Commit Graph

1228 Commits

Author SHA1 Message Date
Linus Torvalds
62c8d92278 Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw
Pull GFS2 changes from Steven Whitehouse.

* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw: (24 commits)
  GFS2: Fix quota adjustment return code
  GFS2: Add rgrp information to block_alloc trace point
  GFS2: Eliminate unused "new" parameter to gfs2_meta_indirect_buffer
  GFS2: Update glock doc to add new stats info
  GFS2: Update main gfs2 doc
  GFS2: Remove redundant metadata block type check
  GFS2: Fix sgid propagation when using ACLs
  GFS2: eliminate log elements and simplify
  GFS2: Eliminate vestigial sd_log_le_rg
  GFS2: Eliminate needless parameter from function gfs2_setbit
  GFS2: Log code fixes
  GFS2: Remove unused argument from gfs2_internal_read
  GFS2: Remove bd_list_tr
  GFS2: Remove duplicate log code
  GFS2: Clean up log write code path
  GFS2: Use variable rather than qa to determine if unstuff necessary
  GFS2: Change variable blk to biblk
  GFS2: Fix function parameter comments in rgrp.c
  GFS2: Eliminate offset parameter to gfs2_setbit
  GFS2: Use slab for block reservation memory
  ...
2012-05-21 19:21:20 -07:00
Bob Peterson
500242ac61 GFS2: Fix quota adjustment return code
This patch changes function gfs2_adjust_quota so that it properly
returns a good (zero) return code on the normal path through the code.
Without this, mounting GFS2 with -o quota=account periodically gave
this error message: GFS2: fsid=cluster:fs: gfs2_quotad: sync error -5

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-05-16 12:22:38 +01:00
Bob Peterson
41db1ab9be GFS2: Add rgrp information to block_alloc trace point
This is a second attempt at a patch that adds rgrp information to the
block allocation trace point for GFS2. As suggested, the patch was
modified to list the rgrp information _after_ the fields that exist today.

Again, the reason for this patch is to allow us to trace and debug
problems with the block reservations patch, which is still in the works.
We can debug problems with reservations if we can see what block allocations
result from the block reservations. It may also be handy in figuring out
if there are problems in rgrp free space accounting. In other words,
we can use it to track the rgrp and its free space along side the allocations
that are taking place.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-05-11 10:31:34 +01:00
Bob Peterson
f2f9c81244 GFS2: Eliminate unused "new" parameter to gfs2_meta_indirect_buffer
It turns out that the "new" parameter to function gfs2_meta_indirect_buffer
was always being passed in as zero. Therefore, this patch eliminates it
and simplifies the function.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-05-11 10:19:23 +01:00
Linus Torvalds
26fe575028 vfs: make it possible to access the dentry hash/len as one 64-bit entry
This allows comparing hash and len in one operation on 64-bit
architectures.  Right now only __d_lookup_rcu() takes advantage of this,
since that is the case we care most about.

