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path: root/fs/ocfs2/dlmglue.c
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2010-03-08Merge branch 'for-next' into for-linusJiri Kosina
Conflicts: Documentation/filesystems/proc.txt arch/arm/mach-u300/include/mach/debug-macro.S drivers/net/qlge/qlge_ethtool.c drivers/net/qlge/qlge_main.c drivers/net/typhoon.c
2010-02-27ocfs2: Use a separate masklog for AST and BASTsSunil Mushran
This patch adds a new masklog and uses it allow tracing ASTs and BASTs in the dlmglue layer. This has been found to be very useful in debugging cluster locking issues. Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-02-26ocfs2: Pass the locking protocol into ocfs2_cluster_connect().Joel Becker
Inside the stackglue, the locking protocol structure is hanging off of the ocfs2_cluster_connection. This takes it one further; the locking protocol is passed into ocfs2_cluster_connect(). Now different cluster connections can have different locking protocols with distinct asts. Note that all locking protocols have to keep their maximum protocol version in lock-step. With the protocol structure set in ocfs2_cluster_connect(), there is no need for the stackglue to have a static pointer to a specific protocol structure. We can change initialization to only pass in the maximum protocol version. Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-02-26ocfs2: Attach the connection to the lksbJoel Becker
We're going to want it in the ast functions, so we convert union ocfs2_dlm_lksb to struct ocfs2_dlm_lksb and let it carry the connection. Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-02-26ocfs2: Pass lksbs back from stackglue ast/bast functions.Joel Becker
The stackglue ast and bast functions tried to maintain the fiction that their arguments were void pointers. In reality, stack_user.c had to know that the argument was an ocfs2_lock_res in order to get the status off of the lksb. That's ugly. This changes stackglue to always pass the lksb as the argument to ast and bast functions. The caller can always use container_of() to get the ocfs2_lock_res or user_dlm_lock_res. The net effect to the caller is zero. They still get back the lockres in their ast. stackglue gets cleaner, and now can use the lksb itself. Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-02-09tree-wide: Assorted spelling fixesDaniel Mack
In particular, several occurances of funny versions of 'success', 'unknown', 'therefore', 'acknowledge', 'argument', 'achieve', 'address', 'beginning', 'desirable', 'separate' and 'necessary' are fixed. Signed-off-by: Daniel Mack <daniel@caiaq.de> Cc: Joe Perches <joe@perches.com> Cc: Junio C Hamano <gitster@pobox.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-02-03ocfs2: Plugs race between the dc thread and an unlock ast messageSunil Mushran
This patch plugs a race between the downconvert thread and an unlock ast message. Specifically, after the downconvert worker has done its task, the dc thread needs to check whether an unlock ast made the downconvert moot. Reported-by: David Teigland <teigland@redhat.com> Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Acked-by: Mark Fasheh <mfasheh@sus.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-02-02ocfs2: Remove overzealous BUG_ON during blocked lock processingSunil Mushran
During blocked lock processing, we should consider the possibility that the lock is no longer blocking. Joel Becker <joel.becker@oracle.com> assisted in fixing this issue. Reported-by: David Teigland <teigland@redhat.com> Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-02-02ocfs2: Do not downconvert if the lock level is already compatibleSunil Mushran
During upconvert, if the master were to send a BAST, dlmglue will detect the upconversion in process and send a cancel convert to the master. Upon receiving the AST for the cancel convert, it will re-process the lock resource to determine whether it needs downconverting. Say, the up was from PR to EX and the BAST was for EX. After the cancel convert, it will need to downconvert to NL. However, if the node was originally upconverting from NL to EX, then there would be no reason to downconvert (assuming the same message sequence). This patch makes dlmglue consider the possibility that the current lock level is already compatible and that downconverting is not required. Joel Becker <joel.becker@oracle.com> assisted in fixing this issue. Fixes ossbz#1178 http://oss.oracle.com/bugzilla/show_bug.cgi?id=1178 Reported-by: Coly Li <coly.li@suse.de> Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-02-02ocfs2: Prevent a livelock in dlmglueSunil Mushran
