This patch copies the body of gfs2_trans_add_bh into the two newly
added gfs2_trans_add_data and gfs2_trans_add_meta functions. We can
then move the .lo_add functions from lops.c into trans.c and call
them directly.
As a result of this, we no longer need to use the .lo_add functions
at all, so that is removed from the log operations structure.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This moves the lo_add function for revokes into trans.c, removing
a function call and making the code easier to read.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
In gfs2_trans_add_bh(), gfs2 was testing if a there was a bd attached to the
buffer without having the gfs2_log_lock held. It was then assuming it would
stay attached for the rest of the function. However, without either the log
lock being held of the buffer locked, __gfs2_ail_flush() could detach bd at any
time. This patch moves the locking before the test. If there isn't a bd
already attached, gfs2 can safely allocate one and attach it before locking.
There is no way that the newly allocated bd could be on the ail list,
and thus no way for __gfs2_ail_flush() to detach it.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cleans up two cases where variables were assigned values but then never
used again.
Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
When we read an invalid block from the journal, we should not call
withdraw, but simply print a message and return an error. It is
up to the caller to then handle that error. In the case of mount
that means a failed mount, rather than a withdraw (requiring a
reboot). In the case of recovering another nodes journal then
we return an error via the uevent.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch eliminates the gfs2_log_element data structure and
rolls its two components into the gfs2_bufdata. This makes the code
easier to understand and makes it easier to migrate to a rbtree
to keep the list sorted.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch removes a log lock from around atomic operation where
it is not needed, removes an unused variable, and also changes
a void pointer used incorrectly to a struct page pointer.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This is another clean up in the logging code. This per-transaction
list was largely unused. Its main function was to ensure that the
number of buffers in a transaction was correct, however that counter
was only used to check the number of buffers in the bd_list_tr, plus
an assert at the end of each transaction. With the assert now changed
to use the calculated buffer counts, we can remove both bd_list_tr and
its associated counter.
This should make the code easier to understand as well as shrinking
a couple of structures.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
The main part of this patch merges the two functions used to
write metadata and data buffers to the log. Most of the code
is common between the two functions, so this provides a nice
clean up, and makes the code more readable.
The gfs2_get_log_desc() function is also extended to take two more
arguments, and thus avoid having to set the length and data1
fields of this strucuture as a separate operation.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Prior to this patch, we have two ways of sending i/o to the log.
One of those is used when we need to allocate both the data
to be written itself and also a buffer head to submit it. This
is done via sb_getblk and friends. This is used mostly for writing
log headers.
The other method is used when writing blocks which have some
in-place counterpart. This is the case for all the metadata
blocks which are journalled, and when journaled data is in use,
for unescaped journalled data blocks.
This patch replaces both of those two methods, and about half
a dozen separate i/o submission points with a single i/o
submission function. We also go direct to bio rather than
using buffer heads, since this allows us to build i/o
requests of the maximum size for the block device in
question. It also reduces the memory required for flushing
the log, which can be very useful in low memory situations.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Since we always write the buffer directly after this function
returns, we might as well merge it into here. This is a clean
up in preparation for some further updates to the log code
which are coming soon.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Pull gfs2 changes from Steven Whitehouse.
* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw:
GFS2: Change truncate page allocation to be GFP_NOFS
GFS2: call gfs2_write_alloc_required for each chunk
GFS2: Clean up log flush header writing
GFS2: Remove a __GFP_NOFAIL allocation
GFS2: Flush pending glock work when evicting an inode
GFS2: make sure rgrps are up to date in func gfs2_blk2rgrpd
GFS2: Eliminate sd_rindex_mutex
GFS2: Unlock rindex mutex on glock error
GFS2: Make bd_cmp() static
GFS2: Sort the ordered write list
GFS2: FITRIM ioctl support
GFS2: Move two functions from log.c to lops.c
GFS2: glock statistics gathering
In order to ensure that we've got enough buffer heads for flushing
the journal, the orignal code used __GFP_NOFAIL when performing
this allocation. Here we dispense with that in favour of using a
mempool. This should improve efficiency in low memory conditions
since flushing the journal is a good way to get memory back, we
don't want to be spinning, waiting on memory allocations. The
buffers which are allocated via this mempool are fairly short lived,
so that we'll recycle them pretty quickly.
