xfs: split out iclog writing from xfs_trans_commit()
Split the the part of xfs_trans_commit() that deals with writing the
transaction into the iclog into a separate function. This isolates the
physical commit process from the logical commit operation and makes
it easier to insert different transaction commit paths without affecting
the existing algorithm adversely.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 6962f2b..e07b329 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -47,8 +47,6 @@
STATIC void xfs_trans_apply_sb_deltas(xfs_trans_t *);
-STATIC uint xfs_trans_count_vecs(xfs_trans_t *);
-STATIC void xfs_trans_fill_vecs(xfs_trans_t *, xfs_log_iovec_t *);
STATIC void xfs_trans_uncommit(xfs_trans_t *, uint);
STATIC void xfs_trans_committed(xfs_trans_t *, int);
STATIC void xfs_trans_chunk_committed(xfs_log_item_chunk_t *, xfs_lsn_t, int);
@@ -764,94 +762,126 @@
}
}
+/*
+ * Total up the number of log iovecs needed to commit this
+ * transaction. The transaction itself needs one for the
+ * transaction header. Ask each dirty item in turn how many
+ * it needs to get the total.
+ */
+static uint
+xfs_trans_count_vecs(
+ xfs_trans_t *tp)
+{
+ int nvecs;
+ xfs_log_item_desc_t *lidp;
+
+ nvecs = 1;
+ lidp = xfs_trans_first_item(tp);
+ ASSERT(lidp != NULL);
+
+ /* In the non-debug case we need to start bailing out if we
+ * didn't find a log_item here, return zero and let trans_commit
+ * deal with it.
+ */
+ if (lidp == NULL)
+ return 0;
+
+ while (lidp != NULL) {
+ /*
+ * Skip items which aren't dirty in this transaction.
+ */
+ if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
+ lidp = xfs_trans_next_item(tp, lidp);
+ continue;
+ }
+ lidp->lid_size = IOP_SIZE(lidp->lid_item);
+ nvecs += lidp->lid_size;
+ lidp = xfs_trans_next_item(tp, lidp);
+ }
+
+ return nvecs;
+}
/*
- * xfs_trans_commit
+ * Fill in the vector with pointers to data to be logged
+ * by this transaction. The transaction header takes
+ * the first vector, and then each dirty item takes the
+ * number of vectors it indicated it needed in xfs_trans_count_vecs().
*
- * Commit the given transaction to the log a/synchronously.
- *
- * XFS disk error handling mechanism is not based on a typical
- * transaction abort mechanism. Logically after the filesystem
- * gets marked 'SHUTDOWN', we can't let any new transactions
- * be durable - ie. committed to disk - because some metadata might
- * be inconsistent. In such cases, this returns an error, and the
- * caller may assume that all locked objects joined to the transaction
- * have already been unlocked as if the commit had succeeded.
- * Do not reference the transaction structure after this call.
+ * As each item fills in the entries it needs, also pin the item
+ * so that it cannot be flushed out until the log write completes.
*/
- /*ARGSUSED*/
-int
-_xfs_trans_commit(
- xfs_trans_t *tp,
- uint flags,
- int *log_flushed)
+static void
+xfs_trans_fill_vecs(
+ struct xfs_trans *tp,
+ struct xfs_log_iovec *log_vector)
{
- xfs_log_iovec_t *log_vector;
- int nvec;
- xfs_mount_t *mp;
- xfs_lsn_t commit_lsn;
- /* REFERENCED */
- int error;
- int log_flags;
- int sync;
-#define XFS_TRANS_LOGVEC_COUNT 16
- xfs_log_iovec_t log_vector_fast[XFS_TRANS_LOGVEC_COUNT];
- struct xlog_in_core *commit_iclog;
- int shutdown;
-
- commit_lsn = -1;
+ xfs_log_item_desc_t *lidp;
+ struct xfs_log_iovec *vecp;
+ uint nitems;
/*
- * Determine whether this commit is releasing a permanent
- * log reservation or not.
+ * Skip over the entry for the transaction header, we'll
+ * fill that in at the end.
*/
- if (flags & XFS_TRANS_RELEASE_LOG_RES) {
- ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
- log_flags = XFS_LOG_REL_PERM_RESERV;
- } else {
- log_flags = 0;
- }
- mp = tp->t_mountp;
+ vecp = log_vector + 1;
- /*
- * If there is nothing to be logged by the transaction,
- * then unlock all of the items associated with the
- * transaction and free the transaction structure.
