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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Linus Torvalds](/assets/img/avatar_default.png)
Pull misc mount API conversions from Al Viro: "Conversions to new API for shmem and friends and for mount_mtd()-using filesystems. As for the rest of the mount API conversions in -next, some of them belong in the individual trees (e.g. binderfs one should definitely go through android folks, after getting redone on top of their changes). I'm going to drop those and send the rest (trivial ones + stuff ACKed by maintainers) in a separate series - by that point they are independent from each other. Some stuff has already migrated into individual trees (NFS conversion, for example, or FUSE stuff, etc.); those presumably will go through the regular merges from corresponding trees." * 'work.mount2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: vfs: Make fs_parse() handle fs_param_is_fd-type params better vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API shmem_parse_one(): switch to use of fs_parse() shmem_parse_options(): take handling a single option into a helper shmem_parse_options(): don't bother with mpol in separate variable shmem_parse_options(): use a separate structure to keep the results make shmem_fill_super() static make ramfs_fill_super() static devtmpfs: don't mix {ramfs,shmem}_fill_super() with mount_single() vfs: Convert squashfs to use the new mount API mtd: Kill mount_mtd() vfs: Convert jffs2 to use the new mount API vfs: Convert cramfs to use the new mount API vfs: Convert romfs to use the new mount API vfs: Add a single-or-reconfig keying to vfs_get_super()
1013 lines
26 KiB
C
1013 lines
26 KiB
C
/*
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* Compressed rom filesystem for Linux.
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*
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* Copyright (C) 1999 Linus Torvalds.
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*
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* This file is released under the GPL.
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*/
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/*
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* These are the VFS interfaces to the compressed rom filesystem.
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* The actual compression is based on zlib, see the other files.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/pagemap.h>
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#include <linux/pfn_t.h>
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#include <linux/ramfs.h>
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#include <linux/init.h>
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#include <linux/string.h>
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#include <linux/blkdev.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/super.h>
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#include <linux/fs_context.h>
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#include <linux/slab.h>
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#include <linux/vfs.h>
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#include <linux/mutex.h>
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#include <uapi/linux/cramfs_fs.h>
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#include <linux/uaccess.h>
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#include "internal.h"
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/*
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* cramfs super-block data in memory
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*/
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struct cramfs_sb_info {
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unsigned long magic;
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unsigned long size;
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unsigned long blocks;
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unsigned long files;
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unsigned long flags;
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void *linear_virt_addr;
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resource_size_t linear_phys_addr;
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size_t mtd_point_size;
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};
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static inline struct cramfs_sb_info *CRAMFS_SB(struct super_block *sb)
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{
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return sb->s_fs_info;
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}
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static const struct super_operations cramfs_ops;
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static const struct inode_operations cramfs_dir_inode_operations;
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static const struct file_operations cramfs_directory_operations;
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static const struct file_operations cramfs_physmem_fops;
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static const struct address_space_operations cramfs_aops;
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static DEFINE_MUTEX(read_mutex);
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/* These macros may change in future, to provide better st_ino semantics. */
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#define OFFSET(x) ((x)->i_ino)
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static unsigned long cramino(const struct cramfs_inode *cino, unsigned int offset)
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{
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if (!cino->offset)
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return offset + 1;
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if (!cino->size)
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return offset + 1;
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/*
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* The file mode test fixes buggy mkcramfs implementations where
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* cramfs_inode->offset is set to a non zero value for entries
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* which did not contain data, like devices node and fifos.
