diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-02-08 16:05:50 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-02-08 16:05:50 -0800 |
commit | a5f28ae4df291d81d9d23066f88c55ca45e388d3 (patch) | |
tree | fdb3e9e7f9dd99148e9c061f31c65272f00d3ed6 /fs/ocfs2/dlmglue.c | |
parent | 8defcaa6ba157f215c437939c3adcd1dbfa1a8fa (diff) | |
parent | 6efd806634f7526f723f3aa7ceffd3887a932d9c (diff) |
Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
ocfs2/cluster: Make o2net connect messages KERN_NOTICE
ocfs2/dlm: Fix printing of lockname
ocfs2: Fix contiguousness check in ocfs2_try_to_merge_extent_map()
ocfs2/dlm: Remove BUG_ON in dlm recovery when freeing locks of a dead node
ocfs2: Plugs race between the dc thread and an unlock ast message
ocfs2: Remove overzealous BUG_ON during blocked lock processing
ocfs2: Do not downconvert if the lock level is already compatible
ocfs2: Prevent a livelock in dlmglue
ocfs2: Fix setting of OCFS2_LOCK_BLOCKED during bast
ocfs2: Use compat_ptr in reflink_arguments.
ocfs2/dlm: Handle EAGAIN for compatibility - v2
ocfs2: Add parenthesis to wrap the check for O_DIRECT.
ocfs2: Only bug out when page size is larger than cluster size.
ocfs2: Fix memory overflow in cow_by_page.
ocfs2/dlm: Print more messages during lock migration
ocfs2/dlm: Ignore LVBs of locks in the Blocked list
ocfs2/trivial: Remove trailing whitespaces
ocfs2: fix a misleading variable name
ocfs2: Sync max_inline_data_with_xattr from tools.
ocfs2: Fix refcnt leak on ocfs2_fast_follow_link() error path
Diffstat (limited to 'fs/ocfs2/dlmglue.c')
-rw-r--r-- | fs/ocfs2/dlmglue.c | 85 |
1 files changed, 76 insertions, 9 deletions
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c index c5e4a49e3a1..e044019cb3b 100644 --- a/fs/ocfs2/dlmglue.c +++ b/fs/ocfs2/dlmglue.c @@ -875,6 +875,14 @@ static inline void ocfs2_generic_handle_convert_action(struct ocfs2_lock_res *lo lockres_or_flags(lockres, OCFS2_LOCK_NEEDS_REFRESH); lockres->l_level = lockres->l_requested; + + /* + * We set the OCFS2_LOCK_UPCONVERT_FINISHING flag before clearing + * the OCFS2_LOCK_BUSY flag to prevent the dc thread from + * downconverting the lock before the upconvert has fully completed. + */ + lockres_or_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING); + lockres_clear_flags(lockres, OCFS2_LOCK_BUSY); mlog_exit_void(); @@ -907,8 +915,6 @@ static int ocfs2_generic_handle_bast(struct ocfs2_lock_res *lockres, assert_spin_locked(&lockres->l_lock); - lockres_or_flags(lockres, OCFS2_LOCK_BLOCKED); - if (level > lockres->l_blocking) { /* only schedule a downconvert if we haven't already scheduled * one that goes low enough to satisfy the level we're @@ -921,6 +927,9 @@ static int ocfs2_generic_handle_bast(struct ocfs2_lock_res *lockres, lockres->l_blocking = level; } + if (needs_downconvert) + lockres_or_flags(lockres, OCFS2_LOCK_BLOCKED); + mlog_exit(needs_downconvert); return needs_downconvert; } @@ -1133,6 +1142,7 @@ static inline void ocfs2_recover_from_dlm_error(struct ocfs2_lock_res *lockres, mlog_entry_void(); spin_lock_irqsave(&lockres->l_lock, flags); lockres_clear_flags(lockres, OCFS2_LOCK_BUSY); + lockres_clear_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING); if (convert) lockres->l_action = OCFS2_AST_INVALID; else @@ -1323,13 +1333,13 @@ static int __ocfs2_cluster_lock(struct ocfs2_super *osb, again: wait = 0; + spin_lock_irqsave(&lockres->l_lock, flags); + if (catch_signals && signal_pending(current)) { ret = -ERESTARTSYS; - goto out; + goto unlock; } - spin_lock_irqsave(&lockres->l_lock, flags); - mlog_bug_on_msg(lockres->l_flags & OCFS2_LOCK_FREEING, "Cluster lock called on freeing lockres %s! flags " "0x%lx\n", lockres->l_name, lockres->l_flags); @@ -1346,6 +1356,25 @@ again: goto unlock; } + if (lockres->l_flags & OCFS2_LOCK_UPCONVERT_FINISHING) { + /* + * We've upconverted. If the lock now has a level we can + * work with, we take it. If, however, the lock is not at the + * required