From: Julian Stecklina <[email protected]> Port cramfs to the new initrd_fs_detect API. There are no functional changes.
Signed-off-by: Julian Stecklina <[email protected]> --- fs/cramfs/Makefile | 5 +++++ fs/cramfs/initrd.c | 41 +++++++++++++++++++++++++++++++++++++++++ init/do_mounts_rd.c | 28 ++-------------------------- 3 files changed, 48 insertions(+), 26 deletions(-) diff --git a/fs/cramfs/Makefile b/fs/cramfs/Makefile index 8c3ed298241924b0312fb489b1fb54d274d25c22..d10e2b72aae06bf9ac42690e3967cfd90ac34d4f 100644 --- a/fs/cramfs/Makefile +++ b/fs/cramfs/Makefile @@ -6,3 +6,8 @@ obj-$(CONFIG_CRAMFS) += cramfs.o cramfs-objs := inode.o uncompress.o + +# If we are built-in, we provide support for cramfs on initrds. +ifeq ($(CONFIG_CRAMFS),y) +cramfs-objs += initrd.o +endif diff --git a/fs/cramfs/initrd.c b/fs/cramfs/initrd.c new file mode 100644 index 0000000000000000000000000000000000000000..c16df09c118226e6350b9f5877863ef31322ab7b --- /dev/null +++ b/fs/cramfs/initrd.c @@ -0,0 +1,41 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include <linux/fs.h> +#include <linux/initrd.h> +#include <uapi/linux/cramfs_fs.h> + +/* + * The filesystem start maybe padded by this many bytes to make space + * for boot loaders. + */ +#define CRAMFS_PAD_OFFSET 512 + +static size_t __init check_cramfs_sb(struct cramfs_super *cramfsb) +{ + if (cramfsb->magic != CRAMFS_MAGIC) + return 0; + + return cramfsb->size; +} + +static size_t __init detect_cramfs(void *block_data) +{ + size_t fssize; + + BUILD_BUG_ON(sizeof(struct cramfs_super) + CRAMFS_PAD_OFFSET + > BLOCK_SIZE); + + fssize = check_cramfs_sb((struct cramfs_super *)block_data); + if (fssize) + return fssize; + + /* + * The header padding doesn't influence the total length of + * the filesystem. + */ + block_data = (char *)block_data + CRAMFS_PAD_OFFSET; + fssize = check_cramfs_sb((struct cramfs_super *)block_data); + return fssize; +} + +initrd_fs_detect(detect_cramfs, 0); diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c index f7e5d4ccf029b2707bc8524ecdbe200c8b305b00..cdc39baaf3a1a65daad5fe6571a82faf3fc95b62 100644 --- a/init/do_mounts_rd.c +++ b/init/do_mounts_rd.c @@ -3,7 +3,7 @@ #include <linux/fs.h> #include <linux/ext2_fs.h> #include <linux/romfs_fs.h> -#include <uapi/linux/cramfs_fs.h> + #include <linux/initrd.h> #include <linux/string.h> #include <linux/slab.h> @@ -43,7 +43,6 @@ static int __init crd_load(decompress_fn deco); * We currently check for the following magic numbers: * ext2 * romfs - * cramfs * squashfs * gzip * bzip2 @@ -58,7 +57,7 @@ identify_ramdisk_image(struct file *file, loff_t pos, { const int size = BLOCK_SIZE; struct romfs_super_block *romfsb; - struct cramfs_super *cramfsb; + struct squashfs_super_block *squashfsb; int nblocks = -1; unsigned char *buf; @@ -72,7 +71,6 @@ identify_ramdisk_image(struct file *file, loff_t pos, return -ENOMEM; romfsb = (struct romfs_super_block *) buf; - cramfsb = (struct cramfs_super *) buf; squashfsb = (struct squashfs_super_block *) buf; memset(buf, 0xe5, size); @@ -104,14 +102,6 @@ identify_ramdisk_image(struct file *file, loff_t pos, goto done; } - if (cramfsb->magic == CRAMFS_MAGIC) { - printk(KERN_NOTICE - "RAMDISK: cramfs filesystem found at block %d\n", - start_block); - nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; - goto done; - } - /* squashfs is at block zero too */ if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) { printk(KERN_NOTICE @@ -122,20 +112,6 @@ identify_ramdisk_image(struct file *file, loff_t pos, goto done; } - /* - * Read 512 bytes further to check if cramfs is padded - */ - pos = start_block * BLOCK_SIZE + 0x200; - kernel_read(file, buf, size, &pos); - - if (cramfsb->magic == CRAMFS_MAGIC) { - printk(KERN_NOTICE - "RAMDISK: cramfs filesystem found at block %d\n", - start_block); - nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS; - goto done; - } - /* * Read block 1 to test for ext2 superblock */ -- 2.47.0