Although there are other memory allocations which occur during the
journal flush process, this is the one which can potentially require
the most memory, so the most important one to fix.
The amount of memory reserved is a fixed amount, and we should not need
to scale it when there are a greater number of filesystems in use.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
The FITRIM ioctl provides an alternative way to send discard requests to
the underlying device. Using the discard mount option results in every
freed block generating a discard request to the block device. This can
be slow, since many block devices can only process discard requests of
larger sizes, and also such operations can be time consuming.
Rather than using the discard mount option, FITRIM allows a sweep of the
filesystem on an occasional basis, and also to optionally avoid sending
down discard requests for smaller regions.
In GFS2 FITRIM will work at resource group granularity. There is a flag
for each resource group which keeps track of which resource groups have
been trimmed. This flag is reset whenever a deallocation occurs in the
resource group, and set whenever a successful FITRIM of that resource
group has taken place. This helps to reduce repeated discard requests
for the same block ranges, again improving performance.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
gfs2_log_get_buf() and gfs2_log_fake_buf() are both used
only in lops.c, so move them next to their callers and they
can then become static.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Some items picked up through automated code analysis. A few bits
of unreachable code and two unchecked return values.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Here is an update of Bob's original rbtree patch which, in addition, also
resolves the rather strange ref counting that was being done relating to
the bitmap blocks.
Originally we had a dual system for journaling resource groups. The metadata
blocks were journaled and also the rgrp itself was added to a list. The reason
for adding the rgrp to the list in the journal was so that the "repolish
clones" code could be run to update the free space, and potentially send any
discard requests when the log was flushed. This was done by comparing the
"cloned" bitmap with what had been written back on disk during the transaction
commit.
Due to this, there was a requirement to hang on to the rgrps' bitmap buffers
until the journal had been flushed. For that reason, there was a rather
complicated set up in the ->go_lock ->go_unlock functions for rgrps involving
both a mutex and a spinlock (the ->sd_rindex_spin) to maintain a reference
count on the buffers.
However, the journal maintains a reference count on the buffers anyway, since
they are being journaled as metadata buffers. So by moving the code which deals
with the post-journal accounting for bitmap blocks to the metadata journaling
code, we can entirely dispense with the rather strange buffer ref counting
scheme and also the requirement to journal the rgrps.
The net result of all this is that the ->sd_rindex_spin is left to do exactly
one job, and that is to look after the rbtree or rgrps.
This patch is designed to be a stepping stone towards using RCU for the rbtree
of resource groups, however the reduction in the number of uses of the
->sd_rindex_spin is likely to have benefits for multi-threaded workloads,
anyway.
The patch retains ->go_lock and ->go_unlock for rgrps, however these maybe also
be removed in future in favour of calling the functions directly where required
in the code. That will allow locking of resource groups without needing to
actually read them in - something that could be useful in speeding up statfs.
In the mean time though it is valid to dereference ->bi_bh only when the rgrp
is locked. This is basically the same rule as before, modulo the references not
being valid until the following journal flush.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Cc: Benjamin Marzinski <bmarzins@redhat.com>
The GLF_LRU flag introduced in the previous patch can be
used to check if a glock is on the lru list when a new
holder is queued and if so remove it, without having first
to get the lru_lock.
The main purpose of this patch however is to optimise the
glocks left over when an inode at end of life is being
evicted. Previously such glocks were left with the GLF_LFLUSH
flag set, so that when reclaimed, each one required a log flush.
This patch resets the GLF_LFLUSH flag when there is nothing
left to flush thus preventing later log flushes as glocks are
reused or demoted.
In order to do this, we need to keep track of the number of
revokes which are outstanding, and also to clear the GLF_LFLUSH
bit after a log commit when only revokes have been processed.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Rather than allowing the glocks to be scheduled for possible
reclaim as soon as they have exited the journal, this patch
delays their entry to the list until the glocks in question
are no longer in use.
This means that we will rely on the vm for writeback of all
dirty data and metadata from now on. When glocks are added
to the lru list they should be freeable much faster since all
the I/O required to free them should have already been completed.