- * Also make sure to return any reserved blocks to
- * the free pool.
- */
-shut_us_down:
- shutdown = XFS_FORCED_SHUTDOWN(mp) ? EIO : 0;
- if (!(tp->t_flags & XFS_TRANS_DIRTY) || shutdown) {
- xfs_trans_unreserve_and_mod_sb(tp);
- /*
- * It is indeed possible for the transaction to be
- * not dirty but the dqinfo portion to be. All that
- * means is that we have some (non-persistent) quota
- * reservations that need to be unreserved.
- */
- xfs_trans_unreserve_and_mod_dquots(tp);
- if (tp->t_ticket) {
- commit_lsn = xfs_log_done(mp, tp->t_ticket,
- NULL, log_flags);
- if (commit_lsn == -1 && !shutdown)
- shutdown = XFS_ERROR(EIO);
+ nitems = 0;
+ lidp = xfs_trans_first_item(tp);
+ ASSERT(lidp);
+ while (lidp) {
+ /* Skip items which aren't dirty in this transaction. */
+ if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
+ lidp = xfs_trans_next_item(tp, lidp);
+ continue;
}
- current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
- xfs_trans_free_items(tp, shutdown? XFS_TRANS_ABORT : 0);
- xfs_trans_free_busy(tp);
- xfs_trans_free(tp);
- XFS_STATS_INC(xs_trans_empty);
- return (shutdown);
+
+ /*
+ * The item may be marked dirty but not log anything. This can
+ * be used to get called when a transaction is committed.
+ */
+ if (lidp->lid_size)
+ nitems++;
+ IOP_FORMAT(lidp->lid_item, vecp);
+ vecp += lidp->lid_size;
+ IOP_PIN(lidp->lid_item);
+ lidp = xfs_trans_next_item(tp, lidp);
}
- ASSERT(tp->t_ticket != NULL);
/*
- * If we need to update the superblock, then do it now.
+ * Now that we've counted the number of items in this transaction, fill
+ * in the transaction header. Note that the transaction header does not
+ * have a log item.
*/
- if (tp->t_flags & XFS_TRANS_SB_DIRTY)
- xfs_trans_apply_sb_deltas(tp);
- xfs_trans_apply_dquot_deltas(tp);
+ tp->t_header.th_magic = XFS_TRANS_HEADER_MAGIC;
+ tp->t_header.th_type = tp->t_type;
+ tp->t_header.th_num_items = nitems;
+ log_vector->i_addr = (xfs_caddr_t)&tp->t_header;
+ log_vector->i_len = sizeof(xfs_trans_header_t);
+ log_vector->i_type = XLOG_REG_TYPE_TRANSHDR;
+}
+
+/*
+ * Format the transaction direct to the iclog. This isolates the physical
+ * transaction commit operation from the logical operation and hence allows
+ * other methods to be introduced without affecting the existing commit path.
+ */
+static int
+xfs_trans_commit_iclog(
+ struct xfs_mount *mp,
+ struct xfs_trans *tp,
+ xfs_lsn_t *commit_lsn,
+ int flags)
+{
+ int shutdown;
+ int error;
+ int log_flags = 0;
+ struct xlog_in_core *commit_iclog;
+#define XFS_TRANS_LOGVEC_COUNT 16
+ struct xfs_log_iovec log_vector_fast[XFS_TRANS_LOGVEC_COUNT];
+ struct xfs_log_iovec *log_vector;
+ uint nvec;
+
/*
* Ask each log item how many log_vector entries it will
@@ -861,8 +891,7 @@
*/
nvec = xfs_trans_count_vecs(tp);
if (nvec == 0) {
- xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
- goto shut_us_down;
+ return ENOMEM; /* triggers a shutdown! */
} else if (nvec <= XFS_TRANS_LOGVEC_COUNT) {
log_vector = log_vector_fast;
} else {
@@ -877,6 +906,9 @@
*/
xfs_trans_fill_vecs(tp, log_vector);
+ if (flags & XFS_TRANS_RELEASE_LOG_RES)
+ log_flags = XFS_LOG_REL_PERM_RESERV;
+
error = xfs_log_write(mp, log_vector, nvec, tp->t_ticket, &(tp->t_lsn));
/*
@@ -884,18 +916,17 @@
* at any time after this call. However, all the items associated
* with the transaction are still locked and pinned in memory.
