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Fixed lblktosize(). It overflowed at 2G. This bug only affected

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ufs_read() and ufs_write().

Found by: looking at warnings for comparing the result of lblktosize()
(which is usually daddr_t = long) with file sizes (which are u_quad_t
for ufs).  File sizes should probably be off_t's to avoid warnings
when the are compared with file offsets, so the fixed lblktosize()
casts to off_t instead of u_quad_t.

Added definition of smalllblksize().  It is the same as the old
lblksize() and is more efficient for small block numbers on 32-bit
machines.

Use smalllblktosize() instead of its expansion in blksize() and
dblksize().  This keeps the line length short and makes it more
obvious that the shift can't overflow.
This commit is contained in:
bde 1996-10-12 22:12:51 +00:00
parent bf13e7f997
commit 9e1f278658
1 changed files with 7 additions and 4 deletions
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11
sys/ufs/ffs/fs.h
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@ -31,7 +31,7 @@
* SUCH DAMAGE.
*
* @(#)fs.h 8.7 (Berkeley) 4/19/94
* $Id: fs.h,v 1.5 1995/05/30 08:15:07 rgrimes Exp $
* $Id: fs.h,v 1.6 1996/01/30 23:02:01 mpp Exp $
*/
#ifndef _UFS_FFS_FS_H_
@ -433,7 +433,10 @@ struct ocg {
((loc) & (fs)->fs_qbmask)
#define fragoff(fs, loc) /* calculates (loc % fs->fs_fsize) */ \
((loc) & (fs)->fs_qfmask)
#define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \
#define lblktosize(fs, blk) /* calculates ((off_t)blk * fs->fs_bsize) */ \
((off_t)(blk) << (fs)->fs_bshift)
/* Use this only when `blk' is known to be small, e.g., < NDADDR. */
#define smalllblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \
((blk) << (fs)->fs_bshift)
#define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \
((loc) >> (fs)->fs_bshift)
@ -464,11 +467,11 @@ struct ocg {
* Determining the size of a file block in the file system.
*/
#define blksize(fs, ip, lbn) \
(((lbn) >= NDADDR || (ip)->i_size >= ((lbn) + 1) << (fs)->fs_bshift) \
(((lbn) >= NDADDR || (ip)->i_size >= smalllblktosize(fs, (lbn) + 1)) \
? (fs)->fs_bsize \
: (fragroundup(fs, blkoff(fs, (ip)->i_size))))
#define dblksize(fs, dip, lbn) \
(((lbn) >= NDADDR || (dip)->di_size >= ((lbn) + 1) << (fs)->fs_bshift) \
(((lbn) >= NDADDR || (dip)->di_size >= smalllblktosize(fs, (lbn) + 1)) \
? (fs)->fs_bsize \
: (fragroundup(fs, blkoff(fs, (dip)->di_size))))