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*/
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switch (cino->mode & S_IFMT) {
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case S_IFREG:
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case S_IFDIR:
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case S_IFLNK:
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return cino->offset << 2;
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default:
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break;
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}
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return offset + 1;
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}
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static struct inode *get_cramfs_inode(struct super_block *sb,
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const struct cramfs_inode *cramfs_inode, unsigned int offset)
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{
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struct inode *inode;
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static struct timespec64 zerotime;
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inode = iget_locked(sb, cramino(cramfs_inode, offset));
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if (!inode)
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return ERR_PTR(-ENOMEM);
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if (!(inode->i_state & I_NEW))
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return inode;
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switch (cramfs_inode->mode & S_IFMT) {
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case S_IFREG:
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inode->i_fop = &generic_ro_fops;
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inode->i_data.a_ops = &cramfs_aops;
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if (IS_ENABLED(CONFIG_CRAMFS_MTD) &&
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CRAMFS_SB(sb)->flags & CRAMFS_FLAG_EXT_BLOCK_POINTERS &&
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CRAMFS_SB(sb)->linear_phys_addr)
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inode->i_fop = &cramfs_physmem_fops;
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break;
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case S_IFDIR:
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inode->i_op = &cramfs_dir_inode_operations;
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inode->i_fop = &cramfs_directory_operations;
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break;
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case S_IFLNK:
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inode->i_op = &page_symlink_inode_operations;
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inode_nohighmem(inode);
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inode->i_data.a_ops = &cramfs_aops;
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break;
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default:
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init_special_inode(inode, cramfs_inode->mode,
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old_decode_dev(cramfs_inode->size));
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}
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inode->i_mode = cramfs_inode->mode;
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i_uid_write(inode, cramfs_inode->uid);
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i_gid_write(inode, cramfs_inode->gid);
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/* if the lower 2 bits are zero, the inode contains data */
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if (!(inode->i_ino & 3)) {
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inode->i_size = cramfs_inode->size;
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inode->i_blocks = (cramfs_inode->size - 1) / 512 + 1;
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}
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/* Struct copy intentional */
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inode->i_mtime = inode->i_atime = inode->i_ctime = zerotime;
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/* inode->i_nlink is left 1 - arguably wrong for directories,
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but it's the best we can do without reading the directory
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contents. 1 yields the right result in GNU find, even
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without -noleaf option. */
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unlock_new_inode(inode);
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return inode;
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}
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/*
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* We have our own block cache: don't fill up the buffer cache
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* with the rom-image, because the way the filesystem is set
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* up the accesses should be fairly regular and cached in the
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* page cache and dentry tree anyway..
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*
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* This also acts as a way to guarantee contiguous areas of up to
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* BLKS_PER_BUF*PAGE_SIZE, so that the caller doesn't need to
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* worry about end-of-buffer issues even when decompressing a full
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* page cache.
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*
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* Note: This is all optimized away at compile time when
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* CONFIG_CRAMFS_BLOCKDEV=n.
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*/
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#define READ_BUFFERS (2)
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/* NEXT_BUFFER(): Loop over [0..(READ_BUFFERS-1)]. */
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#define NEXT_BUFFER(_ix) ((_ix) ^ 1)
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/*
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* BLKS_PER_BUF_SHIFT should be at least 2 to allow for "compressed"
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* data that takes up more space than the original and with unlucky
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* alignment.
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*/
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#define BLKS_PER_BUF_SHIFT (2)
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#define BLKS_PER_BUF (1 << BLKS_PER_BUF_SHIFT)
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#define BUFFER_SIZE (BLKS_PER_BUF*PAGE_SIZE)
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static unsigned char read_buffers[READ_BUFFERS][BUFFER_SIZE];
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static unsigned buffer_blocknr[READ_BUFFERS];
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static struct super_block *buffer_dev[READ_BUFFERS];
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static int next_buffer;
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/*
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* Populate our block cache and return a pointer to it.
