hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8S3GW CVE: NA --------------------------- When a partition of a block device is mounted, opening the entire block device for write operations may also damage the file system. Identify this situation. Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com> --- block/bdev.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/block/bdev.c b/block/bdev.c index 4355a0757eea..02139effd090 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -759,7 +759,7 @@ static void blkdev_dump_conflict_opener(struct block_device *bdev, char *msg) static bool bdev_writes_blocked(struct block_device *bdev) { - return bdev->bd_writers == -1; + return bdev->bd_writers < 0; } static void bdev_block_writes(struct block_device *bdev) @@ -772,6 +772,16 @@ static void bdev_unblock_writes(struct block_device *bdev) bdev->bd_writers = 0; } +static void bdev_partition_block_part0_writes(struct block_device *bdev) +{ + bdev_whole(bdev)->bd_writers--; +} + +static void bdev_partition_unblock_part0_writes(struct block_device *bdev) +{ + bdev_whole(bdev)->bd_writers++; +} + static void bdev_dump_info(struct block_device *bdev, blk_mode_t mode) { if (bdev_write_mounted_quiet) @@ -794,7 +804,8 @@ static bool bdev_may_open(struct block_device *bdev, blk_mode_t mode) /* Writes blocked? */ if (mode & BLK_OPEN_WRITE && bdev_writes_blocked(bdev)) return false; - if (mode & BLK_OPEN_RESTRICT_WRITES && bdev->bd_writers > 0) + if (mode & BLK_OPEN_RESTRICT_WRITES && + (bdev->bd_writers > 0 || bdev_whole(bdev)->bd_writers > 0)) return false; return true; } @@ -818,6 +829,11 @@ static void bdev_claim_write_access(struct block_device *bdev, blk_mode_t mode) bdev_block_writes(bdev); else if (mode & BLK_OPEN_WRITE) bdev->bd_writers++; + + /* For partition, mounting partition block part0 writes */ + if (bdev_is_partition(bdev) && + mode & BLK_OPEN_RESTRICT_WRITES) + bdev_partition_block_part0_writes(bdev); } static void bdev_yield_write_access(struct block_device *bdev, blk_mode_t mode) @@ -830,6 +846,11 @@ static void bdev_yield_write_access(struct block_device *bdev, blk_mode_t mode) bdev_unblock_writes(bdev); else if (mode & BLK_OPEN_WRITE) bdev->bd_writers--; + + /* For partition, unblock part0 writes */ + if (bdev_is_partition(bdev) && + mode & BLK_OPEN_RESTRICT_WRITES) + bdev_partition_unblock_part0_writes(bdev); } /** -- 2.31.1