There is possibility of a livelock in __ocfs2_cluster_lock(). If a node were to get an ast for an upconvert request, followed immediately by a bast, there is a small window where the fs may downconvert the lock before the process requesting the upconvert is able to take the lock. This patch adds a new flag to indicate that the upconvert is still in progress and that the dc thread should not downconvert it right now. Wengang Wang <wen.gang.wang@oracle.com> and Joel Becker <joel.becker@oracle.com> contributed heavily to this patch. Reported-by: David Teigland <teigland@redhat.com> Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-02-02ocfs2: Fix setting of OCFS2_LOCK_BLOCKED during bastWengang Wang
During bast, set the OCFS2_LOCK_BLOCKED flag only if the lock needs to downconverted. Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com> Acked-by: Sunil Mushran <sunil.mushran@oracle.com> Acked-by: Mark Fasheh <mfasheh@suse.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-01-25ocfs2/trivial: Remove trailing whitespacesSunil Mushran
Patch removes trailing whitespaces. Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2009-12-04tree-wide: fix assorted typos all over the placeAndré Goddard Rosa
That is "success", "unknown", "through", "performance", "[re|un]mapping" , "access", "default", "reasonable", "[con]currently", "temperature" , "channel", "[un]used", "application", "example","hierarchy", "therefore" , "[over|under]flow", "contiguous", "threshold", "enough" and others. Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-09-23dlmglue.c: add missed mlog linesColy Li
This patch adds the missed mlog_exit() and mlog_exit_void() lines when routines return. Signed-off-by: Coly Li <coly.li@suse.de> Acked-by: Mark Fasheh <mfasheh@suse.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2009-09-22ocfs2: Add new refcount tree lock resource in dlmglue.Tao Ma
refcount tree lock resource is used to protect refcount tree read/write among multiple nodes. Signed-off-by: Tao Ma <tao.ma@oracle.com>
2009-09-22ocfs2: Abstract caching info checkpoint.Tao Ma
In meta downconvert, we need to checkpoint the metadata in an inode. For refcount tree, we also need it. So abstract the process out. Signed-off-by: Tao Ma <tao.ma@oracle.com>
2009-09-04ocfs2: Pass struct ocfs2_caching_info to the journal functions.Joel Becker
The next step in divorcing metadata I/O management from struct inode is to pass struct ocfs2_caching_info to the journal functions. Thus the journal locks a metadata cache with the cache io_lock function. It also can compare ci_last_trans and ci_created_trans directly. This is a large patch because of all the places we change ocfs2_journal_access..(handle, inode, ...) to ocfs2_journal_access..(handle, INODE_CACHE(inode), ...). Signed-off-by: Joel Becker <joel.becker@oracle.com>
2009-09-04ocfs2: Take the inode out of the metadata read/write paths.Joel Becker
We are really passing the inode into the ocfs2_read/write_blocks() functions to get at the metadata cache. This commit passes the cache directly into the metadata block functions, divorcing them from the inode. Signed-off-by: Joel Becker <joel.becker@oracle.com>
2009-06-22ocfs2: Add lockdep annotationsJan Kara
Add lockdep support to OCFS2. The support also covers all of the cluster locks except for open locks, journal locks, and local quotafile locks. These are special because they are acquired for a node, not for a particular process and lockdep cannot deal with such type of locking. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2009-06-22ocfs2: Disable orphan scanning for local and hard-ro mountsSunil Mushran
Local and Hard-RO mounts do not need orphan scanning. Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2009-06-22ocfs2: Do not initialize lvb in ocfs2_orphan_scan_lock_res_init()Sunil Mushran
We don't access the LVB in our ocfs2_*_lock_res_init() functions. Since the LVB can become invalid during some cluster recovery operations, the dlmglue must be able to handle an uninitialized LVB. For the orphan scan lock, we initialized an uninitialzed LVB with our scan sequence number plus one. This starts a normal orphan scan cycle. Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2009-06-22ocfs2: Provide the ocfs2_dlm_lvb_valid() stack API.Joel Becker
