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2007-05-01[GFS2] Red Hat bz 228540: owner referencesRobert Peterson
In Testing the previously posted and accepted patch for https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=228540 I uncovered some gfs2 badness. It turns out that the current gfs2 code saves off a process pointer when glocks is taken in both the glock and glock holder structures. Those structures will persist in memory long after the process has ended; pointers to poisoned memory. This problem isn't caused by the 228540 fix; the new capability introduced by the fix just uncovered the problem. I wrote this patch that avoids saving process pointers and instead saves off the process pid. Rather than referencing the bad pointers, it now does process lookups. There is special code that makes the output nicer for printing holder information for processes that have ended. This patch also adds a stub for the new "sprint_symbol" function that exists in Andrew Morton's -mm patch set, but won't go into the base kernel until 2.6.22, since it adds functionality but doesn't fix a bug. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-05-01[GFS2] Fix bz 224480 and cleanup glock demotion codeSteven Whitehouse
This patch prevents the printing of a warning message in cases where the fs is functioning normally by handing off responsibility for unlinked, but still open inodes, to another node for eventual deallocation. Also, there is now an improved system for ensuring that such requests to other nodes do not get lost. The callback on the iopen lock is only ever called when i_nlink == 0 and when a node is unable to deallocate it due to it still being in use on another node. When a node receives the callback therefore, it knows that i_nlink must be zero, so we mark it as such (in gfs2_drop_inode) in order that it will then attempt deallocation of the inode itself. As an additional benefit, queuing a demote request no longer requires a memory allocation. This simplifies the code for dealing with gfs2_holders as it removes one special case. There are two new fields in struct gfs2_glock. gl_demote_state is the state which the remote node has requested and gl_demote_time is the time when the request came in. Both fields are only valid when the GLF_DEMOTE flag is set in gl_flags. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-05-01[GFS2] Add gfs2_tool lockdump support to gfs2 (bz 228540)Robert Peterson
The attached patch resolves bz 228540. This adds the capability for gfs2 to dump gfs2 locks through the debugfs file system. This used to exist in gfs1 as "gfs_tool lockdump" but it's missing from gfs2 because all the ioctls were stripped out. Please see the bugzilla for more history about the fix. This patch is also attached to the bugzilla record. The patch is against Steve Whitehouse's latest nmw git tree kernel (2.6.21-rc1) and has been tested on system trin-10. Signed-off-by: Robert Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-02-05[GFS2] Tidy up glops callsSteven Whitehouse
This patch doesn't make any changes to the ordering of the various operations related to glocking, but it does tidy up the calls to the glops.c functions to make the structure more obvious. The two functions: gfs2_glock_xmote_th() and gfs2_glock_drop_th() can be made static within glock.c since they are called by every set of glock operations. The xmote_th and drop_th glock operations are then made conditional upon those two routines existing and called from the previously mentioned functions in glock.c respectively. Also it can be seen that the go_sync operation isn't needed since it can easily be replaced by calls to xmote_bh and drop_bh respectively. This results in no longer (confusingly) calling back into routines in glock.c from glops.c and also reducing the glock operations by one member. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-02-05[GFS2] Remove local exclusive glock modeSteven Whitehouse
Here is a patch for GFS2 to remove the local exclusive flag. In the places it was used, mutex's are always held earlier in the call path, so it appears redundant in the LM_ST_SHARED case. Also, the GFS2 holders were setting local exclusive in any case where the requested lock was LM_ST_EXCLUSIVE. So the other places in the glock code where the flag was tested have been replaced with tests for the lock state being LM_ST_EXCLUSIVE in order to ensure the logic is the same as before (i.e. LM_ST_EXCLUSIVE is always locally exclusive as well as globally exclusive). Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-02-05[GFS2] Remove the "greedy" function from glock.[ch]Steven Whitehouse
