diff options
| -rw-r--r-- | fs/romfs/Kconfig | 24 | ||||
| -rw-r--r-- | fs/romfs/Makefile | 9 | ||||
| -rw-r--r-- | fs/romfs/inode.c | 665 | ||||
| -rw-r--r-- | fs/romfs/internal.h | 47 | ||||
| -rw-r--r-- | fs/romfs/mmap-nommu.c | 75 | ||||
| -rw-r--r-- | fs/romfs/storage.c | 261 | ||||
| -rw-r--r-- | fs/romfs/super.c | 648 |
7 files changed, 1062 insertions, 667 deletions
diff --git a/fs/romfs/Kconfig b/fs/romfs/Kconfig index 1a17020..802c742 100644 --- a/fs/romfs/Kconfig +++ b/fs/romfs/Kconfig @@ -14,3 +14,27 @@ config ROMFS_FS If you don't know whether you need it, then you don't need it: answer N. + +config ROMFS_ON_BLOCK + bool "Block device-backed ROM file system support" if (ROMFS_ON_MTD && EMBEDDED) + depends on ROMFS_FS && BLOCK + help + This permits ROMFS to use block devices buffered through the page + cache as the medium from which to retrieve data. It does not allow + direct mapping of the medium. + + If unsure, answer Y. + +config ROMFS_ON_MTD + bool "MTD-backed ROM file system support" + depends on ROMFS_FS + depends on MTD=y || (ROMFS_FS=m && MTD) + help + This permits ROMFS to use MTD based devices directly, without the + intercession of the block layer (which may have been disabled). It + also allows direct mapping of MTD devices through romfs files under + NOMMU conditions if the underlying device is directly addressable by + the CPU. + + If unsure, answer Y. + diff --git a/fs/romfs/Makefile b/fs/romfs/Makefile index c95b21c..420beb7 100644 --- a/fs/romfs/Makefile +++ b/fs/romfs/Makefile @@ -1,7 +1,12 @@ # -# Makefile for the linux romfs filesystem routines. +# Makefile for the linux RomFS filesystem routines. # obj-$(CONFIG_ROMFS_FS) += romfs.o -romfs-objs := inode.o +romfs-y := storage.o super.o + +ifneq ($(CONFIG_MMU),y) +romfs-$(CONFIG_ROMFS_ON_MTD) += mmap-nommu.o +endif + diff --git a/fs/romfs/inode.c b/fs/romfs/inode.c deleted file mode 100644 index 98a232f..0000000 --- a/fs/romfs/inode.c +++ /dev/null @@ -1,665 +0,0 @@ -/* - * ROMFS file system, Linux implementation - * - * Copyright (C) 1997-1999 Janos Farkas <chexum@shadow.banki.hu> - * - * Using parts of the minix filesystem - * Copyright (C) 1991, 1992 Linus Torvalds - * - * and parts of the affs filesystem additionally - * Copyright (C) 1993 Ray Burr - * Copyright (C) 1996 Hans-Joachim Widmaier - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version - * 2 of the License, or (at your option) any later version. - * - * Changes - * Changed for 2.1.19 modules - * Jan 1997 Initial release - * Jun 1997 2.1.43+ changes - * Proper page locking in readpage - * Changed to work with 2.1.45+ fs - * Jul 1997 Fixed follow_link - * 2.1.47 - * lookup shouldn't return -ENOENT - * from Horst von Brand: - * fail on wrong checksum - * double unlock_super was possible - * correct namelen for statfs - * spotted by Bill Hawes: - * readlink shouldn't iput() - * Jun 1998 2.1.106 from Avery Pennarun: glibc scandir() - * exposed a problem in readdir - * 2.1.107 code-freeze spellchecker run - * Aug 1998 2.1.118+ VFS changes - * Sep 1998 2.1.122 another VFS change (follow_link) - * Apr 1999 2.2.7 no more EBADF checking in - * lookup/readdir, use ERR_PTR - * Jun 1999 2.3.6 d_alloc_root use changed - * 2.3.9 clean up usage of ENOENT/negative - * dentries in lookup - * clean up page flags setting - * (error, uptodate, locking) in - * in readpage - * use init_special_inode for - * fifos/sockets (and streamline) in - * read_inode, fix _ops table order - * Aug 1999 2.3.16 __initfunc() => __init change - * Oct 1999 2.3.24 page->owner hack obsoleted - * Nov 1999 2.3.27 2.3.25+ page->offset => index change - */ - -/* todo: - * - see Documentation/filesystems/romfs.txt - * - use allocated, not stack memory for file names? - * - considering write access... - * - network (tftp) files? - * - merge back some _op tables - */ - -/* - * Sorry about some optimizations and for some goto's. I just wanted - * to squeeze some more bytes out of this code.. :) - */ - -#include <linux/module.h> -#include <linux/types.h> -#include <linux/errno.h> -#include <linux/slab.h> -#include <linux/romfs_fs.h> -#include <linux/fs.h> -#include <linux/init.h> -#include <linux/pagemap.h> -#include <linux/smp_lock.h> -#include <linux/buffer_head.h> -#include <linux/vfs.h> - -#include <asm/uaccess.h> - -struct romfs_inode_info { - unsigned long i_metasize; /* size of non-data area */ - unsigned long i_dataoffset; /* from the start of fs */ - struct inode vfs_inode; -}; - -static struct inode *romfs_iget(struct super_block *, unsigned long); - -/* instead of private superblock data */ -static inline unsigned long romfs_maxsize(struct super_block *sb) -{ - return (unsigned long)sb->s_fs_info; -} - -static inline struct romfs_inode_info *ROMFS_I(struct inode *inode) -{ - return container_of(inode, struct romfs_inode_info, vfs_inode); -} - -static __u32 -romfs_checksum(void *data, int size) -{ - __u32 sum; - __be32 *ptr; - - sum = 0; ptr = data; - size>>=2; - while (size>0) { - sum += be32_to_cpu(*ptr++); - size--; - } - return sum; -} - -static const struct super_operations romfs_ops; - -static int romfs_fill_super(struct super_block *s, void *data, int silent) -{ - struct buffer_head *bh; - struct romfs_super_block *rsb; - struct inode *root; - int sz, ret = -EINVAL; - - /* I would parse the options here, but there are none.. :) */ - - sb_set_blocksize(s, ROMBSIZE); - s->s_maxbytes = 0xFFFFFFFF; - - bh = sb_bread(s, 0); - if (!bh) { - /* XXX merge with other printk? */ - printk ("romfs: unable to read superblock\n"); - goto outnobh; - } - - rsb = (struct romfs_super_block *)bh->b_data; - sz = be32_to_cpu(rsb->size); - if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1 - || sz < ROMFH_SIZE) { - if (!silent) - printk ("VFS: Can't find a romfs filesystem on dev " - "%s.