The Lock Value Block (LVB) of a DLM lock can be lost when nodes die and the DLM cannot reconstruct its state. Clients of the DLM need to know this. ocfs2's internal DLM, o2dlm, explicitly zeroes out the LVB when it loses track of the state. This is not a standard behavior, but ocfs2 has always relied on it. Thus, an o2dlm LVB is always "valid". ocfs2 now supports both o2dlm and fs/dlm via the stack glue. When fs/dlm loses track of an LVBs state, it sets a flag (DLM_SBF_VALNOTVALID) on the Lock Status Block (LKSB). The contents of the LVB may be garbage or merely stale. ocfs2 doesn't want to try to guess at the validity of the stale LVB. Instead, it should be checking the VALNOTVALID flag. As this is the 'standard' way of treating LVBs, we will promote this behavior. We add a stack glue API ocfs2_dlm_lvb_valid(). It returns non-zero when the LVB is valid. o2dlm will always return valid, while fs/dlm will check VALNOTVALID. Signed-off-by: Joel Becker <joel.becker@oracle.com> Acked-by: Mark Fasheh <mfasheh@suse.com>
2009-06-03ocfs2: timer to queue scan of all orphan slotsSrinivas Eeda
When a dentry is unlinked, the unlinking node takes an EX on the dentry lock before moving the dentry to the orphan directory. Other nodes that have this dentry in cache have a PR on the same dentry lock. When the EX is requested, the other nodes flag the corresponding inode as MAYBE_ORPHANED during downconvert. The inode is finally deleted when the last node to iput the inode sees that i_nlink==0 and the MAYBE_ORPHANED flag is set. A problem arises if a node is forced to free dentry locks because of memory pressure. If this happens, the node will no longer get downconvert notifications for the dentries that have been unlinked on another node. If it also happens that node is actively using the corresponding inode and happens to be the one performing the last iput on that inode, it will fail to delete the inode as it will not have the MAYBE_ORPHANED flag set. This patch fixes this shortcoming by introducing a periodic scan of the orphan directories to delete such inodes. Care has been taken to distribute the workload across the cluster so that no one node has to perform the task all the time. Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2009-04-03ocfs2: fix rare stale inode errors when exporting via nfswengang wang
For nfs exporting, ocfs2_get_dentry() returns the dentry for fh. ocfs2_get_dentry() may read from disk when the inode is not in memory, without any cross cluster lock. this leads to the file system loading a stale inode. This patch fixes above problem. Solution is that in case of inode is not in memory, we get the cluster lock(PR) of alloc inode where the inode in question is allocated from (this causes node on which deletion is done sync the alloc inode) before reading out the inode itsself. then we check the bitmap in the group (the inode in question allcated from) to see if the bit is clear. if it's clear then it's stale. if the bit is set, we then check generation as the existing code does. We have to read out the inode in question from disk first to know its alloc slot and allot bit. And if its not stale we read it out using ocfs2_iget(). The second read should then be from cache. And also we have to add a per superblock nfs_sync_lock to cover the lock for alloc inode and that for inode in question. this is because ocfs2_get_dentry() and ocfs2_delete_inode() lock on them in reverse order. nfs_sync_lock is locked in EX mode in ocfs2_get_dentry() and in PR mode in ocfs2_delete_inode(). so that mutliple ocfs2_delete_inode() can run concurrently in normal case. [mfasheh@suse.com: build warning fixes and comment cleanups] Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com> Acked-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2009-02-26ocfs2: Cleanup the lockname print in dlmglue.cSunil Mushran
The dentry lock has a different format than other locks. This patch fixes ocfs2_log_dlm_error() macro to make it print the dentry lock correctly. Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Acked-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2009-02-02ocfs2: Wakeup the downconvert thread after a successful cancel convertSunil Mushran
When two nodes holding PR locks on a resource concurrently attempt to upconvert the locks to EX, the master sends a BAST to one of the nodes. This message tells that node to first cancel convert the upconvert request, followed by downconvert to a NL. Only when this lock is downconverted to NL, can the master upconvert the first node's lock to EX. While the fs was doing the cancel convert, it was forgetting to wake up the dc thread after a successful cancel, leading to a deadlock. Reported-and-Tested-by: David Teigland <teigland@redhat.com> Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2009-01-08fix similar typos to successfullColy Li