*/
- commit_lsn = xfs_log_done(mp, tp->t_ticket, &commit_iclog, log_flags);
+ *commit_lsn = xfs_log_done(mp, tp->t_ticket, &commit_iclog, log_flags);
- tp->t_commit_lsn = commit_lsn;
- if (nvec > XFS_TRANS_LOGVEC_COUNT) {
+ tp->t_commit_lsn = *commit_lsn;
+ if (nvec > XFS_TRANS_LOGVEC_COUNT)
kmem_free(log_vector);
- }
/*
* If we got a log write error. Unpin the logitems that we
* had pinned, clean up, free trans structure, and return error.
*/
- if (error || commit_lsn == -1) {
+ if (error || *commit_lsn == -1) {
current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
xfs_trans_uncommit(tp, flags|XFS_TRANS_ABORT);
return XFS_ERROR(EIO);
@@ -909,8 +940,6 @@
*/
xfs_trans_unreserve_and_mod_sb(tp);
- sync = tp->t_flags & XFS_TRANS_SYNC;
-
/*
* Tell the LM to call the transaction completion routine
* when the log write with LSN commit_lsn completes (e.g.
@@ -953,7 +982,7 @@
* the commit lsn of this transaction for dependency tracking
* purposes.
*/
- xfs_trans_unlock_items(tp, commit_lsn);
+ xfs_trans_unlock_items(tp, *commit_lsn);
/*
* If we detected a log error earlier, finish committing
@@ -973,7 +1002,92 @@
* and the items are released we can finally allow the iclog to
* go to disk.
*/
- error = xfs_log_release_iclog(mp, commit_iclog);
+ return xfs_log_release_iclog(mp, commit_iclog);
+}
+
+
+/*
+ * xfs_trans_commit
+ *
+ * Commit the given transaction to the log a/synchronously.
+ *
+ * XFS disk error handling mechanism is not based on a typical
+ * transaction abort mechanism. Logically after the filesystem
+ * gets marked 'SHUTDOWN', we can't let any new transactions
+ * be durable - ie. committed to disk - because some metadata might
+ * be inconsistent. In such cases, this returns an error, and the
+ * caller may assume that all locked objects joined to the transaction
+ * have already been unlocked as if the commit had succeeded.
+ * Do not reference the transaction structure after this call.
+ */
+ /*ARGSUSED*/
+int
+_xfs_trans_commit(
+ xfs_trans_t *tp,
+ uint flags,
+ int *log_flushed)
+{
+ xfs_mount_t *mp = tp->t_mountp;
+ xfs_lsn_t commit_lsn = -1;
+ int error;
+ int log_flags = 0;
+ int sync = tp->t_flags & XFS_TRANS_SYNC;
+ int shutdown;
+
+ /*
+ * Determine whether this commit is releasing a permanent
+ * log reservation or not.
+ */
+ if (flags & XFS_TRANS_RELEASE_LOG_RES) {
+ ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
+ log_flags = XFS_LOG_REL_PERM_RESERV;
+ }
+
+ /*
+ * If there is nothing to be logged by the transaction,
+ * then unlock all of the items associated with the
+ * transaction and free the transaction structure.
+ * Also make sure to return any reserved blocks to
+ * the free pool.
+ */
+shut_us_down:
+ shutdown = XFS_FORCED_SHUTDOWN(mp) ? EIO : 0;
+ if (!(tp->t_flags & XFS_TRANS_DIRTY) || shutdown) {
+ xfs_trans_unreserve_and_mod_sb(tp);
+ /*
+ * It is indeed possible for the transaction to be
+ * not dirty but the dqinfo portion to be. All that
+ * means is that we have some (non-persistent) quota
+ * reservations that need to be unreserved.
