Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=acaebfd8a7af0019b2edfcf4045c56c3e18375c5
Commit:     acaebfd8a7af0019b2edfcf4045c56c3e18375c5
Parent:     33672f72b24191fb17c3666ec1c620f3fa617b50
Author:     David Howells <[EMAIL PROTECTED]>
AuthorDate: Thu May 10 22:51:50 2007 -0700
Committer:  David Woodhouse <[EMAIL PROTECTED]>
CommitDate: Fri May 11 12:14:15 2007 +0100

    [MTD] generalise the handling of MTD-specific superblocks
    
    Generalise the handling of MTD-specific superblocks so that JFFS2 and ROMFS
    can both share it.
    
    Signed-off-by: David Howells <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: David Woodhouse <[EMAIL PROTECTED]>
---
 drivers/mtd/Makefile      |    3 +-
 drivers/mtd/mtdsuper.c    |  232 +++++++++++++++++++++++++++++++++++++++++++++
 fs/jffs2/super.c          |  194 ++++----------------------------------
 include/linux/fs.h        |    1 +
 include/linux/mtd/super.h |   30 ++++++
 5 files changed, 283 insertions(+), 177 deletions(-)

diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index 9205540..451adcc 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -1,10 +1,9 @@
 #
 # Makefile for the memory technology device drivers.
 #
-# $Id: Makefile.common,v 1.7 2005/07/11 10:39:27 gleixner Exp $
 
 # Core functionality.
-mtd-y                          := mtdcore.o
+mtd-y                          := mtdcore.o mtdsuper.o
 mtd-$(CONFIG_MTD_PARTITIONS)   += mtdpart.o
 obj-$(CONFIG_MTD)              += $(mtd-y)
 
