I don't think the patch is quite correct. In the old code xfs_buf_rele
incremented the buffer reference count before calling ->b_relse,
expecting it do decrement it again.
I think the best fix is to kill ->b_relse entirely. We can simply
do the buffer callback processing and b_flags updates in
xfs_buf_iodone_callbacks. The important thing is to not clear the
buffer error there, so that it actually get propagated to the caller.
As the buffer remains locked until xfs_bwrite calls xfs_buf_relse it
can get the error reliably that way.
Patch below, but it's still running xfqa so far:
Index: xfs/fs/xfs/linux-2.6/xfs_buf.h
===================================================================
--- xfs.orig/fs/xfs/linux-2.6/xfs_buf.h 2011-01-04 09:42:44.763003651 +0100
+++ xfs/fs/xfs/linux-2.6/xfs_buf.h 2011-01-04 09:54:08.443255013 +0100
@@ -152,8 +152,6 @@ typedef struct xfs_buftarg {
struct xfs_buf;
typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
-typedef void (*xfs_buf_relse_t)(struct xfs_buf *);
-typedef int (*xfs_buf_bdstrat_t)(struct xfs_buf *);
#define XB_PAGES 2
@@ -183,7 +181,6 @@ typedef struct xfs_buf {
void *b_addr; /* virtual address of buffer */
struct work_struct b_iodone_work;
xfs_buf_iodone_t b_iodone; /* I/O completion function */
- xfs_buf_relse_t b_relse; /* releasing function */
struct completion b_iowait; /* queue for I/O waiters */
void *b_fspriv;
void *b_fspriv2;
@@ -323,7 +320,6 @@ void xfs_buf_stale(struct xfs_buf *bp);
#define XFS_BUF_FSPRIVATE2(bp, type) ((type)(bp)->b_fspriv2)
#define XFS_BUF_SET_FSPRIVATE2(bp, val) ((bp)->b_fspriv2 = (void*)(val))
#define XFS_BUF_SET_START(bp) do { } while (0)
-#define XFS_BUF_SET_BRELSE_FUNC(bp, func) ((bp)->b_relse = (func))
#define XFS_BUF_PTR(bp) (xfs_caddr_t)((bp)->b_addr)
#define XFS_BUF_SET_PTR(bp, val, cnt) xfs_buf_associate_memory(bp, val, cnt)
@@ -360,8 +356,7 @@ xfs_buf_set_ref(
static inline void xfs_buf_relse(xfs_buf_t *bp)
{
- if (!bp->b_relse)
- xfs_buf_unlock(bp);
+ xfs_buf_unlock(bp);
xfs_buf_rele(bp);
}
Index: xfs/fs/xfs/xfs_buf_item.c
===================================================================
--- xfs.orig/fs/xfs/xfs_buf_item.c 2011-01-04 09:42:44.779005117 +0100
+++ xfs/fs/xfs/xfs_buf_item.c 2011-01-04 09:47:40.798004000 +0100
@@ -141,7 +141,6 @@ xfs_buf_item_log_check(
#define xfs_buf_item_log_check(x)
#endif
-STATIC void xfs_buf_error_relse(xfs_buf_t *bp);
STATIC void xfs_buf_do_callbacks(struct xfs_buf *bp);
/*
@@ -959,128 +958,76 @@ xfs_buf_do_callbacks(
*/
void
xfs_buf_iodone_callbacks(
- xfs_buf_t *bp)
+ struct xfs_buf *bp)
{
- xfs_log_item_t *lip;
- static ulong lasttime;
- static xfs_buftarg_t *lasttarg;
- xfs_mount_t *mp;
+ struct xfs_log_item *lip = bp->b_fspriv;
+ struct xfs_mount *mp = lip->li_mountp;
+ static ulong lasttime;
+ static xfs_buftarg_t *lasttarg;
- ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
- lip = XFS_BUF_FSPRIVATE(bp, xfs_log_item_t *);
+ if (likely(!XFS_BUF_GETERROR(bp)))
+ goto do_callbacks;
- if (XFS_BUF_GETERROR(bp) != 0) {
- /*
- * If we've already decided to shutdown the filesystem
- * because of IO errors, there's no point in giving this
- * a retry.
