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  1. 24 Mar, 2009 11 commits
    • Steven Whitehouse's avatar
      GFS2: Add a "demote a glock" interface to sysfs · 64d576ba
      Steven Whitehouse authored 
      This adds a sysfs file called demote_rq to GFS2's
per filesystem directory. Its possible to use this
file to demote arbitrary glocks in exactly the same
way as if a request had come in from a remote node.

This is intended for testing issues relating to caching
of data under glocks. Despite that, the interface is
generic enough to send requests to any type of glock,
but be careful as its not always safe to send an
arbitrary message to an arbitrary glock. For that reason
and to prevent DoS, this interface is restricted to root
only.

The messages look like this:

<type>:<glocknumber> <mode>

Example:

echo -n "2:13324 EX" >/sys/fs/gfs2/unity:myfs/demote_rq

Which means "please demote inode glock (type 2) number 13324 so that
I can get an EX (exclusive) lock". The lock modes are those which
would normally be sent by a remote node in its callback so if you
want to unlock a glock, you use EX, to demote to shared, use SH or PR
(depending on whether you like GFS2 or DLM lock modes better!).

If the glock doesn't exist, you'll get -ENOENT returned. If the
arguments don't make sense, you'll get -EINVAL returned.

The plan is that this interface will be used in combination with
the blktrace patch which I recently posted for comments although
it is, of course, still useful in its own right.
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
      64d576ba
    • Steven Whitehouse's avatar
      GFS2: Expose UUID via sysfs/uevent · 02e3cc70
      Steven Whitehouse authored 
      Since we have a UUID, we ought to expose it to the user via sysfs
and uevents. We already have the fs name in both of these places
(a combination of the lock proto and lock table name) so if we add
the UUID as well, we have a full set.

For older filesystems (i.e. those created before mkfs.gfs2 was writing
UUIDs by default) the sysfs file will appear zero length, and no UUID
env var will be added to the uevents.
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
      02e3cc70
    • Steven Whitehouse's avatar
      GFS2: Support generation of discard requests · f15ab561
      Steven Whitehouse authored 
      This patch allows GFS2 to generate discard requests for blocks which are
no longer useful to the filesystem (i.e. those which have been freed as
the result of an unlink operation). The requests are generated at the
time which those blocks become available for reuse in the filesystem.

In order to use this new feature, you have to specify the "discard"
mount option. The code coalesces adjacent blocks into a single extent
when generating the discard requests, thus generating the minimum
number.

If an error occurs when the request has been sent to the block device,
then it will print a message and turn off the requests for that
filesystem. If the problem is temporary, then you can use remount to
turn the option back on again. There is also a nodiscard mount option
so that you can use remount to turn discard requests off, if required.
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
      f15ab561
    • Steven Whitehouse's avatar
      GFS2: Fix deadlock on journal flush · d8348de0
      Steven Whitehouse authored 
      This patch fixes a deadlock when the journal is flushed and there
are dirty inodes other than the one which caused the journal flush.
Originally the journal flushing code was trying to obtain the
transaction glock while running the flush code for an inode glock.
We no longer require the transaction glock at this point in time
since we know that any attempt to get the transaction glock from
another node will result in a journal flush. So if we are flushing
the journal, we can be sure that the transaction lock is still
cached from when the transaction was started.

By inlining a version of gfs2_trans_begin() (minus the bit which
gets the transaction glock) we can avoid the deadlock problems
caused if there is a demote request queued up on the transaction
glock.

In addition I've also moved the umount rwsem so that it covers
the glock workqueue, since it all demotions are done by this
workqueue now. That fixes a bug on umount which I came across
while fixing the original problem.
Reported-by: default avatarDavid Teigland <teigland@redhat.com>
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
      d8348de0
    • Steven Whitehouse's avatar
      GFS2: Fix error path ref counting for root inode · e7c8707e
      Steven Whitehouse authored 
      We were keeping hold of an extra ref to the root inode in one
of the error paths, that resulted in a hang.
Reported-by: default avatarNate Straz <nstraz@redhat.com>
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
Tested-by: default avatarRobert Peterson <rpeterso@redhat.com>
      e7c8707e
    • Steven Whitehouse's avatar
      GFS2: Remove unused field from glock · ac2425e7
      Steven Whitehouse authored 
      The time stamp field is unused in the glock now that we are
using a shrinker, so that we can remove it and save sizeof(unsigned long)
bytes in each glock.
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
      ac2425e7
    • Steven Whitehouse's avatar
      GFS2: Merge lock_dlm module into GFS2 · f057f6cd
      Steven Whitehouse authored 
      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: default avatarSteven Whitehouse <swhiteho@redhat.com>
      f057f6cd
    • Steven Whitehouse's avatar
      GFS2: Remove "double" locking in quota · 22077f57
      Steven Whitehouse authored 
      We only really need a single spin lock for the quota data, so
lets just use the lru lock for now.
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
Cc: Abhijith Das <adas@redhat.com>
      22077f57
    • Abhijith Das's avatar
      GFS2: change gfs2_quota_scan into a shrinker · 0a7ab79c
      Abhijith Das authored 
      Deallocation of gfs2_quota_data objects now happens on-demand through a
shrinker instead of routinely deallocating through the quotad daemon.
Signed-off-by: default avatarAbhijith Das <adas@redhat.com>
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
      0a7ab79c
    • Abhijith Das's avatar
      GFS2: Bring back lvb-related stuff to lock_nolock to support quotas · 2db2aac2
      Abhijith Das authored 
      The quota code uses lvbs and this is currently not implemented in
lock_nolock, thereby causing panics when quota is enabled with
lock_nolock. This patch adds the relevant bits.
Signed-off-by: default avatarAbhijith Das <adas@redhat.com>
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
      2db2aac2
    • Steven Whitehouse's avatar
      GFS2: Fix remount argument parsing · 6f04c1c7
      Steven Whitehouse authored 
      The following patch fixes an issue relating to remount and argument
parsing. After this fix is applied, remount becomes atomic in that
it either succeeds changing the mount to the new state, or it fails
and leaves it in the old state. Previously it was possible for the
parsing of options to fail part way though and for the fs to be left
in a state where some of the new arguments had been applied, but some
had not.
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
      6f04c1c7
  3. 23 Mar, 2009 11 commits
  5. 22 Mar, 2009 6 commits
  7. 21 Mar, 2009 2 commits
  9. 20 Mar, 2009 5 commits
  11. 19 Mar, 2009 5 commits