From: "zhangyi (F)" <yi.zhang@huawei.com>
To: <viro@zeniv.linux.org.uk>
Cc: <linux-fsdevel@vger.kernel.org>, <yi.zhang@huawei.com>,
<miaoxie@huawei.com>
Subject: [PATCH 2/2] block: add info when opening a write opend block device exclusively
Date: Tue, 14 May 2019 22:45:06 +0800 [thread overview]
Message-ID: <1557845106-60163-3-git-send-email-yi.zhang@huawei.com> (raw)
In-Reply-To: <1557845106-60163-1-git-send-email-yi.zhang@huawei.com>
Just like open an exclusive opened block device for write, open a block
device exclusively which has been opened for write by some other
processes may also lead to potential data corruption. This patch record
the write openers and give a hint if that happens.
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
---
fs/block_dev.c | 20 ++++++++++++++++++--
include/linux/fs.h | 1 +
2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index d92aa45..c278195 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1606,6 +1606,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
bdev->bd_openers++;
if (for_part)
bdev->bd_part_count++;
+ if (mode & FMODE_WRITE)
+ bdev->bd_write_openers++;
mutex_unlock(&bdev->bd_mutex);
disk_unblock_events(disk);
/* only one opener holds refs to the module and disk */
@@ -1654,6 +1656,7 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
{
struct block_device *whole = NULL;
int res;
+ char name[BDEVNAME_SIZE];
WARN_ON_ONCE((mode & FMODE_EXCL) && !holder);
@@ -1673,6 +1676,19 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
if (whole) {
struct gendisk *disk = whole->bd_disk;
+ /*
+ * Open an write opened block device exclusively, the
+ * writing process may probability corrupt the device,
+ * such as a mounted file system, give a hint here.
+ */
+ if (!res && (bdev->bd_write_openers >
+ ((mode & FMODE_WRITE) ? 1 : 0)) && !bdev->bd_holders) {
+ pr_info_ratelimited("VFS: Open an write opened "
+ "block device exclusively %s [%d %s].\n",
+ bdevname(bdev, name), current->pid,
+ current->comm);
+ }
+
/* finish claiming */
if (!res) {
BUG_ON(!bd_may_claim(bdev, whole, holder));
@@ -1712,8 +1728,6 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
bdput(whole);
} else {
if (!res && (mode & FMODE_WRITE) && bdev->bd_holders) {
- char name[BDEVNAME_SIZE];
-
/*
* Open an exclusive opened device for write may
* probability corrupt the device, such as a
@@ -1848,6 +1862,8 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
struct block_device *victim = NULL;
mutex_lock_nested(&bdev->bd_mutex, for_part);
+ if (mode & FMODE_WRITE)
+ bdev->bd_write_openers--;
if (for_part)
bdev->bd_part_count--;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index dd28e76..0dc066d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -463,6 +463,7 @@ struct request_queue;
struct block_device {
dev_t bd_dev; /* not a kdev_t - it's a search key */
int bd_openers;
+ int bd_write_openers;
struct inode * bd_inode; /* will die */
struct super_block * bd_super;
struct mutex bd_mutex; /* open/close mutex */
--
2.7.4
prev parent reply other threads:[~2019-05-14 14:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-14 14:45 [PATCH 0/2] block: add info messages when opening a block device O_WRITE and O_EXCL concurrently zhangyi (F)
2019-05-14 14:45 ` [PATCH 1/2] block: add info when opening an exclusive opened block device for write zhangyi (F)
2019-05-14 14:45 ` zhangyi (F) [this message]
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