\n", s->s_id); - goto out; - } - if (romfs_checksum(rsb, min_t(int, sz, 512))) { - printk ("romfs: bad initial checksum on dev " - "%s.\n", s->s_id); - goto out; - } - - s->s_magic = ROMFS_MAGIC; - s->s_fs_info = (void *)(long)sz; - - s->s_flags |= MS_RDONLY; - - /* Find the start of the fs */ - sz = (ROMFH_SIZE + - strnlen(rsb->name, ROMFS_MAXFN) + 1 + ROMFH_PAD) - & ROMFH_MASK; - - s->s_op = &romfs_ops; - root = romfs_iget(s, sz); - if (IS_ERR(root)) { - ret = PTR_ERR(root); - goto out; - } - - ret = -ENOMEM; - s->s_root = d_alloc_root(root); - if (!s->s_root) - goto outiput; - - brelse(bh); - return 0; - -outiput: - iput(root); -out: - brelse(bh); -outnobh: - return ret; -} - -/* That's simple too. */ - -static int -romfs_statfs(struct dentry *dentry, struct kstatfs *buf) -{ - buf->f_type = ROMFS_MAGIC; - buf->f_bsize = ROMBSIZE; - buf->f_bfree = buf->f_bavail = buf->f_ffree; - buf->f_blocks = (romfs_maxsize(dentry->d_sb)+ROMBSIZE-1)>>ROMBSBITS; - buf->f_namelen = ROMFS_MAXFN; - return 0; -} - -/* some helper routines */ - -static int -romfs_strnlen(struct inode *i, unsigned long offset, unsigned long count) -{ - struct buffer_head *bh; - unsigned long avail, maxsize, res; - - maxsize = romfs_maxsize(i->i_sb); - if (offset >= maxsize) - return -1; - - /* strnlen is almost always valid */ - if (count > maxsize || offset+count > maxsize) - count = maxsize-offset; - - bh = sb_bread(i->i_sb, offset>>ROMBSBITS); - if (!bh) - return -1; /* error */ - - avail = ROMBSIZE - (offset & ROMBMASK); - maxsize = min_t(unsigned long, count, avail); - res = strnlen(((char *)bh->b_data)+(offset&ROMBMASK), maxsize); - brelse(bh); - - if (res < maxsize) - return res; /* found all of it */ - - while (res < count) { - offset += maxsize; - - bh = sb_bread(i->i_sb, offset>>ROMBSBITS); - if (!bh) - return -1; - maxsize = min_t(unsigned long, count - res, ROMBSIZE); - avail = strnlen(bh->b_data, maxsize); - res += avail; - brelse(bh); - if (avail < maxsize) - return res; - } - return res; -} - -static int -romfs_copyfrom(struct inode *i, void *dest, unsigned long offset, unsigned long count) -{ - struct buffer_head *bh; - unsigned long avail, maxsize, res; - - maxsize = romfs_maxsize(i->i_sb); - if (offset >= maxsize || count > maxsize || offset+count>maxsize) - return -1; - - bh = sb_bread(i->i_sb, offset>>ROMBSBITS); - if (!bh) - return -1; /* error */ - - avail = ROMBSIZE - (offset & ROMBMASK); - maxsize = min_t(unsigned long, count, avail); - memcpy(dest, ((char *)bh->b_data) + (offset & ROMBMASK), maxsize); - brelse(bh); - - res = maxsize; /* all of it */ - - while (res < count) { - offset += maxsize; - dest += maxsize; - - bh = sb_bread(i->i_sb, offset>>ROMBSBITS); - if (!bh) - return -1; - maxsize = min_t(unsigned long, count - res, ROMBSIZE); - memcpy(dest, bh->b_data, maxsize); - brelse(bh); - res += maxsize; - } - return res; -} - -static unsigned char romfs_dtype_table[] = { - DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_SOCK, DT_FIFO -}; - -static int -romfs_readdir(struct file *filp, void *dirent, filldir_t filldir) -{ - struct inode *i = filp->f_path.dentry->d_inode; - struct romfs_inode ri; - unsigned long offset, maxoff; - int j, ino, nextfh; - int stored = 0; - char fsname[ROMFS_MAXFN]; /* XXX dynamic? */ - - lock_kernel(); - - maxoff = romfs_maxsize(i->i_sb); - - offset = filp->f_pos; - if (!offset) { - offset = i->i_ino & ROMFH_MASK; - if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0) - goto out; - offset = be32_to_cpu(ri.spec) & ROMFH_MASK; - } - - /* Not really failsafe, but we are read-only... */ - for(;;) { - if (!offset || offset >= maxoff) { - offset = maxoff; - filp->f_pos = offset; - goto out; - } - filp->f_pos = offset; - - /* Fetch inode info */ - if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0) - goto out; - - j = romfs_strnlen(i, offset+ROMFH_SIZE, sizeof(fsname)-1); - if (j < 0) - goto out; - - fsname[j]=0; - romfs_copyfrom(i, fsname, offset+ROMFH_SIZE, j); - - ino = offset; - nextfh = be32_to_cpu(ri.next); - if ((nextfh & ROMFH_TYPE) == ROMFH_HRD) - ino = be32_to_cpu(ri.spec); - if (filldir(dirent, fsname, j, offset, ino, - romfs_dtype_table[nextfh & ROMFH_TYPE]) < 0) { - goto out; - } - stored++; - offset = nextfh & ROMFH_MASK; - } -out: - unlock_kernel(); - return stored; -} - -static struct dentry * -romfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) -{ - unsigned long offset, maxoff; - long res; - int fslen; - struct inode *inode = NULL; - char fsname[ROMFS_MAXFN]; /* XXX dynamic? */ - struct romfs_inode ri; - const char *name; /* got from dentry */ - int len; - - res = -EACCES; /* placeholder