diff --git a/drivers/mtd/mtdsuper.c b/drivers/mtd/mtdsuper.c
new file mode 100644
index 0000000..a279540
--- /dev/null
+++ b/drivers/mtd/mtdsuper.c
@@ -0,0 +1,232 @@
+/* MTD-based superblock management
+ *
+ * Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved.
+ * Written by:  David Howells <[EMAIL PROTECTED]>
+ *              David Woodhouse <[EMAIL PROTECTED]>
+ *
+ * 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/mtd/super.h>
+#include <linux/namei.h>
+#include <linux/ctype.h>
+
+/*
+ * compare superblocks to see if they're equivalent
+ * - they are if the underlying MTD device is the same
+ */
+static int get_sb_mtd_compare(struct super_block *sb, void *_mtd)
+{
+       struct mtd_info *mtd = _mtd;
+
+       if (sb->s_mtd == mtd) {
+               DEBUG(2, "MTDSB: Match on device %d (\"%s\")\n",
+                     mtd->index, mtd->name);
+               return 1;
+       }
+
+       DEBUG(2, "MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n",
+             sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name);
+       return 0;
+}
+
+/*
+ * mark the superblock by the MTD device it is using
+ * - set the device number to be the correct MTD block device for pesuperstence
+ *   of NFS exports
+ */
+static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
+{
+       struct mtd_info *mtd = _mtd;
+
+       sb->s_mtd = mtd;
+       sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
+       return 0;
+}
+
+/*
+ * get a superblock on an MTD-backed filesystem
+ */
+static int get_sb_mtd_aux(struct file_system_type *fs_type, int flags,
+                         const char *dev_name, void *data,
+                         struct mtd_info *mtd,
+                         int (*fill_super)(struct super_block *, void *, int),
+                         struct vfsmount *mnt)
+{
+       struct super_block *sb;
+       int ret;
+
+       sb = sget(fs_type, get_sb_mtd_compare, get_sb_mtd_set, mtd);
+       if (IS_ERR(sb))
+               goto out_error;
+
+       if (sb->s_root)
+               goto already_mounted;
+
+       /* fresh new superblock */
+       DEBUG(1, "MTDSB: New superblock for device %d (\"%s\")\n",
+             mtd->index, mtd->name);
+
+       ret = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
+       if (ret < 0) {
+               up_write(&sb->s_umount);
+               deactivate_super(sb);
+               return ret;
+       }
+
+       /* go */
+       sb->s_flags |= MS_ACTIVE;
+       return simple_set_mnt(mnt, sb);
+
+       /* new mountpoint for an already mounted superblock */
+already_mounted:
+       DEBUG(1, "MTDSB: Device %d (\"%s\") is already mounted\n",
+             mtd->index, mtd->name);
+       ret = simple_set_mnt(mnt, sb);
+       goto out_put;
+
+out_error:
+       ret = PTR_ERR(sb);
+out_put:
+       put_mtd_device(mtd);
+       return ret;
+}
+
+/*
+ * get a superblock on an MTD-backed filesystem by MTD device number
+ */
+static int get_sb_mtd_nr(struct file_system_type *fs_type, int flags,
+                        const char *dev_name, void *data, int mtdnr,
+                        int (*fill_super)(struct super_block *, void *, int),
+                        struct vfsmount *mnt)
+{
+       struct mtd_info *mtd;
+
+       mtd = get_mtd_device(NULL, mtdnr);
+       if (!mtd) {
+               DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
+               return -EINVAL;
+       }
+
+       return get_sb_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super,
+                             mnt);
+}
+
+/*
+ * set up an MTD-based superblock
+ */
+int get_sb_mtd(struct file_system_type *fs_type, int flags,
+              const char *dev_name, void *data,
+              int (*fill_super)(struct super_block *, void *, int),
+              struct vfsmount *mnt)
+{
+       struct nameidata nd;
+       int mtdnr, ret;
+
+       if (!dev_name)
+               return -EINVAL;
+
+       DEBUG(2, "MTDSB: dev_name \"%s\"\n", dev_name);
+
+       /* the preferred way of mounting in future; especially when
+        * CONFIG_BLOCK=n - we specify the underlying MTD device by number or
+        * by name, so that we don't require block device support to be present
+        * in the kernel. */
+       if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
+               if (dev_name[3] == ':') {
+                       struct mtd_info *mtd;
+
+                       /* mount by MTD device name */
+                       DEBUG(1, "MTDSB: mtd:%%s, name \"%s\"\n",
+                             dev_name + 4);
+
+                       for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
+                               mtd = get_mtd_device(NULL, mtdnr);
+                               if (mtd) {
+                                       if (!strcmp(mtd->name, dev_name + 4))
+                                               return get_sb_mtd_aux(
+                                                       fs_type, flags,
+                                                       dev_name, data, mtd,
+                                                       fill_super, mnt);
+
+                                       put_mtd_device(mtd);
+                               }
+                       }
+
+                       printk(KERN_NOTICE "MTD:"
+                              " MTD device with name \"%s\" not found.\n",
+                              dev_name + 4);
+
+               } else if (isdigit(dev_name[3])) {
+                       /* mount by MTD device number name */
+                       char *endptr;
+
+                       mtdnr = simple_strtoul(dev_name + 3, &endptr, 0);
+                       if (!*endptr) {
+                               /* It was a valid number */
+                               DEBUG(1, "MTDSB: mtd%%d, mtdnr %d\n",
+                                     mtdnr);
+                               return get_sb_mtd_nr(fs_type, flags,
+                                                    dev_name, data,
+                                                    mtdnr, fill_super, mnt);
+                       }
+               }
+       }
+
+       /* try the old way - the hack where we allowed users to mount
+        * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
+        */
+       ret = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
+
+       DEBUG(1, "MTDSB: path_lookup() returned %d, inode %p\n",
+             ret, nd.dentry ? nd.dentry->d_inode : NULL);
+
+       if (ret)
+               return ret;
+
+       ret = -EINVAL;
+
+       if (!S_ISBLK(nd.dentry->d_inode->i_mode))
+               goto out;
+
+       if (nd.mnt->mnt_flags & MNT_NODEV) {
+               ret = -EACCES;
+               goto out;
+       }
+
+       if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR)
+               goto not_an_MTD_device;
+
+       mtdnr = iminor(nd.dentry->d_inode);
+       path_release(&nd);
+
+       return get_sb_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super,
+                            mnt);
+
+not_an_MTD_device:
+       if (!(flags & MS_SILENT))
+               printk(KERN_NOTICE
+                      "MTD: Attempt to mount non-MTD device \"%s\"\n",
+                      dev_name);
+out:
+       path_release(&nd);
+       return ret;
+
+}
+
+EXPORT_SYMBOL_GPL(get_sb_mtd);
+
+/*
+ * destroy an MTD-based superblock
+ */
+void kill_mtd_super(struct super_block *sb)
+{
+       generic_shutdown_super(sb);
+       put_mtd_device(sb->s_mtd);
+       sb->s_mtd = NULL;
+}
+
+EXPORT_SYMBOL_GPL(kill_mtd_super);
diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index e51164a..e3c69e6 100644
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -19,7 +19,7 @@
 #include <linux/mount.h>
 #include <linux/jffs2.h>
 #include <linux/pagemap.h>
-#include <linux/mtd/mtd.h>
+#include <linux/mtd/super.h>
 #include <linux/ctype.h>
 #include <linux/namei.h>
 #include "compr.h"
@@ -78,69 +78,27 @@ static const struct super_operations jffs2_super_operations 
=
        .sync_fs =      jffs2_sync_fs,
 };
 
