diff options
| -rw-r--r-- | arch/blackfin/kernel/setup.c | 7 | ||||
| -rw-r--r-- | include/linux/ext2_fs.h | 22 | ||||
| -rw-r--r-- | init/do_mounts_rd.c | 9 |
3 files changed, 30 insertions, 8 deletions
diff --git a/arch/blackfin/kernel/setup.c b/arch/blackfin/kernel/setup.c index 2aa019368504..2ad747e909fb 100644 --- a/arch/blackfin/kernel/setup.c +++ b/arch/blackfin/kernel/setup.c @@ -550,6 +550,7 @@ static __init void memory_setup(void) { #ifdef CONFIG_MTD_UCLINUX unsigned long mtd_phys = 0; + unsigned long n; #endif unsigned long max_mem; @@ -593,9 +594,9 @@ static __init void memory_setup(void) mtd_size = PAGE_ALIGN(*((unsigned long *)(mtd_phys + 8))); # if defined(CONFIG_EXT2_FS) || defined(CONFIG_EXT3_FS) - if (*((unsigned short *)(mtd_phys + 0x438)) == EXT2_SUPER_MAGIC) - mtd_size = - PAGE_ALIGN(*((unsigned long *)(mtd_phys + 0x404)) << 10); + n = ext2_image_size((void *)(mtd_phys + 0x400)); + if (n) + mtd_size = PAGE_ALIGN(n * 1024); # endif # if defined(CONFIG_CRAMFS) diff --git a/include/linux/ext2_fs.h b/include/linux/ext2_fs.h index f28dba518a4a..5f65ec75b48a 100644 --- a/include/linux/ext2_fs.h +++ b/include/linux/ext2_fs.h @@ -536,4 +536,26 @@ enum { ~EXT2_DIR_ROUND) #define EXT2_MAX_REC_LEN ((1<<16)-1) +#define EXT2_SB_MAGIC_OFFSET 0x38 +#define EXT2_SB_BLOCKS_OFFSET 0x04 +#define EXT2_SB_BSIZE_OFFSET 0x18 + +static inline u64 ext2_image_size(void *ext2_sb) +{ + __u8 *p = ext2_sb; + if (*(__le16 *)(p + EXT2_SB_MAGIC_OFFSET) != cpu_to_le16(EXT2_SUPER_MAGIC)) + return 0; + return (u64)le32_to_cpup((__le32 *)(p + EXT2_SB_BLOCKS_OFFSET)) << + le32_to_cpup((__le32 *)(p + EXT2_SB_BSIZE_OFFSET)); +} + +static inline void verify_offsets(void) +{ +#define A(x,y) BUILD_BUG_ON(x != offsetof(struct ext2_super_block, y)); + A(EXT2_SB_MAGIC_OFFSET, s_magic); + A(EXT2_SB_BLOCKS_OFFSET, s_blocks_count); + A(EXT2_SB_BSIZE_OFFSET, s_log_block_size); +#undef A +} + #endif /* _LINUX_EXT2_FS_H */ diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c index 01f1306aa26e..6212586df29a 100644 --- a/init/do_mounts_rd.c +++ b/init/do_mounts_rd.c @@ -54,20 +54,19 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor) { const int size = 512; struct minix_super_block *minixsb; - struct ext2_super_block *ext2sb; struct romfs_super_block *romfsb; struct cramfs_super *cramfsb; struct squashfs_super_block *squashfsb; int nblocks = -1; unsigned char *buf; const char *compress_name; + unsigned long n; buf = kmalloc(size, GFP_KERNEL); if (!buf) return -ENOMEM; minixsb = (struct minix_super_block *) buf; - ext2sb = (struct ext2_super_block *) buf; romfsb = (struct romfs_super_block *) buf; cramfsb = (struct cramfs_super *) buf; squashfsb = (struct squashfs_super_block *) buf; @@ -150,12 +149,12 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor) } /* Try ext2 */ - if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) { + n = ext2_image_size(buf); + if (n) { printk(KERN_NOTICE "RAMDISK: ext2 filesystem found at block %d\n", start_block); - nblocks = le32_to_cpu(ext2sb->s_blocks_count) << - le32_to_cpu(ext2sb->s_log_block_size); + nblocks = n; goto done; } |