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Put a lock on the disk structure while we open to avoid races.

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PR:		14486
This commit is contained in:
Poul-Henning Kamp 1999-11-06 10:25:58 +00:00
parent 91eef0b873
commit 8db34b3a11
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=52917
2 changed files with 20 additions and 4 deletions
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18
sys/kern/subr_disk.c
View File

@ -52,7 +52,7 @@ disk_create(int unit, struct disk *dp, int flags, struct cdevsw *cdevsw, struct
dev->si_disk = dp;
dp->d_dev = dev;
dp->d_flags = flags;
dp->d_dsflags = flags;
dp->d_devsw = cdevsw;
return (dev);
}
@ -114,6 +114,12 @@ diskopen(dev_t dev, int oflags, int devtype, struct proc *p)
if (!dp)
return (ENXIO);
while (dp->d_flags & DISKFLAG_LOCK) {
dp->d_flags |= DISKFLAG_WANTED;
tsleep(dp, PRIBIO | PCATCH, "diskopen", hz);
}
dp->d_flags |= DISKFLAG_LOCK;
if (!dsisopen(dp->d_slice)) {
if (!pdev->si_iosize_max)
pdev->si_iosize_max = dev->si_iosize_max;
@ -129,12 +135,18 @@ diskopen(dev_t dev, int oflags, int devtype, struct proc *p)
dev->si_bsize_best = pdev->si_bsize_best;
if (error)
return(error);
goto out;
error = dsopen(dev, devtype, dp->d_flags, &dp->d_slice, &dp->d_label);
error = dsopen(dev, devtype, dp->d_dsflags, &dp->d_slice, &dp->d_label);
if (!dsisopen(dp->d_slice))
dp->d_devsw->d_close(pdev, oflags, devtype, p);
out:
dp->d_flags &= ~DISKFLAG_LOCK;
if (dp->d_flags & DISKFLAG_WANTED) {
dp->d_flags &= ~DISKFLAG_WANTED;
wakeup(dp);
}
return(error);
}

6
sys/sys/disk.h
View File

@ -22,13 +22,17 @@
#endif /* _SYS_DISKLABEL */
struct disk {
int d_flags;
u_int d_flags;
u_int d_dsflags;
struct cdevsw *d_devsw;
dev_t d_dev;
struct diskslices *d_slice;
struct disklabel d_label;
};
#define DISKFLAG_LOCK 0x1
#define DISKFLAG_WANTED 0x2
dev_t disk_create __P((int unit, struct disk *disk, int flags, struct cdevsw *cdevsw, struct cdevsw *diskdevsw));
void disk_delete __P((dev_t dev));
int disk_dumpcheck __P((dev_t dev, u_int *count, u_int *blkno, u_int *secsize));