This should lead to much better I/O patterns under low memory
conditions.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits)
Documentation/iostats.txt: bit-size reference etc.
cfq-iosched: removing unnecessary think time checking
cfq-iosched: Don't clear queue stats when preempt.
blk-throttle: Reset group slice when limits are changed
blk-cgroup: Only give unaccounted_time under debug
cfq-iosched: Don't set active queue in preempt
block: fix non-atomic access to genhd inflight structures
block: attempt to merge with existing requests on plug flush
block: NULL dereference on error path in __blkdev_get()
cfq-iosched: Don't update group weights when on service tree
fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away
block: Require subsystems to explicitly allocate bio_set integrity mempool
jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
fs: make fsync_buffers_list() plug
mm: make generic_writepages() use plugging
blk-cgroup: Add unaccounted time to timeslice_used.
block: fixup plugging stubs for !CONFIG_BLOCK
block: remove obsolete comments for blkdev_issue_zeroout.
blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.
...
Fix up conflicts in fs/{aio.c,super.c}
The previous patch missed a couple of places where the AIL list
needed locking, so this fixes up those places, plus a comment
is corrected too.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Chinner <dchinner@redhat.com>
The log lock is currently used to protect the AIL lists and
the movements of buffers into and out of them. The lists
are self contained and no log specific items outside the
lists are accessed when starting or emptying the AIL lists.
Hence the operation of the AIL does not require the protection
of the log lock so split them out into a new AIL specific lock
to reduce the amount of traffic on the log lock. This will
also reduce the amount of serialisation that occurs when
the gfs2_logd pushes on the AIL to move it forward.
This reduces the impact of log pushing on sequential write
throughput.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
With the plugging now being explicitly controlled by the
submitter, callers need not pass down unplugging hints
to the block layer. If they want to unplug, it's because they
manually plugged on their own - in which case, they should just
unplug at will.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This has a number of advantages:
- Reduces contention on the hash table lock
- Makes the code smaller and simpler
- Should speed up glock dumps when under load
- Removes ref count changing in examine_bucket
- No longer need hash chain lock in glock_put() in common case
There are some further changes which this enables and which
we may do in the future. One is to look at using SLAB_RCU,
and another is to look at using a per-cpu counter for the
per-sb glock counter, since that is touched twice in the
lifetime of each glock (but only used at umount time).
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch contains various tweaks to how log flushes and active item writeback
work. gfs2_logd is now managed by a waitqueue, and gfs2_log_reseve now waits
for gfs2_logd to do the log flushing. Multiple functions were rewritten to
remove the need to call gfs2_log_lock(). Instead of using one test to see if
gfs2_logd had work to do, there are now seperate tests to check if there
are two many buffers in the incore log or if there are two many items on the
active items list.
This patch is a port of a patch Steve Whitehouse wrote about a year ago, with
some minor changes. Since gfs2_ail1_start always submits all the active items,
it no longer needs to keep track of the first ai submitted, so this has been
removed. In gfs2_log_reserve(), the order of the calls to
prepare_to_wait_exclusive() and wake_up() when firing off the logd thread has
been switched. If it called wake_up first there was a small window for a race,
where logd could run and return before gfs2_log_reserve was ready to get woken
up. If gfs2_logd ran, but did not free up enough blocks, gfs2_log_reserve()
would be left waiting for gfs2_logd to eventualy run because it timed out.
Finally, gt_logd_secs, which controls how long to wait before gfs2_logd times
out, and flushes the log, can now be set on mount with ar_commit.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
When we queue data buffers for ordered write, the buffers are added
to the head of the ordered write list. When the log needs to push
these buffers to disk, it also walks the list from the head. The
result is that the the ordered buffers are submitted to disk in
reverse order.
For large writes, this means that whenever the log flushes large
streams of reverse sequential order buffers are pushed down into the
block layers. The elevators don't handle this particularly well, so
IO rates tend to be significantly lower than if the IO was issued in
ascending block order.
Queue new ordered buffers to the tail of the ordered buffer list to
ensure that IO is dispatched in the order it was submitted. This
should significantly improve large sequential write speeds. On a
disk capable of 85MB/s, speeds increase from 50MB/s to 65MB/s for
noop and from 38MB/s to 50MB/s for cfq.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
There are two spare field in the header common to all GFS2
metadata. One is just the right size to fit a journal id
in it, and this patch updates the journal code so that each
time a metadata block is modified, we tag it with the journal
id of the node which is performing the modification.