When I review ocfs2 code, find there are 2 typos to "successfull". After doing grep "successfull " in kernel tree, 22 typos found totally -- great minds always think alike :) This patch fixes all the similar typos. Thanks for Randy's ack and comments. Signed-off-by: Coly Li <coyli@suse.de> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: Roland Dreier <rolandd@cisco.com> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: Jeff Garzik <jeff@garzik.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Vlad Yasevich <vladislav.yasevich@hp.com> Cc: Sridhar Samudrala <sri@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-05ocfs2: remove unneeded lvb castsMark Fasheh
dlmglue.c has lots of code which casts the return value of ocfs2_dlm_lvb(). This is pointless however, as ocfs2_dlm_lvb() returns void *. Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2009-01-05ocfs2: Fix ocfs2_read_quota_block() error handling.Joel Becker
ocfs2_bread() has become ocfs2_read_virt_blocks(), with a prototype to match ocfs2_read_blocks(). The quota code, converting from ocfs2_bread(), wraps the call to ocfs2_read_virt_blocks() in ocfs2_read_quota_block(). Unfortunately, the prototype of ocfs2_read_quota_block() matches the old prototype of ocfs2_bread(). The problem is that ocfs2_bread() returned the buffer head, and callers assumed that a NULL pointer was indicative of error. It wasn't. This is why ocfs2_bread() took an int*err argument as well. The new prototype of ocfs2_read_virt_blocks() avoids this error handling confusion. Let's change ocfs2_read_quota_block() to match. Signed-off-by: Joel Becker <joel.becker@oracle.com> Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2009-01-05ocfs2: Implementation of local and global quota file handlingJan Kara
For each quota type each node has local quota file. In this file it stores changes users have made to disk usage via this node. Once in a while this information is synced to global file (and thus with other nodes) so that limits enforcement at least aproximately works. Global quota files contain all the information about usage and limits. It's mostly handled by the generic VFS code (which implements a trie of structures inside a quota file). We only have to provide functions to convert structures from on-disk format to in-memory one. We also have to provide wrappers for various quota functions starting transactions and acquiring necessary cluster locks before the actual IO is really started. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2009-01-05ocfs2: Wrap inode block reads in a dedicated function.Joel Becker
The ocfs2 code currently reads inodes off disk with a simple ocfs2_read_block() call. Each place that does this has a different set of sanity checks it performs. Some check only the signature. A couple validate the block number (the block read vs di->i_blkno). A couple others check for VALID_FL. Only one place validates i_fs_generation. A couple check nothing. Even when an error is found, they don't all do the same thing. We wrap inode reading into ocfs2_read_inode_block(). This will validate all the above fields, going readonly if they are invalid (they never should be). ocfs2_read_inode_block_full() is provided for the places that want to pass read_block flags. Every caller is passing a struct inode with a valid ip_blkno, so we don't need a separate blkno argument either. We will remove the validation checks from the rest of the code in a later commit, as they are no longer necessary. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-12-01ocfs2: fix wake_up in unlock_astDavid Teigland
In ocfs2_unlock_ast(), call wake_up() on lockres before releasing the spin lock on it. As soon as the spin lock is released, the lockres can be freed. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-10-14ocfs2: Simplify ocfs2_read_block()Joel Becker
More than 30 callers of ocfs2_read_block() pass exactly OCFS2_BH_CACHED. Only six pass a different flag set. Rather than have every caller care, let's make ocfs2_read_block() take no flags and always do a cached read. The remaining six places can call ocfs2_read_blocks() directly. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-10-14ocfs2: Require an inode for ocfs2_read_block(s)().Joel Becker
Now that synchronous readers are using ocfs2_read_blocks_sync(), all callers of ocfs2_read_blocks() are passing an inode. Use it unconditionally. Since it's there, we don't need to pass the ocfs2_super either. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-07-14ocfs2: fix printk format warnings with OCFS2_FS_STATS=nRandy Dunlap
Fix printk format warnings when OCFS2_FS_STATS=n: linux-next-20080528/fs/ocfs2/dlmglue.c: In function 'ocfs2_dlm_seq_show': linux-next-20080528/fs/ocfs2/dlmglue.c:2623: warning: format '%llu' expects type 'long long unsigned int', but argument 3 has type 'int' linux-next-20080528/fs/ocfs2/dlmglue.c:2623: warning: format '%llu' expects type 'long long unsigned int', but argument 4 has type 'int' linux-next-20080528/fs/ocfs2/dlmglue.c:2623: warning: format '%llu' expects type 'long long unsigned int', but argument 7 has type 'int' linux-next-20080528/fs/ocfs2/dlmglue.c:2623: warning: format '%llu' expects type 'long long unsigned int', but argument 8 has type 'int' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-07-14[PATCH 2/2] ocfs2: Instrument fs cluster locksSunil Mushran