for "no data here" */ - offset = dir->i_ino & ROMFH_MASK; - lock_kernel(); - if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0) - goto error; - - maxoff = romfs_maxsize(dir->i_sb); - offset = be32_to_cpu(ri.spec) & ROMFH_MASK; - - /* OK, now find the file whose name is in "dentry" in the - * directory specified by "dir". */ - - name = dentry->d_name.name; - len = dentry->d_name.len; - - for(;;) { - if (!offset || offset >= maxoff) - goto success; /* negative success */ - if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0) - goto error; - - /* try to match the first 16 bytes of name */ - fslen = romfs_strnlen(dir, offset+ROMFH_SIZE, ROMFH_SIZE); - if (len < ROMFH_SIZE) { - if (len == fslen) { - /* both are shorter, and same size */ - romfs_copyfrom(dir, fsname, offset+ROMFH_SIZE, len+1); - if (strncmp (name, fsname, len) == 0) - break; - } - } else if (fslen >= ROMFH_SIZE) { - /* both are longer; XXX optimize max size */ - fslen = romfs_strnlen(dir, offset+ROMFH_SIZE, sizeof(fsname)-1); - if (len == fslen) { - romfs_copyfrom(dir, fsname, offset+ROMFH_SIZE, len+1); - if (strncmp(name, fsname, len) == 0) - break; - } - } - /* next entry */ - offset = be32_to_cpu(ri.next) & ROMFH_MASK; - } - - /* Hard link handling */ - if ((be32_to_cpu(ri.next) & ROMFH_TYPE) == ROMFH_HRD) - offset = be32_to_cpu(ri.spec) & ROMFH_MASK; - - inode = romfs_iget(dir->i_sb, offset); - if (IS_ERR(inode)) { - res = PTR_ERR(inode); - goto error; - } - -success: - d_add(dentry, inode); - res = 0; -error: - unlock_kernel(); - return ERR_PTR(res); -} - -/* - * Ok, we do readpage, to be able to execute programs. Unfortunately, - * we can't use bmap, since we may have looser alignments. - */ - -static int -romfs_readpage(struct file *file, struct page * page) -{ - struct inode *inode = page->mapping->host; - loff_t offset, size; - unsigned long filled; - void *buf; - int result = -EIO; - - page_cache_get(page); - lock_kernel(); - buf = kmap(page); - if (!buf) - goto err_out; - - /* 32 bit warning -- but not for us :) */ - offset = page_offset(page); - size = i_size_read(inode); - filled = 0; - result = 0; - if (offset < size) { - unsigned long readlen; - - size -= offset; - readlen = size > PAGE_SIZE ? PAGE_SIZE : size; - - filled = romfs_copyfrom(inode, buf, ROMFS_I(inode)->i_dataoffset+offset, readlen); - - if (filled != readlen) { - SetPageError(page); - filled = 0; - result = -EIO; - } - } - - if (filled < PAGE_SIZE) - memset(buf + filled, 0, PAGE_SIZE-filled); - - if (!result) - SetPageUptodate(page); - flush_dcache_page(page); - - unlock_page(page); - - kunmap(page); -err_out: - page_cache_release(page); - unlock_kernel(); - - return result; -} - -/* Mapping from our types to the kernel */ - -static const struct address_space_operations romfs_aops = { - .readpage = romfs_readpage -}; - -static const struct file_operations romfs_dir_operations = { - .read = generic_read_dir, - .readdir = romfs_readdir, -}; - -static const struct inode_operations romfs_dir_inode_operations = { - .lookup = romfs_lookup, -}; - -static mode_t romfs_modemap[] = -{ - 0, S_IFDIR+0644, S_IFREG+0644, S_IFLNK+0777, - S_IFBLK+0600, S_IFCHR+0600, S_IFSOCK+0644, S_IFIFO+0644 -}; - -static struct inode * -romfs_iget(struct super_block *sb, unsigned long ino) -{ - int nextfh, ret; - struct romfs_inode ri; - struct inode *i; - - ino &= ROMFH_MASK; - i = iget_locked(sb, ino); - if (!i) - return ERR_PTR(-ENOMEM); - if (!(i->i_state & I_NEW)) - return i; - - i->i_mode = 0; - - /* Loop for finding the real hard link */ - for(;;) { - if (romfs_copyfrom(i, &ri, ino, ROMFH_SIZE) <= 0) { - printk(KERN_ERR "romfs: read error for inode 0x%lx\n", - ino); - iget_failed(i); - return ERR_PTR(-EIO); - } - /* XXX: do romfs_checksum here too (with name) */ - - nextfh = be32_to_cpu(ri.next); - if ((nextfh & ROMFH_TYPE) != ROMFH_HRD) - break; - - ino = be32_to_cpu(ri.spec) & ROMFH_MASK; - } - - i->i_nlink = 1; /* Hard to decide.. */ - i->i_size = be32_to_cpu(ri.size); - i->i_mtime.tv_sec = i->i_atime.tv_sec = i->i_ctime.tv_sec = 0; - i->i_mtime.tv_nsec = i->i_atime.tv_nsec = i->i_ctime.tv_nsec = 0; - - /* Precalculate the data offset */ - ret = romfs_strnlen(i, ino + ROMFH_SIZE, ROMFS_MAXFN); - if (ret >= 0) - ino = (ROMFH_SIZE + ret + 1 + ROMFH_PAD) & ROMFH_MASK; - else - ino = 0; - - ROMFS_I(i)->i_metasize = ino; - ROMFS_I(i)->i_dataoffset = ino+(i->i_ino&ROMFH_MASK); - - /* Compute permissions */ - ino = romfs_modemap[nextfh & ROMFH_TYPE]; - /* only "normal" files have ops */ - switch (nextfh & ROMFH_TYPE) { - case 1: - i->i_size = ROMFS_I(i)->i_metasize; - i->i_op = &romfs_dir_inode_operations; - i->i_fop = &romfs_dir_operations; - if (nextfh & ROMFH_EXEC) - ino |= S_IXUGO; - i->i_mode = ino; - break; - case 2: - i->i_fop = &generic_ro_fops; - i->i_data.a_ops = &romfs_aops; - if (nextfh & ROMFH_EXEC) - ino |= S_IXUGO; - i->i_mode = ino; - break; - case 3: - i->i_op = &page_symlink_inode_operations; - i->i_data.a_ops = &romfs_aops; - i->i_mode = ino | S_IRWXUGO; - break; - default: - /* depending on MBZ for sock/fifos */ - nextfh = be32_to_cpu(ri.spec); - init_special_inode(i, ino, - MKDEV(nextfh>>16,nextfh&0xffff)); - } - unlock_new_inode(i); - return i; -} - -static struct