hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8S3GW CVE: NA
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When writing to a mounted block device is allowed, we need to identify which processes may write to the block device to prevent the file system from being damaged in silence.
Signed-off-by: Li Lingfeng lilingfeng3@huawei.com --- block/Kconfig | 7 +++++++ block/bdev.c | 49 +++++++++++++++++++++++++++++++++++++++++++++---- 2 files changed, 52 insertions(+), 4 deletions(-)
diff --git a/block/Kconfig b/block/Kconfig index 05fdd81a708f..214c1caeab4c 100644 --- a/block/Kconfig +++ b/block/Kconfig @@ -249,6 +249,13 @@ config BLK_DEV_DETECT_WRITING_PART0 As a supplement to BLK_DEV_WRITE_MOUNTED(_QUIET), enabling this to detect the scenario above.
+config BLK_DEV_WRITE_MOUNTED_DUMP + bool "Dump info when detecting conflict of opening block device" + default n + help + Enabling this to dump info when opening mounted block devices + for write or trying to mount write opened block devices. + source "block/partitions/Kconfig"
config BLK_MQ_PCI diff --git a/block/bdev.c b/block/bdev.c index 4b0e6c49a9e7..f383b2cacc46 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -30,14 +30,20 @@ #include "../fs/internal.h" #include "blk.h"
+#define OPEN_EXCLUSIVE "VFS: Open an exclusive opened block device for write" +#define OPEN_FOR_EXCLUSIVE "VFS: Open a write opened block device exclusively" + /* Should we allow writing to mounted block devices? */ #define BLKDEV_ALLOW_WRITE_MOUNTED 0 /* Should we detect writing to part0 when partitions mounted */ #define BLKDEV_DETECT_WRITING_PART0 1 +/* Should we dump info when opening mounted block devices for write? */ +#define BLKDEV_WRITE_MOUNTED_DUMP 2
static u8 bdev_allow_write_mounted = IS_ENABLED(CONFIG_BLK_DEV_WRITE_MOUNTED) << BLKDEV_ALLOW_WRITE_MOUNTED || - IS_ENABLED(CONFIG_BLK_DEV_DETECT_WRITING_PART0) << BLKDEV_DETECT_WRITING_PART0; + IS_ENABLED(CONFIG_BLK_DEV_DETECT_WRITING_PART0) << BLKDEV_DETECT_WRITING_PART0 || + IS_ENABLED(CONFIG_BLK_DEV_WRITE_MOUNTED_DUMP) << BLKDEV_WRITE_MOUNTED_DUMP;
struct bdev_inode { struct block_device bdev; @@ -739,6 +745,27 @@ void blkdev_put_no_open(struct block_device *bdev) put_device(&bdev->bd_device); }
+static void blkdev_dump_conflict_opener(struct block_device *bdev, char *msg) +{ + char name[BDEVNAME_SIZE]; + struct task_struct *p = NULL; + char comm_buf[TASK_COMM_LEN]; + pid_t p_pid; + + rcu_read_lock(); + p = rcu_dereference(current->real_parent); + task_lock(p); + strncpy(comm_buf, p->comm, TASK_COMM_LEN); + p_pid = p->pid; + task_unlock(p); + rcu_read_unlock(); + + snprintf(name, sizeof(name), "%pg", bdev); + pr_info_ratelimited("%s [%s]. current [%d %s]. parent [%d %s]\n", + msg, name, + current->pid, current->comm, p_pid, comm_buf); +} + static bool bdev_writes_blocked(struct block_device *bdev) { return !!bdev->bd_mounters; @@ -767,15 +794,29 @@ static bool bdev_mount_blocked(struct block_device *bdev) return bdev->bd_writers > 0; }
-static bool bdev_may_open(struct block_device *bdev, blk_mode_t mode) +bool bdev_may_conflict_open(struct block_device *bdev, char *msg) { + if (bdev_allow_write_mounted & (1 << BLKDEV_WRITE_MOUNTED_DUMP)) + blkdev_dump_conflict_opener(bdev, msg); + if (bdev_allow_write_mounted & (1 << BLKDEV_ALLOW_WRITE_MOUNTED)) return true; + + return false; +} + +static bool bdev_may_open(struct block_device *bdev, blk_mode_t mode) +{ + if (bdev_allow_write_mounted & (1 << BLKDEV_ALLOW_WRITE_MOUNTED) && + !(bdev_allow_write_mounted & (1 << BLKDEV_WRITE_MOUNTED_DUMP))) + return true; + /* Writes blocked? */ if (mode & BLK_OPEN_WRITE && bdev_writes_blocked(bdev)) - return false; + return bdev_may_conflict_open(bdev, OPEN_EXCLUSIVE); if (mode & BLK_OPEN_RESTRICT_WRITES && bdev_mount_blocked(bdev)) - return false; + return bdev_may_conflict_open(bdev, OPEN_FOR_EXCLUSIVE); + return true; }