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*/
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static void *cramfs_blkdev_read(struct super_block *sb, unsigned int offset,
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unsigned int len)
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{
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struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
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struct page *pages[BLKS_PER_BUF];
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unsigned i, blocknr, buffer;
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unsigned long devsize;
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char *data;
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if (!len)
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return NULL;
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blocknr = offset >> PAGE_SHIFT;
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offset &= PAGE_SIZE - 1;
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/* Check if an existing buffer already has the data.. */
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for (i = 0; i < READ_BUFFERS; i++) {
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unsigned int blk_offset;
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if (buffer_dev[i] != sb)
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continue;
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if (blocknr < buffer_blocknr[i])
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continue;
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blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_SHIFT;
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blk_offset += offset;
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if (blk_offset > BUFFER_SIZE ||
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blk_offset + len > BUFFER_SIZE)
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continue;
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return read_buffers[i] + blk_offset;
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}
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devsize = mapping->host->i_size >> PAGE_SHIFT;
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/* Ok, read in BLKS_PER_BUF pages completely first. */
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for (i = 0; i < BLKS_PER_BUF; i++) {
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struct page *page = NULL;
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if (blocknr + i < devsize) {
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page = read_mapping_page(mapping, blocknr + i, NULL);
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/* synchronous error? */
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if (IS_ERR(page))
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page = NULL;
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}
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pages[i] = page;
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}
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for (i = 0; i < BLKS_PER_BUF; i++) {
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struct page *page = pages[i];
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if (page) {
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wait_on_page_locked(page);
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if (!PageUptodate(page)) {
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/* asynchronous error */
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put_page(page);
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pages[i] = NULL;
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}
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}
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}
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buffer = next_buffer;
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next_buffer = NEXT_BUFFER(buffer);
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buffer_blocknr[buffer] = blocknr;
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buffer_dev[buffer] = sb;
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data = read_buffers[buffer];
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for (i = 0; i < BLKS_PER_BUF; i++) {
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struct page *page = pages[i];
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if (page) {
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memcpy(data, kmap(page), PAGE_SIZE);
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kunmap(page);
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put_page(page);
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} else
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memset(data, 0, PAGE_SIZE);
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data += PAGE_SIZE;
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}
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return read_buffers[buffer] + offset;
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}
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/*
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* Return a pointer to the linearly addressed cramfs image in memory.
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*/
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static void *cramfs_direct_read(struct super_block *sb, unsigned int offset,
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unsigned int len)
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{
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struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
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if (!len)
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return NULL;
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if (len > sbi->size || offset > sbi->size - len)
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return page_address(ZERO_PAGE(0));
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return sbi->linear_virt_addr + offset;
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}
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/*
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* Returns a pointer to a buffer containing at least LEN bytes of
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* filesystem starting at byte offset OFFSET into the filesystem.
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*/
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static void *cramfs_read(struct super_block *sb, unsigned int offset,
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unsigned int len)
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{
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struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
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if (IS_ENABLED(CONFIG_CRAMFS_MTD) && sbi->linear_virt_addr)
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return cramfs_direct_read(sb, offset, len);
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else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV))
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return cramfs_blkdev_read(sb, offset, len);
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else
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return NULL;
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}
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/*
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* For a mapping to be possible, we need a range of uncompressed and
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* contiguous blocks. Return the offset for the first block and number of
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* valid blocks for which that is true, or zero otherwise.
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*/
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static u32 cramfs_get_block_range(struct inode *inode, u32 pgoff, u32 *pages)
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{
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struct cramfs_sb_info *sbi = CRAMFS_SB(inode->i_sb);
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int i;
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u32 *blockptrs, first_block_addr;
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/*
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* We can dereference memory directly here as this code may be
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* reached only when there is a direct filesystem image mapping
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* available in memory.
