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Allow dev_open to work on read-only /dev 

/dev could be read-only in which case we cannot make devices
there.
So dev_open should first try to use an existing device name,
and if that doesn't work try creating a node in /dev or /tmp.

Reported-by:  Paweł Sikora <pluto@agmk.net>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2010-08-30 08:48:48 +10:00
parent ef83fe7cba
commit 6df6a774bf
1 changed files with 20 additions and 6 deletions
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26
util.c
View File

@ -959,19 +959,33 @@ int dev_open(char *dev, int flags)
int minor;
if (!dev) return -1;
flags |= O_DIRECT;
major = strtoul(dev, &e, 0);
if (e > dev && *e == ':' && e[1] &&
(minor = strtoul(e+1, &e, 0)) >= 0 &&
*e == 0) {
snprintf(devname, sizeof(devname), "/dev/.tmp.md.%d:%d:%d",
(int)getpid(), major, minor);
if (mknod(devname, S_IFBLK|0600, makedev(major, minor))==0) {
fd = open(devname, flags|O_DIRECT);
unlink(devname);
char *path = map_dev(major, minor, 0);
if (path)
fd = open(path, flags);
if (fd < 0) {
snprintf(devname, sizeof(devname), "/dev/.tmp.md.%d:%d:%d",
(int)getpid(), major, minor);
if (mknod(devname, S_IFBLK|0600, makedev(major, minor))==0) {
fd = open(devname, flags);
unlink(devname);
}
}
if (fd < 0) {
snprintf(devname, sizeof(devname), "/tmp/.tmp.md.%d:%d:%d",
(int)getpid(), major, minor);
if (mknod(devname, S_IFBLK|0600, makedev(major, minor))==0) {
fd = open(devname, flags);
unlink(devname);
}
}
} else
fd = open(dev, flags|O_DIRECT);
fd = open(dev, flags);
return fd;
}