The reason for this is that it should make it much easier to
debug issues which arise if we can tell which node was the
last to modify a particular metadata block.
Since the field is updated before the block is written into
the journal, each journal should only contain metadata which
is tagged with its own journal id. The one exception to this
is the journal header block, which might have a different node's
id in it, if that journal was recovered by another node in the
cluster.
Thus each journal will contain a record of which nodes recovered
it, via the journal header.
The other field in the metadata header could potentially be
used to hold information about what kind of operation was
performed, but for the time being we just zero it on each
transaction so that if we use it for that in future, we'll
know that the information (where it exists) is reliable.
I did consider using the other field to hold the journal
sequence number, however since in GFS2's journaling we write
the modified data into the journal and not the original
data, this gives no information as to what action caused the
modification, so I think we can probably come up with a better
use for those 64 bits in the future.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch adds the ability to trace various aspects of the GFS2
filesystem. The trace points are divided into three groups,
glocks, logging and bmap. These points have been chosen because
they allow inspection of the major internal functions of GFS2
and they are also generic enough that they are unlikely to need
any major changes as the filesystem evolves.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
After Jens recent updates:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=a1f242524c3c1f5d40f1c9c343427e34d1aadd6e
et al. this is a patch to bring gfs2 uptodate with the core
code. Also I've managed to squash another call to ll_rw_block()
along the way.
There is still one part of the GFS2 I/O paths which are not correctly
annotated and that is due to the sharing of the writeback code between
the data and metadata address spaces. I would like to change that too,
but this patch is still worth doing on its own, I think.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This is the big patch that I've been working on for some time
now. There are many reasons for wanting to make this change
such as:
o Reducing overhead by eliminating duplicated fields between structures
o Simplifcation of the code (reduces the code size by a fair bit)
o The locking interface is now the DLM interface itself as proposed
some time ago.
o Fewer lookups of glocks when processing replies from the DLM
o Fewer memory allocations/deallocations for each glock
o Scope to do further optimisations in the future (but this patch is
more than big enough for now!)
Please note that (a) this patch relates to the lock_dlm module and
not the DLM itself, that is still a separate module; and (b) that
we retain the ability to build GFS2 as a standalone single node
filesystem with out requiring the DLM.
This patch needs a lot of testing, hence my keeping it I restarted
my -git tree after the last merge window. That way, this has the maximum
exposure before its merged. This is (modulo a few minor bug fixes) the
same patch that I've been posting on and off the the last three months
and its passed a number of different tests so far.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch is performance related. When we're doing a log flush,
I noticed we were calling buf_lo_incore_commit twice: once for
data bufs and once for metadata bufs. Since this is the same
function and does the same thing in both cases, there should be
no reason to call it twice. Since we only need to call it once,
we can also make it faster by removing it from the generic "lops"
code and making it a stand-along static function.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
The only reason for adding glocks to the journal was to keep track
of which locks required a log flush prior to release. We add a
flag to the glock to allow this check to be made in a simpler way.
This reduces the size of a glock (by 12 bytes on i386, 24 on x86_64)
and means that we can avoid extra work during the journal flush.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch splits gfs2_writepage into separate functions for each of
the three cases: writeback, ordered and journalled. As a result
it becomes a lot easier to see what each one is doing. The common
code is moved into gfs2_writepage_common.
This fixes a performance bug where we were doing more work than
strictly required in the ordered write case.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch cleans up the code for writing journaled data into the log.
It also removes the need to allocate a small "tag" structure for each
block written into the log. Instead we just keep count of the outstanding
I/O so that we can be sure that its all been written at the correct time.
Another result of this patch is that a number of ll_rw_block() calls
have become submit_bh() calls, closing some races at the same time.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
The following alters gfs2_trans_add_revoke() to take a struct
gfs2_bufdata as an argument. This eliminates the memory allocation which
was previously required by making use of the already existing struct
gfs2_bufdata. It makes some sanity checks to ensure that the
gfs2_bufdata has been removed from all the lists before its recycled as
a revoke structure. This saves one memory allocation and one free per
revoke structure.