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*/
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blockptrs = (u32 *)(sbi->linear_virt_addr + OFFSET(inode) + pgoff * 4);
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first_block_addr = blockptrs[0] & ~CRAMFS_BLK_FLAGS;
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i = 0;
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do {
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u32 block_off = i * (PAGE_SIZE >> CRAMFS_BLK_DIRECT_PTR_SHIFT);
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u32 expect = (first_block_addr + block_off) |
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CRAMFS_BLK_FLAG_DIRECT_PTR |
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CRAMFS_BLK_FLAG_UNCOMPRESSED;
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if (blockptrs[i] != expect) {
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pr_debug("range: block %d/%d got %#x expects %#x\n",
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pgoff+i, pgoff + *pages - 1,
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blockptrs[i], expect);
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if (i == 0)
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return 0;
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break;
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}
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} while (++i < *pages);
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*pages = i;
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return first_block_addr << CRAMFS_BLK_DIRECT_PTR_SHIFT;
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}
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#ifdef CONFIG_MMU
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/*
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* Return true if the last page of a file in the filesystem image contains
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* some other data that doesn't belong to that file. It is assumed that the
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* last block is CRAMFS_BLK_FLAG_DIRECT_PTR | CRAMFS_BLK_FLAG_UNCOMPRESSED
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* (verified by cramfs_get_block_range() and directly accessible in memory.
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*/
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static bool cramfs_last_page_is_shared(struct inode *inode)
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{
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struct cramfs_sb_info *sbi = CRAMFS_SB(inode->i_sb);
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u32 partial, last_page, blockaddr, *blockptrs;
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char *tail_data;
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partial = offset_in_page(inode->i_size);
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if (!partial)
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return false;
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last_page = inode->i_size >> PAGE_SHIFT;
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blockptrs = (u32 *)(sbi->linear_virt_addr + OFFSET(inode));
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blockaddr = blockptrs[last_page] & ~CRAMFS_BLK_FLAGS;
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blockaddr <<= CRAMFS_BLK_DIRECT_PTR_SHIFT;
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tail_data = sbi->linear_virt_addr + blockaddr + partial;
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return memchr_inv(tail_data, 0, PAGE_SIZE - partial) ? true : false;
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}
|
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|
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static int cramfs_physmem_mmap(struct file *file, struct vm_area_struct *vma)
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{
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struct inode *inode = file_inode(file);
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struct cramfs_sb_info *sbi = CRAMFS_SB(inode->i_sb);
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unsigned int pages, max_pages, offset;
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unsigned long address, pgoff = vma->vm_pgoff;
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char *bailout_reason;
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int ret;
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ret = generic_file_readonly_mmap(file, vma);
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if (ret)
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return ret;
|
|
|
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/*
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* Now try to pre-populate ptes for this vma with a direct
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* mapping avoiding memory allocation when possible.
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*/
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/* Could COW work here? */
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bailout_reason = "vma is writable";
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if (vma->vm_flags & VM_WRITE)
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goto bailout;
|
|
|
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max_pages = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
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bailout_reason = "beyond file limit";
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if (pgoff >= max_pages)
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goto bailout;
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pages = min(vma_pages(vma), max_pages - pgoff);
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|
|
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offset = cramfs_get_block_range(inode, pgoff, &pages);
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bailout_reason = "unsuitable block layout";
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if (!offset)
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goto bailout;
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address = sbi->linear_phys_addr + offset;
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bailout_reason = "data is not page aligned";
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if (!PAGE_ALIGNED(address))
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goto bailout;
|
|
|
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/* Don't map the last page if it contains some other data */
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if (pgoff + pages == max_pages && cramfs_last_page_is_shared(inode)) {
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pr_debug("mmap: %s: last page is shared\n",
|
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file_dentry(file)->d_name.name);
|
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pages--;
|
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}
|
|
|
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if (!pages) {
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bailout_reason = "no suitable block remaining";
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goto bailout;
|
|
}
|
|
|
|
if (pages == vma_pages(vma)) {
|
|
/*
|
|
* The entire vma is mappable. remap_pfn_range() will
|
|
* make it distinguishable from a non-direct mapping
|
|
* in /proc/<pid>/maps by substituting the file offset
|
|
* with the actual physical address.
|
|
*/
|
|
ret = remap_pfn_range(vma, vma->vm_start, address >> PAGE_SHIFT,
|
|
pages * PAGE_SIZE, vma->vm_page_prot);
|
|
} else {
|
|
/*
|
|
* Let's create a mixed map if we can't map it all.
|
|
* The normal paging machinery will take care of the
|
|
* unpopulated ptes via cramfs_readpage().