level, we go thru the full cycle. One way this could + * happen is if a process requesting an upconvert to PR is + * closely followed by another requesting upconvert to an EX. + * If the process requesting EX lands here, we want it to + * continue attempting to upconvert and let the process + * requesting PR take the lock. + * If multiple processes request upconvert to PR, the first one + * here will take the lock. The others will have to go thru the + * OCFS2_LOCK_BLOCKED check to ensure that there is no pending + * downconvert request. + */ + if (level <= lockres->l_level) + goto update_holders; + } + if (lockres->l_flags & OCFS2_LOCK_BLOCKED && !ocfs2_may_continue_on_blocked_lock(lockres, level)) { /* is the lock is currently blocked on behalf of @@ -1416,11 +1445,14 @@ again: goto again; } +update_holders: /* Ok, if we get here then we're good to go. */ ocfs2_inc_holders(lockres, level); ret = 0; unlock: + lockres_clear_flags(lockres, OCFS2_LOCK_UPCONVERT_FINISHING); + spin_unlock_irqrestore(&lockres->l_lock, flags); out: /* @@ -3155,7 +3187,7 @@ out: /* Mark the lockres as being dropped. It will no longer be * queued if blocking, but we still may have to wait on it * being dequeued from the downconvert thread before we can consider - * it safe to drop. + * it safe to drop. * * You can *not* attempt to call cluster_lock on this lockres anymore. */ void ocfs2_mark_lockres_freeing(struct ocfs2_lock_res *lockres) @@ -3352,6 +3384,7 @@ static int ocfs2_unblock_lock(struct ocfs2_super *osb, unsigned long flags; int blocking; int new_level; + int level; int ret = 0; int set_lvb = 0; unsigned int gen; @@ -3360,9 +3393,17 @@ static int ocfs2_unblock_lock(struct ocfs2_super *osb, spin_lock_irqsave(&lockres->l_lock, flags); - BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BLOCKED)); - recheck: + /* + * Is it still blocking? If not, we have no more work to do. + */ + if (!(lockres->l_flags & OCFS2_LOCK_BLOCKED)) { + BUG_ON(lockres->l_blocking != DLM_LOCK_NL); + spin_unlock_irqrestore(&lockres->l_lock, flags); + ret = 0; + goto leave; + } + if (lockres->l_flags & OCFS2_LOCK_BUSY) { /* XXX * This is a *big* race. The OCFS2_LOCK_PENDING flag @@ -3401,6 +3442,31 @@ recheck: goto leave; } + /* + * This prevents livelocks. OCFS2_LOCK_UPCONVERT_FINISHING flag is + * set when the ast is received for an upconvert just before the + * OCFS2_LOCK_BUSY flag is cleared. Now if the fs received a bast + * on the heels of the ast, we want to delay the downconvert just + * enough to allow the up requestor to do its task. Because this + * lock is in the blocked queue, the lock will be downconverted + * as soon as the requestor is done with the lock. + */ + if (lockres->l_flags & OCFS2_LOCK_UPCONVERT_FINISHING) + goto leave_requeue; + + /* + * How can we block and yet be at NL? We were trying to upconvert + * from NL and got canceled. The code comes back here, and now + * we notice and clear BLOCKING. + */ + if (lockres->l_level == DLM_LOCK_NL) { + BUG_ON(lockres->l_ex_holders || lockres->l_ro_holders); + lockres->l_blocking = DLM_LOCK_NL; + lockres_clear_flags(lockres, OCFS2_LOCK_BLOCKED); + spin_unlock_irqrestore(&lockres->l_lock, flags); + goto leave; + } + /* if we're blocking an exclusive and we have *any* holders, * then requeue. */ if ((lockres->l_blocking == DLM_LOCK_EX) @@ -3438,6 +3504,7 @@ recheck: * may sleep, so we save off a copy of what we're blocking as * it may change while we're not holding the spin lock. */ blocking = lockres->l_blocking; + level = lockres->l_level; spin_unlock_irqrestore(&lockres->l_lock, flags); ctl->unblock_action = lockres->l_ops->downconvert_worker(lockres, blocking); @@ -3446,7 +3513,7 @@ recheck: goto leave; spin_lock_irqsave(&lockres->l_lock, flags); - if (blocking != lockres->l_blocking) { + if ((blocking != lockres->l_blocking) || (level != lockres->l_level)) { /* If this changed underneath us, then we can't drop * it just yet. */ goto recheck; |