-static int jffs2_sb_compare(struct super_block *sb, void *data)
-{
-       struct jffs2_sb_info *p = data;
-       struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
-
-       /* The superblocks are considered to be equivalent if the underlying MTD
-          device is the same one */
-       if (c->mtd == p->mtd) {
-               D1(printk(KERN_DEBUG "jffs2_sb_compare: match on device %d 
(\"%s\")\n", p->mtd->index, p->mtd->name));
-               return 1;
-       } else {
-               D1(printk(KERN_DEBUG "jffs2_sb_compare: No match, device %d 
(\"%s\"), device %d (\"%s\")\n",
-                         c->mtd->index, c->mtd->name, p->mtd->index, 
p->mtd->name));
-               return 0;
-       }
-}
-
-static int jffs2_sb_set(struct super_block *sb, void *data)
-{
-       struct jffs2_sb_info *p = data;
-
-       /* For persistence of NFS exports etc. we use the same s_dev
-          each time we mount the device, don't just use an anonymous
-          device */
-       sb->s_fs_info = p;
-       p->os_priv = sb;
-       sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, p->mtd->index);
-
-       return 0;
-}
-
-static int jffs2_get_sb_mtd(struct file_system_type *fs_type,
-                           int flags, const char *dev_name,
-                           void *data, struct mtd_info *mtd,
-                           struct vfsmount *mnt)
+/*
+ * fill in the superblock
+ */
+static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 {
-       struct super_block *sb;
        struct jffs2_sb_info *c;
-       int ret;
+
+       D1(printk(KERN_DEBUG "jffs2_get_sb_mtd():"
+                 " New superblock for device %d (\"%s\")\n",
+                 sb->s_mtd->index, sb->s_mtd->name));
 
        c = kzalloc(sizeof(*c), GFP_KERNEL);
        if (!c)
                return -ENOMEM;
-       c->mtd = mtd;
-
-       sb = sget(fs_type, jffs2_sb_compare, jffs2_sb_set, c);
-
-       if (IS_ERR(sb))
-               goto out_error;
-
-       if (sb->s_root) {
-               /* New mountpoint for JFFS2 which is already mounted */
-               D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): Device %d (\"%s\") is 
already mounted\n",
-                         mtd->index, mtd->name));
-               ret = simple_set_mnt(mnt, sb);
-               goto out_put;
-       }
 
-       D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): New superblock for device %d 
(\"%s\")\n",
-                 mtd->index, mtd->name));
+       c->mtd = sb->s_mtd;
+       c->os_priv = sb;
+       sb->s_fs_info = c;
 
-       /* Initialize JFFS2 superblock locks, the further initialization will be
-        * done later */
+       /* Initialize JFFS2 superblock locks, the further initialization will
+        * be done later */
        init_MUTEX(&c->alloc_sem);
        init_MUTEX(&c->erase_free_sem);
        init_waitqueue_head(&c->erase_wait);
@@ -149,133 +107,20 @@ static int jffs2_get_sb_mtd(struct file_system_type 
*fs_type,
        spin_lock_init(&c->inocache_lock);
 
        sb->s_op = &jffs2_super_operations;
-       sb->s_flags = flags | MS_NOATIME;
+       sb->s_flags = sb->s_flags | MS_NOATIME;
        sb->s_xattr = jffs2_xattr_handlers;
 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
        sb->s_flags |= MS_POSIXACL;
 #endif
-       ret = jffs2_do_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
-
-       if (ret) {
-               /* Failure case... */
-               up_write(&sb->s_umount);
-               deactivate_super(sb);
-               return ret;
-       }
-
-       sb->s_flags |= MS_ACTIVE;
-       return simple_set_mnt(mnt, sb);
-
-out_error:
-       ret = PTR_ERR(sb);
- out_put:
-       kfree(c);
-       put_mtd_device(mtd);
-
-       return ret;
-}
-
-static int jffs2_get_sb_mtdnr(struct file_system_type *fs_type,
-                             int flags, const char *dev_name,
-                             void *data, int mtdnr,
-                             struct vfsmount *mnt)
-{
-       struct mtd_info *mtd;
-
-       mtd = get_mtd_device(NULL, mtdnr);
-       if (IS_ERR(mtd)) {
-               D1(printk(KERN_DEBUG "jffs2: MTD device #%u doesn't appear to 
exist\n", mtdnr));
-               return PTR_ERR(mtd);
-       }
-
-       return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd, mnt);
+       return jffs2_do_fill_super(sb, data, silent);
 }
 
