#include <linux/init.h>
#include <linux/string.h>
#include <linux/blkdev.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/super.h>
#include <linux/slab.h>
#include <linux/vfs.h>
#include <linux/mutex.h>
unsigned long blocks;
unsigned long files;
unsigned long flags;
+ void *linear_virt_addr;
+ resource_size_t linear_phys_addr;
+ size_t mtd_point_size;
};
static inline struct cramfs_sb_info *CRAMFS_SB(struct super_block *sb)
* BLKS_PER_BUF*PAGE_SIZE, so that the caller doesn't need to
* worry about end-of-buffer issues even when decompressing a full
* page cache.
+ *
+ * Note: This is all optimized away at compile time when
+ * CONFIG_CRAMFS_BLOCKDEV=n.
*/
#define READ_BUFFERS (2)
/* NEXT_BUFFER(): Loop over [0..(READ_BUFFERS-1)]. */
static int next_buffer;
/*
- * Returns a pointer to a buffer containing at least LEN bytes of
- * filesystem starting at byte offset OFFSET into the filesystem.
+ * Populate our block cache and return a pointer to it.
*/
-static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned int len)
+static void *cramfs_blkdev_read(struct super_block *sb, unsigned int offset,
+ unsigned int len)
{
struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
struct page *pages[BLKS_PER_BUF];
return read_buffers[buffer] + offset;
}
+/*
+ * Return a pointer to the linearly addressed cramfs image in memory.
+ */
+static void *cramfs_direct_read(struct super_block *sb, unsigned int offset,
+ unsigned int len)
+{
+ struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
+
+ if (!len)
+ return NULL;
+ if (len > sbi->size || offset > sbi->size - len)
+ return page_address(ZERO_PAGE(0));
+ return sbi->linear_virt_addr + offset;
+}
+
+/*
+ * Returns a pointer to a buffer containing at least LEN bytes of
+ * filesystem starting at byte offset OFFSET into the filesystem.
+ */
+static void *cramfs_read(struct super_block *sb, unsigned int offset,
+ unsigned int len)
+{
+ struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
+
+ if (IS_ENABLED(CONFIG_CRAMFS_MTD) && sbi->linear_virt_addr)
+ return cramfs_direct_read(sb, offset, len);
+ else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV))
+ return cramfs_blkdev_read(sb, offset, len);
+ else
+ return NULL;
+}
+
static void cramfs_kill_sb(struct super_block *sb)
{
struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
- kill_block_super(sb);
+ if (IS_ENABLED(CCONFIG_CRAMFS_MTD) && sb->s_mtd) {
+ if (sbi && sbi->mtd_point_size)
+ mtd_unpoint(sb->s_mtd, 0, sbi->mtd_point_size);
+ kill_mtd_super(sb);
+ } else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV) && sb->s_bdev) {
+ kill_block_super(sb);
+ }
kfree(sbi);
}
return 0;
}
-static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
+static int cramfs_read_super(struct super_block *sb,
+ struct cramfs_super *super, int silent)
{
- int i;
- struct cramfs_super super;
+ struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
unsigned long root_offset;
- struct cramfs_sb_info *sbi;
- struct inode *root;
-
- sb->s_flags |= MS_RDONLY;
-
- sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
- if (!sbi)
- return -ENOMEM;
- sb->s_fs_info = sbi;
- /* Invalidate the read buffers on mount: think disk change.. */
- mutex_lock(&read_mutex);
- for (i = 0; i < READ_BUFFERS; i++)
- buffer_blocknr[i] = -1;
+ /* We don't know the real size yet */
+ sbi->size = PAGE_SIZE;
/* Read the first block and get the superblock from it */
- memcpy(&super, cramfs_read(sb, 0, sizeof(super)), sizeof(super));
+ mutex_lock(&read_mutex);
+ memcpy(super, cramfs_read(sb, 0, sizeof(*super)), sizeof(*super));
mutex_unlock(&read_mutex);
/* Do sanity checks on the superblock */
- if (super.magic != CRAMFS_MAGIC) {
+ if (super->magic != CRAMFS_MAGIC) {
/* check for wrong endianness */
- if (super.magic == CRAMFS_MAGIC_WEND) {
+ if (super->magic == CRAMFS_MAGIC_WEND) {
if (!silent)
pr_err("wrong endianness\n");
return -EINVAL;
/* check at 512 byte offset */
mutex_lock(&read_mutex);
- memcpy(&super, cramfs_read(sb, 512, sizeof(super)), sizeof(super));
+ memcpy(super,
+ cramfs_read(sb, 512, sizeof(*super)),
+ sizeof(*super));
mutex_unlock(&read_mutex);
- if (super.magic != CRAMFS_MAGIC) {
- if (super.magic == CRAMFS_MAGIC_WEND && !silent)
+ if (super->magic != CRAMFS_MAGIC) {
+ if (super->magic == CRAMFS_MAGIC_WEND && !silent)
pr_err("wrong endianness\n");
else if (!silent)
pr_err("wrong magic\n");
}
/* get feature flags first */
- if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) {
+ if (super->flags & ~CRAMFS_SUPPORTED_FLAGS) {
pr_err("unsupported filesystem features\n");
return -EINVAL;
}
/* Check that the root inode is in a sane state */