|
|
*/
|
|
int i;
|
|
vma->vm_flags |= VM_MIXEDMAP;
|
|
for (i = 0; i < pages && !ret; i++) {
|
|
vm_fault_t vmf;
|
|
unsigned long off = i * PAGE_SIZE;
|
|
pfn_t pfn = phys_to_pfn_t(address + off, PFN_DEV);
|
|
vmf = vmf_insert_mixed(vma, vma->vm_start + off, pfn);
|
|
if (vmf & VM_FAULT_ERROR)
|
|
ret = vm_fault_to_errno(vmf, 0);
|
|
}
|
|
}
|
|
|
|
if (!ret)
|
|
pr_debug("mapped %s[%lu] at 0x%08lx (%u/%lu pages) "
|
|
"to vma 0x%08lx, page_prot 0x%llx\n",
|
|
file_dentry(file)->d_name.name, pgoff,
|
|
address, pages, vma_pages(vma), vma->vm_start,
|
|
(unsigned long long)pgprot_val(vma->vm_page_prot));
|
|
return ret;
|
|
|
|
bailout:
|
|
pr_debug("%s[%lu]: direct mmap impossible: %s\n",
|
|
file_dentry(file)->d_name.name, pgoff, bailout_reason);
|
|
/* Didn't manage any direct map, but normal paging is still possible */
|
|
return 0;
|
|
}
|
|
|
|
#else /* CONFIG_MMU */
|
|
|
|
static int cramfs_physmem_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -ENOSYS;
|
|
}
|
|
|
|
static unsigned long cramfs_physmem_get_unmapped_area(struct file *file,
|
|
unsigned long addr, unsigned long len,
|
|
unsigned long pgoff, unsigned long flags)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
struct super_block *sb = inode->i_sb;
|
|
struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
|
|
unsigned int pages, block_pages, max_pages, offset;
|
|
|
|
pages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
max_pages = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
if (pgoff >= max_pages || pages > max_pages - pgoff)
|
|
return -EINVAL;
|
|
block_pages = pages;
|
|
offset = cramfs_get_block_range(inode, pgoff, &block_pages);
|
|
if (!offset || block_pages != pages)
|
|
return -ENOSYS;
|
|
addr = sbi->linear_phys_addr + offset;
|
|
pr_debug("get_unmapped for %s ofs %#lx siz %lu at 0x%08lx\n",
|
|
file_dentry(file)->d_name.name, pgoff*PAGE_SIZE, len, addr);
|
|
return addr;
|
|
}
|
|
|
|
static unsigned int cramfs_physmem_mmap_capabilities(struct file *file)
|
|
{
|
|
return NOMMU_MAP_COPY | NOMMU_MAP_DIRECT |
|
|
NOMMU_MAP_READ | NOMMU_MAP_EXEC;
|
|
}
|
|
|
|
#endif /* CONFIG_MMU */
|
|
|
|
static const struct file_operations cramfs_physmem_fops = {
|
|
.llseek = generic_file_llseek,
|
|
.read_iter = generic_file_read_iter,
|
|
.splice_read = generic_file_splice_read,
|
|
.mmap = cramfs_physmem_mmap,
|
|
#ifndef CONFIG_MMU
|
|
.get_unmapped_area = cramfs_physmem_get_unmapped_area,
|
|
.mmap_capabilities = cramfs_physmem_mmap_capabilities,
|
|
#endif
|
|
};
|
|
|
|
static void cramfs_kill_sb(struct super_block *sb)
|
|
{
|
|
struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
|
|
|
|
if (IS_ENABLED(CONFIG_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);
|
|
}
|
|
|
|
static int cramfs_reconfigure(struct fs_context *fc)
|
|
{
|
|
sync_filesystem(fc->root->d_sb);
|
|
fc->sb_flags |= SB_RDONLY;
|
|
return 0;
|
|
}
|
|
|
|
static int cramfs_read_super(struct super_block *sb, struct fs_context *fc,
|
|