- */
- mp = lip->li_mountp;
- if (XFS_FORCED_SHUTDOWN(mp)) {
- ASSERT(XFS_BUF_TARGET(bp) == mp->m_ddev_targp);
- XFS_BUF_SUPER_STALE(bp);
- trace_xfs_buf_item_iodone(bp, _RET_IP_);
- xfs_buf_do_callbacks(bp);
- XFS_BUF_SET_FSPRIVATE(bp, NULL);
- XFS_BUF_CLR_IODONE_FUNC(bp);
- xfs_buf_ioend(bp, 0);
- return;
- }
+ /*
+ * If we've already decided to shutdown the filesystem because of
+ * I/O errors, there's no point in giving this a retry.
+ */
+ if (XFS_FORCED_SHUTDOWN(mp)) {
+ XFS_BUF_SUPER_STALE(bp);
+ trace_xfs_buf_item_iodone(bp, _RET_IP_);
+ goto do_callbacks;
+ }
- if ((XFS_BUF_TARGET(bp) != lasttarg) ||
- (time_after(jiffies, (lasttime + 5*HZ)))) {
- lasttime = jiffies;
- cmn_err(CE_ALERT, "Device %s, XFS metadata write error"
- " block 0x%llx in %s",
- XFS_BUFTARG_NAME(XFS_BUF_TARGET(bp)),
- (__uint64_t)XFS_BUF_ADDR(bp), mp->m_fsname);
- }
- lasttarg = XFS_BUF_TARGET(bp);
+ if (XFS_BUF_TARGET(bp) != lasttarg ||
+ time_after(jiffies, (lasttime + 5*HZ))) {
+ lasttime = jiffies;
+ cmn_err(CE_ALERT, "Device %s, XFS metadata write error"
+ " block 0x%llx in %s",
+ XFS_BUFTARG_NAME(XFS_BUF_TARGET(bp)),
+ (__uint64_t)XFS_BUF_ADDR(bp), mp->m_fsname);
+ }
+ lasttarg = XFS_BUF_TARGET(bp);
- if (XFS_BUF_ISASYNC(bp)) {
- /*
- * If the write was asynchronous then noone will be
- * looking for the error. Clear the error state
- * and write the buffer out again delayed write.
- *
- * XXXsup This is OK, so long as we catch these
- * before we start the umount; we don't want these
- * DELWRI metadata bufs to be hanging around.
- */
- XFS_BUF_ERROR(bp,0); /* errno of 0 unsets the flag */
+ /*
+ * If the write was asynchronous then noone will be looking for the
+ * error. Clear the error state and write the buffer out again.
+ *
+ * During sync or umount we'll write all pending buffers again
+ * synchronous, which will catch these errors if they keep hanging
+ * around.
+ */
+ if (XFS_BUF_ISASYNC(bp)) {
+ XFS_BUF_ERROR(bp, 0); /* errno of 0 unsets the flag */
- if (!(XFS_BUF_ISSTALE(bp))) {
- XFS_BUF_DELAYWRITE(bp);
- XFS_BUF_DONE(bp);
- XFS_BUF_SET_START(bp);
- }
- ASSERT(XFS_BUF_IODONE_FUNC(bp));
- trace_xfs_buf_item_iodone_async(bp, _RET_IP_);
- xfs_buf_relse(bp);
- } else {
- /*
- * If the write of the buffer was not asynchronous,
- * then we want to make sure to return the error
- * to the caller of bwrite(). Because of this we
- * cannot clear the B_ERROR state at this point.
- * Instead we install a callback function that
- * will be called when the buffer is released, and
- * that routine will clear the error state and
- * set the buffer to be written out again after
- * some delay.
