From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
In certain cases we need to be able to maintain a buffer lock across a
defer_finish call. Since there could be many (large) transactions
committed as a result of a defer_finish, we have to hold the buffer
across the roll, then immediately rejoin the buffer and mark it dirty in
each transaction to keep the log moving forward.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_defer.c | 37 ++++++++++++++++++++++++++++++++++---
fs/xfs/libxfs/xfs_defer.h | 5 ++++-
2 files changed, 38 insertions(+), 4 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
index 072ebfe..b5b3414 100644
--- a/fs/xfs/libxfs/xfs_defer.c
+++ b/fs/xfs/libxfs/xfs_defer.c
@@ -249,6 +249,10 @@ xfs_defer_trans_roll(
for (i = 0; i < XFS_DEFER_OPS_NR_INODES && dop->dop_inodes[i]; i++)
xfs_trans_log_inode(*tp, dop->dop_inodes[i], XFS_ILOG_CORE);
+ /* Hold the (previously bjoin'd) buffer locked across the roll. */
+ for (i = 0; i < XFS_DEFER_OPS_NR_BUFS && dop->dop_bufs[i]; i++)
+ xfs_trans_bhold(*tp, dop->dop_bufs[i]);
+
trace_xfs_defer_trans_roll((*tp)->t_mountp, dop);
/* Roll the transaction. */
@@ -264,6 +268,12 @@ xfs_defer_trans_roll(
for (i = 0; i < XFS_DEFER_OPS_NR_INODES && dop->dop_inodes[i]; i++)
xfs_trans_ijoin(*tp, dop->dop_inodes[i], 0);
+ /* Rejoin the buffers and dirty them so the log moves forward. */
+ for (i = 0; i < XFS_DEFER_OPS_NR_BUFS && dop->dop_bufs[i]; i++) {
+ xfs_trans_bjoin(*tp, dop->dop_bufs[i]);
+ xfs_trans_dirty_buf(*tp, dop->dop_bufs[i]);
+ }
+
return error;
}
@@ -299,6 +309,29 @@ xfs_defer_ijoin(
}
/*
+ * Add this buffer to the deferred op. Each joined buffer is relogged
+ * each time we roll the transaction.
+ */
+int
+xfs_defer_bjoin(
+ struct xfs_defer_ops *dop,
+ struct xfs_buf *bp)
+{
+ int i;
+
+ for (i = 0; i < XFS_DEFER_OPS_NR_BUFS; i++) {
+ if (dop->dop_bufs[i] == bp)
+ return 0;
+ else if (dop->dop_bufs[i] == NULL) {
+ dop->dop_bufs[i] = bp;
+ return 0;
+ }
+ }
+
+ return -EFSCORRUPTED;
+}
+
+/*
* Finish all the pending work. This involves logging intent items for
* any work items that wandered in since the last transaction roll (if
* one has even happened), rolling the transaction, and finishing the
@@ -493,9 +526,7 @@ xfs_defer_init(
struct xfs_defer_ops *dop,
xfs_fsblock_t *fbp)
{
- dop->dop_committed = false;
- dop->dop_low = false;
- memset(&dop->dop_inodes, 0, sizeof(dop->dop_inodes));
+ memset(dop, 0, sizeof(struct xfs_defer_ops));
*fbp = NULLFSBLOCK;
INIT_LIST_HEAD(&dop->dop_intake);
INIT_LIST_HEAD(&dop->dop_pending);
diff --git a/fs/xfs/libxfs/xfs_defer.h b/fs/xfs/libxfs/xfs_defer.h
index d4f046d..045beac 100644
--- a/fs/xfs/libxfs/xfs_defer.h
+++ b/fs/xfs/libxfs/xfs_defer.h
@@ -59,6 +59,7 @@ enum xfs_defer_ops_type {
};
#define XFS_DEFER_OPS_NR_INODES 2 /* join up to two inodes */
+#define XFS_DEFER_OPS_NR_BUFS 2 /* join up to two buffers */
struct xfs_defer_ops {
bool dop_committed; /* did any trans commit? */
@@ -66,8 +67,9 @@ struct xfs_defer_ops {
struct list_head dop_intake; /* unlogged pending work */
struct list_head dop_pending; /* logged pending work */
- /* relog these inodes with each roll */
+ /* relog these with each roll */
struct xfs_inode *dop_inodes[XFS_DEFER_OPS_NR_INODES];
+ struct xfs_buf *dop_bufs[XFS_DEFER_OPS_NR_BUFS];
};
void xfs_defer_add(struct xfs_defer_ops *dop, enum xfs_defer_ops_type type,
@@ -77,6 +79,7 @@ void xfs_defer_cancel(struct xfs_defer_ops *dop);
void xfs_defer_init(struct xfs_defer_ops *dop, xfs_fsblock_t *fbp);
bool xfs_defer_has_unfinished_work(struct xfs_defer_ops *dop);
int xfs_defer_ijoin(struct xfs_defer_ops *dop, struct xfs_inode *ip);
+int xfs_defer_bjoin(struct xfs_defer_ops *dop, struct xfs_buf *bp);
/* Description of a deferred type. */
struct xfs_defer_op_type {
--
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