struct cramfs_super *super)
|
|
{
|
|
struct cramfs_sb_info *sbi = CRAMFS_SB(sb);
|
|
unsigned long root_offset;
|
|
bool silent = fc->sb_flags & SB_SILENT;
|
|
|
|
/* We don't know the real size yet */
|
|
sbi->size = PAGE_SIZE;
|
|
|
|
/* Read the first block and get the superblock from it */
|
|
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) {
|
|
/* check for wrong endianness */
|
|
if (super->magic == CRAMFS_MAGIC_WEND) {
|
|
if (!silent)
|
|
errorf(fc, "cramfs: wrong endianness");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* check at 512 byte offset */
|
|
mutex_lock(&read_mutex);
|
|
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)
|
|
errorf(fc, "cramfs: wrong endianness");
|
|
else if (!silent)
|
|
errorf(fc, "cramfs: wrong magic");
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
/* get feature flags first */
|
|
if (super->flags & ~CRAMFS_SUPPORTED_FLAGS) {
|
|
errorf(fc, "cramfs: unsupported filesystem features");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Check that the root inode is in a sane state */
|
|
if (!S_ISDIR(super->root.mode)) {
|
|
errorf(fc, "cramfs: root is not a directory");
|
|
return -EINVAL;
|
|
}
|
|
/* correct strange, hard-coded permissions of mkcramfs */
|
|
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;
|
|
} else {
|
|
sbi->size = 1<<28;
|
|
sbi->blocks = 0;
|
|
sbi->files = 0;
|
|
}
|
|
sbi->magic = super->magic;
|
|
sbi->flags = super->flags;
|
|
if (root_offset == 0)
|
|
infof(fc, "cramfs: empty filesystem");
|
|
else if (!(super->flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
|
|
((root_offset != sizeof(struct cramfs_super)) &&
|
|
(root_offset != 512 + sizeof(struct cramfs_super))))
|
|
{
|
|
errorf(fc, "cramfs: bad root offset %lu", root_offset);
|
|
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 |= SB_RDONLY;
|
|
sb->s_time_min = 0;
|
|
sb->s_time_max = 0;
|
|
sb->s_op = &cramfs_ops;
|
|
root = get_cramfs_inode(sb, cramfs_root, 0);
|
|
if (IS_ERR(root))
|
|
return PTR_ERR(root);
|
|
sb->s_root = d_make_root(root);
|
|
if (!sb->s_root)
|
|
return -ENOMEM;
|
|
return 0;
|
|
}
|
|
|
|
static int cramfs_blkdev_fill_super(struct super_block *sb, struct fs_context *fc)
|
|
{
|
|
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, fc, &super);
|
|
if (err)
|
|
return err;
|
|
return cramfs_finalize_super(sb, &super.root);
|
|
}
|
|
|
|
static int cramfs_mtd_fill_super(struct super_block *sb, struct fs_context *fc)
|
|
{
|
|
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, fc, &super);
|
|
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 = 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;
|
|
buf->f_blocks = CRAMFS_SB(sb)->blocks;
|
|
buf->f_bfree = 0;
|
|
buf->f_bavail = 0;
|
|
buf->f_files = CRAMFS_SB(sb)->files;
|
|
buf->f_ffree = 0;
|
|
buf->f_fsid.val[0] = (u32)id;
|
|
buf->f_fsid.val[1] = (u32)(id >> 32);
|
|
buf->f_namelen = CRAMFS_MAXPATHLEN;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Read a cramfs directory entry.
