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Diffstat (limited to 'fs/xfs/xfs_log.c')
-rw-r--r--fs/xfs/xfs_log.c55
1 files changed, 42 insertions, 13 deletions
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 8556c59628ba..81323d73a4ee 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -664,7 +664,10 @@ xfs_log_item_init(
/*
* Write region vectors to log. The write happens using the space reservation
* of the ticket (tic). It is not a requirement that all writes for a given
- * transaction occur with one call to xfs_log_write().
+ * transaction occur with one call to xfs_log_write(). However, it is important
+ * to note that the transaction reservation code makes an assumption about the
+ * number of log headers a transaction requires that may be violated if you
+ * don't pass all the transaction vectors in one call....
*/
int
xfs_log_write(
@@ -3170,14 +3173,16 @@ xfs_log_ticket_get(
* Allocate and initialise a new log ticket.
*/
STATIC xlog_ticket_t *
-xlog_ticket_alloc(xlog_t *log,
- int unit_bytes,
- int cnt,
- char client,
- uint xflags)
+xlog_ticket_alloc(
+ struct log *log,
+ int unit_bytes,
+ int cnt,
+ char client,
+ uint xflags)
{
- xlog_ticket_t *tic;
+ struct xlog_ticket *tic;
uint num_headers;
+ int iclog_space;
tic = kmem_zone_zalloc(xfs_log_ticket_zone, KM_SLEEP|KM_MAYFAIL);
if (!tic)
@@ -3221,16 +3226,40 @@ xlog_ticket_alloc(xlog_t *log,
/* for start-rec */
unit_bytes += sizeof(xlog_op_header_t);
- /* for LR headers */
- num_headers = ((unit_bytes + log->l_iclog_size-1) >> log->l_iclog_size_log);
+ /*
+ * for LR headers - the space for data in an iclog is the size minus
+ * the space used for the headers. If we use the iclog size, then we
+ * undercalculate the number of headers required.
+ *
+ * Furthermore - the addition of op headers for split-recs might
+ * increase the space required enough to require more log and op
+ * headers, so take that into account too.
+ *
+ * IMPORTANT: This reservation makes the assumption that if this
+ * transaction is the first in an iclog and hence has the LR headers
+ * accounted to it, then the remaining space in the iclog is
+ * exclusively for this transaction. i.e. if the transaction is larger
+ * than the iclog, it will be the only thing in that iclog.
+ * Fundamentally, this means we must pass the entire log vector to
+ * xlog_write to guarantee this.
+ */
+ iclog_space = log->l_iclog_size - log->l_iclog_hsize;
+ num_headers = howmany(unit_bytes, iclog_space);
+
+ /* for split-recs - ophdrs added when data split over LRs */
+ unit_bytes += sizeof(xlog_op_header_t) * num_headers;
+
+ /* add extra header reservations if we overrun */
+ while (!num_headers ||
+ howmany(unit_bytes, iclog_space) > num_headers) {
+ unit_bytes += sizeof(xlog_op_header_t);
+ num_headers++;
+ }
unit_bytes += log->l_iclog_hsize * num_headers;
/* for commit-rec LR header - note: padding will subsume the ophdr */
unit_bytes += log->l_iclog_hsize;
- /* for split-recs - ophdrs added when data split over LRs */
- unit_bytes += sizeof(xlog_op_header_t) * num_headers;
-
/* for roundoff padding for transaction data and one for commit record */
if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
log->l_mp->m_sb.sb_logsunit > 1) {
@@ -3252,7 +3281,7 @@ xlog_ticket_alloc(xlog_t *log,
tic->t_trans_type = 0;
if (xflags & XFS_LOG_PERM_RESERV)
tic->t_flags |= XLOG_TIC_PERM_RESERV;
- sv_init(&(tic->t_wait), SV_DEFAULT, "logtick");
+ sv_init(&tic->t_wait, SV_DEFAULT, "logtick");
xlog_tic_reset_res(tic);