.
Also move it to xfs_buf.c and stop printing the device name given
that we already get the fs name as part of xfs_alert, and we know
what device is operates on because of the caller that gets printed,
finally rename it to xfs_buf_ioerror_alert and pass __func__ as
argument where it makes sense.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
Change _xfs_buf_initialize to allocate the buffer directly and rename it to
xfs_buf_alloc now that is the only buffer allocation routine. Also remove
the xfs_buf_deallocate wrapper around the kmem_zone_free calls for buffers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
Remove the definition and usages of the macro XFS_BUF_SET_PTR.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Remove the definition and usages of the macro XFS_BUF_PTR.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Remove the definitions and uses of the macros XFS_BUF_BUSY,
XFS_BUF_UNBUSY, and XFS_BUF_ISBUSY.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Remove the definitions and usage of the macros XFS_BUF_ERROR,
XFS_BUF_GETERROR and XFS_BUF_ISERROR.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Replace the typeless b_fspriv2 and the ugly macros around it with a properly
typed transaction pointer. As a fallout the log buffer state debug checks
are also removed. We could have kept them using casts, but as they do
not have a real purpose we can as well just remove them.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
There is no need for a pre-flush when doing writing the second part of a
split log buffer, and if we are using an external log there is no need
to do a full cache flush of the log device at all given that all writes
to it use the FUA flag.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Remove the unused and misnamed _XBF_RUN_QUEUES flag, rename XBF_LOG_BUFFER
to the more fitting XBF_SYNCIO, and split XBF_ORDERED into XBF_FUA and
XBF_FLUSH to allow more fine grained control over the bio flags. Also
cleanup processing of the flags in _xfs_buf_ioapply to make more sense,
and renumber the sparse flag number space to group flags by purpose.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
All other xfs_buf_get/read-like helpers return the buffer locked, make sure
xfs_buf_get_uncached isn't different for no reason. Half of the callers
already lock it directly after, and the others probably should also keep
it locked if only for consistency and beeing able to use xfs_buf_rele,
but I'll leave that for later.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Rename xfs_buf_cond_lock and reverse it's return value to fit most other
trylock operations in the Kernel and XFS (with the exception of down_trylock,
after which xfs_buf_cond_lock was modelled), and replace xfs_buf_lock_val
with an xfs_buf_islocked for use in asserts, or and opencoded variant in
tracing. remove the XFS_BUF_* wrappers for all the locking helpers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Micro-optimize various comparisms by always byteswapping the constant
instead of the variable, which allows to do the swap at compile instead
of runtime.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
There's no reason not to support cache flushing on external log devices.
The only thing this really requires is flushing the data device first
both in fsync and log commits. A side effect is that we also have to
remove the barrier write test during mount, which has been superflous
since the new FLUSH+FUA code anyway. Also use the chance to flush the
RT subvolume write cache before the fsync commit, which is required
for correct semantics.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
When we free a vmapped buffer, we need to ensure the vmap address
and length we free is the same as when it was allocated. In various
places in the log code we change the memory the buffer is pointing
to before issuing IO, but we never reset the buffer to point back to
it's original memory (or no memory, if that is the case for the
buffer).
As a result, when we free the buffer it points to memory that is
owned by something else and attempts to unmap and free it. Because
the range does not match any known mapped range, it can trigger
BUG_ON() traps in the vmap code, and potentially corrupt the vmap
area tracking.
Fix this by always resetting these buffers to their original state
before freeing them.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Update the extent tree in case we have to reuse a busy extent, so that it
always is kept uptodate. This is done by replacing the busy list searches
with a new xfs_alloc_busy_reuse helper, which updates the busy extent tree
in case of a reuse. This allows us to allow reusing metadata extents
unconditionally, and thus avoid log forces especially for allocation btree
blocks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
On the Power platform, the log tail debug checks fire excessively
causing the system to panic early in testing. The debug checks are
known to be racy, though on x86_64 there is no evidence that they
trigger at all.
We want to keep the checks active on debug systems to alert us to
problems with log space accounting, but we need to reduce the impact
of a racy check on testing on the Power platform.
As a result, convert the ASSERT conditions to warnings, and
allow them to fire only once per filesystem mount. This will prevent
false positives from interfering with testing, whilst still
providing us with the indication that they may be a problem with log
space accounting should that occur.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
When we are short on memory, we want to expedite the cleaning of
dirty objects. Hence when we run short on memory, we need to kick
the AIL flushing into action to clean as many dirty objects as
quickly as possible. To implement this, sample the lsn of the log
item at the head of the AIL and use that as the push target for the
AIL flush.
Further, we keep items in the AIL that are dirty that are not
tracked any other way, so we can get objects sitting in the AIL that
don't get written back until the AIL is pushed. Hence to get the
filesystem to the idle state, we might need to push the AIL to flush
out any remaining dirty objects sitting in the AIL. This requires
the same push mechanism as the reclaim push.
