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MD: Prevent sysfs operations on uninitialized kobjects

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MD: Prevent sysfs operations on uninitialized kobjects

Device-mapper does not use sysfs; but when device-mapper is leveraging
MD's RAID personalities, MD sometimes attempts to update sysfs.  This
patch adds checks for 'mddev-kobj.sd' in sysfs_[un]link_rdev to ensure
it is about to operate on something valid.  This patch also checks for
'mddev->kobj.sd' before calling 'sysfs_notify' in 'remove_and_add_spares'.
Although 'sysfs_notify' already makes this check, doing so in
'remove_and_add_spares' prevents an additional mutex operation.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
Jonathan Brassow 2013-03-07 16:24:26 -06:00 committed by NeilBrown
parent e3620a3ad5
commit 90584fc93d
2 changed files with 4 additions and 6 deletions
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6
drivers/md/md.c
View File

@ -7663,10 +7663,8 @@ static int remove_and_add_spares(struct mddev *mddev)
removed++;
}
}
if (removed)
sysfs_notify(&mddev->kobj, NULL,
"degraded");
if (removed && mddev->kobj.sd)
sysfs_notify(&mddev->kobj, NULL, "degraded");
rdev_for_each(rdev, mddev) {
if (rdev->raid_disk >= 0 &&

4
drivers/md/md.h
View File

@ -506,7 +506,7 @@ static inline char * mdname (struct mddev * mddev)
static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
{
char nm[20];
if (!test_bit(Replacement, &rdev->flags)) {
if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
sprintf(nm, "rd%d", rdev->raid_disk);
return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
} else
@ -516,7 +516,7 @@ static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
{
char nm[20];
if (!test_bit(Replacement, &rdev->flags)) {
if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
sprintf(nm, "rd%d", rdev->raid_disk);
sysfs_remove_link(&mddev->kobj, nm);
}