The use of anonymous struct/unions hides the alternate 64-bit approach
from most users, the exception being a few cases where we initialize a
'struct qstr' with a static initializer.  This makes the problematic
cases use a new QSTR_INIT() helper function for that (but initializing
just the name pointer with a "{ .name = xyzzy }" initializer remains
valid, as does just copying another qstr structure).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-10 19:54:35 -07:00
Bob Peterson
6de1e2f34a GFS2: Remove redundant metadata block type check
This patch removes a redundant metadata block check. See description below.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-05-08 16:18:55 +01:00
Steven Whitehouse
f9425ad4e5 GFS2: Fix sgid propagation when using ACLs
This cleans up the mode setting code when creating inodes. The
SGID bit was being reset by setattr_copy() when the user creating a
subdirectory was not in the owning group. When ACLs are in use this
SGID bit should have been propagated if the ACL allows creation of
a subdirectory. GFS2's behaviour now matches that of the other ACL
supporting filesystems in this regard.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-05-04 14:33:06 +01:00
Bob Peterson
c0752aa7e4 GFS2: eliminate log elements and simplify
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>
2012-05-02 09:14:36 +01:00
Bob Peterson
1c47f09592 GFS2: Eliminate vestigial sd_log_le_rg
This patch eliminates gfs2 superblock variable sd_log_le_rg which
is no longer used.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-30 10:41:04 +01:00
Bob Peterson
06344b9186 GFS2: Eliminate needless parameter from function gfs2_setbit
This patch eliminates parameter "buf1" from function gfs2_setbit.
This is possible because it was always passed in as bi->bi_bh->b_data.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-27 10:46:07 +01:00
Steven Whitehouse
144a4c2ff7 GFS2: Log code fixes
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>
2012-04-24 16:44:38 +01:00
Andrew Price
4306629e1c GFS2: Remove unused argument from gfs2_internal_read
gfs2_internal_read accepts an unused ra_state argument, left over from
when we did readahead on the rindex. Since there are currently no plans
to add back this readahead, this patch removes the ra_state parameter
and updates the functions which call gfs2_internal_read accordingly.

Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24 16:44:37 +01:00
Steven Whitehouse
c50b91c4bd GFS2: Remove bd_list_tr
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>
2012-04-24 16:44:36 +01:00
Steven Whitehouse
dad30e9031 GFS2: Remove duplicate log code
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>
2012-04-24 16:44:35 +01:00
Steven Whitehouse
e8c92ed769 GFS2: Clean up log write code path
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>
2012-04-24 16:44:34 +01:00
Bob Peterson
2f7ee358e5 GFS2: Use variable rather than qa to determine if unstuff necessary
In the future, the qadata structure will be eliminated and merged
back in with the block reservation structure, after we extend the
lifespan of that. This patch is a step forward in eliminating the
qadata structure. It adds a variable to the do_grow function to
determine when unstuffing is necessary, and has been done.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24 16:44:33 +01:00
Bob Peterson
9598d25ed9 GFS2: Change variable blk to biblk
In the resource group code, we have no less than three different
kinds of block references: block relative to the file system (u64),
block relative to the rgrp (u32), and block relative to the bitmap.
This is a small step to making the code more readable; it renames
variable blk to biblk to solidify in my mind that it's relative to
the bitmap and nothing else.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24 16:44:32 +01:00
Bob Peterson
886b141675 GFS2: Fix function parameter comments in rgrp.c
This patch just fixes a bunch of function parameter comments.
Slowly, over the years, the comments have gotten out of date
(mostly my fault, as I haven't been good at keeping them up to date).
This patch rectifies some of that.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24 16:44:31 +01:00
Bob Peterson
29c578f567 GFS2: Eliminate offset parameter to gfs2_setbit
This patch eliminates a redundant parameter.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24 16:44:30 +01:00
Bob Peterson
36f5580be1 GFS2: Use slab for block reservation memory
This patch changes block reservations so it uses slab storage.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24 16:44:29 +01:00
Bob Peterson
b120193e36 GFS2: make function gfs2_page_add_databufs static
This patch makes function gfs2_page_add_databufs static.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24 16:44:28 +01:00
Bob Peterson
df3fd117f9 GFS2: Rename function gfs2_close to gfs2_release
This patch renames function gfs2_close to gfs2_release.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24 16:44:27 +01:00
Steven Whitehouse
14e5f1848d GFS2: Make gfs2_log_fake_buf() write the buffer too
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>
2012-04-24 16:44:26 +01:00
Steven Whitehouse
fdb76a4228 GFS2: Drop "pull" argument from log_write_header()
The "pull" argument to log_write_header() is only used
for debug purposes and it is not really needed any more. There
are other tests for this particular problem, so I think we can
dispose of it in order to simplify the code.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24 16:44:24 +01:00
Bob Peterson
4c569a72c3 GFS2: Instruct DLM to avoid queue convert slowdown
This patch instructs DLM to prevent an "in place" conversion, where the
lock just stays on the granted queue, and instead forces the conversion to
the back of the convert queue. This is done on upward conversions only.
    
