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staging: erofs: add requirements field in superblock
There are some backward incompatible features 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: ba2b77a820
("staging: erofs: add super block operations")
Cc: <stable@vger.kernel.org> # 4.19+
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
f2c7c76c5d
commit
5efe5137f0
3 changed files with 31 additions and 3 deletions
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@ -17,10 +17,16 @@
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#define EROFS_SUPER_MAGIC_V1 0xE0F5E1E2
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#define EROFS_SUPER_MAGIC_V1 0xE0F5E1E2
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#define EROFS_SUPER_OFFSET 1024
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#define EROFS_SUPER_OFFSET 1024
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/*
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* Any bits that aren't in EROFS_ALL_REQUIREMENTS should be
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* incompatible with this kernel version.
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*/
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#define EROFS_ALL_REQUIREMENTS 0
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struct erofs_super_block {
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struct erofs_super_block {
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/* 0 */__le32 magic; /* in the little endian */
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/* 0 */__le32 magic; /* in the little endian */
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/* 4 */__le32 checksum; /* crc32c(super_block) */
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/* 4 */__le32 checksum; /* crc32c(super_block) */
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/* 8 */__le32 features;
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/* 8 */__le32 features; /* (aka. feature_compat) */
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/* 12 */__u8 blkszbits; /* support block_size == PAGE_SIZE only */
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/* 12 */__u8 blkszbits; /* support block_size == PAGE_SIZE only */
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/* 13 */__u8 reserved;
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/* 13 */__u8 reserved;
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@ -34,9 +40,10 @@ struct erofs_super_block {
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/* 44 */__le32 xattr_blkaddr;
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/* 44 */__le32 xattr_blkaddr;
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/* 48 */__u8 uuid[16]; /* 128-bit uuid for volume */
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/* 48 */__u8 uuid[16]; /* 128-bit uuid for volume */
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/* 64 */__u8 volume_name[16]; /* volume name */
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/* 64 */__u8 volume_name[16]; /* volume name */
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/* 80 */__le32 requirements; /* (aka. feature_incompat) */
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/* 80 */__u8 reserved2[48]; /* 128 bytes */
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/* 84 */__u8 reserved2[44];
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} __packed;
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} __packed; /* 128 bytes */
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/*
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/*
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* erofs inode data mapping:
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* erofs inode data mapping:
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@ -115,6 +115,8 @@ struct erofs_sb_info {
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u8 uuid[16]; /* 128-bit uuid for volume */
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u8 uuid[16]; /* 128-bit uuid for volume */
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u8 volume_name[16]; /* volume name */
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u8 volume_name[16]; /* volume name */
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u32 requirements;
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char *dev_name;
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char *dev_name;
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unsigned int mount_opt;
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unsigned int mount_opt;
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@ -71,6 +71,22 @@ static void free_inode(struct inode *inode)
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kmem_cache_free(erofs_inode_cachep, vi);
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kmem_cache_free(erofs_inode_cachep, vi);
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}
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}
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static bool check_layout_compatibility(struct super_block *sb,
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struct erofs_super_block *layout)
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{
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const unsigned int requirements = le32_to_cpu(layout->requirements);
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EROFS_SB(sb)->requirements = requirements;
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/* check if current kernel meets all mandatory requirements */
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if (requirements & (~EROFS_ALL_REQUIREMENTS)) {
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errln("unidentified requirements %x, please upgrade kernel version",
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requirements & ~EROFS_ALL_REQUIREMENTS);
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return false;
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}
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return true;
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}
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static int superblock_read(struct super_block *sb)
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static int superblock_read(struct super_block *sb)
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{
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{
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struct erofs_sb_info *sbi;
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struct erofs_sb_info *sbi;
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@ -104,6 +120,9 @@ static int superblock_read(struct super_block *sb)
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goto out;
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goto out;
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}
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}
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if (!check_layout_compatibility(sb, layout))
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goto out;
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sbi->blocks = le32_to_cpu(layout->blocks);
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sbi->blocks = le32_to_cpu(layout->blocks);
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sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
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sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
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#ifdef CONFIG_EROFS_FS_XATTR
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#ifdef CONFIG_EROFS_FS_XATTR
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