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Code Issues Releases Activity

- Define a new flag for getblk(): GB_NOCREAT. This flag causes getblk() to

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bail out if the buffer is not already present.
 - The buffer returned by incore() is not locked and should not be sent to
   brelse().  Use getblk() with the new GB_NOCREAT flag to preserve the
   desired semantics.
This commit is contained in:
Jeff Roberson 2003-08-31 08:50:11 +00:00
parent a707b683e7
commit d919a11d06
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=119603
3 changed files with 14 additions and 3 deletions
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8
sys/kern/vfs_bio.c
View File

@ -2537,6 +2537,14 @@ getblk(struct vnode * vp, daddr_t blkno, int size, int slpflag, int slptimeo,
* buffer is also considered valid (not marked B_INVAL).
*/
VI_UNLOCK(vp);
/*
* If the user does not want us to create the buffer, bail out
* here.
*/
if (flags & GB_NOCREAT) {
splx(s);
return NULL;
}
if (vn_isdisk(vp, NULL))
bsize = DEV_BSIZE;
else if (vp->v_mountedhere)

1
sys/sys/buf.h
View File

@ -461,6 +461,7 @@ buf_countdeps(struct buf *bp, int i)
* Flags for getblk's last parameter.
*/
#define GB_LOCK_NOWAIT 0x0001 /* Fail if we block on a buf lock. */
#define GB_NOCREAT 0x0002 /* Don't create a buf if not found. */
#ifdef _KERNEL
extern int nbuf; /* The number of buffer headers */

8
sys/ufs/ffs/ffs_softdep.c
View File

@ -2563,10 +2563,10 @@ indir_trunc(freeblks, dbn, level, lbn, countp)
* a complete copy of the indirect block in memory for our use.
* Otherwise we have to read the blocks in from the disk.
*/
bp = getblk(freeblks->fb_devvp, dbn, (int)fs->fs_bsize, 0, 0,
GB_NOCREAT);
ACQUIRE_LOCK(&lk);
/* XXX Buf not locked! */
if ((bp = incore(freeblks->fb_devvp, dbn)) != NULL &&
(wk = LIST_FIRST(&bp->b_dep)) != NULL) {
if (bp != NULL && (wk = LIST_FIRST(&bp->b_dep)) != NULL) {
if (wk->wk_type != D_INDIRDEP ||
(indirdep = WK_INDIRDEP(wk))->ir_savebp != bp ||
(indirdep->ir_state & GOINGAWAY) == 0) {
@ -2582,6 +2582,8 @@ indir_trunc(freeblks, dbn, level, lbn, countp)
VFSTOUFS(freeblks->fb_mnt)->um_numindirdeps -= 1;
FREE_LOCK(&lk);
} else {
if (bp)
brelse(bp);
FREE_LOCK(&lk);
error = bread(freeblks->fb_devvp, dbn, (int)fs->fs_bsize,
NOCRED, &bp);