kmem_cache * romfs_inode_cachep; - -static struct inode *romfs_alloc_inode(struct super_block *sb) -{ - struct romfs_inode_info *ei; - ei = kmem_cache_alloc(romfs_inode_cachep, GFP_KERNEL); - if (!ei) - return NULL; - return &ei->vfs_inode; -} - -static void romfs_destroy_inode(struct inode *inode) -{ - kmem_cache_free(romfs_inode_cachep, ROMFS_I(inode)); -} - -static void init_once(void *foo) -{ - struct romfs_inode_info *ei = foo; - - inode_init_once(&ei->vfs_inode); -} - -static int init_inodecache(void) -{ - romfs_inode_cachep = kmem_cache_create("romfs_inode_cache", - sizeof(struct romfs_inode_info), - 0, (SLAB_RECLAIM_ACCOUNT| - SLAB_MEM_SPREAD), - init_once); - if (romfs_inode_cachep == NULL) - return -ENOMEM; - return 0; -} - -static void destroy_inodecache(void) -{ - kmem_cache_destroy(romfs_inode_cachep); -} - -static int romfs_remount(struct super_block *sb, int *flags, char *data) -{ - *flags |= MS_RDONLY; - return 0; -} - -static const struct super_operations romfs_ops = { - .alloc_inode = romfs_alloc_inode, - .destroy_inode = romfs_destroy_inode, - .statfs = romfs_statfs, - .remount_fs = romfs_remount, -}; - -static int romfs_get_sb(struct file_system_type *fs_type, - int flags, const char *dev_name, void *data, struct vfsmount *mnt) -{ - return get_sb_bdev(fs_type, flags, dev_name, data, romfs_fill_super, - mnt); -} - -static struct file_system_type romfs_fs_type = { - .owner = THIS_MODULE, - .name = "romfs", - .get_sb = romfs_get_sb, - .kill_sb = kill_block_super, - .fs_flags = FS_REQUIRES_DEV, -}; - -static int __init init_romfs_fs(void) -{ - int err = init_inodecache(); - if (err) - goto out1; - err = register_filesystem(&romfs_fs_type); - if (err) - goto out; - return 0; -out: - destroy_inodecache(); -out1: - return err; -} - -static void __exit exit_romfs_fs(void) -{ - unregister_filesystem(&romfs_fs_type); - destroy_inodecache(); -} - -/* Yes, works even as a module... :) */ - -module_init(init_romfs_fs) -module_exit(exit_romfs_fs) -MODULE_LICENSE("GPL"); diff --git a/fs/romfs/internal.h b/fs/romfs/internal.h new file mode 100644 index 0000000..06044a9 --- /dev/null +++ b/fs/romfs/internal.h @@ -0,0 +1,47 @@ +/* RomFS internal definitions + * + * Copyright © 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/romfs_fs.h> + +struct romfs_inode_info { + struct inode vfs_inode; + unsigned long i_metasize; /* size of non-data area */ + unsigned long i_dataoffset; /* from the start of fs */ +}; + +static inline size_t romfs_maxsize(struct super_block *sb) +{ + return (size_t) (unsigned long) sb->s_fs_info; +} + +static inline struct romfs_inode_info *ROMFS_I(struct inode *inode) +{ + return container_of(inode, struct romfs_inode_info, vfs_inode); +} + +/* + * mmap-nommu.c + */ +#if !defined(CONFIG_MMU) && defined(CONFIG_ROMFS_ON_MTD) +extern const struct file_operations romfs_ro_fops; +#else +#define romfs_ro_fops generic_ro_fops +#endif + +/* + * storage.c + */ +extern int romfs_dev_read(struct super_block *sb, unsigned long pos, + void *buf, size_t buflen); +extern ssize_t romfs_dev_strnlen(struct super_block *sb, + unsigned long pos, size_t maxlen); +extern int romfs_dev_strncmp(struct super_block *sb, unsigned long pos, + const char *str, size_t size); diff --git a/fs/romfs/mmap-nommu.c b/fs/romfs/mmap-nommu.c new file mode 100644 index 0000000..f0511e8 --- /dev/null +++ b/fs/romfs/mmap-nommu.c @@ -0,0 +1,75 @@ +/* NOMMU mmap support for RomFS on MTD devices + * + * Copyright © 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/mm.h> +#include <linux/mtd/super.h> +#include "internal.h" + +/* + * try to determine where a shared mapping can be made + * - only supported for NOMMU at the moment (MMU can't doesn't copy private + * mappings) + * - attempts to map through to the underlying MTD device + */ +static unsigned long romfs_get_unmapped_area(struct file *file, + unsigned long addr, + unsigned long len, + unsigned long pgoff, + unsigned long flags) +{ + struct inode *inode = file->f_mapping->host; + struct mtd_info *mtd = inode->i_sb->s_mtd; + unsigned long isize, offset; + + if (!mtd) + goto cant_map_directly; + + isize = i_size_read(inode); + offset = pgoff << PAGE_SHIFT; + if (offset > isize || len > isize || offset > isize - len) + return (unsigned long) -EINVAL; + + /* we need to call down to the MTD layer to do the actual mapping */ + if (mtd->get_unmapped_area) { + if (addr != 0) + return (unsigned long) -EINVAL; + + if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT)) + return (unsigned long) -EINVAL; + + offset += ROMFS_I(inode)->i_dataoffset; + if (offset > mtd->size - len) + return (unsigned long) -EINVAL; + + return mtd->get_unmapped_area(mtd, len, offset, flags); + } + +cant_map_directly: + return (unsigned long) -ENOSYS; +} + +/* + * permit a R/O mapping to be made directly through onto an MTD device if + * possible + */ +static int romfs_mmap(struct file *file, struct vm_area_struct *vma) +{ + return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -ENOSYS; +} + +const struct file_operations romfs_ro_fops = { + .llseek = generic_file_llseek, + .read = do_sync_read, + .aio_read = generic_file_aio_read, + .splice_read = generic_file_splice_read, + .mmap = romfs_mmap, + .get_unmapped_area = romfs_get_unmapped_area, +}; diff --git a/fs/romfs/storage.c b/fs/romfs/storage.c new file mode 100644 index 0000000..7e3e1e1 --- /dev/null +++ b/fs/romfs/storage.c @@ -0,0 +1,261 @@ +/* RomFS storage access routines + * + * Copyright © 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/fs.h> +#include <linux/mtd/super.h> +#include <linux/buffer_head.h> +#include "internal.h" + +#if !defined(CONFIG_ROMFS_ON_MTD) && !defined(CONFIG_ROMFS_ON_BLOCK) +#error no ROMFS backing store interface configured +#endif + +#ifdef CONFIG_ROMFS_ON_MTD +#define ROMFS_MTD_READ(sb, ...) ((sb)->s_mtd->read((sb)->s_mtd, ##__VA_ARGS__)) + +/* + * read data from an romfs image on an MTD device + */ +static int romfs_mtd_read(struct super_block *sb, unsigned long pos, + void *buf, size_t buflen) +{ + size_t rlen; + int ret; + + ret = ROMFS_MTD_READ(sb, pos, buflen, &rlen, buf); + return (ret < 0 || rlen != buflen) ? -EIO : 0; +} + +/* + * determine the length of a string in a romfs image on an MTD device + */ +static ssize_t romfs_mtd_strnlen(struct super_block *sb, + unsigned long pos, size_t maxlen) +{ + ssize_t n = 0; + size_t segment; + u_char buf[16], *p; + size_t len; + int ret; + + /* scan the string up to 16 bytes at a time */ + while (maxlen > 0) { + segment = min_t(size_t, maxlen, 16); + ret = ROMFS_MTD_READ(sb, pos, segment, &len, buf); + if (ret < 0) + return ret; + p = memchr(buf, 0, len); + if (p) + return n + (p - buf); + maxlen -= len; + pos += len; + n += len; + } + + return n; +} + +/* + * compare a string to one in a romfs image on MTD + * - return 1 if matched, 0 if differ, -ve if error + */ +static int romfs_mtd_strncmp(struct super_block *sb, unsigned long pos, + const char *str, size_t size) +{ + u_char buf[16]; + size_t len, segment; + int ret; + + /* scan the string up to 16 bytes at a time */ + while (size > 0) { + segment = min_t(size_t, size, 16); + ret = ROMFS_MTD_READ(sb, pos, segment, &len, buf); + if (ret < 0) + return ret; + if (memcmp(buf, str, len) != 0) + return 0; + size -= len; + pos += len; + str += len; + } + + return 1; +} +#endif /* CONFIG_ROMFS_ON_MTD */ + +#ifdef CONFIG_ROMFS_ON_BLOCK +/* + * read data from an romfs image on a block device + */ +static int romfs_blk_read(struct super_block *sb, unsigned long pos, + void *buf, size_t buflen) +{ + struct buffer_head *bh; + unsigned long offset; + size_t segment; + + /* copy the string up to blocksize bytes at a time */ + while (buflen > 0) { + offset = pos & (ROMBSIZE - 1); + segment = min_t(size_t, buflen, ROMBSIZE - offset); + bh = sb_bread(sb, pos >> ROMBSBITS); + if (!bh) + return -EIO; + memcpy(buf, bh->b_data + offset, segment); + brelse(bh); + buflen -= segment; + pos += segment; + } + + return 0; +} + +/* + * determine the length of a string in romfs on a block device + */ +static ssize_t romfs_blk_strnlen(struct super_block *sb, + unsigned long pos, size_t limit) +{ + struct buffer_head *bh; + unsigned long offset; + ssize_t n = 0; + size_t segment; + u_char *buf, *p; + + /* scan the string up to blocksize bytes at a time */ + while (limit > 0) { + offset = pos & (ROMBSIZE - 1); + segment = min_t(size_t, limit, ROMBSIZE - offset); + bh = sb_bread(sb, pos >> ROMBSBITS); + if (!bh) + return -EIO; + buf = bh->b_data + offset; + p = memchr(buf, 0, segment); + brelse(bh); + if (p) + return n + (p - buf); + limit -= segment; + pos += segment; + n += segment; + } + + return n; +} + +/* + * compare a string to one in a romfs image on a block device + * - return 1 if matched, 0 if differ, -ve if error + */ +static int romfs_blk_strncmp(struct super_block *sb, unsigned long pos, + const char *str, size_t size) +{ + struct buffer_head *bh; + unsigned long offset; + size_t segment; + bool x; + + /* scan the string up to 16 bytes at a time */ + while (size > 0) { + offset = pos & (ROMBSIZE - 1); + segment = min_t(size_t, size, ROMBSIZE - offset); + bh = sb_bread(sb, pos >> ROMBSBITS); + if (!bh) + return -EIO; + x = (memcmp(bh->b_data + offset, str, segment) != 0); + brelse(bh); + if (x) + return 0; + size -= segment; + pos += segment; + str += segment; + } + + return 1; +} +#endif /* CONFIG_ROMFS_ON_BLOCK */ + +/* + * read data from the romfs image + */ +int romfs_dev_read(struct super_block *sb, unsigned long pos, + void *buf, size_t buflen) +{ + size_t limit; + + limit = romfs_maxsize(sb); + if (pos >= limit) + return -EIO; + if (buflen > limit - pos) + buflen = limit - pos; + +#ifdef CONFIG_ROMFS_ON_MTD + if (sb->s_mtd) + return romfs_mtd_read(sb, pos, buf, buflen); +#endif +#ifdef CONFIG_ROMFS_ON_BLOCK + if (sb->s_bdev) + return romfs_blk_read(sb, pos, buf, buflen); +#endif + return -EIO; +} + +/* + * determine the length of a string in romfs + */ +ssize_t romfs_dev_strnlen(struct super_block *sb, + unsigned long pos, size_t maxlen) +{ + size_t limit; + + limit = romfs_maxsize(sb); + if (pos >= limit) + return -EIO; + if (maxlen > limit - pos) + maxlen = limit - pos; + +#ifdef CONFIG_ROMFS_ON_MTD + if (sb->s_mtd) + return romfs_mtd_strnlen(sb, pos, limit); +#endif +#ifdef CONFIG_ROMFS_ON_BLOCK + if (sb->s_bdev) + return romfs_blk_strnlen(sb, pos, limit); +#endif + return -EIO; +} + +/* + * compare a string to one in romfs + * - return 1 if matched, 0 if differ, -ve if error + */ +int romfs_dev_strncmp(struct super_block *sb, unsigned long pos, + const char *str, size_t size) +{ + size_t limit; + + limit = romfs_maxsize(sb); + if (pos >= limit) + return -EIO; + if (size > ROMFS_MAXFN) + return -ENAMETOOLONG; + if (size > limit - pos) + return -EIO; + +#ifdef CONFIG_ROMFS_ON_MTD + if (sb->s_mtd) + return romfs_mtd_strncmp(sb, pos, str, size); +#endif +#ifdef CONFIG_ROMFS_ON_BLOCK + if (sb->s_bdev) + return romfs_blk_strncmp(sb, pos, str, size); +#endif + return -EIO; +} diff --git a/fs/romfs/super.c b/fs/romfs/super.c new file mode 100644 index 0000000..1e548a4 --- /dev/null +++ b/fs/romfs/super.c @@ -0,0 +1,648 @@ +/* Block- or MTD-based romfs + * + * Copyright © 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * Derived from: ROMFS file system, Linux implementation + * + * Copyright © 1997-1999 Janos Farkas <chexum@shadow.banki.hu> + * + * Using parts of the minix filesystem + * Copyright © 1991, 1992 Linus Torvalds + * + * and parts of the affs filesystem additionally + * Copyright © 1993 Ray Burr + * Copyright © 1996 Hans-Joachim Widmaier + * + * Changes + * Changed for 2.1.19 modules + * Jan 1997 Initial release + * Jun 1997 2.1.43+ changes + * Proper page locking in readpage + * Changed to work with 2.1.45+ fs + * Jul 1997 Fixed follow_link + * 2.1.47 + * lookup shouldn't return -ENOENT + * from Horst von Brand: + * fail on wrong checksum + * double unlock_super was possible + * correct namelen for statfs + * spotted by Bill Hawes: + * readlink shouldn't iput() + * Jun 1998 2.1.106 from Avery Pennarun: glibc scandir() + * exposed a problem in readdir + * 2.1.107 code-freeze spellchecker run + * Aug 1998 2.1.118+ VFS changes + * Sep 1998 2.1.122 another VFS change (follow_link) + * Apr 1999 2.2.7 no more EBADF checking in + * lookup/readdir, use ERR_PTR + * Jun 1999 2.3.6 d_alloc_root use changed + * 2.3.9 clean up usage of ENOENT/negative + * dentries in lookup + * clean up page flags setting + * (error, uptodate, locking) in + * in readpage + * use init_special_inode for + * fifos/sockets (and streamline) in + * read_inode, fix _ops table order + * Aug 1999 2.3.16 __initfunc() => __init change + * Oct 1999 2.3.24 page->owner hack obsoleted + * Nov 1999 2.3.27 2.3.25+ page->offset => index change + * + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/string.h> +#include <linux/fs.h> +#include <linux/time.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/blkdev.h> +#include <linux/parser.h> +#include <linux/mount.h> +#include <linux/namei.h> +#include <linux/statfs.h> +#include <linux/mtd/super.h> +#include <linux/ctype.h> +#include <linux/highmem.h> +#include <linux/pagemap.h> +#include <linux/uaccess.h> +#include "internal.h" + +static struct kmem_cache *romfs_inode_cachep; + +static const umode_t romfs_modemap[8] = { + 0, /* hard link */ + S_IFDIR | 0644, /* directory */ + S_IFREG | 0644, /* regular file */ + S_IFLNK | 0777, /* symlink */ + S_IFBLK | 0600, /* blockdev */ + S_IFCHR | 0600, /* chardev */ + S_IFSOCK | 0644, /* socket */ + S_IFIFO | 0644 /* FIFO */ +}; + +static const unsigned char romfs_dtype_table[] = { + DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_SOCK, DT_FIFO +}; + +static struct inode *romfs_iget(struct super_block *sb, unsigned long pos); + +/* + * read a page worth of data from the image + */ +static int romfs_readpage(struct file *file, struct page *page) +{ + struct inode *inode = page->mapping->host; + loff_t offset, size; + unsigned long fillsize, pos; + void *buf; + int ret; + + buf = kmap(page); + if (!buf) + return -ENOMEM; + + /* 32 bit warning -- but not for us :) */ + offset = page_offset(page); + size = i_size_read(inode); + fillsize = 0; + ret = 0; + if (offset < size) { + size -= offset; + fillsize = size > PAGE_SIZE ? PAGE_SIZE : size; + + pos = ROMFS_I(inode)->i_dataoffset + offset; + + ret = romfs_dev_read(inode->i_sb, pos, buf, fillsize); + if (ret < 0) { + SetPageError(page); + fillsize = 0; + ret = -EIO; + } + } + + if (fillsize < PAGE_SIZE) + memset(buf + fillsize, 0, PAGE_SIZE - fillsize); + if (ret == 0) + SetPageUptodate(page); + + flush_dcache_page(page); + kunmap(page); + unlock_page(page); + return ret; +} + +static const struct address_space_operations romfs_aops = { + .readpage = romfs_readpage +}; + +/* + * read the entries from a directory + */ +static int romfs_readdir(struct file *filp, void *dirent, filldir_t filldir) +{ + struct inode *i = filp->f_dentry->d_inode; + struct romfs_inode ri; + unsigned long offset, maxoff; + int j, ino, nextfh; + int stored = 0; + char fsname[ROMFS_MAXFN]; /* XXX dynamic? */ + int ret; + + maxoff = romfs_maxsize(i->i_sb); + + offset = filp->f_pos; + if (!offset) { + offset = i->i_ino & ROMFH_MASK; + ret = romfs_dev_read(i->i_sb, offset, &ri, ROMFH_SIZE); + if (ret < 0) + goto out; + offset = be32_to_cpu(ri.spec) & ROMFH_MASK; + } + + /* Not really failsafe, but we are read-only... */ + for (;;) { + if (!offset || offset >= maxoff) { + offset = maxoff; + filp->f_pos = offset; + goto out; + } + filp->f_pos = offset; + + /* Fetch inode info */ + ret = romfs_dev_read(i->i_sb, offset, &ri, ROMFH_SIZE); + if (ret < 0) + goto