BMC/Intel-BMC/linux.git/fs/gfs2/trans.c, branch dev

GFS2: update freeze code to use freeze/thaw_super on all nodes

2014-11-17T10:36:39+00:00

The current gfs2 freezing code is considerably more complicated than it should be because it doesn't use the vfs freezing code on any node except the one that begins the freeze. This is because it needs to acquire a cluster glock before calling the vfs code to prevent a deadlock, and without the new freeze_super and thaw_super hooks, that was impossible. To deal with the issue, gfs2 had to do some hacky locking tricks to make sure that a frozen node couldn't be holding on a lock it needed to do the unfreeze ioctl. This patch makes use of the new hooks to simply the gfs2 locking code. Now, all the nodes in the cluster freeze and thaw in exactly the same way. Every node in the cluster caches the freeze glock in the shared state. The new freeze_super hook allows the freezing node to grab this freeze glock in the exclusive state without first calling the vfs freeze_super function. All the nodes in the cluster see this lock change, and call the vfs freeze_super function. The vfs locking code guarantees that the nodes can't get stuck holding the glocks necessary to unfreeze the system. To unfreeze, the freezing node uses the new thaw_super hook to drop the freeze glock. Again, all the nodes notice this, reacquire the glock in shared mode and call the vfs thaw_super function. Signed-off-by: Benjamin Marzinski Signed-off-by: Steven Whitehouse

GFS2: use _RET_IP_ instead of (unsigned long)__builtin_return_address(0)

2014-10-08T08:57:07+00:00

use macro definition Signed-off-by: Fabian Frederick Signed-off-by: Steven Whitehouse

GFS2: remove transaction glock

2014-05-14T09:04:34+00:00

GFS2 has a transaction glock, which must be grabbed for every transaction, whose purpose is to deal with freezing the filesystem. Aside from this involving a large amount of locking, it is very easy to make the current fsfreeze code hang on unfreezing. This patch rewrites how gfs2 handles freezing the filesystem. The transaction glock is removed. In it's place is a freeze glock, which is cached (but not held) in a shared state by every node in the cluster when the filesystem is mounted. This lock only needs to be grabbed on freezing, and actions which need to be safe from freezing, like recovery. When a node wants to freeze the filesystem, it grabs this glock exclusively. When the freeze glock state changes on the nodes (either from shared to unlocked, or shared to exclusive), the filesystem does a special log flush. gfs2_log_flush() does all the work for flushing out the and shutting down the incore log, and then it tries to grab the freeze glock in a shared state again. Since the filesystem is stuck in gfs2_log_flush, no new transaction can start, and nothing can be written to disk. Unfreezing the filesytem simply involes dropping the freeze glock, allowing gfs2_log_flush() to grab and then release the shared lock, so it is cached for next time. However, in order for the unfreezing ioctl to occur, gfs2 needs to get a shared lock on the filesystem root directory inode to check permissions. If that glock has already been grabbed exclusively, fsfreeze will be unable to get the shared lock and unfreeze the filesystem. In order to allow the unfreeze, this patch makes gfs2 grab a shared lock on the filesystem root directory during the freeze, and hold it until it unfreezes the filesystem. The functions which need to grab a shared lock in order to allow the unfreeze ioctl to be issued now use the lock grabbed by the freeze code instead. The freeze and unfreeze code take care to make sure that this shared lock will not be dropped while another process is using it. Signed-off-by: Benjamin Marzinski Signed-off-by: Steven Whitehouse

GFS2: Use pr_ more consistently

2014-03-07T09:30:51+00:00

Add pr_fmt, remove embedded "GFS2: " prefixes. This now consistently emits lower case "gfs2: " for each message. Other miscellanea around these changes: o Add missing newlines o Coalesce formats o Realign arguments Signed-off-by: Joe Perches Signed-off-by: Steven Whitehouse

GFS2: global conversion to pr_foo()

2014-03-06T17:34:06+00:00

-All printk(KERN_foo converted to pr_foo(). -Messages updated to fit in 80 columns. -fs_macros converted as well. -fs_printk removed. Signed-off-by: Fabian Frederick Signed-off-by: Steven Whitehouse

GFS2: Move log buffer accounting to transaction

2014-02-24T19:49:12+00:00

Now we have a master transaction into which other transactions are merged, the accounting can be done using this master transaction. We no longer require the superblock fields which were being used for this function. In addition, this allows for a clean up in calc_reserved() making it rather easier understand. Also, by reducing the number of variables used to track the buffers being added and removed from the journal, a number of error checks are now no longer required. Signed-off-by: Steven Whitehouse

GFS2: Move log buffer lists into transaction

2014-02-24T16:54:54+00:00

Over time, we hope to be able to improve the concurrency available in the log code. This is one small step towards that, by moving the buffer lists from the super block, and into the transaction structure, so that each transaction builds its own buffer lists. At transaction commit time, the buffer lists are merged into the currently accumulating transaction. That transaction then is passed into the before and after commit functions at journal flush time. Thus there should be no change in overall behaviour yet. Signed-off-by: Steven Whitehouse

GFS2: Reduce struct gfs2_trans in size

2014-02-21T11:52:00+00:00

A couple of "int" fields were being used as boolean values so we can make them bitfields of one bit, and put them in what might otherwise be a hole in the structure with 64 bit alignment. Signed-off-by: Steven Whitehouse

GFS2: fix warning message

2013-06-19T20:29:19+00:00

This patch fixes a warning message introduced in the recent "GFS2: aggressively issue revokes in gfs2_log_flush" patch. Signed-off-by: Benjamin Marzinski Signed-off-by: Steven Whitehouse

GFS2: aggressively issue revokes in gfs2_log_flush

2013-06-19T08:41:59+00:00

This patch looks at all the outstanding blocks in all the transactions on the log, and moves the completed ones to the ail2 list. Then it issues revokes for these blocks. This will hopefully speed things up in situations where there is a lot of contention for glocks, especially if they are acquired serially. revoke_lo_before_commit will issue at most one log block's full of these preemptive revokes. The amount of reserved log space that gfs2_log_reserve() ignores has been incremented to allow for this extra block. This patch also consolidates the common revoke instructions into one function, gfs2_add_revoke(). Signed-off-by: Benjamin Marzinski Signed-off-by: Steven Whitehouse