dect
/
linux-2.6
Archived
13
0
Fork 0
Code Releases Activity

blkfront: fixes for 'xm block-detach ... --force' 

Prevent prematurely freeing 'struct blkfront_info' instances (when the
xenbus data structures are gone, but the Linux ones are still needed).

Prevent adding a disk with the same (major, minor) [and hence the same
name and sysfs entries, which leads to oopses] when the previous
instance wasn't fully de-allocated yet.

This still doesn't address all issues resulting from forced detach:
I/O submitted after the detach still blocks forever, likely preventing
subsequent un-mounting from completing. It's not clear to me (not
knowing much about the block layer) how this can be avoided.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Jan Beulich 2010-08-07 18:28:55 +02:00 committed by Jens Axboe
parent 203fd61f42
commit 0e34582699
1 changed files with 81 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

88
drivers/block/xen-blkfront.c
View File

@ -105,6 +105,10 @@ struct blkfront_info
static DEFINE_SPINLOCK(blkif_io_lock);
static unsigned int nr_minors;
static unsigned long *minors;
static DEFINE_SPINLOCK(minor_lock);
#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
(BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
#define GRANT_INVALID_REF 0
@ -139,6 +143,55 @@ static void add_id_to_freelist(struct blkfront_info *info,
info->shadow_free = id;
}
static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
{
unsigned int end = minor + nr;
int rc;
if (end > nr_minors) {
unsigned long *bitmap, *old;
bitmap = kzalloc(BITS_TO_LONGS(end) * sizeof(*bitmap),
GFP_KERNEL);
if (bitmap == NULL)
return -ENOMEM;
spin_lock(&minor_lock);
if (end > nr_minors) {
old = minors;
memcpy(bitmap, minors,
BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
minors = bitmap;
nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
} else
old = bitmap;
spin_unlock(&minor_lock);
kfree(old);
}
spin_lock(&minor_lock);
if (find_next_bit(minors, end, minor) >= end) {
for (; minor < end; ++minor)
__set_bit(minor, minors);
rc = 0;
} else
rc = -EBUSY;
spin_unlock(&minor_lock);
return rc;
}
static void xlbd_release_minors(unsigned int minor, unsigned int nr)
{
unsigned int end = minor + nr;
BUG_ON(end > nr_minors);
spin_lock(&minor_lock);
for (; minor < end; ++minor)
__clear_bit(minor, minors);
spin_unlock(&minor_lock);
}
static void blkif_restart_queue_callback(void *arg)
{
struct blkfront_info *info = (struct blkfront_info *)arg;
@ -417,9 +470,14 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
if ((minor % nr_parts) == 0)
nr_minors = nr_parts;
err = xlbd_reserve_minors(minor, nr_minors);
if (err)
goto out;
err = -ENODEV;
gd = alloc_disk(nr_minors);
if (gd == NULL)
goto out;
goto release;
offset = minor / nr_parts;
@ -450,7 +508,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
if (xlvbd_init_blk_queue(gd, sector_size)) {
del_gendisk(gd);
goto out;
goto release;
}
info->rq = gd->queue;
@ -470,6 +528,8 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
return 0;
release:
xlbd_release_minors(minor, nr_minors);
out:
return err;
}
@ -924,6 +984,7 @@ static void blkfront_connect(struct blkfront_info *info)
static void blkfront_closing(struct xenbus_device *dev)
{
struct blkfront_info *info = dev_get_drvdata(&dev->dev);
unsigned int minor, nr_minors;
unsigned long flags;
dev_dbg(&dev->dev, "blkfront_closing: %s removed\n", dev->nodename);
@ -946,7 +1007,10 @@ static void blkfront_closing(struct xenbus_device *dev)
blk_cleanup_queue(info->rq);
info->rq = NULL;
minor = info->gd->first_minor;
nr_minors = info->gd->minors;
del_gendisk(info->gd);
xlbd_release_minors(minor, nr_minors);
out:
xenbus_frontend_closed(dev);
@ -1004,7 +1068,10 @@ static int blkfront_remove(struct xenbus_device *dev)
blkif_free(info, 0);
kfree(info);
if(info->users == 0)
kfree(info);
else
info->is_ready = -1;
return 0;
}
@ -1013,18 +1080,22 @@ static int blkfront_is_ready(struct xenbus_device *dev)
{
struct blkfront_info *info = dev_get_drvdata(&dev->dev);
return info->is_ready;
return info->is_ready > 0;
}
static int blkif_open(struct block_device *bdev, fmode_t mode)
{
struct blkfront_info *info = bdev->bd_disk->private_data;
int ret = 0;
lock_kernel();
info->users++;
if (info->is_ready < 0)
ret = -ENODEV;
else
info->users++;
unlock_kernel();
return 0;
return ret;
}
static int blkif_release(struct gendisk *disk, fmode_t mode)
@ -1039,7 +1110,10 @@ static int blkif_release(struct gendisk *disk, fmode_t mode)
struct xenbus_device *dev = info->xbdev;
enum xenbus_state state = xenbus_read_driver_state(dev->otherend);
if (state == XenbusStateClosing && info->is_ready)
if(info->is_ready < 0) {
blkfront_closing(dev);
kfree(info);
} else if (state == XenbusStateClosing && info->is_ready)
blkfront_closing(dev);
}
unlock_kernel();