Also as a result, and to simplify the locking, since there is no longer
any blocking code in gfs2_trans_add_revoke() we must hold the log lock
whenever this function is called. This reduces the amount of times we
take and unlock the log lock.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
The old revoke structure was allocated using kalloc/kfree but
there is a slab cache for gfs2_bufdata, so we should use that
now that the structures have been converted.
This is part two of the patch series to merge the revoke
and gfs2_bufdata structures.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Both the revoke structure and the bufdata structure are quite similar.
They are basically small tags which are put on lists. In addition to
which the revoke structure is always allocated when there is a bufdata
structure which is (or can be) freed. As such it should be possible to
reduce the number of frees and allocations by using the same structure
for both purposes.
This patch is the first step along that path. It replaces existing uses
of the revoke structure with the bufdata structure.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
The following patch removes the ordered write processing from
databuf_lo_before_commit() and moves it to log.c. This has the effect of
greatly simplyfying databuf_lo_before_commit() and well as potentially
making the ordered write code more efficient.
As a side effect of this, its now possible to remove ordered buffers
from the ordered buffer list at any time, so we now make use of this in
invalidatepage and releasepage to ensure timely release of these
buffers.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
gfs2_pin and gfs2_unpin are only used in lops.c, despite being
defined in meta_io.c, so this patch moves them into lops.c and
makes them static. At the same time, its possible to clean up
the locking in the buf and databuf _lo_add() functions so that
we only need to grab the spinlock once. Also we have to move
lock_buffer() around the _lo_add() functions since we can't
do that in gfs2_pin() any more since we hold the spinlock
for the duration of that function.
As a result, the code shrinks by 12 lines and we do far fewer
operations when adding buffers to the log. It also makes the
code somewhat easier to read & understand.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This is a patch to GFS2 to protect sd_log_num_jdata with the
gfs2_log_lock. Without this patch, there is a timing window
where you can get hit the following assert from function
gfs2_log_flush():
gfs2_assert_withdraw(sdp,
sdp->sd_log_num_buf + sdp->sd_log_num_jdata ==
sdp->sd_log_commited_buf +
sdp->sd_log_commited_databuf);
I've tested it on my roth cluster and it fixes the problem.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This is the first of five patches for bug #248176:
There were still some critical variables being manipulated outside
the log_lock spinlock. That usually resulted in a hang.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This is part 2 of the patch for bug #245832, part 1 of which is already
in the git tree.
The problem was that sdp->sd_log_num_databuf was not always being
protected by the gfs2_log_lock spinlock, but the sd_log_le_databuf
(which it is supposed to reflect) was protected. That meant there
was a timing window during which gfs2_log_flush called
databuf_lo_before_commit and the count didn't match what was
really on the linked list in that window. So when it ran out of
items on the linked list, it decremented total_dbuf from 0 to -1 and
thus never left the "while(total_dbuf)" loop.
The solution is to protect the variable sdp->sd_log_num_databuf so
that the value will always match the contents of the linked list,
and therefore the number will never go negative, and therefore, the
loop will be exited properly.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch is an addendum to the previous journaled file/unmount patch.
It fixes a problem discovered during testing.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch passes all my nasty tests that were causing the code to
fail under one circumstance or another. Here is a complete summary
of all changes from today's git tree, in order of appearance:
1. There are now separate variables for metadata buffer accounting.
2. Variable sd_log_num_hdrs is no longer needed, since the header
accounting is taken care of by the reserve/refund sequence.
3. Fixed a tiny grammatical problem in a comment.
4. Added a new function "calc_reserved" to calculate the reserved
log space. This isn't entirely necessary, but it has two benefits:
First, it simplifies the gfs2_log_refund function greatly.
Second, it allows for easier debugging because I could sprinkle the
code with calls to this function to make sure the accounting is
proper (by adding asserts and printks) at strategic point of the code.
5. In log_pull_tail there apparently was a kludge to fix up the
accounting based on a "pull" parameter. The buffer accounting is
now done properly, so the kludge was removed.
6. File sync operations were making a call to gfs2_log_flush that
writes another journal header. Since that header was unplanned
for (reserved) by the reserve/refund sequence, the free space had
to be decremented so that when log_pull_tail gets called, the free
space is be adjusted properly. (Did I hear you call that a kludge?
well, maybe, but a lot more justifiable than the one I removed).