This patch also renames xfs_trans_ail_tail() to xfs_ail_min_lsn() to
match the new xfs_ail_max_lsn() function introduced in this patch.
Similarly for xfs_trans_ail_push -> xfs_ail_push.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Alex Elder <aelder@sgi.com>
Convert the xfs log operations to use the new error logging
interfaces. This removes the xlog_{warn,panic} wrappers and makes
almost all errors emit the device they belong to instead of just
refering to "XFS".
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
We currently have a global error message buffer in cmn_err that is
protected by a spin lock that disables interrupts. Recently there
have been reports of NMI timeouts occurring when the console is
being flooded by SCSI error reports due to cmn_err() getting stuck
trying to print to the console while holding this lock (i.e. with
interrupts disabled). The NMI watchdog is seeing this CPU as
non-responding and so is triggering a panic. While the trigger for
the reported case is SCSI errors, pretty much anything that spams
the kernel log could cause this to occur.
Realistically the only reason that we have the intemediate message
buffer is to prepend the correct kernel log level prefix to the log
message. The only reason we have the lock is to protect the global
message buffer and the only reason the message buffer is global is
to keep it off the stack. Hence if we can avoid needing a global
message buffer we avoid needing the lock, and we can do this with a
small amount of cleanup and some preprocessor tricks:
1. clean up xfs_cmn_err() panic mask functionality to avoid
needing debug code in xfs_cmn_err()
2. remove the couple of "!" message prefixes that still exist that
the existing cmn_err() code steps over.
3. redefine CE_* levels directly to KERN_*
4. redefine cmn_err() and friends to use printk() directly
via variable argument length macros.
By doing this, we can completely remove the cmn_err() code and the
lock that is causing the problems, and rely solely on printk()
serialisation to ensure that we don't get garbled messages.
A series of followup patches is really needed to clean up all the
cmn_err() calls and related messages properly, but that results in a
series that is not easily back portable to enterprise kernels. Hence
this initial fix is only to address the direct problem in the lowest
impact way possible.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
The only thing that the grant lock remains to protect is the grant head
manipulations when adding or removing space from the log. These calculations
are already based on atomic variables, so we can already update them safely
without locks. However, the grant head manpulations require atomic multi-step
calculations to be executed, which the algorithms currently don't allow.
To make these multi-step calculations atomic, convert the algorithms to
compare-and-exchange loops on the atomic variables. That is, we sample the old
value, perform the calculation and use atomic64_cmpxchg() to attempt to update
the head with the new value. If the head has not changed since we sampled it,
it will succeed and we are done. Otherwise, we rerun the calculation again from
a new sample of the head.
This allows us to remove the grant lock from around all the grant head space
manipulations, and that effectively removes the grant lock from the log
completely. Hence we can remove the grant lock completely from the log at this
point.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
The log grant ticket wait queues are currently protected by the log
grant lock. However, the queues are functionally independent from
each other, and operations on them only require serialisation
against other queue operations now that all of the other log
variables they use are atomic values.
Hence, we can make them independent of the grant lock by introducing
new locks just to protect the lists operations. because the lists
are independent, we can use a lock per list and ensure that reserve
and write head queuing do not contend.
To ensure forced shutdowns work correctly in conjunction with the
new fast paths, ensure that we check whether the log has been shut
down in the grant functions once we hold the relevant spin locks but
before we go to sleep. This is needed to co-ordinate correctly with
the wakeups that are issued on the ticket queues so we don't leave
any processes sleeping on the queues during a shutdown.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Convert the log grant heads to atomic64_t types in preparation for
converting the accounting algorithms to atomic operations. his patch
just converts the variables; the algorithmic changes are in a
separate patch for clarity.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
log->l_tail_lsn is currently protected by the log grant lock. The
lock is only needed for serialising readers against writers, so we
don't really need the lock if we make the l_tail_lsn variable an
atomic. Converting the l_tail_lsn variable to an atomic64_t means we
can start to peel back the grant lock from various operations.
Also, provide functions to safely crack an atomic LSN variable into
it's component pieces and to recombined the components into an
atomic variable. Use them where appropriate.
This also removes the need for explicitly holding a spinlock to read
the l_tail_lsn on 32 bit platforms.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
log->l_last_sync_lsn is updated in only one critical spot - log
buffer Io completion - and is protected by the grant lock here. This
requires the grant lock to be taken for every log buffer IO
completion. Converting the l_last_sync_lsn variable to an atomic64_t
means that we do not need to take the grant lock in log buffer IO
completion to update it.