This patch adds code to track the number of times the fs takes various cluster locks as well as the times associated with it. The information is made available to users via debugfs. This patch was originally written by Jan Kara <jack@suse.cz>. Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-07-10ocfs2: Fix flags in ocfs2_file_lockMark Fasheh
The stack-glue merge changed the way we use flags in dlmglue in that we now use the fs/dlm equivalents. Unfortunately, a merge error left the new flock code only partially updated. This took a while to show up though, because the lock level constants are actually identical between o2dlm and fs/dlm. The *_CONVERT and *_NOQUEUE flags have different values though, which is eventually causing a crash in flags_to_o2dlm(). Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Add the 'cluster_stack' sysfs file.Joel Becker
Userspace can now query and specify the cluster stack in use via the /sys/fs/ocfs2/cluster_stack file. By default, it is 'o2cb', which is the classic stack. Thus, old tools that do not know how to modify this file will work just fine. The stack cannot be modified if there is a live filesystem. ocfs2_cluster_connect() now takes the expected cluster stack as an argument. This way, the filesystem and the stack glue ensure they are speaking to the same backend. If the stack is 'o2cb', the o2cb stack plugin is used. For any other value, the fsdlm stack plugin is selected. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Break out stackglue into modules.Joel Becker
We define the ocfs2_stack_plugin structure to represent a stack driver. The o2cb stack code is split into stack_o2cb.c. This becomes the ocfs2_stack_o2cb.ko module. The stackglue generic functions are similarly split into the ocfs2_stackglue.ko module. This module now provides an interface to register drivers. The ocfs2_stack_o2cb driver registers itself. As part of this interface, ocfs2_stackglue can load drivers on demand. This is accomplished in ocfs2_cluster_connect(). ocfs2_cluster_disconnect() is now notified when a _hangup() is pending. If a hangup is pending, it will not release the driver module and will let _hangup() do that. Signed-off-by: Joel Becker <joel.becker@oracle.com>
2008-04-18ocfs2: Clean up stackglue initializationJoel Becker
The stack glue initialization function needs a better name so that it can be used cleanly when stackglue becomes a module. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Abstract out a debugging function for underlying dlms.Joel Becker
dlmglue.c was still referencing a raw o2dlm lksb in one instance. Let's create a generic ocfs2_dlm_dump_lksb() function. This allows underlying DLMs to print whatever they want about their lock. We then move the o2dlm dump into stackglue.c where it belongs. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: handle async EAGAIN from NOQUEUE requestDavid Teigland
When using fsdlm, -EAGAIN is returned in the async callback for NOQUEUE requests. Fix up dlmglue to expect this. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Remove CANCELGRANT from the view of dlmglue.Joel Becker
o2dlm has the non-standard behavior of providing a cancel callback (unlock_ast) even when the cancel has failed (the locking operation succeeded without canceling). This is called CANCELGRANT after the status code sent to the callback. fs/dlm does not provide this callback, so dlmglue must be changed to live without it. o2dlm_unlock_ast_wrapper() in stackglue now ignores CANCELGRANT calls. Because dlmglue no longer sees CANCELGRANT, ocfs2_unlock_ast() no longer needs to check for it. ocfs2_locking_ast() must catch that a cancel was tried and clear the cancel state. Making these changes opens up a locking race. dlmglue uses the the OCFS2_LOCK_BUSY flag to ensure only one thread is calling the dlm at any one time. But dlmglue must unlock the lockres before calling into the dlm. In the small window of time between unlocking the lockres and calling the dlm, the downconvert thread can try to cancel the lock. The downconvert thread is checking the OCFS2_LOCK_BUSY flag - it doesn't know that ocfs2_dlm_lock() has not yet been called. Because ocfs2_dlm_lock() has not yet been called, the cancel operation will just be a no-op. There's nothing to cancel. With CANCELGRANT, dlmglue uses the CANCELGRANT callback to clear up the cancel state. When