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path: root/fs/gfs2/log.h
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2014-05-14GFS2: remove transaction glockBenjamin Marzinski
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 <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-06-19GFS2: aggressively issue revokes in gfs2_log_flushBenjamin Marzinski
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 <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-01-29GFS2: Use ->writepages for ordered writesSteven Whitehouse
Instead of using a list of buffers to write ahead of the journal flush, this now uses a list of inodes and calls ->writepages via filemap_fdatawrite() in order to achieve the same thing. For most use cases this results in a shorter ordered write list, as well as much larger i/os being issued. The ordered write list is sorted by inode number before writing in order to retain the disk block ordering between inodes as per the previous code. The previous ordered write code used to conflict in its assumptions about how to write out the disk blocks with mpage_writepages() so that with this updated version we can also use mpage_writepages() for GFS2's ordered write, writepages implementation. So we will also send larger i/os from writeback too. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24GFS2: Clean up log write code pathSteven Whitehouse
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>
2012-02-28GFS2: Move two functions from log.c to lops.cSteven Whitehouse
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>
2011-04-20GFS2: Make writeback more responsive to system conditionsSteven Whitehouse
This patch adds writeback_control to writing back the AIL list. This means that we can then take advantage of the information we get in ->write_inode() in order to set off some pre-emptive writeback. In addition, the AIL code is cleaned up a bit to make it a bit simpler to understand. There is still more which can usefully be done in this area, but this is a good start at least. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2010-05-21GFS2: Rework reclaiming unlinked dinodesBob Peterson
The previous patch I wrote for reclaiming unlinked dinodes had some shortcomings and did not prevent all hangs. This version is much cleaner and more logical, and has passed very difficult testing. Sorry for the churn. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2010-05-05GFS2: Various gfs2_logd improvementsBenjamin Marzinski
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>
2008-06-27[GFS2] trivial sparse lock annotationsHarvey Harrison
Annotate the &sdp->sd_log_lock. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Move gfs2_logd into log.cSteven Whitehouse
This means that we can mark gfs2_ail1_empty static and prepares the way for further changes. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Don't add glocks to the journalSteven Whitehouse
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>
2008-01-25[GFS2] Remove useless i_cache from inodesSteven Whitehouse
The i_cache was designed to keep references to the indirect blocks used during block mapping so that they didn't have to be looked up continually. The idea failed because there are too many places where the i_cache needs to be freed, and this has in the past been the cause of many bugs. In addition there was no performance benefit being gained since the disk blocks in question were cached anyway. So this patch removes it in order to simplify the code to prepare for other changes which would otherwise have had to add further support for this feature. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10[GFS2] Clean up journaled data writingSteven Whitehouse
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>
2007-10-10[GFS2] Introduce gfs2_remove_from_ailSteven Whitehouse
This collects together the operations required to remove a gfs2_bufdata from the ail lists. Its only called from two places to start with, but expect to see more of this function in future. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Move gfs2_meta_syncfs() into log.cSteven Whitehouse
By moving gfs2_meta_syncfs() into log.c, gfs2_ail1_start() can be made static. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-05[GFS2] Make headers compile on their ownSteven Whitehouse
As per Jan Engelhardt's comments, this should make all the headers compile on their own by including and/or declaring structures early. Cc: Jan Engelhardt <jengelh@linux01.gwdg.de> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-01[GFS2] Update copyright, tidy up incore.hSteven Whitehouse
As per comments from Jan Engelhardt <jengelh@linux01.gwdg.de> this updates the copyright message to say "version" in full rather than "v.2". Also incore.h has been updated to remove forward structure declarations which are not required. The gfs2_quota_lvb structure has now had endianess annotations added to it. Also quota.c has been updated so that we now store the lvb data locally in endian independant format to avoid needing a structure in host endianess too. As a result the endianess conversions are done as required at various points and thus the conversion routines in lvb.[ch] are no longer required. I've moved the one remaining constant in lvb.h thats used into lm.h and removed the unused lvb.[ch]. I have not changed the HIF_ constants. That is left to a later patch which I hope will unify the gh_flags and gh_iflags fields of the struct gfs2_holder. Cc: Jan Engelhardt <jengelh@linux01.gwdg.de> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-05-18[GFS2] Update copyright date to 2006Steven Whitehouse
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-04-07[GFS2] Fix a ref count bug and other clean upsSteven Whitehouse
This fixes a ref count bug that sometimes showed up a umount time (causing it to hang) but it otherwise mostly harmless. At the same time there are some clean ups including making the log operations structures const, moving a memory allocation so that its not done in the fast path of checking to see if there is an outstanding transaction related to a particular glock. Removes the sd_log_wrap varaible which was updated, but never actually used anywhere. Updates the gfs2 ioctl() to run without the kernel lock (which it never needed anyway). Removes the "invalidate inodes" loop from GFS2's put_super routine. This is done in kill super anyway so we don't need to do it here. The loop was also bogus in that if there are any inodes "stuck" at this point its a bug and we need to know about it rather than hide it by hanging forever. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-02-21[GFS2] Use mutices rather than semaphoresSteven Whitehouse
As well as a number of minor bug fixes, this patch changes GFS to use mutices rather than semaphores. This results in better information in case there are any locking problems. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-01-16[GFS2] The core of GFS2David Teigland
This patch contains all the core files for GFS2. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>