This also removes the need for explicitly holding a spinlock to read
the l_last_sync_lsn on 32 bit platforms.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
The xlog_grant_push_ail() currently takes the grant lock internally to sample
the tail lsn, last sync lsn and the reserve grant head. Most of the callers
already hold the grant lock but have to drop it before calling
xlog_grant_push_ail(). This is a left over from when the AIL tail pushing was
done in line and hence xlog_grant_push_ail had to drop the grant lock. AIL push
is now done in another thread and hence we can safely hold the grant lock over
the entire xlog_grant_push_ail call.
Push the grant lock outside of xlog_grant_push_ail() to simplify the locking
and synchronisation needed for tail pushing. This will reduce traffic on the
grant lock by itself, but this is only one step in preparing for the complete
removal of the grant lock.
While there, clean up the formatting of xlog_grant_push_ail() to match the
rest of the XFS code.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
The log grant queues are one of the few places left using sv_t
constructs for waiting. Given we are touching this code, we should
convert them to plain wait queues. While there, convert all the
other sv_t users in the log code as well.
Seeing as this removes the last users of the sv_t type, remove the
header file defining the wrapper and the fragments that still
reference it.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Prepare for switching the grant heads to atomic variables by
combining the two 32 bit values that make up the grant head into a
single 64 bit variable. Provide wrapper functions to combine and
split the grant heads appropriately for calculations and use them as
necessary.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
The log grant space calculations are repeated for both write and
reserve grant heads. To make it simpler to convert the calculations
toa different algorithm, factor them so both the gratn heads use the
same calculation functions. Once this is done we can drop the
wrappers that are used in only a couple of place to update both
grant heads at once as they don't provide any particular value.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Factor repeated debug code out of grant head manipulation functions into a
separate function. This removes ifdef DEBUG spagetti from the code and makes
the code easier to follow.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
The grant write and reserve queues use a roll-your-own double linked
list, so convert it to a standard list_head structure and convert
all the list traversals to use list_for_each_entry(). We can also
get rid of the XLOG_TIC_IN_Q flag as we can use the list_empty()
check to tell if the ticket is in a list or not.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
* 'for-linus' of git://oss.sgi.com/xfs/xfs: (36 commits)
xfs: semaphore cleanup
xfs: Extend project quotas to support 32bit project ids
xfs: remove xfs_buf wrappers
xfs: remove xfs_cred.h
xfs: remove xfs_globals.h
xfs: remove xfs_version.h
xfs: remove xfs_refcache.h
xfs: fix the xfs_trans_committed
xfs: remove unused t_callback field in struct xfs_trans
xfs: fix bogus m_maxagi check in xfs_iget
xfs: do not use xfs_mod_incore_sb_batch for per-cpu counters
xfs: do not use xfs_mod_incore_sb for per-cpu counters
xfs: remove XFS_MOUNT_NO_PERCPU_SB
xfs: pack xfs_buf structure more tightly
xfs: convert buffer cache hash to rbtree
xfs: serialise inode reclaim within an AG
xfs: batch inode reclaim lookup
xfs: implement batched inode lookups for AG walking
xfs: split out inode walk inode grabbing
xfs: split inode AG walking into separate code for reclaim
...
Stop having two different names for many buffer functions and use
the more descriptive xfs_buf_* names directly.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
xfs_buf_get_nodaddr() is really used to allocate a buffer that is
uncached. While it is not directly assigned a disk address, the fact
that they are not cached is a more important distinction. With the
upcoming uncached buffer read primitive, we should be consistent
with this disctinction.
While there, make page allocation in xfs_buf_get_nodaddr() safe
against memory reclaim re-entrancy into the filesystem by allowing
a flags parameter to be passed.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Switch to the WRITE_FLUSH_FUA flag for log writes and remove the EOPNOTSUPP
detection for barriers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Delayed logging adds some serialisation to the log force process to
ensure that it does not deference a bad commit context structure
when determining if a CIL push is necessary or not. It does this by
grabing the CIL context lock exclusively, then dropping it before
pushing the CIL if necessary. This causes serialisation of all log
forces and pushes regardless of whether a force is necessary or not.
As a result fsync heavy workloads (like dbench) can be significantly
slower with delayed logging than without.
To avoid this penalty, copy the current sequence from the context to
the CIL structure when they are swapped. This allows us to do
unlocked checks on the current sequence without having to worry
about dereferencing context structures that may have already been
freed. Hence we can remove the CIL context locking in the forcing
code and only call into the push code if the current context matches
the sequence we need to force.
By passing the sequence into the push code, we can check the
sequence again once we have the CIL lock held exclusive and abort if
the sequence has already been pushed. This avoids a lock round-trip
and unnecessary CIL pushes when we have racing push calls.
The result is that the regression in dbench performance goes away -
this change improves dbench performance on a ramdisk from ~2100MB/s
to ~2500MB/s. This compares favourably to not using delayed logging
which retuns ~2500MB/s for the same workload.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[hch: dropped a few hunks that need structural changes instead]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
