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path: root/fs/xfs/xfs_buf.c
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Diffstat (limited to 'fs/xfs/xfs_buf.c')
-rw-r--r--fs/xfs/xfs_buf.c202
1 files changed, 156 insertions, 46 deletions
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index a843873b095..82bb8123ab2 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -164,14 +164,49 @@ xfs_buf_stale(
ASSERT(atomic_read(&bp->b_hold) >= 1);
}
+static int
+xfs_buf_get_maps(
+ struct xfs_buf *bp,
+ int map_count)
+{
+ ASSERT(bp->b_maps == NULL);
+ bp->b_map_count = map_count;
+
+ if (map_count == 1) {
+ bp->b_maps = &bp->b_map;
+ return 0;
+ }
+
+ bp->b_maps = kmem_zalloc(map_count * sizeof(struct xfs_buf_map),
+ KM_NOFS);
+ if (!bp->b_maps)
+ return ENOMEM;
+ return 0;
+}
+
+/*
+ * Frees b_pages if it was allocated.
+ */
+static void
+xfs_buf_free_maps(
+ struct xfs_buf *bp)
+{
+ if (bp->b_maps != &bp->b_map) {
+ kmem_free(bp->b_maps);
+ bp->b_maps = NULL;
+ }
+}
+
struct xfs_buf *
-xfs_buf_alloc(
+_xfs_buf_alloc(
struct xfs_buftarg *target,
- xfs_daddr_t blkno,
- size_t numblks,
+ struct xfs_buf_map *map,
+ int nmaps,
xfs_buf_flags_t flags)
{
struct xfs_buf *bp;
+ int error;
+ int i;
bp = kmem_zone_zalloc(xfs_buf_zone, KM_NOFS);
if (unlikely(!bp))
@@ -192,18 +227,28 @@ xfs_buf_alloc(
sema_init(&bp->b_sema, 0); /* held, no waiters */
XB_SET_OWNER(bp);
bp->b_target = target;
+ bp->b_flags = flags;
/*
* Set length and io_length to the same value initially.
* I/O routines should use io_length, which will be the same in
* most cases but may be reset (e.g. XFS recovery).
*/
- bp->b_length = numblks;
- bp->b_io_length = numblks;
- bp->b_flags = flags;
- bp->b_bn = blkno;
- bp->b_map.bm_bn = blkno;
- bp->b_map.bm_len = numblks;
+ error = xfs_buf_get_maps(bp, nmaps);
+ if (error) {
+ kmem_zone_free(xfs_buf_zone, bp);
+ return NULL;
+ }
+
+ bp->b_bn = map[0].bm_bn;
+ bp->b_length = 0;
+ for (i = 0; i < nmaps; i++) {
+ bp->b_maps[i].bm_bn = map[i].bm_bn;
+ bp->b_maps[i].bm_len = map[i].bm_len;
+ bp->b_length += map[i].bm_len;
+ }
+ bp->b_io_length = bp->b_length;
+
atomic_set(&bp->b_pin_count, 0);
init_waitqueue_head(&bp->b_waiters);
@@ -282,6 +327,7 @@ xfs_buf_free(
} else if (bp->b_flags & _XBF_KMEM)
kmem_free(bp->b_addr);
_xfs_buf_free_pages(bp);
+ xfs_buf_free_maps(bp);
kmem_zone_free(xfs_buf_zone, bp);
}
@@ -428,8 +474,8 @@ _xfs_buf_map_pages(
xfs_buf_t *
_xfs_buf_find(
struct xfs_buftarg *btp,
- xfs_daddr_t blkno,
- size_t numblks,
+ struct xfs_buf_map *map,
+ int nmaps,
xfs_buf_flags_t flags,
xfs_buf_t *new_bp)
{
@@ -438,7 +484,12 @@ _xfs_buf_find(
struct rb_node **rbp;
struct rb_node *parent;
xfs_buf_t *bp;
+ xfs_daddr_t blkno = map[0].bm_bn;
+ int numblks = 0;
+ int i;
+ for (i = 0; i < nmaps; i++)
+ numblks += map[i].bm_len;
numbytes = BBTOB(numblks);
/* Check for IOs smaller than the sector size / not sector aligned */
@@ -539,22 +590,23 @@ xfs_buf_get(
struct xfs_buf *bp;
struct xfs_buf *new_bp;
int error = 0;
+ DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
- bp = _xfs_buf_find(target, blkno, numblks, flags, NULL);
+ bp = _xfs_buf_find(target, &map, 1, flags, NULL);
if (likely(bp))
goto found;
- new_bp = xfs_buf_alloc(target, blkno, numblks, flags);
+ new_bp = _xfs_buf_alloc(target, &map, 1, flags);
if (unlikely(!new_bp))
return NULL;
error = xfs_buf_allocate_memory(new_bp, flags);
if (error) {
- kmem_zone_free(xfs_buf_zone, new_bp);
+ xfs_buf_free(new_bp);
return NULL;
}
- bp = _xfs_buf_find(target, blkno, numblks, flags, new_bp);
+ bp = _xfs_buf_find(target, &map, 1, flags, new_bp);
if (!bp) {
xfs_buf_free(new_bp);
return NULL;
@@ -666,7 +718,9 @@ xfs_buf_read_uncached(
return NULL;
/* set up the buffer for a read IO */
- bp->b_map.bm_bn = daddr;
+ ASSERT(bp->b_map_count == 1);
+ bp->b_bn = daddr;
+ bp->b_maps[0].bm_bn = daddr;