it comes around again, it will retry the cancel. Eventually, the first thread will have called into ocfs2_dlm_lock(), and either the lock or the cancel will succeed. The downconvert thread can then do its downconvert. Without CANCELGRANT, there is nothing to clean up the cancellation state. The downconvert thread does not know to retry its operations. More importantly, the original lock may be blocking on the other node that is trying to cancel us. With neither able to make progress, the ast is never called and the cancellation state is never cleaned up that way. dlmglue is deadlocked. The OCFS2_LOCK_PENDING flag is introduced to remedy this window. It is set at the same time OCFS2_LOCK_BUSY is. Thus, the downconvert thread can check whether the lock is cancelable. If not, it just loops around to try again. Once ocfs2_dlm_lock() is called, the thread then clears OCFS2_LOCK_PENDING and wakes the downconvert thread. Now, if the downconvert thread finds the lock BUSY, it can safely try to cancel it. Whether the cancel works or not, the state will be properly set and the lock processing can continue. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Fill node number during cluster stack initMark Fasheh
It doesn't make sense to query for a node number before connecting to the cluster stack. This should be safe to do because node_num is only just printed, and we're actually only moving the setting of node num a small amount further in the mount process. [ Disconnect when node query fails -- Joel ] Reviewed-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Move o2hb functionality into the stack glue.Joel Becker
The last bit of classic stack used directly in ocfs2 code is o2hb. Specifically, the check for heartbeat during mount and the call to ocfs2_hb_ctl during unmount. We create an extra API, ocfs2_cluster_hangup(), to encapsulate the call to ocfs2_hb_ctl. Other stacks will just leave hangup() empty. The check for heartbeat is moved into ocfs2_cluster_connect(). It will be matched by a similar check for other stacks. With this change, only stackglue.c includes cluster/ headers. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Introduce the new ocfs2_cluster_connect/disconnect() API.Joel Becker
This step introduces a cluster stack agnostic API for initializing and exiting. fs/ocfs2/dlmglue.c no longer uses o2cb/o2dlm knowledge to connect to the stack. It is all handled in stackglue.c. heartbeat.c no longer needs to know how it gets called. ocfs2_do_node_down() is now a clean recovery trigger. The big gotcha is the ordering of initializations and de-initializations done underneath ocfs2_cluster_connect(). ocfs2_dlm_init() used to do all o2dlm initialization in one block. Thus, the o2dlm functionality of ocfs2_cluster_connect() is very straightforward. ocfs2_dlm_shutdown(), however, did a few things between de-registration of the eviction callback and actually shutting down the domain. Now de-registration and shutdown of the domain are wrapped within the single ocfs2_cluster_disconnect() call. I've checked the code paths to make sure we can safely tear down things in ocfs2_dlm_shutdown() before calling ocfs2_cluster_disconnect(). The filesystem has already set itself to ignore the callback. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Create the lock status block union.Joel Becker
Wrap the lock status block (lksb) in a union. Later we will add a union element for the fs/dlm lksb. Create accessors for the status and lvb fields. Other than a debugging function, dlmglue.c does not directly reference the o2dlm locking path anymore. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Use -errno instead of dlm_status for ocfs2_dlm_lock/unlock() API.Joel Becker
Change the ocfs2_dlm_lock/unlock() functions to return -errno values. This is the first step towards elminiating dlm_status in fs/ocfs2/dlmglue.c. The change also passes -errno values to ->unlock_ast(). [ Fix a return code in dlmglue.c and change the error translation table into an array of ints. --Mark ] Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Use global DLM_ constants in generic code.Joel Becker
The ocfs2 generic code should use the values in <linux/dlmconstants.h>. stackglue.c will convert them to o2dlm values. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18ocfs2: Separate out dlm lock functions.Joel Becker
This is the first in a series of patches to isolate ocfs2 from the underlying cluster stack. Here we wrap the dlm locking functions with ocfs2-specific calls. Because ocfs2 always uses the same dlm lock status callbacks, we can eliminate the callbacks from the filesystem visible functions. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>