This is useful in cases where, for example, a lock is frequently needed in
PR on one node, but another node needs it temporarily in EX to update it.
This may happen, for example, when the rindex is being updated by gfs2_grow.
The gfs2_grow needs to have the lock in EX, but the other nodes need to
re-read it to retrieve the updates. The glock is already granted in PR on
the non-growing nodes, so this prevents them from continually re-granting
the lock in PR, and forces the EX from gfs2_grow to go through.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24 13:26:50 +01:00
Linus Torvalds
1b6150fe82 Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-fixes
Pull GFS2 fixes from Steven Whitehouse

* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-fixes:
  GFS2: Allow caching of rindex glock
  GFS2: Make sure rindex is uptodate before starting transactions
  GFS2: use depends instead of select in kconfig
  GFS2: put glock reference in error patch of read_rindex_entry
2012-04-11 11:04:45 -07:00
Bob Peterson
ca9248d833 GFS2: Allow caching of rindex glock
This patch allows caching of the rindex glock. We were previously
setting the GL_NOCACHE bit when the glock was released. That forced
the rindex inode to be invalidated, which caused us to re-read
rindex at the next access. However, it caused the glock to be
unnecessarily bounced around the cluster. This patch allows
the glock to remain cached, but it still causes the rindex to be
re-read once it has been written to by gfs2_grow.

Ben and I have tested single-node gfs2_grow cases and I've tested
clustered gfs2_grow cases on my four-node cluster.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-10 13:49:53 +01:00
Bob Peterson
5e2f7d617b GFS2: Make sure rindex is uptodate before starting transactions
This patch removes the call from gfs2_blk2rgrd to function
gfs2_rindex_update and replaces it with individual calls.
The former way turned out to be too problematic.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-05 10:20:10 +01:00
Al Viro
2f99c36986 get rid of pointless includes of ext2_fs.h
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-31 16:03:15 -04:00
Benjamin Poirier
97cc008aaa GFS2: use depends instead of select in kconfig
Avoids having to duplicate the dependencies of what is 'select'ed (and on
down...)

Those dependencies are currently incomplete, leading to broken builds with
GFS2_FS_LOCKING_DLM=y and IP_SCTP=n.

Signed-off-by: Benjamin Poirier <bpoirier@suse.de>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-03-26 09:18:02 +01:00
Bob Peterson
c1ac539ed4 GFS2: put glock reference in error patch of read_rindex_entry
This patch fixes the error path of function read_rindex_entry
so that it correctly gives up its glock reference in cases where
there is a race to re-read the rindex after gfs2_grow.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-03-26 09:16:56 +01:00
Linus Torvalds
ad12ab259d Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw
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
2012-03-21 18:00:03 -07:00
Linus Torvalds
e2a0883e40 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs pile 1 from Al Viro:
 "This is _not_ all; in particular, Miklos' and Jan's stuff is not there
  yet."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (64 commits)
  ext4: initialization of ext4_li_mtx needs to be done earlier
  debugfs-related mode_t whack-a-mole
  hfsplus: add an ioctl to bless files
  hfsplus: change finder_info to u32
  hfsplus: initialise userflags
  qnx4: new helper - try_extent()
  qnx4: get rid of qnx4_bread/qnx4_getblk
  take removal of PF_FORKNOEXEC to flush_old_exec()
  trim includes in inode.c
  um: uml_dup_mmap() relies on ->mmap_sem being held, but activate_mm() doesn't hold it
  um: embed ->stub_pages[] into mmu_context
  gadgetfs: list_for_each_safe() misuse
  ocfs2: fix leaks on failure exits in module_init
  ecryptfs: make register_filesystem() the last potential failure exit
  ntfs: forgets to unregister sysctls on register_filesystem() failure
  logfs: missing cleanup on register_filesystem() failure
  jfs: mising cleanup on register_filesystem() failure
  make configfs_pin_fs() return root dentry on success
  configfs: configfs_create_dir() has parent dentry in dentry->d_parent
  configfs: sanitize configfs_create()
  ...
2012-03-21 13:36:41 -07:00
Al Viro
48fde701af switch open-coded instances of d_make_root() to new helper
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-20 21:29:35 -04:00
Cong Wang
d93492855f gfs2: remove the second argument of k[un]map_atomic()
Signed-off-by: Cong Wang <amwang@redhat.com>
2012-03-20 21:48:23 +08:00
Bob Peterson
220cca2a4f GFS2: Change truncate page allocation to be GFP_NOFS
This patch changes the page allocation in gfs2_block_truncate_page
and two others to GFP_NOFS to avoid deadlock in low-memory conditions.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-03-20 11:05:00 +00:00
Benjamin Marzinski
58a7d5fb8e GFS2: call gfs2_write_alloc_required for each chunk
gfs2_fallocate was calling gfs2_write_alloc_required() once at the start of
the function. This caused problems since gfs2_write_alloc_required used a
long unsigned int for the len, but gfs2_fallocate could allocate a much
larger amount.  This patch will move the call into the loop where the
chunks are actually allocated and zeroed out. This will keep the allocation
size under the limit, and also allow gfs2_fallocate to quickly skip over
sections of the file that are already completely allocated.

