From: Christoph Hellwig hch@lst.de
mainline inclusion from mainline-v5.9-rc1 commit 58e46ed9cc634b3c64ea402789f8a92ce45cee48 category: bugfix bugzilla: 41569 CVE: NA
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Move the locking and assignment of bd_claiming from bd_start_claiming to bd_prepare_to_claim.
Signed-off-by: Christoph Hellwig hch@lst.de Acked-by: Tejun Heo tj@kernel.org Signed-off-by: Jens Axboe axboe@kernel.dk
conflcit: fs/block_dev.c
Signed-off-by: Ye Bin yebin10@huawei.com Reviewed-by: zhangyi (F) yi.zhang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/block_dev.c | 33 +++++++++++++-------------------- 1 file changed, 13 insertions(+), 20 deletions(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c index 862a01a0a15d..dcc2a73168a6 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1033,19 +1033,14 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, }
/** - * bd_prepare_to_claim - prepare to claim a block device + * bd_prepare_to_claim - claim a block device * @bdev: block device of interest * @whole: the whole device containing @bdev, may equal @bdev * @holder: holder trying to claim @bdev * - * Prepare to claim @bdev. This function fails if @bdev is already - * claimed by another holder and waits if another claiming is in - * progress. This function doesn't actually claim. On successful - * return, the caller has ownership of bd_claiming and bd_holder[s]. - * - * CONTEXT: - * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab - * it multiple times. + * Claim @bdev. This function fails if @bdev is already claimed by another + * holder and waits if another claiming is in progress. return, the caller + * has ownership of bd_claiming and bd_holder[s]. * * RETURNS: * 0 if @bdev can be claimed, -EBUSY otherwise. @@ -1054,9 +1049,12 @@ static int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole, void *holder) { retry: + spin_lock(&bdev_lock); /* if someone else claimed, fail */ - if (!bd_may_claim(bdev, whole, holder)) + if (!bd_may_claim(bdev, whole, holder)) { + spin_unlock(&bdev_lock); return -EBUSY; + }
/* if claiming is already in progress, wait for it to finish */ if (whole->bd_claiming) { @@ -1067,11 +1065,12 @@ static int bd_prepare_to_claim(struct block_device *bdev, spin_unlock(&bdev_lock); schedule(); finish_wait(wq, &wait); - spin_lock(&bdev_lock); goto retry; }
/* yay, all mine */ + whole->bd_claiming = holder; + spin_unlock(&bdev_lock); return 0; }
@@ -1153,19 +1152,13 @@ static struct block_device *bd_start_claiming(struct block_device *bdev, if (!whole) return ERR_PTR(-ENOMEM);
- /* prepare to claim, if successful, mark claiming in progress */ - spin_lock(&bdev_lock); - err = bd_prepare_to_claim(bdev, whole, holder); - if (err == 0) { - whole->bd_claiming = holder; - spin_unlock(&bdev_lock); - return whole; - } else { - spin_unlock(&bdev_lock); + if (err) { bdput(whole); return ERR_PTR(err); } + + return whole; }
#ifdef CONFIG_SYSFS