The "greedy" code was an attempt to retain glocks for a minimum length of time when they relate to mmap()ed files. The current implementation of this feature is not, however, ideal in that it required allocating memory in order to do this and its overly complicated. It also misses the mark by ignoring the other I/O operations which are just as likely to suffer from the same problem. So the plan is to remove this now and then add the functionality back as part of the glock state machine at a later date (and thus take into account all the possible users of this feature) Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-02-05[GFS2] Clean up/speed up readdirSteven Whitehouse
This removes the extra filldir callback which gfs2 was using to enclose an attempt at readahead for inodes during readdir. The code was too complicated and also hurts performance badly in the case that the getdents64/readdir call isn't being followed by stat() and it wasn't even getting it right all the time when it was. As a result, on my test box an "ls" of a directory containing 250000 files fell from about 7mins (freshly mounted, so nothing cached) to between about 15 to 25 seconds. When the directory content was cached, the time taken fell from about 3mins to about 4 or 5 seconds. Interestingly in the cached case, running "ls -l" once reduced the time taken for subsequent runs of "ls" to about 6 secs even without this patch. Now it turns out that there was a special case of glocks being used for prefetching the metadata, but because of the timeouts for these locks (set to 10 secs) the metadata was being timed out before it was being used and this the prefetch code was constantly trying to prefetch the same data over and over. Calling "ls -l" meant that the inodes were brought into memory and once the inodes are cached, the glocks are not disposed of until the inodes are pushed out of the cache, thus extending the lifetime of the glocks, and thus bringing down the time for subsequent runs of "ls" considerably. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Fix journal flush problemSteven Whitehouse
This fixes a bug which resulted in poor performance due to flushing the journal too often. The code path in question was via the inode_go_sync() function in glops.c. The solution is not to flush the journal immediately when inodes are ejected from memory, but batch up the work for glockd to deal with later on. This means that glocks may now live on beyond the end of the lifetime of their inodes (but not very much longer in the normal case). Also fixed in this patch is a bug (which was hidden by the bug mentioned above) in calculation of the number of free journal blocks. The gfs2_logd process has been altered to be more responsive to the journal filling up. We now wake it up when the number of uncommitted journal blocks has reached the threshold level rather than trying to flush directly at the end of each transaction. This again means doing fewer, but larger, log flushes in general. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Fix page lock/glock deadlockSteven Whitehouse
This fixes a race between the glock and the page lock encountered during truncate in gfs2_readpage and gfs2_prepare_write. The gfs2_readpages function doesn't need the same fix since it only uses a try lock anyway, so it will fail back to gfs2_readpage in the case of a potential deadlock. This bug was spotted by Russell Cattelan. Cc: Russell Cattelan <cattelan@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Remove unused GL_DUMP flagSteven Whitehouse
There is no way to set the GL_DUMP flag, and in any case the same thing can be done with systemtap if required for debugging, so this removes it. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-09[GFS2] Remove unused function from glock.cSteven Whitehouse
The callback for iopen locks is unused, so this removes it. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-08[GFS2] Use void * instead of typedef for locking module interfaceSteven Whitehouse
As requested by Jan Engelhardt, this removes the typedefs in the locking module interface and replaces them with void *. Also since we are changing the interface, I've added a few consts as well. Cc: Jan Engelhardt <jengelh@linux01.gwdg.de> Cc: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-07[GFS2] Remove one typedefSteven Whitehouse
This removes one of the typedefs from the locking interface. It is replaced by a forward declaration of the gfs2 superblock. The other two are not so easy to solve since in their case, they can refer to one of two possible structures. Cc: David Teigland <teigland@redhat.com> Cc: Jan Engelhardt <jengelh@linux01.gwdg.de> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-07[GFS2] Move glock hash table out of superblockSteven Whitehouse
There are several reasons why we want to do this: - Firstly its large and thus we'll scale better with multiple GFS2 fs mounted at the same time - Secondly its easier to scale its size as required (thats a plan for later patches) - Thirdly, we can use kzalloc rather than vmalloc when allocating the superblock (its now only 4888 bytes) - Fourth its all part of my plan to eventually be able to use RCU with the glock hash. 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>