+ */
+ xfs_trans_unreserve_and_mod_dquots(tp);
+ if (tp->t_ticket) {
+ commit_lsn = xfs_log_done(mp, tp->t_ticket,
+ NULL, log_flags);
+ if (commit_lsn == -1 && !shutdown)
+ shutdown = XFS_ERROR(EIO);
+ }
+ current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
+ xfs_trans_free_items(tp, shutdown? XFS_TRANS_ABORT : 0);
+ xfs_trans_free_busy(tp);
+ xfs_trans_free(tp);
+ XFS_STATS_INC(xs_trans_empty);
+ return (shutdown);
+ }
+ ASSERT(tp->t_ticket != NULL);
+
+ /*
+ * If we need to update the superblock, then do it now.
+ */
+ if (tp->t_flags & XFS_TRANS_SB_DIRTY)
+ xfs_trans_apply_sb_deltas(tp);
+ xfs_trans_apply_dquot_deltas(tp);
+
+ error = xfs_trans_commit_iclog(mp, tp, &commit_lsn, flags);
+ if (error == ENOMEM) {
+ xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
+ goto shut_us_down;
+ }
/*
* If the transaction needs to be synchronous, then force the
@@ -992,47 +1106,6 @@
return (error);
}
-
-/*
- * Total up the number of log iovecs needed to commit this
- * transaction. The transaction itself needs one for the
- * transaction header. Ask each dirty item in turn how many
- * it needs to get the total.
- */
-STATIC uint
-xfs_trans_count_vecs(
- xfs_trans_t *tp)
-{
- int nvecs;
- xfs_log_item_desc_t *lidp;
-
- nvecs = 1;
- lidp = xfs_trans_first_item(tp);
- ASSERT(lidp != NULL);
-
- /* In the non-debug case we need to start bailing out if we
- * didn't find a log_item here, return zero and let trans_commit
- * deal with it.
- */
- if (lidp == NULL)
- return 0;
-
- while (lidp != NULL) {
- /*
- * Skip items which aren't dirty in this transaction.
- */
- if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
- lidp = xfs_trans_next_item(tp, lidp);
- continue;
- }
- lidp->lid_size = IOP_SIZE(lidp->lid_item);
- nvecs += lidp->lid_size;
- lidp = xfs_trans_next_item(tp, lidp);
- }
-
- return nvecs;
-}
-
/*
* Called from the trans_commit code when we notice that
* the filesystem is in the middle of a forced shutdown.
@@ -1063,68 +1136,6 @@
}
/*
- * Fill in the vector with pointers to data to be logged
- * by this transaction. The transaction header takes
- * the first vector, and then each dirty item takes the
- * number of vectors it indicated it needed in xfs_trans_count_vecs().
- *
- * As each item fills in the entries it needs, also pin the item
- * so that it cannot be flushed out until the log write completes.
- */
-STATIC void
-xfs_trans_fill_vecs(
- xfs_trans_t *tp,
- xfs_log_iovec_t *log_vector)
-{
- xfs_log_item_desc_t *lidp;
- xfs_log_iovec_t *vecp;
- uint nitems;
-
- /*
- * Skip over the entry for the transaction header, we'll
- * fill that in at the end.
- */
- vecp = log_vector + 1; /* pointer arithmetic */
-
- nitems = 0;
- lidp = xfs_trans_first_item(tp);
- ASSERT(lidp != NULL);
- while (lidp != NULL) {
- /*
- * Skip items which aren't dirty in this transaction.
- */
- if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
- lidp = xfs_trans_next_item(tp, lidp);
- continue;
- }
- /*
- * The item may be marked dirty but not log anything.
- * This can be used to get called when a transaction
- * is committed.
- */
- if (lidp->lid_size) {
- nitems++;
- }
- IOP_FORMAT(lidp->lid_item, vecp);
- vecp += lidp->lid_size; /* pointer arithmetic */
- IOP_PIN(lidp->lid_item);
- lidp = xfs_trans_next_item(tp, lidp);
- }
-
- /*
- * Now that we've counted the number of items in this
- * transaction, fill in the transaction header.
- */
- tp->t_header.th_magic = XFS_TRANS_HEADER_MAGIC;
- tp->t_header.th_type = tp->t_type;
- tp->t_header.th_num_items = nitems;
- log_vector->i_addr = (xfs_caddr_t)&tp->t_header;
- log_vector->i_len = sizeof(xfs_trans_header_t);
- log_vector->i_type = XLOG_REG_TYPE_TRANSHDR;
-}
-
-
-/*
* Unlock all of the transaction's items and free the transaction.
* The transaction must not have modified any of its items, because
* there is no way to restore them to their previous state.