|
|
*/
|
|
static int cramfs_readdir(struct file *file, struct dir_context *ctx)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
struct super_block *sb = inode->i_sb;
|
|
char *buf;
|
|
unsigned int offset;
|
|
|
|
/* Offset within the thing. */
|
|
if (ctx->pos >= inode->i_size)
|
|
return 0;
|
|
offset = ctx->pos;
|
|
/* Directory entries are always 4-byte aligned */
|
|
if (offset & 3)
|
|
return -EINVAL;
|
|
|
|
buf = kmalloc(CRAMFS_MAXPATHLEN, GFP_KERNEL);
|
|
if (!buf)
|
|
return -ENOMEM;
|
|
|
|
while (offset < inode->i_size) {
|
|
struct cramfs_inode *de;
|
|
unsigned long nextoffset;
|
|
char *name;
|
|
ino_t ino;
|
|
umode_t mode;
|
|
int namelen;
|
|
|
|
mutex_lock(&read_mutex);
|
|
de = cramfs_read(sb, OFFSET(inode) + offset, sizeof(*de)+CRAMFS_MAXPATHLEN);
|
|
name = (char *)(de+1);
|
|
|
|
/*
|
|
* Namelengths on disk are shifted by two
|
|
* and the name padded out to 4-byte boundaries
|
|
* with zeroes.
|
|
*/
|
|
namelen = de->namelen << 2;
|
|
memcpy(buf, name, namelen);
|
|
ino = cramino(de, OFFSET(inode) + offset);
|
|
mode = de->mode;
|
|
mutex_unlock(&read_mutex);
|
|
nextoffset = offset + sizeof(*de) + namelen;
|
|
for (;;) {
|
|
if (!namelen) {
|
|
kfree(buf);
|
|
return -EIO;
|
|
}
|
|
if (buf[namelen-1])
|
|
break;
|
|
namelen--;
|
|
}
|
|
if (!dir_emit(ctx, buf, namelen, ino, mode >> 12))
|
|
break;
|
|
|
|
ctx->pos = offset = nextoffset;
|
|
}
|
|
kfree(buf);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Lookup and fill in the inode data..
|
|
*/
|
|
static struct dentry *cramfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
|
|
{
|
|
unsigned int offset = 0;
|
|
struct inode *inode = NULL;
|
|
int sorted;
|
|
|
|
mutex_lock(&read_mutex);
|
|
sorted = CRAMFS_SB(dir->i_sb)->flags & CRAMFS_FLAG_SORTED_DIRS;
|
|
while (offset < dir->i_size) {
|
|
struct cramfs_inode *de;
|
|
char *name;
|
|
int namelen, retval;
|
|
int dir_off = OFFSET(dir) + offset;
|
|
|
|
de = cramfs_read(dir->i_sb, dir_off, sizeof(*de)+CRAMFS_MAXPATHLEN);
|
|
name = (char *)(de+1);
|
|
|
|
/* Try to take advantage of sorted directories */
|
|
if (sorted && (dentry->d_name.name[0] < name[0]))
|
|
break;
|
|
|
|
namelen = de->namelen << 2;
|
|
offset += sizeof(*de) + namelen;
|
|
|
|
/* Quick check that the name is roughly the right length */
|
|
if (((dentry->d_name.len + 3) & ~3) != namelen)
|
|
continue;
|
|
|
|
for (;;) {
|
|
if (!namelen) {
|
|
inode = ERR_PTR(-EIO);
|
|
goto out;
|
|
}
|
|
if (name[namelen-1])
|
|
break;
|
|
namelen--;
|
|
}
|
|
if (namelen != dentry->d_name.len)
|
|
continue;
|
|
retval = memcmp(dentry->d_name.name, name, namelen);
|
|
if (retval > 0)
|
|
continue;
|
|
if (!retval) {
|
|
inode = get_cramfs_inode(dir->i_sb, de, dir_off);
|
|
break;
|
|
}
|
|
/* else (retval < 0) */
|
|
if (sorted)
|
|
break;
|
|
}
|
|
out:
|
|
mutex_unlock(&read_mutex);
|
|
return d_splice_alias(inode, dentry);
|
|
}
|
|
|
|
static int cramfs_readpage(struct file *file, struct page *page)