fallcate_chunk was also not correctly setting the file size.  It was using the
len veriable to find the last block written to, but by the time it was setting
the size, the len variable had already been decremented to 0.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-03-09 15:29:10 +00:00
Steven Whitehouse
34cc1781c2 GFS2: Clean up log flush header writing
We already send both a pre and post flush to the block device
when writing a journal header. There is no need to wait for
the previous I/O specifically when we do this, unless we've
turned "barriers" off.

As a side effect, this also cleans up the code path for flushing
the journal and makes it more readable.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-03-09 14:07:06 +00:00
Steven Whitehouse
75ca61c101 GFS2: Remove a __GFP_NOFAIL allocation
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>
2012-03-08 12:10:23 +00:00
Steven Whitehouse
35e478f422 GFS2: Flush pending glock work when evicting an inode
This ensures that we will not try to access the inode thats
being flushed via the glock after it has been freed.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-03-07 10:43:02 +00:00
Bob Peterson
58884c4df0 GFS2: make sure rgrps are up to date in func gfs2_blk2rgrpd
This patch adds a call to gfs2_rindex_update from function gfs2_blk2rgrpd
and removes calls to it that are made redundant by it. The problem is
that a gfs2_grow can add rgrps to the rindex, then put those rgrps into
use, thus rendering the rindex we read in at mount time incomplete.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-03-05 15:10:34 +00:00
Bob Peterson
6aad1c3d3e GFS2: Eliminate sd_rindex_mutex
Over time, we've slowly eliminated the use of sd_rindex_mutex.
Up to this point, it was only used in two places: function
gfs2_ri_total (which totals the file system size by reading
and parsing the rindex file) and function gfs2_rindex_update
which updates the rgrps in memory. Both of these functions have
the rindex glock to protect them, so the rindex is unnecessary.
Since gfs2_grow writes to the rindex via the meta_fs, the mutex
is in the wrong order according to the normal rules. This patch
eliminates the mutex entirely to avoid the problem.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-03-05 15:06:56 +00:00
Bob Peterson
a08fd280b5 GFS2: Unlock rindex mutex on glock error
This patch fixes an error path in function gfs2_rindex_update
that leaves the rindex mutex held.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-03-01 09:25:21 +00:00
Steven Whitehouse
08728f2d8b GFS2: Make bd_cmp() static
Add missing static to bd_cmp()

