xfs: clean up buffer get/read call API
The xfs_buf_get/read API is not consistent in the units it uses, and
does not use appropriate or consistent units/types for the
variables.
Convert the API to use disk addresses and block counts for all
buffer get and read calls. Use consistent naming for all the
functions and their declarations, and convert the internal functions
to use disk addresses and block counts to avoid need to convert them
from one type to another and back again.
Fix all the callers to use disk addresses and block counts. In many
cases, this removes an additional conversion from the function call
as the callers already have a block count.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index f463dce..d3a1974 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -172,8 +172,8 @@
struct xfs_buf *
xfs_buf_alloc(
struct xfs_buftarg *target,
- xfs_off_t range_base,
- size_t range_length,
+ xfs_daddr_t blkno,
+ size_t numblks,
xfs_buf_flags_t flags)
{
struct xfs_buf *bp;
@@ -196,14 +196,21 @@
sema_init(&bp->b_sema, 0); /* held, no waiters */
XB_SET_OWNER(bp);
bp->b_target = target;
- bp->b_file_offset = range_base;
+ bp->b_file_offset = blkno << BBSHIFT;
/*
* Set buffer_length and count_desired to the same value initially.
* I/O routines should use count_desired, which will be the same in
* most cases but may be reset (e.g. XFS recovery).
*/
- bp->b_buffer_length = bp->b_count_desired = range_length;
+ bp->b_buffer_length = bp->b_count_desired = numblks << BBSHIFT;
bp->b_flags = flags;
+
+ /*
+ * We do not set the block number here in the buffer because we have not
+ * finished initialising the buffer. We insert the buffer into the cache
+ * in this state, so this ensures that we are unable to do IO on a
+ * buffer that hasn't been fully initialised.
+ */
bp->b_bn = XFS_BUF_DADDR_NULL;
atomic_set(&bp->b_pin_count, 0);
init_waitqueue_head(&bp->b_waiters);
@@ -426,29 +433,29 @@
*/
xfs_buf_t *
_xfs_buf_find(
- xfs_buftarg_t *btp, /* block device target */
- xfs_off_t ioff, /* starting offset of range */
- size_t isize, /* length of range */
+ struct xfs_buftarg *btp,
+ xfs_daddr_t blkno,
+ size_t numblks,
xfs_buf_flags_t flags,
xfs_buf_t *new_bp)
{
- xfs_off_t range_base;
- size_t range_length;
+ xfs_off_t offset;
+ size_t numbytes;
struct xfs_perag *pag;
struct rb_node **rbp;
struct rb_node *parent;
xfs_buf_t *bp;
- range_base = (ioff << BBSHIFT);
- range_length = (isize << BBSHIFT);
+ offset = BBTOB(blkno);
+ numbytes = BBTOB(numblks);
/* Check for IOs smaller than the sector size / not sector aligned */
- ASSERT(!(range_length < (1 << btp->bt_sshift)));
- ASSERT(!(range_base & (xfs_off_t)btp->bt_smask));
+ ASSERT(!(numbytes < (1 << btp->bt_sshift)));
+ ASSERT(!(offset & (xfs_off_t)btp->bt_smask));
/* get tree root */
pag = xfs_perag_get(btp->bt_mount,
- xfs_daddr_to_agno(btp->bt_mount, ioff));
+ xfs_daddr_to_agno(btp->bt_mount, blkno));
/* walk tree */
spin_lock(&pag->pag_buf_lock);
@@ -459,9 +466,9 @@
parent = *rbp;
bp = rb_entry(parent, struct xfs_buf, b_rbnode);
- if (range_base < bp->b_file_offset)
+ if (offset < bp->b_file_offset)
rbp = &(*rbp)->rb_left;
- else if (range_base > bp->b_file_offset)
+ else if (offset > bp->b_file_offset)
rbp = &(*rbp)->rb_right;
else {
/*
@@ -472,7 +479,7 @@
* reallocating a busy extent. Skip this buffer and
* continue searching to the right for an exact match.