|
|
{
|
|
struct inode *inode = page->mapping->host;
|
|
u32 maxblock;
|
|
int bytes_filled;
|
|
void *pgdata;
|
|
|
|
maxblock = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
bytes_filled = 0;
|
|
pgdata = kmap(page);
|
|
|
|
if (page->index < maxblock) {
|
|
struct super_block *sb = inode->i_sb;
|
|
u32 blkptr_offset = OFFSET(inode) + page->index * 4;
|
|
u32 block_ptr, block_start, block_len;
|
|
bool uncompressed, direct;
|
|
|
|
mutex_lock(&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 (block_len == 0)
|
|
; /* hole */
|
|
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 {
|
|
bytes_filled = cramfs_uncompress_block(pgdata,
|
|
PAGE_SIZE,
|
|
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);
|
|
flush_dcache_page(page);
|
|
kunmap(page);
|
|
SetPageUptodate(page);
|
|
unlock_page(page);
|
|
return 0;
|
|
|
|
err:
|
|
kunmap(page);
|
|
ClearPageUptodate(page);
|
|
SetPageError(page);
|
|
unlock_page(page);
|
|
return 0;
|
|
}
|
|
|
|
static const struct address_space_operations cramfs_aops = {
|
|
.readpage = cramfs_readpage
|
|
};
|
|
|
|
/*
|
|
* Our operations:
|
|
*/
|
|
|
|
/*
|
|
* A directory can only readdir
|
|
*/
|
|
static const struct file_operations cramfs_directory_operations = {
|
|
.llseek = generic_file_llseek,
|
|
.read = generic_read_dir,
|
|
.iterate_shared = cramfs_readdir,
|
|
};
|
|
|
|
static const struct inode_operations cramfs_dir_inode_operations = {
|
|
.lookup = cramfs_lookup,
|
|
};
|
|
|
|
static const struct super_operations cramfs_ops = {
|
|
.statfs = cramfs_statfs,
|
|
};
|
|
|
|
static int cramfs_get_tree(struct fs_context *fc)
|
|
{
|
|
int ret = -ENOPROTOOPT;
|
|
|
|
if (IS_ENABLED(CONFIG_CRAMFS_MTD)) {
|
|
ret = get_tree_mtd(fc, cramfs_mtd_fill_super);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV))
|
|
ret = get_tree_bdev(fc, cramfs_blkdev_fill_super);
|
|
return ret;
|
|
}
|
|
|
|
static const struct fs_context_operations cramfs_context_ops = {
|
|
.get_tree = cramfs_get_tree,
|
|
.reconfigure = cramfs_reconfigure,
|
|
};
|
|
|
|
/*
|
|
* Set up the filesystem mount context.
|
|
*/
|
|
static int cramfs_init_fs_context(struct fs_context *fc)
|
|
{
|
|
fc->ops = &cramfs_context_ops;
|
|
return 0;
|
|
}
|
|
|
|
static struct file_system_type cramfs_fs_type = {
|
|
.owner = THIS_MODULE,
|
|
.name = "cramfs",
|
|
.init_fs_context = cramfs_init_fs_context,
|
|
.kill_sb = cramfs_kill_sb,
|
|
.fs_flags = FS_REQUIRES_DEV,
|
|
};
|
|
MODULE_ALIAS_FS("cramfs");
|
|
|
|
static int __init init_cramfs_fs(void)
|
|
{
|
|
int rv;
|
|
|
|
rv = cramfs_uncompress_init();
|
|
if (rv < 0)
|
|
return rv;
|
|
rv = register_filesystem(&cramfs_fs_type);
|
|
if (rv < 0)
|
|
cramfs_uncompress_exit();
|
|
return rv;
|
|
}
|
|
|
|
static void __exit exit_cramfs_fs(void)
|
|
{
|
|
cramfs_uncompress_exit();
|
|
unregister_filesystem(&cramfs_fs_type);
|
|
}
|
|
|
|
module_init(init_cramfs_fs)
|
|
module_exit(exit_cramfs_fs)
|
|
MODULE_LICENSE("GPL");
|