 static int jffs2_get_sb(struct file_system_type *fs_type,
                        int flags, const char *dev_name,
                        void *data, struct vfsmount *mnt)
 {
-       int err;
-       struct nameidata nd;
-       int mtdnr;
-
-       if (!dev_name)
-               return -EINVAL;
-
-       D1(printk(KERN_DEBUG "jffs2_get_sb(): dev_name \"%s\"\n", dev_name));
-
-       /* The preferred way of mounting in future; especially when
-          CONFIG_BLK_DEV is implemented - we specify the underlying
-          MTD device by number or by name, so that we don't require
-          block device support to be present in the kernel. */
-
-       /* FIXME: How to do the root fs this way? */
-
-       if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
-               /* Probably mounting without the blkdev crap */
-               if (dev_name[3] == ':') {
-                       struct mtd_info *mtd;
-
-                       /* Mount by MTD device name */
-                       D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd:%%s, name 
\"%s\"\n", dev_name+4));
-                       for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
-                               mtd = get_mtd_device(NULL, mtdnr);
-                               if (!IS_ERR(mtd)) {
-                                       if (!strcmp(mtd->name, dev_name+4))
-                                               return 
jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd, mnt);
-                                       put_mtd_device(mtd);
-                               }
-                       }
-                       printk(KERN_NOTICE "jffs2_get_sb(): MTD device with 
name \"%s\" not found.\n", dev_name+4);
-               } else if (isdigit(dev_name[3])) {
-                       /* Mount by MTD device number name */
-                       char *endptr;
-
-                       mtdnr = simple_strtoul(dev_name+3, &endptr, 0);
-                       if (!*endptr) {
-                               /* It was a valid number */
-                               D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd%%d, 
mtdnr %d\n", mtdnr));
-                               return jffs2_get_sb_mtdnr(fs_type, flags, 
dev_name, data, mtdnr, mnt);
-                       }
-               }
-       }
-
-       /* Try the old way - the hack where we allowed users to mount
-          /dev/mtdblock$(n) but didn't actually _use_ the blkdev */
-
-       err = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
-
-       D1(printk(KERN_DEBUG "jffs2_get_sb(): path_lookup() returned %d, inode 
%p\n",
-                 err, nd.dentry->d_inode));
-
-       if (err)
-               return err;
-
-       err = -EINVAL;
-
-       if (!S_ISBLK(nd.dentry->d_inode->i_mode))
-               goto out;
-
-       if (nd.mnt->mnt_flags & MNT_NODEV) {
-               err = -EACCES;
-               goto out;
-       }
-
-       if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR) {
-               if (!(flags & MS_SILENT))
-                       printk(KERN_NOTICE "Attempt to mount non-MTD device 
\"%s\" as JFFS2\n",
-                              dev_name);
-               goto out;
-       }
-
-       mtdnr = iminor(nd.dentry->d_inode);
-       path_release(&nd);
-
-       return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr, mnt);
-
-out:
-       path_release(&nd);
-       return err;
+       return get_sb_mtd(fs_type, flags, dev_name, data, jffs2_fill_super,
+                         mnt);
 }
 
 static void jffs2_put_super (struct super_block *sb)
@@ -310,8 +155,7 @@ static void jffs2_kill_sb(struct super_block *sb)
        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
        if (!(sb->s_flags & MS_RDONLY))
                jffs2_stop_garbage_collect_thread(c);
-       generic_shutdown_super(sb);
-       put_mtd_device(c->mtd);
+       kill_mtd_super(sb);
        kfree(c);
 }
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 095a9c9..151739a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -937,6 +937,7 @@ struct super_block {
        struct list_head        s_files;
 
        struct block_device     *s_bdev;
+       struct mtd_info         *s_mtd;
        struct list_head        s_instances;
        struct quota_info       s_dquot;        /* Diskquota specific options */
 
diff --git a/include/linux/mtd/super.h b/include/linux/mtd/super.h
new file mode 100644
index 0000000..4016dd6
--- /dev/null
+++ b/include/linux/mtd/super.h
@@ -0,0 +1,30 @@
+/* MTD-based superblock handling
+ *
+ * Copyright © 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells ([EMAIL PROTECTED])
+ *
+ * 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.
+ */
+
+#ifndef __MTD_SUPER_H__
+#define __MTD_SUPER_H__
+
+#ifdef __KERNEL__
+
+#include <linux/mtd/mtd.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+
+extern int get_sb_mtd(struct file_system_type *fs_type, int flags,
+                     const char *dev_name, void *data,
+                     int (*fill_super)(struct super_block *, void *, int),
+                     struct vfsmount *mnt);
+extern void kill_mtd_super(struct super_block *sb);
+
+
+#endif /* __KERNEL__ */
+
+#endif /* __MTD_SUPER_H__ */
-
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