out; + + j = romfs_dev_strnlen(i->i_sb, offset + ROMFH_SIZE, + sizeof(fsname) - 1); + if (j < 0) + goto out; + + ret = romfs_dev_read(i->i_sb, offset + ROMFH_SIZE, fsname, j); + if (ret < 0) + goto out; + fsname[j] = '\0'; + + ino = offset; + nextfh = be32_to_cpu(ri.next); + if ((nextfh & ROMFH_TYPE) == ROMFH_HRD) + ino = be32_to_cpu(ri.spec); + if (filldir(dirent, fsname, j, offset, ino, + romfs_dtype_table[nextfh & ROMFH_TYPE]) < 0) + goto out; + + stored++; + offset = nextfh & ROMFH_MASK; + } + +out: + return stored; +} + +/* + * look up an entry in a directory + */ +static struct dentry *romfs_lookup(struct inode *dir, struct dentry *dentry, + struct nameidata *nd) +{ + unsigned long offset, maxoff; + struct inode *inode; + struct romfs_inode ri; + const char *name; /* got from dentry */ + int len, ret; + + offset = dir->i_ino & ROMFH_MASK; + ret = romfs_dev_read(dir->i_sb, offset, &ri, ROMFH_SIZE); + if (ret < 0) + goto error; + + /* search all the file entries in the list starting from the one + * pointed to by the directory's special data */ + maxoff = romfs_maxsize(dir->i_sb); + offset = be32_to_cpu(ri.spec) & ROMFH_MASK; + + name = dentry->d_name.name; + len = dentry->d_name.len; + + for (;;) { + if (!offset || offset >= maxoff) + goto out0; + + ret = romfs_dev_read(dir->i_sb, offset, &ri, sizeof(ri)); + if (ret < 0) + goto error; + + /* try to match the first 16 bytes of name */ + ret = romfs_dev_strncmp(dir->i_sb, offset + ROMFH_SIZE, name, + len); + if (ret < 0) + goto error; + if (ret == 1) + break; + + /* next entry */ + offset = be32_to_cpu(ri.next) & ROMFH_MASK; + } + + /* Hard link handling */ + if ((be32_to_cpu(ri.next) & ROMFH_TYPE) == ROMFH_HRD) + offset = be32_to_cpu(ri.spec) & ROMFH_MASK; + + inode = romfs_iget(dir->i_sb, offset); + if (IS_ERR(inode)) { + ret = PTR_ERR(inode); + goto error; + } + goto outi; + + /* + * it's a bit funky, _lookup needs to return an error code + * (negative) or a NULL, both as a dentry. ENOENT should not + * be returned, instead we need to create a negative dentry by + * d_add(dentry, NULL); and return 0 as no error. + * (Although as I see, it only matters on writable file + * systems). + */ +out0: + inode = NULL; +outi: + d_add(dentry, inode); + ret = 0; +error: + return ERR_PTR(ret); +} + +static const struct file_operations romfs_dir_operations = { + .read = generic_read_dir, + .readdir = romfs_readdir, +}; + +static struct inode_operations romfs_dir_inode_operations = { + .lookup = romfs_lookup, +}; + +/* + * get a romfs inode based on its position in the image (which doubles as the + * inode number) + */ +static struct inode *romfs_iget(struct super_block *sb, unsigned long pos) +{ + struct romfs_inode_info *inode; + struct romfs_inode ri; + struct inode *i; + unsigned long nlen; + unsigned nextfh, ret; + umode_t mode; + + /* we might have to traverse a chain of "hard link" file entries to get + * to the actual file */ + for (;;) { + ret = romfs_dev_read(sb, pos, &ri, sizeof(ri)); + if (ret < 0) + goto error; + + /* XXX: do romfs_checksum here too (with name) */ + + nextfh = be32_to_cpu(ri.next); + if ((nextfh & ROMFH_TYPE) != ROMFH_HRD) + break; + + pos = be32_to_cpu(ri.spec) & ROMFH_MASK; + } + + /* determine the length of the filename */ + nlen = romfs_dev_strnlen(sb, pos + ROMFH_SIZE, ROMFS_MAXFN); + if (IS_ERR_VALUE(nlen)) + goto eio; + + /* get an inode for this image position */ + i = iget_locked(sb, pos); + if (!i) + return ERR_PTR(-ENOMEM); + + if (!(i->i_state & I_NEW)) + return i; + + /* precalculate the data offset */ + inode = ROMFS_I(i); + inode->i_metasize = (ROMFH_SIZE + nlen + 1 + ROMFH_PAD) & ROMFH_MASK; + inode->i_dataoffset = pos + inode->i_metasize; + + i->i_nlink = 1; /* Hard to decide.. */ + i->i_size = be32_to_cpu(ri.size); + i->i_mtime.tv_sec = i->i_atime.tv_sec = i->i_ctime.tv_sec = 0; + i->i_mtime.tv_nsec = i->i_atime.tv_nsec = i->i_ctime.tv_nsec = 0; + + /* set up mode and ops */ + mode = romfs_modemap[nextfh & ROMFH_TYPE]; + + switch (nextfh & ROMFH_TYPE) { + case ROMFH_DIR: + i->i_size = ROMFS_I(i)->i_metasize; + i->i_op = &romfs_dir_inode_operations; + i->i_fop = &romfs_dir_operations; + if (nextfh & ROMFH_EXEC) + mode |= S_IXUGO; + break; + case ROMFH_REG: + i->i_fop = &romfs_ro_fops; + i->i_data.a_ops = &romfs_aops; + if (i->i_sb->s_mtd) + i->i_data.backing_dev_info = + i->i_sb->s_mtd->backing_dev_info; + if (nextfh & ROMFH_EXEC) + mode |= S_IXUGO; + break; + case ROMFH_SYM: + i->i_op = &page_symlink_inode_operations; + i->i_data.a_ops = &romfs_aops; + mode |= S_IRWXUGO; + break; + default: + /* depending on MBZ for sock/fifos */ + nextfh = be32_to_cpu(ri.spec); + init_special_inode(i, mode, MKDEV(nextfh >> 16, + nextfh & 0xffff)); + break; + } + + i->i_mode = mode; + + unlock_new_inode(i); + return i; + +eio: + ret = -EIO; +error: + printk(KERN_ERR "ROMFS: read error for inode 0x%lx\n", pos); + return ERR_PTR(ret); +} + +/* + * allocate a new inode + */ +static struct inode *romfs_alloc_inode(struct super_block *sb) +{ + struct romfs_inode_info *inode; + inode = kmem_cache_alloc(romfs_inode_cachep, GFP_KERNEL); + return inode ? &inode->vfs_inode : NULL; +} + +/* + * return a spent inode to the slab cache + */ +static void