*/
- if (bp->b_buffer_length != range_length) {
+ if (bp->b_buffer_length != numbytes) {
ASSERT(bp->b_flags & XBF_STALE);
rbp = &(*rbp)->rb_right;
continue;
@@ -532,21 +539,20 @@
*/
struct xfs_buf *
xfs_buf_get(
- xfs_buftarg_t *target,/* target for buffer */
- xfs_off_t ioff, /* starting offset of range */
- size_t isize, /* length of range */
+ xfs_buftarg_t *target,
+ xfs_daddr_t blkno,
+ size_t numblks,
xfs_buf_flags_t flags)
{
struct xfs_buf *bp;
struct xfs_buf *new_bp;
int error = 0;
- bp = _xfs_buf_find(target, ioff, isize, flags, NULL);
+ bp = _xfs_buf_find(target, blkno, numblks, flags, NULL);
if (likely(bp))
goto found;
- new_bp = xfs_buf_alloc(target, ioff << BBSHIFT, isize << BBSHIFT,
- flags);
+ new_bp = xfs_buf_alloc(target, blkno, numblks, flags);
if (unlikely(!new_bp))
return NULL;
@@ -556,7 +562,7 @@
return NULL;
}
- bp = _xfs_buf_find(target, ioff, isize, flags, new_bp);
+ bp = _xfs_buf_find(target, blkno, numblks, flags, new_bp);
if (!bp) {
xfs_buf_free(new_bp);
return NULL;
@@ -569,7 +575,7 @@
* Now we have a workable buffer, fill in the block number so
* that we can do IO on it.
*/
- bp->b_bn = ioff;
+ bp->b_bn = blkno;
bp->b_count_desired = bp->b_buffer_length;
found:
@@ -613,15 +619,15 @@
xfs_buf_t *
xfs_buf_read(
xfs_buftarg_t *target,
- xfs_off_t ioff,
- size_t isize,
+ xfs_daddr_t blkno,
+ size_t numblks,
xfs_buf_flags_t flags)
{
xfs_buf_t *bp;
flags |= XBF_READ;
- bp = xfs_buf_get(target, ioff, isize, flags);
+ bp = xfs_buf_get(target, blkno, numblks, flags);
if (bp) {
trace_xfs_buf_read(bp, flags, _RET_IP_);
@@ -656,13 +662,13 @@
void
xfs_buf_readahead(
xfs_buftarg_t *target,
- xfs_off_t ioff,
- size_t isize)
+ xfs_daddr_t blkno,
+ size_t numblks)
{
if (bdi_read_congested(target->bt_bdi))
return;
- xfs_buf_read(target, ioff, isize,
+ xfs_buf_read(target, blkno, numblks,
XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD|XBF_DONT_BLOCK);
}
@@ -672,16 +678,15 @@
*/
struct xfs_buf *
xfs_buf_read_uncached(
- struct xfs_mount *mp,
struct xfs_buftarg *target,
xfs_daddr_t daddr,
- size_t length,
+ size_t numblks,
int flags)
{
xfs_buf_t *bp;
int error;
- bp = xfs_buf_get_uncached(target, length, flags);
+ bp = xfs_buf_get_uncached(target, numblks, flags);
if (!bp)
return NULL;
@@ -689,7 +694,7 @@
XFS_BUF_SET_ADDR(bp, daddr);
XFS_BUF_READ(bp);
- xfsbdstrat(mp, bp);
+ xfsbdstrat(target->bt_mount, bp);
error = xfs_buf_iowait(bp);
if (error) {
xfs_buf_relse(bp);
@@ -705,7 +710,7 @@
void
xfs_buf_set_empty(
struct xfs_buf *bp,
- size_t len)
+ size_t numblks)
{
if (bp->b_pages)
_xfs_buf_free_pages(bp);
@@ -714,7 +719,7 @@
bp->b_page_count = 0;
bp->b_addr = NULL;
bp->b_file_offset = 0;
- bp->b_buffer_length = bp->b_count_desired = len;
+ bp->b_buffer_length = bp->b_count_desired = numblks << BBSHIFT;
bp->b_bn = XFS_BUF_DADDR_NULL;
bp->b_flags &= ~XBF_MAPPED;
}
@@ -776,17 +781,18 @@
xfs_buf_t *
xfs_buf_get_uncached(
struct xfs_buftarg *target,
- size_t len,
+ size_t numblks,
int flags)
{
- unsigned long page_count = PAGE_ALIGN(len) >> PAGE_SHIFT;
+ unsigned long page_count;
int error, i;
xfs_buf_t *bp;
- bp = xfs_buf_alloc(target, 0, len, 0);
+ bp = xfs_buf_alloc(target, 0, numblks, 0);
if (unlikely(bp == NULL))
goto fail;
+ page_count = PAGE_ALIGN(numblks << BBSHIFT) >> PAGE_SHIFT;
error = _xfs_buf_get_pages(bp, page_count, 0);
if (error)
goto fail_free_buf;