[PATCH 16/30] db: rewrite bbmap to use xfs_buf_map

Dave Chinner
2013-10-30T04:31:35Z

From: Dave Chinner <dchinner@redhat.com>

Use the libxfs struct xfs_buf_map for recording the extent layout of
discontiguous buffers and convert the read/write to decode them
directory and use read_buf/write_buf to do the extent IO. This
brings the physical xfs_db IO code to be very close to the model
that libxfs uses.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
db/bmap.c | 15 ++++-----------
db/io.c | 58 ++++++++++++----------------------------------------------
db/io.h | 3 ++-
3 files changed, 18 insertions(+), 58 deletions(-)

diff --git a/db/bmap.c b/db/bmap.c
index 0ef7a62..3951b9f 100644
--- a/db/bmap.c
+++ b/db/bmap.c
@@ -293,20 +293,13 @@ make_bbmap(
int nex,
bmap_ext_t *bmp)
{
- int d;
- xfs_dfsbno_t dfsbno;
int i;
- int j;
- int k;

- for (i = 0, d = 0; i < nex; i++) {
- dfsbno = bmp[i].startblock;
- for (j = 0; j < bmp[i].blockcount; j++, dfsbno++) {
- for (k = 0; k < blkbb; k++)
- bbmap->b[d++] =
- XFS_FSB_TO_DADDR(mp, dfsbno) + k;
- }
+ for (i = 0; i < nex; i++) {
+ bbmap->b[i].bm_bn = XFS_FSB_TO_DADDR(mp, bmp[i].startblock);
+ bbmap->b[i].bm_len = XFS_FSB_TO_BB(mp, bmp[i].blockcount);
}
+ bbmap->nmaps = nex;
}

static xfs_fsblock_t
diff --git a/db/io.c b/db/io.c
index fa11646..01a5970 100644
--- a/db/io.c
+++ b/db/io.c
@@ -478,28 +478,16 @@ write_bbs(
void *bufp,
bbmap_t *bbmap)
{
- int c;
- int i;
int j;
int rval = EINVAL; /* initialize for zero `count' case */

- for (j = 0; j < count; j++) {
- bbno = bbmap->b[j];
- if (lseek64(x.dfd, bbno << BBSHIFT, SEEK_SET) < 0) {
- rval = errno;
- dbprintf(_("can't seek in filesystem at bb %lld\n"), bbno);
- return rval;
- }
- c = BBTOB(1);
- i = (int)write(x.dfd, (char *)bufp + BBTOB(j), c);
- if (i < 0) {
- rval = errno;
- } else if (i < c) {
- rval = -1;
- } else
- rval = 0;
+ for (j = 0; j < count;) {
+ rval = write_buf(bbmap->b[j].bm_bn, bbmap->b[j].bm_len,
+ (char *)bufp + BBTOB(j));
if (rval)
break;
+
+ j += bbmap->b[j].bm_len;
}
return rval;
}
@@ -512,45 +500,23 @@ read_bbs(
bbmap_t *bbmap)
{
void *buf;
- int c;
- int i;
int j;
int rval = EINVAL;

if (count <= 0)
count = 1;

- c = BBTOB(count);
if (*bufp == NULL)
- buf = xmalloc(c);
+ buf = xmalloc(BBTOB(count));
else
buf = *bufp;
- for (j = 0; j < count; j++) {
- bbno = bbmap->b[j];
- if (lseek64(x.dfd, bbno << BBSHIFT, SEEK_SET) < 0) {
- rval = errno;
- dbprintf(_("can't seek in filesystem at bb %lld\n"), bbno);
- if (*bufp == NULL)
- xfree(buf);
- buf = NULL;
- } else {
- c = BBTOB(1);
- i = (int)read(x.dfd, (char *)buf + BBTOB(j), c);
- if (i < 0) {
- rval = errno;
- if (*bufp == NULL)
- xfree(buf);
- buf = NULL;
- } else if (i < c) {
- rval = -1;
- if (*bufp == NULL)
- xfree(buf);
- buf = NULL;
- } else
- rval = 0;
- }
- if (buf == NULL)
+ for (j = 0; j < count;) {
+ rval = read_buf(bbmap->b[j].bm_bn, bbmap->b[j].bm_len,
+ (char *)buf + BBTOB(j));
+ if (rval)
break;
+
+ j += bbmap->b[j].bm_len;
}
if (*bufp == NULL)
*bufp = buf;
diff --git a/db/io.h b/db/io.h
index 9ea6223..c7641d5 100644
--- a/db/io.h
+++ b/db/io.h
@@ -20,7 +20,8 @@ struct typ;

#define BBMAP_SIZE (XFS_MAX_BLOCKSIZE / BBSIZE)
typedef struct bbmap {
- __int64_t b[BBMAP_SIZE];
+ int nmaps;
+ struct xfs_buf_map b[BBMAP_SIZE];
} bbmap_t;

typedef struct iocur {
--
1.8.4.rc3