romfs_destroy_inode(struct inode *inode) +{ + kmem_cache_free(romfs_inode_cachep, ROMFS_I(inode)); +} + +/* + * get filesystem statistics + */ +static int romfs_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + buf->f_type = ROMFS_MAGIC; + buf->f_namelen = ROMFS_MAXFN; + buf->f_bsize = ROMBSIZE; + buf->f_bfree = buf->f_bavail = buf->f_ffree; + buf->f_blocks = + (romfs_maxsize(dentry->d_sb) + ROMBSIZE - 1) >> ROMBSBITS; + return 0; +} + +/* + * remounting must involve read-only + */ +static int romfs_remount(struct super_block *sb, int *flags, char *data) +{ + *flags |= MS_RDONLY; + return 0; +} + +static const struct super_operations romfs_super_ops = { + .alloc_inode = romfs_alloc_inode, + .destroy_inode = romfs_destroy_inode, + .statfs = romfs_statfs, + .remount_fs = romfs_remount, +}; + +/* + * checksum check on part of a romfs filesystem + */ +static __u32 romfs_checksum(const void *data, int size) +{ + const __be32 *ptr = data; + __u32 sum; + + sum = 0; + size >>= 2; + while (size > 0) { + sum += be32_to_cpu(*ptr++); + size--; + } + return sum; +} + +/* + * fill in the superblock + */ +static int romfs_fill_super(struct super_block *sb, void *data, int silent) +{ + struct romfs_super_block *rsb; + struct inode *root; + unsigned long pos, img_size; + const char *storage; + size_t len; + int ret; + +#ifdef CONFIG_BLOCK + if (!sb->s_mtd) { + sb_set_blocksize(sb, ROMBSIZE); + } else { + sb->s_blocksize = ROMBSIZE; + sb->s_blocksize_bits = blksize_bits(ROMBSIZE); + } +#endif + + sb->s_maxbytes = 0xFFFFFFFF; + sb->s_magic = ROMFS_MAGIC; + sb->s_flags |= MS_RDONLY | MS_NOATIME; + sb->s_op = &romfs_super_ops; + + /* read the image superblock and check it */ + rsb = kmalloc(512, GFP_KERNEL); + if (!rsb) + return -ENOMEM; + + sb->s_fs_info = (void *) 512; + ret = romfs_dev_read(sb, 0, rsb, 512); + if (ret < 0) + goto error_rsb; + + img_size = be32_to_cpu(rsb->size); + + if (sb->s_mtd && img_size > sb->s_mtd->size) + goto error_rsb_inval; + + sb->s_fs_info = (void *) img_size; + + if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1 || + img_size < ROMFH_SIZE) { + if (!silent) + printk(KERN_WARNING "VFS:" + " Can't find a romfs filesystem on dev %s.\n", + sb->s_id); + goto error_rsb_inval; + } + + if (romfs_checksum(rsb, min_t(size_t, img_size, 512))) { + printk(KERN_ERR "ROMFS: bad initial checksum on dev %s.\n", + sb->s_id); + goto error_rsb_inval; + } + + storage = sb->s_mtd ? "MTD" : "the block layer"; + + len = strnlen(rsb->name, ROMFS_MAXFN); + if (!silent) + printk(KERN_NOTICE "ROMFS: Mounting image '%*.*s' through %s\n", + (unsigned) len, (unsigned) len, rsb->name, storage); + + kfree(rsb); + rsb = NULL; + + /* find the root directory */ + pos = (ROMFH_SIZE + len + 1 + ROMFH_PAD) & ROMFH_MASK; + + root = romfs_iget(sb, pos); + if (!root) + goto error; + + sb->s_root = d_alloc_root(root); + if (!sb->s_root) + goto error_i; + + return 0; + +error_i: + iput(root); +error: + return -EINVAL; +error_rsb_inval: + ret = -EINVAL; +error_rsb: + return ret; +} + +/* + * get a superblock for mounting + */ +static int romfs_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, + void *data, struct vfsmount *mnt) +{ + int ret = -EINVAL; + +#ifdef CONFIG_ROMFS_ON_MTD + ret = get_sb_mtd(fs_type, flags, dev_name, data, romfs_fill_super, + mnt); +#endif +#ifdef CONFIG_ROMFS_ON_BLOCK + if (ret == -EINVAL) + ret = get_sb_bdev(fs_type, flags, dev_name, data, + romfs_fill_super, mnt); +#endif + return ret; +} + +/* + * destroy a romfs superblock in the appropriate manner + */ +static void romfs_kill_sb(struct super_block *sb) +{ +#ifdef CONFIG_ROMFS_ON_MTD + if (sb->s_mtd) { + kill_mtd_super(sb); + return; + } +#endif +#ifdef CONFIG_ROMFS_ON_BLOCK + if (sb->s_bdev) { + kill_block_super(sb); + return; + } +#endif +} + +static struct file_system_type romfs_fs_type = { + .owner = THIS_MODULE, + .name = "romfs", + .get_sb = romfs_get_sb, + .kill_sb = romfs_kill_sb, + .fs_flags = FS_REQUIRES_DEV, +}; + +/* + * inode storage initialiser + */ +static void romfs_i_init_once(void *_inode) +{ + struct romfs_inode_info *inode = _inode; + + inode_init_once(&inode->vfs_inode); +} + +/* + * romfs module initialisation + */ +static int __init init_romfs_fs(void) +{ + int ret; + + printk(KERN_INFO "ROMFS MTD (C) 2007 Red Hat, Inc.\n"); + + romfs_inode_cachep = + kmem_cache_create("romfs_i", + sizeof(struct romfs_inode_info), 0, + SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, + romfs_i_init_once); + + if (!romfs_inode_cachep) { + printk(KERN_ERR + "ROMFS error: Failed to initialise inode cache\n"); + return -ENOMEM; + } + ret = register_filesystem(&romfs_fs_type); + if (ret) { + printk(KERN_ERR "ROMFS error: Failed to register filesystem\n"); + goto error_register; + } + return 0; + +error_register: + kmem_cache_destroy(romfs_inode_cachep); + return ret; +} + +/* + * romfs module removal + */ +static void __exit exit_romfs_fs(void) +{ + unregister_filesystem(&romfs_fs_type); + kmem_cache_destroy(romfs_inode_cachep); +} + +module_init(init_romfs_fs); +module_exit(exit_romfs_fs); + +MODULE_DESCRIPTION("Direct-MTD Capable RomFS"); +MODULE_AUTHOR("Red Hat, Inc."); +MODULE_LICENSE("GPL"); /* Actually dual-licensed, but it doesn't matter for */ |