/*
* Allocate a new buf log item to go with the given buffer.
* Set the buffer's b_fsprivate field to point to the new
* buf log item. If there are other item's attached to the
* buffer (see xfs_buf_attach_iodone() below), then put the
* buf log item at the front.
*/
void
xfs_buf_item_init(
xfs_buf_t *bp,
xfs_mount_t *mp)
{
xfs_log_item_t *lip = bp->b_fspriv;
xfs_buf_log_item_t *bip;
int chunks;
int map_size;
int error;
int i;
/*
* Check to see if there is already a buf log item for
* this buffer. If there is, it is guaranteed to be
* the first. If we do already have one, there is
* nothing to do here so return.
*/
ASSERT(bp->b_target->bt_mount == mp);
if (lip != NULL && lip->li_type == XFS_LI_BUF)
return;
bip = kmem_zone_zalloc(xfs_buf_item_zone, KM_SLEEP);
xfs_log_item_init(mp, &bip->bli_item, XFS_LI_BUF, &xfs_buf_item_ops);
bip->bli_buf = bp;
xfs_buf_hold(bp);
/*
* chunks is the number of XFS_BLF_CHUNK size pieces the buffer
* can be divided into. Make sure not to truncate any pieces.
* map_size is the size of the bitmap needed to describe the
* chunks of the buffer.
*
* Discontiguous buffer support follows the layout of the underlying
* buffer. This makes the implementation as simple as possible.
*/
error = xfs_buf_item_get_format(bip, bp->b_map_count);
ASSERT(error == 0);
for (i = 0; i < bip->bli_format_count; i++) {
chunks = DIV_ROUND_UP(BBTOB(bp->b_maps[i].bm_len),
XFS_BLF_CHUNK);
map_size = DIV_ROUND_UP(chunks, NBWORD);
bip->bli_formats[i].blf_type = XFS_LI_BUF;
bip->bli_formats[i].blf_blkno = bp->b_maps[i].bm_bn;
bip->bli_formats[i].blf_len = bp->b_maps[i].bm_len;
bip->bli_formats[i].blf_map_size = map_size;
}
/*
* Put the buf item into the list of items attached to the
* buffer at the front.
*/
if (bp->b_fspriv)
bip->bli_item.li_bio_list = bp->b_fspriv;
bp->b_fspriv = bip;
}
/*
* Allocate a new buf log item to go with the given buffer.
* Set the buffer's b_fsprivate field to point to the new
* buf log item. If there are other item's attached to the
* buffer (see xfs_buf_attach_iodone() below), then put the
* buf log item at the front.
*/
void
xfs_buf_item_init(
xfs_buf_t *bp,
xfs_mount_t *mp)
{
xfs_log_item_t *lip = bp->b_fspriv;
xfs_buf_log_item_t *bip;
int chunks;
int map_size;
int error;
int i;
/*
* Check to see if there is already a buf log item for
* this buffer. If there is, it is guaranteed to be
* the first. If we do already have one, there is
* nothing to do here so return.
*/
ASSERT(bp->b_target->bt_mount == mp);
if (lip != NULL && lip->li_type == XFS_LI_BUF)
return;
bip = kmem_zone_zalloc(xfs_buf_item_zone, KM_SLEEP);
xfs_log_item_init(mp, &bip->bli_item, XFS_LI_BUF, &xfs_buf_item_ops);
bip->bli_buf = bp;
xfs_buf_hold(bp);
/*
* chunks is the number of XFS_BLF_CHUNK size pieces the buffer
* can be divided into. Make sure not to truncate any pieces.
* map_size is the size of the bitmap needed to describe the
* chunks of the buffer.
*
* Discontiguous buffer support follows the layout of the underlying
* buffer. This makes the implementation as simple as possible.
*/
error = xfs_buf_item_get_format(bip, bp->b_map_count);
ASSERT(error == 0);
for (i = 0; i < bip->bli_format_count; i++) {
chunks = DIV_ROUND_UP(BBTOB(bp->b_maps[i].bm_len),
XFS_BLF_CHUNK);
map_size = DIV_ROUND_UP(chunks, NBWORD);
bip->bli_formats[i].blf_type = XFS_LI_BUF;
bip->bli_formats[i].blf_blkno = bp->b_maps[i].bm_bn;
bip->bli_formats[i].blf_len = bp->b_maps[i].bm_len;
bip->bli_formats[i].blf_map_size = map_size;
}
#ifdef XFS_TRANS_DEBUG
/*
* Allocate the arrays for tracking what needs to be logged
* and what our callers request to be logged. bli_orig
* holds a copy of the original, clean buffer for comparison
* against, and bli_logged keeps a 1 bit flag per byte in
* the buffer to indicate which bytes the callers have asked
* to have logged.