- if (!S_ISDIR(super.root.mode)) {
+ if (!S_ISDIR(super->root.mode)) {
pr_err("root is not a directory\n");
return -EINVAL;
}
/* correct strange, hard-coded permissions of mkcramfs */
- super.root.mode |= (S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
+ super->root.mode |= 0555;
- root_offset = super.root.offset << 2;
- if (super.flags & CRAMFS_FLAG_FSID_VERSION_2) {
- sbi->size = super.size;
- sbi->blocks = super.fsid.blocks;
- sbi->files = super.fsid.files;
+ root_offset = super->root.offset << 2;
+ if (super->flags & CRAMFS_FLAG_FSID_VERSION_2) {
+ sbi->size = super->size;
+ sbi->blocks = super->fsid.blocks;
+ sbi->files = super->fsid.files;
} else {
sbi->size = 1<<28;
sbi->blocks = 0;
sbi->files = 0;
}
- sbi->magic = super.magic;
- sbi->flags = super.flags;
+ sbi->magic = super->magic;
+ sbi->flags = super->flags;
if (root_offset == 0)
pr_info("empty filesystem");
- else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
+ else if (!(super->flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
((root_offset != sizeof(struct cramfs_super)) &&
(root_offset != 512 + sizeof(struct cramfs_super))))
{
return -EINVAL;
}
+ return 0;
+}
+
+static int cramfs_finalize_super(struct super_block *sb,
+ struct cramfs_inode *cramfs_root)
+{
+ struct inode *root;
+
/* Set it all up.. */
+ sb->s_flags |= MS_RDONLY;
sb->s_op = &cramfs_ops;
- root = get_cramfs_inode(sb, &super.root, 0);
+ root = get_cramfs_inode(sb, cramfs_root, 0);
if (IS_ERR(root))
return PTR_ERR(root);
sb->s_root = d_make_root(root);
return 0;
}
+static int cramfs_blkdev_fill_super(struct super_block *sb, void *data,
+ int silent)
+{
+ struct cramfs_sb_info *sbi;
+ struct cramfs_super super;
+ int i, err;
+
+ sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
+ if (!sbi)
+ return -ENOMEM;
+ sb->s_fs_info = sbi;
+
+ /* Invalidate the read buffers on mount: think disk change.. */
+ for (i = 0; i < READ_BUFFERS; i++)
+ buffer_blocknr[i] = -1;
+
+ err = cramfs_read_super(sb, &super, silent);
+ if (err)
+ return err;
+ return cramfs_finalize_super(sb, &super.root);
+}
+
+static int cramfs_mtd_fill_super(struct super_block *sb, void *data,
+ int silent)
+{
+ struct cramfs_sb_info *sbi;
+ struct cramfs_super super;
+ int err;
+
+ sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
+ if (!sbi)
+ return -ENOMEM;
+ sb->s_fs_info = sbi;
+
+ /* Map only one page for now. Will remap it when fs size is known. */
+ err = mtd_point(sb->s_mtd, 0, PAGE_SIZE, &sbi->mtd_point_size,
+ &sbi->linear_virt_addr, &sbi->linear_phys_addr);
+ if (err || sbi->mtd_point_size != PAGE_SIZE) {
+ pr_err("unable to get direct memory access to mtd:%s\n",
+ sb->s_mtd->name);
+ return err ? : -ENODATA;
+ }
+
+ pr_info("checking physical address %pap for linear cramfs image\n",
+ &sbi->linear_phys_addr);
+ err = cramfs_read_super(sb, &super, silent);
+ if (err)
+ return err;
+
+ /* Remap the whole filesystem now */
+ pr_info("linear cramfs image on mtd:%s appears to be %lu KB in size\n",
+ sb->s_mtd->name, sbi->size/1024);
+ mtd_unpoint(sb->s_mtd, 0, PAGE_SIZE);
+ err = mtd_point(sb->s_mtd, 0, sbi->size, &sbi->mtd_point_size,
+ &sbi->linear_virt_addr, &sbi->linear_phys_addr);
+ if (err || sbi->mtd_point_size != sbi->size) {
+ pr_err("unable to get direct memory access to mtd:%s\n",
+ sb->s_mtd->name);
+ return err ? : -ENODATA;
+ }
+
+ return cramfs_finalize_super(sb, &super.root);
+}
+
static int cramfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
- u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
+ u64 id = 0;
+
+ if (sb->s_bdev)
+ id = huge_encode_dev(sb->s_bdev->bd_dev);
+ else if (sb->s_dev)
+ id = huge_encode_dev(sb->s_dev);
buf->f_type = CRAMFS_MAGIC;
buf->f_bsize = PAGE_SIZE;
if (page->index < maxblock) {
struct super_block *sb = inode->i_sb;
- u32 blkptr_offset = OFFSET(inode) + page->index*4;
- u32 start_offset, compr_len;
+ u32 blkptr_offset = OFFSET(inode) + page->index * 4;
+ u32 block_ptr, block_start, block_len;
+ bool uncompressed, direct;
- start_offset = OFFSET(inode) + maxblock*4;
mutex_lock(&read_mutex);
- if (page->index)
- start_offset = *(u32 *) cramfs_read(sb, blkptr_offset-4,
- 4);
- compr_len = (*(u32 *) cramfs_read(sb, blkptr_offset, 4) -
- start_offset);
- mutex_unlock(&read_mutex);
+ block_ptr = *(u32 *) cramfs_read(sb, blkptr_offset, 4);
+ uncompressed = (block_ptr & CRAMFS_BLK_FLAG_UNCOMPRESSED);
+ direct = (block_ptr & CRAMFS_BLK_FLAG_DIRECT_PTR);
+ block_ptr &= ~CRAMFS_BLK_FLAGS;
+
+ if (direct) {
+ /*
+ * The block pointer is an absolute start pointer,
+ * shifted by 2 bits. The size is included in the
+ * first 2 bytes of the data block when compressed,
+ * or PAGE_SIZE otherwise.
