* [PATCH 1/4] staging: erofs: add requirements field in superblock
@ 2019-06-10 15:06 Gao Xiang
2019-06-10 15:07 ` Gao Xiang
0 siblings, 1 reply; 2+ messages in thread
From: Gao Xiang @ 2019-06-10 15:06 UTC (permalink / raw)
To: xiang; +Cc: miaoxie, Gao Xiang, stable
There are some backward incompatible optimizations pending
for months, mainly due to on-disk format expensions.
However, we should ensure that it cannot be mounted with
old kernels. Otherwise, it will causes unexpected behaviors.
Fixes: ba2b77a82022 ("staging: erofs: add super block operations")
Cc: <stable@vger.kernel.org> # 4.19+
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
drivers/staging/erofs/erofs_fs.h | 11 +++++++++--
drivers/staging/erofs/super.c | 8 ++++++++
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/erofs/erofs_fs.h b/drivers/staging/erofs/erofs_fs.h
index fa52898df006..531821757845 100644
--- a/drivers/staging/erofs/erofs_fs.h
+++ b/drivers/staging/erofs/erofs_fs.h
@@ -17,10 +17,16 @@
#define EROFS_SUPER_MAGIC_V1 0xE0F5E1E2
#define EROFS_SUPER_OFFSET 1024
+/*
+ * Any bits that aren't in EROFS_ALL_REQUIREMENTS should be
+ * incompatible with this kernel version.
+ */
+#define EROFS_ALL_REQUIREMENTS 0
+
struct erofs_super_block {
/* 0 */__le32 magic; /* in the little endian */
/* 4 */__le32 checksum; /* crc32c(super_block) */
-/* 8 */__le32 features;
+/* 8 */__le32 features; /* extra features for the image */
/* 12 */__u8 blkszbits; /* support block_size == PAGE_SIZE only */
/* 13 */__u8 reserved;
@@ -34,8 +40,9 @@ struct erofs_super_block {
/* 44 */__le32 xattr_blkaddr;
/* 48 */__u8 uuid[16]; /* 128-bit uuid for volume */
/* 64 */__u8 volume_name[16]; /* volume name */
+/* 80 */__le32 requirements; /* all mandatory minimum requirements */
-/* 80 */__u8 reserved2[48]; /* 128 bytes */
+/* 84 */__u8 reserved2[44]; /* 128 bytes */
} __packed;
/*
diff --git a/drivers/staging/erofs/super.c b/drivers/staging/erofs/super.c
index f580d4ef77a1..815e5825db59 100644
--- a/drivers/staging/erofs/super.c
+++ b/drivers/staging/erofs/super.c
@@ -104,6 +104,14 @@ static int superblock_read(struct super_block *sb)
goto out;
}
+ /* check if the kernel meets all mandatory requirements */
+ if (le32_to_cpu(layout->requirements) & (~EROFS_ALL_REQUIREMENTS)) {
+ errln("too old to meet minimum requirements: %x supported: %x",
+ le32_to_cpu(layout->requirements),
+ EROFS_ALL_REQUIREMENTS);
+ goto out;
+ }
+
sbi->blocks = le32_to_cpu(layout->blocks);
sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
#ifdef CONFIG_EROFS_FS_XATTR
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH 1/4] staging: erofs: add requirements field in superblock
2019-06-10 15:06 [PATCH 1/4] staging: erofs: add requirements field in superblock Gao Xiang
@ 2019-06-10 15:07 ` Gao Xiang
0 siblings, 0 replies; 2+ messages in thread
From: Gao Xiang @ 2019-06-10 15:07 UTC (permalink / raw)
To: stable; +Cc: xiang, miaoxie
[ sorry...please ignore this email... ]
On 2019/6/10 23:06, Gao Xiang wrote:
> There are some backward incompatible optimizations pending
> for months, mainly due to on-disk format expensions.
>
> However, we should ensure that it cannot be mounted with
> old kernels. Otherwise, it will causes unexpected behaviors.
>
> Fixes: ba2b77a82022 ("staging: erofs: add super block operations")
> Cc: <stable@vger.kernel.org> # 4.19+
> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
> ---
> drivers/staging/erofs/erofs_fs.h | 11 +++++++++--
> drivers/staging/erofs/super.c | 8 ++++++++
> 2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/erofs/erofs_fs.h b/drivers/staging/erofs/erofs_fs.h
> index fa52898df006..531821757845 100644
> --- a/drivers/staging/erofs/erofs_fs.h
> +++ b/drivers/staging/erofs/erofs_fs.h
> @@ -17,10 +17,16 @@
> #define EROFS_SUPER_MAGIC_V1 0xE0F5E1E2
> #define EROFS_SUPER_OFFSET 1024
>
> +/*
> + * Any bits that aren't in EROFS_ALL_REQUIREMENTS should be
> + * incompatible with this kernel version.
> + */
> +#define EROFS_ALL_REQUIREMENTS 0
> +
> struct erofs_super_block {
> /* 0 */__le32 magic; /* in the little endian */
> /* 4 */__le32 checksum; /* crc32c(super_block) */
> -/* 8 */__le32 features;
> +/* 8 */__le32 features; /* extra features for the image */
> /* 12 */__u8 blkszbits; /* support block_size == PAGE_SIZE only */
> /* 13 */__u8 reserved;
>
> @@ -34,8 +40,9 @@ struct erofs_super_block {
> /* 44 */__le32 xattr_blkaddr;
> /* 48 */__u8 uuid[16]; /* 128-bit uuid for volume */
> /* 64 */__u8 volume_name[16]; /* volume name */
> +/* 80 */__le32 requirements; /* all mandatory minimum requirements */
>
> -/* 80 */__u8 reserved2[48]; /* 128 bytes */
> +/* 84 */__u8 reserved2[44]; /* 128 bytes */
> } __packed;
>
> /*
> diff --git a/drivers/staging/erofs/super.c b/drivers/staging/erofs/super.c
> index f580d4ef77a1..815e5825db59 100644
> --- a/drivers/staging/erofs/super.c
> +++ b/drivers/staging/erofs/super.c
> @@ -104,6 +104,14 @@ static int superblock_read(struct super_block *sb)
> goto out;
> }
>
> + /* check if the kernel meets all mandatory requirements */
> + if (le32_to_cpu(layout->requirements) & (~EROFS_ALL_REQUIREMENTS)) {
> + errln("too old to meet minimum requirements: %x supported: %x",
> + le32_to_cpu(layout->requirements),
> + EROFS_ALL_REQUIREMENTS);
> + goto out;
> + }
> +
> sbi->blocks = le32_to_cpu(layout->blocks);
> sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
> #ifdef CONFIG_EROFS_FS_XATTR
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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