2006-09-04[GFS2] Change all types to uX styleSteven Whitehouse
This makes all fixed size types have consistent names. Cc: Jan Engelhardt <jengelh@linux01.gwdg.de> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-04[GFS2] Tidy up locking codeSteven Whitehouse
As per Jan Engelhardt's second email, this removes some unused code, and fixes up indenting in various places. 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>
2006-08-30[GFS2] Remove unused code from glock layerSteven Whitehouse
Remove the unused sync feature from glocks. This is currently done by calling the required functions to sync pages/blocks directly so this code isn't needed. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-08-30[GFS2] Make glock operations constSteven Whitehouse
For all the usual reasons of enforcing correctness and potentially reducing code size, this patch makes the glock operations const. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-06-14[GFS2] Fix unlinked file handlingSteven Whitehouse
This patch fixes the way we have been dealing with unlinked, but still open files. It removes all limits (other than memory for inodes, as per every other filesystem) on numbers of these which we can support on GFS2. It also means that (like other fs) its the responsibility of the last process to close the file to deallocate the storage, rather than the person who did the unlinking. Note that with GFS2, those two events might take place on different nodes. Also there are a number of other changes: o We use the Linux inode subsystem as it was intended to be used, wrt allocating GFS2 inodes o The Linux inode cache is now the point which we use for local enforcement of only holding one copy of the inode in core at once (previous to this we used the glock layer). o We no longer use the unlinked "special" file. We just ignore it completely. This makes unlinking more efficient. o We now use the 4th block allocation state. The previously unused state is used to track unlinked but still open inodes. o gfs2_inoded is no longer needed o Several fields are now no longer needed (and removed) from the in core struct gfs2_inode o Several fields are no longer needed (and removed) from the in core superblock There are a number of future possible optimisations and clean ups which have been made possible by this patch. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-05-18[GFS2] glock debugging and inode cache changesSteven Whitehouse
This adds some extra debugging to glock.c and changes inode.c's deallocation code to call the debugging code at a suitable moment. I'm chasing down a particular bug to do with deallocation at the moment and the code can go again once the bug is fixed. Also this includes the first part of some changes to unify the Linux struct inode and GFS2's struct gfs2_inode. This transformation will happen in small parts over the next short period. 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>
2006-04-28[GFS2] [-mm patch] fs/gfs2/: possible cleanupsAdrian Bunk
This patch contains the following possible cleanups: - make needlessly global code static - #if 0 unused functions - remove the following global function that was both unused and unimplemented: - super.c: gfs2_do_upgrade() Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-04-26[GFS2] Remove GL_NEVER_RECURSE flagSteven Whitehouse
There is no point in keeping this flag since recursion is not now allowed for any glock. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-04-20[GFS2] Fix a bug: scheduling under a spinlockSteven Whitehouse
At some stage, a mutex was added to gfs2_glock_put() without checking all its call sites. Two of them were called from under a spinlock causing random delays at various points and crashes. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-04-18[GFS2] Use vmalloc() in dir codeSteven Whitehouse
When allocating memory to sort directory entries, use vmalloc() rather than kmalloc() since for larger directories, the required size can easily be graeter than the 128k maximum of kmalloc(). Also adding the first steps towards getting the AOP_TRUNCATED_PAGE return code get in the glock code by flagging all places where we request a glock and we are holding a page lock. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-03-29[GFS2] Update debugging codeSteven Whitehouse
Update the debugging code in trans.c and at the same time improve the debugging code for gfs2_holders. The new code should be pretty fast during the normal case and provide just as much information in case of errors (or more). One small function from glock.c has moved to glock.h as a static inline so that its return address won't get in the way of the debugging. 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>