+ */
+ block_start = block_ptr << CRAMFS_BLK_DIRECT_PTR_SHIFT;
+ if (uncompressed) {
+ block_len = PAGE_SIZE;
+ /* if last block: cap to file length */
+ if (page->index == maxblock - 1)
+ block_len =
+ offset_in_page(inode->i_size);
+ } else {
+ block_len = *(u16 *)
+ cramfs_read(sb, block_start, 2);
+ block_start += 2;
+ }
+ } else {
+ /*
+ * The block pointer indicates one past the end of
+ * the current block (start of next block). If this
+ * is the first block then it starts where the block
+ * pointer table ends, otherwise its start comes
+ * from the previous block's pointer.
+ */
+ block_start = OFFSET(inode) + maxblock * 4;
+ if (page->index)
+ block_start = *(u32 *)
+ cramfs_read(sb, blkptr_offset - 4, 4);
+ /* Beware... previous ptr might be a direct ptr */
+ if (unlikely(block_start & CRAMFS_BLK_FLAG_DIRECT_PTR)) {
+ /* See comments on earlier code. */
+ u32 prev_start = block_start;
+ block_start = prev_start & ~CRAMFS_BLK_FLAGS;
+ block_start <<= CRAMFS_BLK_DIRECT_PTR_SHIFT;
+ if (prev_start & CRAMFS_BLK_FLAG_UNCOMPRESSED) {
+ block_start += PAGE_SIZE;
+ } else {
+ block_len = *(u16 *)
+ cramfs_read(sb, block_start, 2);
+ block_start += 2 + block_len;
+ }
+ }
+ block_start &= ~CRAMFS_BLK_FLAGS;
+ block_len = block_ptr - block_start;
+ }
- if (compr_len == 0)
+ if (block_len == 0)
; /* hole */
- else if (unlikely(compr_len > (PAGE_SIZE << 1))) {
- pr_err("bad compressed blocksize %u\n",
- compr_len);
+ else if (unlikely(block_len > 2*PAGE_SIZE ||
+ (uncompressed && block_len > PAGE_SIZE))) {
+ mutex_unlock(&read_mutex);
+ pr_err("bad data blocksize %u\n", block_len);
goto err;
+ } else if (uncompressed) {
+ memcpy(pgdata,
+ cramfs_read(sb, block_start, block_len),
+ block_len);
+ bytes_filled = block_len;
} else {
- mutex_lock(&read_mutex);
bytes_filled = cramfs_uncompress_block(pgdata,
PAGE_SIZE,
- cramfs_read(sb, start_offset, compr_len),
- compr_len);
- mutex_unlock(&read_mutex);
- if (unlikely(bytes_filled < 0))
- goto err;
+ cramfs_read(sb, block_start, block_len),
+ block_len);
}
+ mutex_unlock(&read_mutex);
+ if (unlikely(bytes_filled < 0))
+ goto err;
}
memset(pgdata + bytes_filled, 0, PAGE_SIZE - bytes_filled);
.statfs = cramfs_statfs,
};
-static struct dentry *cramfs_mount(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data)
+static struct dentry *cramfs_mount(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data)
{
- return mount_bdev(fs_type, flags, dev_name, data, cramfs_fill_super);
+ struct dentry *ret = ERR_PTR(-ENOPROTOOPT);
+
+ if (IS_ENABLED(CONFIG_CRAMFS_MTD)) {
+ ret = mount_mtd(fs_type, flags, dev_name, data,
+ cramfs_mtd_fill_super);
+ if (!IS_ERR(ret))
+ return ret;
+ }
+ if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV)) {
+ ret = mount_bdev(fs_type, flags, dev_name, data,
+ cramfs_blkdev_fill_super);
+ }
+ return ret;
}
static struct file_system_type cramfs_fs_type = {
projects / linux-block.git / blobdiff