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authorTejun Heo <tj@kernel.org>2008-11-05 10:21:06 +0100
committerJens Axboe <jens.axboe@oracle.com>2008-11-06 08:41:56 +0100
commit89f97496e81d2112b5e41416fe3020688c443818 (patch)
treee78122150d550bf644ca1a96916a5880823d3e04 /fs/block_dev.c
parent561920a0d2bb6d63343e83acfd784c0a77bd28d1 (diff)
downloadlwn-89f97496e81d2112b5e41416fe3020688c443818.tar.gz
lwn-89f97496e81d2112b5e41416fe3020688c443818.zip
block: fix __blkdev_get() for removable devices
Commit 0762b8bde9729f10f8e6249809660ff2ec3ad735 moved disk_get_part() in front of recursive get on the whole disk, which caused removable devices to try disk_get_part() before rescanning after a new media is inserted, which might fail legit open attempts or give the old partition. This patch fixes the problem by moving disk_get_part() after __blkdev_get() on the whole disk. This problem was spotted by Borislav Petkov. Signed-off-by: Tejun Heo <tj@kernel.org> Tested-by: Borislav Petkov <petkovbb@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'fs/block_dev.c')
-rw-r--r--fs/block_dev.c23
1 files changed, 11 insertions, 12 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 88a776fa0ef6..db831efbdbbd 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -986,7 +986,6 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
{
struct gendisk *disk;
- struct hd_struct *part = NULL;
int ret;
int partno;
int perm = 0;
@@ -1004,24 +1003,25 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
return ret;
}
- ret = -ENXIO;
-
lock_kernel();
+ ret = -ENXIO;
disk = get_gendisk(bdev->bd_dev, &partno);
if (!disk)
goto out_unlock_kernel;
- part = disk_get_part(disk, partno);
- if (!part)
- goto out_unlock_kernel;
mutex_lock_nested(&bdev->bd_mutex, for_part);
if (!bdev->bd_openers) {
bdev->bd_disk = disk;
- bdev->bd_part = part;
bdev->bd_contains = bdev;
if (!partno) {
struct backing_dev_info *bdi;
+
+ ret = -ENXIO;
+ bdev->bd_part = disk_get_part(disk, partno);
+ if (!bdev->bd_part)
+ goto out_clear;
+
if (disk->fops->open) {
ret = disk->fops->open(bdev, mode);
if (ret)
@@ -1049,18 +1049,17 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
bdev->bd_contains = whole;
bdev->bd_inode->i_data.backing_dev_info =
whole->bd_inode->i_data.backing_dev_info;
+ bdev->bd_part = disk_get_part(disk, partno);
if (!(disk->flags & GENHD_FL_UP) ||
- !part || !part->nr_sects) {
+ !bdev->bd_part || !bdev->bd_part->nr_sects) {
ret = -ENXIO;
goto out_clear;
}
- bd_set_size(bdev, (loff_t)part->nr_sects << 9);
+ bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
}
} else {
- disk_put_part(part);
put_disk(disk);
module_put(disk->fops->owner);
- part = NULL;
disk = NULL;
if (bdev->bd_contains == bdev) {
if (bdev->bd_disk->fops->open) {
@@ -1080,6 +1079,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
return 0;
out_clear:
+ disk_put_part(bdev->bd_part);
bdev->bd_disk = NULL;
bdev->bd_part = NULL;
bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
@@ -1091,7 +1091,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
out_unlock_kernel:
unlock_kernel();
- disk_put_part(part);
if (disk)
module_put(disk->fops->owner);
put_disk(disk);