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-02-28 17:11:27 +00:00
Bob Peterson
4a36d08d0d GFS2: Sort the ordered write list
This patch sorts the ordered write list for GFS2 writes.
This increases the throughput for simultaneous writes.
For example, if you have ten processes, all doing:
dd if=/dev/zero of=/mnt/gfs2/fileX
on different files, the throughput will be much better.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-02-28 17:10:53 +00:00
Steven Whitehouse
66fc061bda GFS2: FITRIM ioctl support
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>
2012-02-28 17:10:21 +00:00
Steven Whitehouse
47ac5537a7 GFS2: Move two functions from log.c to lops.c
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>
2012-02-28 17:09:59 +00:00
Steven Whitehouse
a245769f25 GFS2: glock statistics gathering
The stats are divided into two sets: those relating to the
super block and those relating to an individual glock. The
super block stats are done on a per cpu basis in order to
try and reduce the overhead of gathering them. They are also
further divided by glock type.

In the case of both the super block and glock statistics,
the same information is gathered in each case. The super
block statistics are used to provide default values for
most of the glock statistics, so that newly created glocks
should have, as far as possible, a sensible starting point.

The statistics are divided into three pairs of mean and
variance, plus two counters. The mean/variance pairs are
smoothed exponential estimates and the algorithm used is
one which will be very familiar to those used to calculation
of round trip times in network code.

The three pairs of mean/variance measure the following
things:

 1. DLM lock time (non-blocking requests)
 2. DLM lock time (blocking requests)
 3. Inter-request time (again to the DLM)

A non-blocking request is one which will complete right
away, whatever the state of the DLM lock in question. That
currently means any requests when (a) the current state of
the lock is exclusive (b) the requested state is either null
or unlocked or (c) the "try lock" flag is set. A blocking
request covers all the other lock requests.

There are two counters. The first is there primarily to show
how many lock requests have been made, and thus how much data
has gone into the mean/variance calculations. The other counter
is counting queueing of holders at the top layer of the glock
code. Hopefully that number will be a lot larger than the number
of dlm lock requests issued.

So why gather these statistics? There are several reasons
we'd like to get a better idea of these timings:

1. To be able to better set the glock "min hold time"
2. To spot performance issues more easily
3. To improve the algorithm for selecting resource groups for
allocation (to base it on lock wait time, rather than blindly
using a "try lock")
Due to the smoothing action of the updates, a step change in
some input quantity being sampled will only fully be taken
into account after 8 samples (or 4 for the variance) and this
needs to be carefully considered when interpreting the
results.

Knowing both the time it takes a lock request to complete and
the average time between lock requests for a glock means we
can compute the total percentage of the time for which the
node is able to use a glock vs. time that the rest of the
cluster has its share. That will be very useful when setting
the lock min hold time.

The other point to remember is that all times are in
nanoseconds. Great care has been taken to ensure that we
measure exactly the quantities that we want, as accurately
as possible. There are always inaccuracies in any
measuring system, but I hope this is as accurate as we
can reasonably make it.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-02-28 17:09:42 +00:00
Steven Whitehouse
a365fbf354 GFS2: Read resource groups on mount
This makes mount take slightly longer, but at the same time, the first
write to the filesystem will be faster too. It also means that if there
is a problem in the resource index, then we can refuse to mount rather
than having to try and report that when the first write occurs.

In addition, to avoid recursive locking, we hvae to take account of
instances when the rindex glock may already be held when we are
trying to update the rbtree of resource groups.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-02-28 09:52:39 +00:00
Bob Peterson
9e73f571ea GFS2: Ensure rindex is uptodate for fallocate
This patch fixes a problem whereby gfs2_grow was failing and causing GFS2
to assert. The problem was that when GFS2's fallocate operation tried to
acquire an "allocation" it made sure the rindex was up to date, and if not,
it called gfs2_rindex_update. However, if the file being fallocated was
the rindex itself, it was already locked at that point. By calling
gfs2_rindex_update at an earlier point in time, we bring rindex up to date
and thereby avoid trying to lock it when the "allocation" is acquired.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-02-28 09:48:30 +00:00