Added modifications to s_errors in the modification framework of
superblock's attrs. There is no lock protection when the user mode
operates on the same block, so I modify the s_errors by the modification
framework of superblock's attrs.
The parameters passed in from the user mode will be checked by
sb_attr_errors_check first, if the check is passed, It will call
buffer_lock in ext4_update_superblocks_fn and use sb_attr_errors_set, so
it can ensure the atomicity of a modification.
Signed-off-by: zhanchengbin <zhanchengbin1@xxxxxxxxxx>
---
fs/ext4/ioctl.c | 22 ++++++++++++++++++++++
include/uapi/linux/ext4.h | 4 +++-
2 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 76653d855073..81cb403bacf7 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -30,10 +30,32 @@
typedef void ext4_update_sb_callback(struct ext4_super_block *es,
const void *arg);
+int sb_attr_errors_check(struct ext4_sbattr *p_sbattr)
+{
+ __u16 error_behavior = *(__u16 *)(p_sbattr->sba_value);
+
+ if (p_sbattr->sba_len != EXT4_IOC_SUPERBLOCK_LEN_S_ERRORS)
+ return -EINVAL;
+
+ if (error_behavior < EXT4_ERRORS_CONTINUE ||
+ error_behavior > EXT4_ERRORS_PANIC)
+ return -EINVAL;
+
+ return 0;
+}
+
+void sb_attr_errors_set(struct ext4_super_block *es, const void *arg)
+{
+ struct ext4_sbattr *p_sbattr = (struct ext4_sbattr *)arg;
+
+ es->s_errors = cpu_to_le16(*(__u16 *)p_sbattr->sba_value);
+}
+
/*
* Check and modify functions for each superblock variable
*/
struct ext4_sbattr_operation ext4_sbattr_ops[] = {
+ {EXT4_IOC_SUPERBLOCK_KEY_S_ERRORS, sb_attr_errors_check, sb_attr_errors_set},
{EXT4_IOC_SUPERBLOCK_KEY_MAX, NULL, NULL},
};
diff --git a/include/uapi/linux/ext4.h b/include/uapi/linux/ext4.h
index a9f33a0399e8..aad2de6528dd 100644
--- a/include/uapi/linux/ext4.h
+++ b/include/uapi/linux/ext4.h
@@ -90,8 +90,10 @@ struct ext4_sbattr {
};
enum ext4_ioc_superblock_key {
- EXT4_IOC_SUPERBLOCK_KEY_MAX = 0,
+ EXT4_IOC_SUPERBLOCK_KEY_S_ERRORS = 0,
+ EXT4_IOC_SUPERBLOCK_KEY_MAX,
};
+#define EXT4_IOC_SUPERBLOCK_LEN_S_ERRORS 2
#define EXT4_SBATTR_MAX_COUNT 20
--
2.31.1