- */
- /* We actually overwrite the existing b-relse
- function at times, but we're gonna be shutting down
- anyway. */
- XFS_BUF_SET_BRELSE_FUNC(bp,xfs_buf_error_relse);
+ if (!XFS_BUF_ISSTALE(bp)) {
+ XFS_BUF_DELAYWRITE(bp);
XFS_BUF_DONE(bp);
- XFS_BUF_FINISH_IOWAIT(bp);
+ XFS_BUF_SET_START(bp);
}
+ ASSERT(XFS_BUF_IODONE_FUNC(bp));
+ trace_xfs_buf_item_iodone_async(bp, _RET_IP_);
+ xfs_buf_relse(bp);
return;
}
- xfs_buf_do_callbacks(bp);
- XFS_BUF_SET_FSPRIVATE(bp, NULL);
- XFS_BUF_CLR_IODONE_FUNC(bp);
- xfs_buf_ioend(bp, 0);
-}
-
-/*
- * This is a callback routine attached to a buffer which gets an error
- * when being written out synchronously.
- */
-STATIC void
-xfs_buf_error_relse(
- xfs_buf_t *bp)
-{
- xfs_log_item_t *lip;
- xfs_mount_t *mp;
-
- lip = XFS_BUF_FSPRIVATE(bp, xfs_log_item_t *);
- mp = (xfs_mount_t *)lip->li_mountp;
- ASSERT(XFS_BUF_TARGET(bp) == mp->m_ddev_targp);
-
+ /*
+ * If the write of the buffer was synchronous, we want to make
+ * sure to return the error to the caller of xfs_bwrite().
+ */
XFS_BUF_STALE(bp);
XFS_BUF_DONE(bp);
XFS_BUF_UNDELAYWRITE(bp);
- XFS_BUF_ERROR(bp,0);
trace_xfs_buf_error_relse(bp, _RET_IP_);
+ xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
- if (! XFS_FORCED_SHUTDOWN(mp))
- xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
- /*
- * We have to unpin the pinned buffers so do the
- * callbacks.
- */
+do_callbacks:
xfs_buf_do_callbacks(bp);
XFS_BUF_SET_FSPRIVATE(bp, NULL);
XFS_BUF_CLR_IODONE_FUNC(bp);
- XFS_BUF_SET_BRELSE_FUNC(bp,NULL);
- xfs_buf_relse(bp);
+ xfs_buf_ioend(bp, 0);
}
-
/*
* This is the iodone() function for buffers which have been
* logged. It is called when they are eventually flushed out.
Index: xfs/fs/xfs/linux-2.6/xfs_buf.c
===================================================================
--- xfs.orig/fs/xfs/linux-2.6/xfs_buf.c 2011-01-04 09:42:44.770009657 +0100
+++ xfs/fs/xfs/linux-2.6/xfs_buf.c 2011-01-04 09:46:41.233255990 +0100
@@ -896,7 +896,6 @@ xfs_buf_rele(
trace_xfs_buf_rele(bp, _RET_IP_);
if (!pag) {
- ASSERT(!bp->b_relse);
ASSERT(list_empty(&bp->b_lru));
ASSERT(RB_EMPTY_NODE(&bp->b_rbnode));
if (atomic_dec_and_test(&bp->b_hold))
@@ -908,11 +907,7 @@ xfs_buf_rele(
ASSERT(atomic_read(&bp->b_hold) > 0);
if (atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock)) {
- if (bp->b_relse) {
- atomic_inc(&bp->b_hold);
- spin_unlock(&pag->pag_buf_lock);
- bp->b_relse(bp);
- } else if (!(bp->b_flags & XBF_STALE) &&
+ if (!(bp->b_flags & XBF_STALE) &&
atomic_read(&bp->b_lru_ref)) {
xfs_buf_lru_add(bp);
spin_unlock(&pag->pag_buf_lock);
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