bp->b_flags |= XBF_READ;
xfsbdstrat(target->bt_mount, bp);
@@ -695,9 +749,11 @@ xfs_buf_set_empty(
bp->b_addr = NULL;
bp->b_length = numblks;
bp->b_io_length = numblks;
+
+ ASSERT(bp->b_map_count == 1);
bp->b_bn = XFS_BUF_DADDR_NULL;
- bp->b_map.bm_bn = XFS_BUF_DADDR_NULL;
- bp->b_map.bm_len = bp->b_length;
+ bp->b_maps[0].bm_bn = XFS_BUF_DADDR_NULL;
+ bp->b_maps[0].bm_len = bp->b_length;
}
static inline struct page *
@@ -761,9 +817,10 @@ xfs_buf_get_uncached(
{
unsigned long page_count;
int error, i;
- xfs_buf_t *bp;
+ struct xfs_buf *bp;
+ DEFINE_SINGLE_BUF_MAP(map, XFS_BUF_DADDR_NULL, numblks);
- bp = xfs_buf_alloc(target, XFS_BUF_DADDR_NULL, numblks, 0);
+ bp = _xfs_buf_alloc(target, &map, 1, 0);
if (unlikely(bp == NULL))
goto fail;
@@ -794,6 +851,7 @@ xfs_buf_get_uncached(
__free_page(bp->b_pages[i]);
_xfs_buf_free_pages(bp);
fail_free_buf:
+ xfs_buf_free_maps(bp);
kmem_zone_free(xfs_buf_zone, bp);
fail:
return NULL;
@@ -1154,36 +1212,39 @@ xfs_buf_bio_end_io(
bio_put(bio);
}
-STATIC void
-_xfs_buf_ioapply(
- xfs_buf_t *bp)
+static void
+xfs_buf_ioapply_map(
+ struct xfs_buf *bp,
+ int map,
+ int *buf_offset,
+ int *count,
+ int rw)
{
- int rw, map_i, total_nr_pages, nr_pages;
- struct bio *bio;
- int offset = bp->b_offset;
- int size = BBTOB(bp->b_io_length);
- sector_t sector = bp->b_map.bm_bn;
+ int page_index;
+ int total_nr_pages = bp->b_page_count;
+ int nr_pages;
+ struct bio *bio;
+ sector_t sector = bp->b_maps[map].bm_bn;
+ int size;
+ int offset;
total_nr_pages = bp->b_page_count;
- map_i = 0;
- if (bp->b_flags & XBF_WRITE) {
- if (bp->b_flags & XBF_SYNCIO)
- rw = WRITE_SYNC;
- else
- rw = WRITE;
- if (bp->b_flags & XBF_FUA)
- rw |= REQ_FUA;
- if (bp->b_flags & XBF_FLUSH)
- rw |= REQ_FLUSH;
- } else if (bp->b_flags & XBF_READ_AHEAD) {
- rw = READA;
- } else {
- rw = READ;
+ /* skip the pages in the buffer before the start offset */
+ page_index = 0;
+ offset = *buf_offset;
+ while (offset >= PAGE_SIZE) {
+ page_index++;
+ offset -= PAGE_SIZE;
}
- /* we only use the buffer cache for meta-data */
- rw |= REQ_META;
+ /*
+ * Limit the IO size to the length of the current vector, and update the
+ * remaining IO count for the next time around.
+ */
+ size = min_t(int, BBTOB(bp->b_maps[map].bm_len), *count);
+ *count -= size;
+ *buf_offset += size;
next_chunk:
atomic_inc(&bp->b_io_remaining);
@@ -1198,13 +1259,14 @@ next_chunk:
bio->bi_private = bp;
- for (; size && nr_pages; nr_pages--, map_i++) {
+ for (; size && nr_pages; nr_pages--, page_index++) {
int rbytes, nbytes = PAGE_SIZE - offset;
if (nbytes > size)
nbytes = size;
- rbytes = bio_add_page(bio, bp->b_pages[map_i], nbytes, offset);
+ rbytes = bio_add_page(bio, bp->b_pages[page_index], nbytes,
+ offset);
if (rbytes < nbytes)
break;
@@ -1226,6 +1288,54 @@ next_chunk:
xfs_buf_ioerror(bp, EIO);
bio_put(bio);
}
+
+}
+
+STATIC void
+_xfs_buf_ioapply(
+ struct xfs_buf *bp)
+{
+ struct blk_plug plug;
+ int rw;
+ int offset;
+ int size;
+ int i;
+
+ if (bp->b_flags & XBF_WRITE) {
+ if (bp->b_flags & XBF_SYNCIO)
+ rw = WRITE_SYNC;
+ else
+ rw = WRITE;
+ if (bp->b_flags & XBF_FUA)
+ rw |= REQ_FUA;
+ if (bp->b_flags & XBF_FLUSH)
+ rw |= REQ_FLUSH;
+ } else if (bp->b_flags & XBF_READ_AHEAD) {
+ rw = READA;
+ } else {
+ rw = READ;
+ }
+
+ /* we only use the buffer cache for meta-data */
+ rw |= REQ_META;
+
+ /*
+ * Walk all the vectors issuing IO on them. Set up the initial offset
+ * into the buffer and the desired IO size before we start -
+ * _xfs_buf_ioapply_vec() will modify them appropriately for each
+ * subsequent call.
+ */
+ offset = bp->b_offset;
+ size = BBTOB(bp->b_io_length);
+ blk_start_plug(&plug);
+ for (i = 0; i < bp->b_map_count; i++) {
+ xfs_buf_ioapply_map(bp, i, &offset, &size, rw);
+ if (bp->b_error)
+ break;
+ if (size <= 0)
+ break; /* all done */
+ }
+ blk_finish_plug(&plug);
}
void