diff options
| -rw-r--r-- | fs/xfs/xfs_log_cil.c | 52 |
1 files changed, 39 insertions, 13 deletions
diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c index cdebd832c3db..1270ded7610d 100644 --- a/fs/xfs/xfs_log_cil.c +++ b/fs/xfs/xfs_log_cil.c @@ -488,13 +488,6 @@ xlog_cil_push( cil->xc_ctx = new_ctx; /* - * mirror the new sequence into the cil structure so that we can do - * unlocked checks against the current sequence in log forces without - * risking deferencing a freed context pointer. - */ - cil->xc_current_sequence = new_ctx->sequence; - - /* * The switch is now done, so we can drop the context lock and move out * of a shared context. We can't just go straight to the commit record, * though - we need to synchronise with previous and future commits so @@ -512,8 +505,15 @@ xlog_cil_push( * Hence we need to add this context to the committing context list so * that higher sequences will wait for us to write out a commit record * before they do. + * + * xfs_log_force_lsn requires us to mirror the new sequence into the cil + * structure atomically with the addition of this sequence to the + * committing list. This also ensures that we can do unlocked checks + * against the current sequence in log forces without risking + * deferencing a freed context pointer. */ spin_lock(&cil->xc_push_lock); + cil->xc_current_sequence = new_ctx->sequence; list_add(&ctx->committing, &cil->xc_committing); spin_unlock(&cil->xc_push_lock); up_write(&cil->xc_ctx_lock); @@ -651,8 +651,14 @@ xlog_cil_push_background( } +/* + * xlog_cil_push_now() is used to trigger an immediate CIL push to the sequence + * number that is passed. When it returns, the work will be queued for + * @push_seq, but it won't be completed. The caller is expected to do any + * waiting for push_seq to complete if it is required. + */ static void -xlog_cil_push_foreground( +xlog_cil_push_now( struct xlog *log, xfs_lsn_t push_seq) { @@ -677,10 +683,8 @@ xlog_cil_push_foreground( } cil->xc_push_seq = push_seq; + queue_work(log->l_mp->m_cil_workqueue, &cil->xc_push_work); spin_unlock(&cil->xc_push_lock); - - /* do the push now */ - xlog_cil_push(log); } bool @@ -785,7 +789,8 @@ xlog_cil_force_lsn( * xlog_cil_push() handles racing pushes for the same sequence, * so no need to deal with it here. */ - xlog_cil_push_foreground(log, sequence); +restart: + xlog_cil_push_now(log, sequence); /* * See if we can find a previous sequence still committing. @@ -793,7 +798,6 @@ xlog_cil_force_lsn( * before allowing the force of push_seq to go ahead. Hence block * on commits for those as well. */ -restart: spin_lock(&cil->xc_push_lock); list_for_each_entry(ctx, &cil->xc_committing, committing) { if (ctx->sequence > sequence) @@ -811,6 +815,28 @@ restart: /* found it! */ commit_lsn = ctx->commit_lsn; } + + /* + * The call to xlog_cil_push_now() executes the push in the background. + * Hence by the time we have got here it our sequence may not have been + * pushed yet. This is true if the current sequence still matches the + * push sequence after the above wait loop and the CIL still contains + * dirty objects. + * + * When the push occurs, it will empty the CIL and + * atomically increment the currect sequence past the push sequence and + * move it into the committing list. Of course, if the CIL is clean at + * the time of the push, it won't have pushed the CIL at all, so in that + * case we should try the push for this sequence again from the start + * just in case. + */ + + if (sequence == cil->xc_current_sequence && + !list_empty(&cil->xc_cil)) { + spin_unlock(&cil->xc_push_lock); + goto restart; + } + spin_unlock(&cil->xc_push_lock); return commit_lsn; } |