*/
bip->bli_orig = kmem_alloc(BBTOB(bp->b_length), KM_SLEEP);
memcpy(bip->bli_orig, bp->b_addr, BBTOB(bp->b_length));
bip->bli_logged = kmem_zalloc(BBTOB(bp->b_length) / NBBY, KM_SLEEP);
#endif
/*
* Put the buf item into the list of items attached to the
* buffer at the front.
*/
if (bp->b_fspriv)
bip->bli_item.li_bio_list = bp->b_fspriv;
bp->b_fspriv = bip;
}
/*
* This is called to unpin the buffer associated with the buf log
* item which was previously pinned with a call to xfs_buf_item_pin().
*
* Also drop the reference to the buf item for the current transaction.
* If the XFS_BLI_STALE flag is set and we are the last reference,
* then free up the buf log item and unlock the buffer.
*
* If the remove flag is set we are called from uncommit in the
* forced-shutdown path. If that is true and the reference count on
* the log item is going to drop to zero we need to free the item's
* descriptor in the transaction.
*/
STATIC void
xfs_buf_item_unpin(
struct xfs_log_item *lip,
int remove)
{
struct xfs_buf_log_item *bip = BUF_ITEM(lip);
xfs_buf_t *bp = bip->bli_buf;
struct xfs_ail *ailp = lip->li_ailp;
int stale = bip->bli_flags & XFS_BLI_STALE;
int freed;
ASSERT(bp->b_fspriv == bip);
ASSERT(atomic_read(&bip->bli_refcount) > 0);
trace_xfs_buf_item_unpin(bip);
freed = atomic_dec_and_test(&bip->bli_refcount);
if (atomic_dec_and_test(&bp->b_pin_count))
wake_up_all(&bp->b_waiters);
if (freed && stale) {
ASSERT(bip->bli_flags & XFS_BLI_STALE);
ASSERT(xfs_buf_islocked(bp));
ASSERT(XFS_BUF_ISSTALE(bp));
ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);
trace_xfs_buf_item_unpin_stale(bip);
if (remove) {
/*
* If we are in a transaction context, we have to
* remove the log item from the transaction as we are
* about to release our reference to the buffer. If we
* don't, the unlock that occurs later in
* xfs_trans_uncommit() will try to reference the
* buffer which we no longer have a hold on.
*/
if (lip->li_desc)
xfs_trans_del_item(lip);
/*
* Since the transaction no longer refers to the buffer,
* the buffer should no longer refer to the transaction.
*/
bp->b_transp = NULL;
}
/*
* If we get called here because of an IO error, we may
* or may not have the item on the AIL. xfs_trans_ail_delete()
* will take care of that situation.
* xfs_trans_ail_delete() drops the AIL lock.
*/
if (bip->bli_flags & XFS_BLI_STALE_INODE) {
xfs_buf_do_callbacks(bp);
bp->b_fspriv = NULL;
bp->b_iodone = NULL;
} else {
spin_lock(&ailp->xa_lock);
xfs_trans_ail_delete(ailp, lip, SHUTDOWN_LOG_IO_ERROR);
xfs_buf_item_relse(bp);
ASSERT(bp->b_fspriv == NULL);
}
xfs_buf_relse(bp);
} else if (freed && remove) {
/*
* There are currently two references to the buffer - the active
* LRU reference and the buf log item. What we are about to do
* here - simulate a failed IO completion - requires 3
* references.
*
* The LRU reference is removed by the xfs_buf_stale() call. The
* buf item reference is removed by the xfs_buf_iodone()
* callback that is run by xfs_buf_do_callbacks() during ioend
* processing (via the bp->b_iodone callback), and then finally
* the ioend processing will drop the IO reference if the buffer
* is marked XBF_ASYNC.
*
* Hence we need to take an additional reference here so that IO
* completion processing doesn't free the buffer prematurely.
*/
xfs_buf_lock(bp);
xfs_buf_hold(bp);
bp->b_flags |= XBF_ASYNC;
xfs_buf_ioerror(bp, EIO);
XFS_BUF_UNDONE(bp);
xfs_buf_stale(bp);
xfs_buf_ioend(bp, 0);
}
}
