xfs: use blocks for storing the desired IO size

Now that we pass block counts everywhere, and index buffers by block
number and length in units of blocks, convert the desired IO size
into block counts rather than bytes. Convert the code to use block
counts, and those that need byte counts get converted at the time of
use.

Rename the b_desired_count variable to something closer to it's
purpose - b_io_length - as it is only used to specify the length of
an IO for a subset of the buffer.  The only time this is used is for
log IO - both writing iclogs and during log recovery. In all other
cases, the b_io_length matches b_length, and hence a lot of code
confuses the two. e.g. the buf item code uses the io count
exclusively when it should be using the buffer length. Fix these
apprpriately as they are found.

Also, remove the XFS_BUF_{SET_}COUNT() macros that are just wrappers
around the desired IO length. They only serve to make the code
shouty loud, don't actually add any real value, and are often used
incorrectly.

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>

1 files changed, 13 insertions, 13 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 382c49a42ac..ab3c4491777 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -198,12 +198,12 @@ xfs_buf_alloc(
         bp->b_target = target;
 
         /*
-         * Set length and count_desired to the same value initially.
-         * I/O routines should use count_desired, which will be the same in
+         * 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_count_desired = numblks << BBSHIFT;
+        bp->b_io_length = numblks;
         bp->b_flags = flags;
 
         /*
@@ -302,7 +302,7 @@ xfs_buf_allocate_memory(
         xfs_buf_t               *bp,
         uint                    flags)
 {
-        size_t                  size = bp->b_count_desired;
+        size_t                  size;
         size_t                  nbytes, offset;
         gfp_t                   gfp_mask = xb_to_gfp(flags);
         unsigned short          page_count, i;
@@ -345,6 +345,7 @@ use_alloc_page:
                 return error;
 
         offset = bp->b_offset;
+        size = BBTOB(bp->b_length);
         bp->b_flags |= _XBF_PAGES;
 
         for (i = 0; i < bp->b_page_count; i++) {
@@ -575,7 +576,7 @@ xfs_buf_get(
          * that we can do IO on it.
          */
         bp->b_bn = blkno;
-        bp->b_count_desired = BBTOB(bp->b_length);
+        bp->b_io_length = bp->b_length;
 
 found:
         if (!(bp->b_flags & XBF_MAPPED)) {
@@ -718,7 +719,7 @@ xfs_buf_set_empty(
         bp->b_page_count = 0;
         bp->b_addr = NULL;
         bp->b_length = numblks;
-        bp->b_count_desired = numblks << BBSHIFT;
+        bp->b_io_length = numblks;
         bp->b_bn = XFS_BUF_DADDR_NULL;
         bp->b_flags &= ~XBF_MAPPED;
 }
@@ -770,7 +771,7 @@ xfs_buf_associate_memory(
                 pageaddr += PAGE_SIZE;
         }
 
-        bp->b_count_desired = len;
+        bp->b_io_length = BTOBB(len);
         bp->b_length = BTOBB(buflen);
         bp->b_flags |= XBF_MAPPED;
 
@@ -1012,9 +1013,8 @@ xfs_buf_ioerror_alert(
         const char              *func)
 {
         xfs_alert(bp->b_target->bt_mount,
-"metadata I/O error: block 0x%llx (\"%s\") error %d buf count %zd",
-                (__uint64_t)XFS_BUF_ADDR(bp), func,
-                bp->b_error, XFS_BUF_COUNT(bp));
+"metadata I/O error: block 0x%llx (\"%s\") error %d numblks %d",
+                (__uint64_t)XFS_BUF_ADDR(bp), func, bp->b_error, bp->b_length);
 }
 
 int
@@ -1186,7 +1186,7 @@ _xfs_buf_ioapply(
         int                     rw, map_i, total_nr_pages, nr_pages;
         struct bio              *bio;
         int                     offset = bp->b_offset;
-        int                     size = bp->b_count_desired;
+        int                     size = BBTOB(bp->b_io_length);
         sector_t                sector = bp->b_bn;
 
         total_nr_pages = bp->b_page_count;
@@ -1234,7 +1234,7 @@ next_chunk:
                         break;
 
                 offset = 0;
-                sector += nbytes >> BBSHIFT;
+                sector += BTOBB(nbytes);
                 size -= nbytes;
                 total_nr_pages--;
         }
@@ -1328,7 +1328,7 @@ xfs_buf_iomove(
                 page = bp->b_pages[xfs_buf_btoct(boff + bp->b_offset)];
                 cpoff = xfs_buf_poff(boff + bp->b_offset);
                 csize = min_t(size_t,
-                              PAGE_SIZE-cpoff, bp->b_count_desired-boff);
+                              PAGE_SIZE - cpoff, BBTOB(bp->b_io_length) - boff);
 
                 ASSERT(((csize + cpoff) <= PAGE_SIZE));