7. In the gfs2_log_shutdown code, it optionally syncs the log by
specifying the PULL parameter to log_write_header. I'm not sure
this is necessary anymore. It just seems to me there could be
cases where shutdown is called while there are outstanding log
buffers.
8. In the (data)buf_lo_before_commit functions, I changed some offset
values from being calculated on the fly to being constants. That
simplified some code and we might as well let the compiler do the
calculation once rather than redoing those cycles at run time.
9. This version has my rewritten databuf_lo_add function.
This version is much more like its predecessor, buf_lo_add, which
makes it easier to understand. Again, this might not be necessary,
but it seems as if this one works as well as the previous one,
maybe even better, so I decided to leave it in.
10. In databuf_lo_before_commit, a previous data corruption problem
was caused by going off the end of the buffer. The proper solution
is to have the proper limit in place, rather than stopping earlier.
(Thus my previous attempt to fix it is wrong).
If you don't wrap the buffer, you're stopping too early and that
causes more log buffer accounting problems.
11. In lops.h there are two new (previously mentioned) constants for
figuring out the data offset for the journal buffers.
12. There are also two new functions, buf_limit and databuf_limit to
calculate how many entries will fit in the buffer.
13. In function gfs2_meta_wipe, it needs to distinguish between pinned
metadata buffers and journaled data buffers for proper journal buffer
accounting. It can't use the JDATA gfs2_inode flag because it's
sometimes passed the "real" inode and sometimes the "metadata
inode" and the inode flags will be random bits in a metadata
gfs2_inode. It needs to base its decision on which was passed in.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch is for bugzilla bug 283162, which uncovered a number of
bugs pertaining to writing to files that have the journaled bit on.
These bugs happen most often when writing to the meta_fs because
the files are always journaled. So operations like gfs2_grow were
particularly vulnerable, although many of the problems could be
recreated with normal files after setting the journaled bit on.
The problems fixed are:
-GFS2 wasn't ever writing unstuffed journaled data blocks to their
in-place location on disk. Now it does.
-If you unmounted too quickly after doing IO to a journaled file,
GFS2 was crashing because you would discard a buffer whose bufdata
was still on the active items list. GFS2 now deals with this
gracefully.
-GFS2 was losing track of the bufdata for journaled data blocks,
and it wasn't getting freed, causing an error when you tried to
unmount the module. GFS2 now frees all the bufdata structures.
-There was a memory corruption occurring because GFS2 wrote
twice as many log entries for journaled buffers.
-It was occasionally trying to write journal headers in buffers
that weren't currently mapped.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This is a patch for the first three issues of RHBZ #238162
The first issue is that when you allocate a new page for a file, it will not
start off uptodate. This makes sense, since you haven't written anything to that
part of the file yet. Unfortunately, gfs2_pin() checks to make sure that the
buffers are uptodate. The solution to this is to mark the buffers uptodate in
gfs2_commit_write(), after they have been zeroed out and have the data written
into them. I'm pretty confident with this fix, although it's not completely
obvious that there is no problem with marking the buffers uptodate here.
The second issue is simply that you can try to pin a data buffer that is already
on the incore log, and thus, already pinned. This patch checks to see if this
buffer is already on the log, and exits databuf_lo_add() if it is, just like
buf_lo_add() does.
The third issue is that gfs2_log_flush() doesn't do it's block accounting
correctly. Both metadata and journaled data are logged, but gfs2_log_flush()
only compares the number of metadata blocks with the number of blocks to commit
to the ondisk journal. This patch also counts the journaled data blocks.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
When glock_lo_add and rg_lo_add attempt to add an element to the log, they
check to see if has already been added before locking the log. If another
process adds that element to the log in this window between the check and
locking the log, the element will be added to the list twice. This causes
the log element list to become corrupted in such a way that the log element
can never be successfully removed from the list. This patch pulls the
list_empty() check inside the log lock, to remove this window.
Signed-off-by: Benjamin E. Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
The patch below appears to fix the list corruption that we are seeing on
occasion. Although the transaction structure is private to a single
thread, when the queued structures are dismantled during an in-core
commit, its possible for a different thread to be trying to add the same
structure to another, new, transaction at the same time.
To avoid this, this patch takes the log spinlock during this operation.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
