jffs2: Stop triggering block erases from jffs2_write_super()
[safe/jmp/linux-2.6] / fs / jffs2 / super.c
index 45368f8..511e2d6 100644 (file)
@@ -12,6 +12,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/fs.h>
 #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 <linux/exportfs.h>
 #include "compr.h"
 #include "nodelist.h"
 
@@ -31,11 +33,12 @@ static struct kmem_cache *jffs2_inode_cachep;
 
 static struct inode *jffs2_alloc_inode(struct super_block *sb)
 {
-       struct jffs2_inode_info *ei;
-       ei = (struct jffs2_inode_info *)kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
-       if (!ei)
+       struct jffs2_inode_info *f;
+
+       f = kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
+       if (!f)
                return NULL;
-       return &ei->vfs_inode;
+       return &f->vfs_inode;
 }
 
 static void jffs2_destroy_inode(struct inode *inode)
@@ -43,31 +46,91 @@ static void jffs2_destroy_inode(struct inode *inode)
        kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
 }
 
-static void jffs2_i_init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
+static void jffs2_i_init_once(void *foo)
+{
+       struct jffs2_inode_info *f = foo;
+
+       mutex_init(&f->sem);
+       inode_init_once(&f->vfs_inode);
+}
+
+static void jffs2_write_super(struct super_block *sb)
 {
-       struct jffs2_inode_info *ei = (struct jffs2_inode_info *) foo;
+       struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 
-       if (flags & SLAB_CTOR_CONSTRUCTOR) {
-               init_MUTEX(&ei->sem);
-               inode_init_once(&ei->vfs_inode);
+       lock_super(sb);
+       sb->s_dirt = 0;
+
+       if (!(sb->s_flags & MS_RDONLY)) {
+               D1(printk(KERN_DEBUG "jffs2_write_super()\n"));
+               jffs2_flush_wbuf_gc(c, 0);
        }
+
+       unlock_super(sb);
 }
 
 static int jffs2_sync_fs(struct super_block *sb, int wait)
 {
        struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 
-       down(&c->alloc_sem);
+       jffs2_write_super(sb);
+
+       mutex_lock(&c->alloc_sem);
        jffs2_flush_wbuf_pad(c);
-       up(&c->alloc_sem);
+       mutex_unlock(&c->alloc_sem);
        return 0;
 }
 
+static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
+                                        uint32_t generation)
+{
+       /* We don't care about i_generation. We'll destroy the flash
+          before we start re-using inode numbers anyway. And even
+          if that wasn't true, we'd have other problems...*/
+       return jffs2_iget(sb, ino);
+}
+
+static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
+                                        int fh_len, int fh_type)
+{
+        return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+                                    jffs2_nfs_get_inode);
+}
+
+static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
+                                        int fh_len, int fh_type)
+{
+        return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+                                    jffs2_nfs_get_inode);
+}
+
+static struct dentry *jffs2_get_parent(struct dentry *child)
+{
+       struct jffs2_inode_info *f;
+       uint32_t pino;
+
+       BUG_ON(!S_ISDIR(child->d_inode->i_mode));
+
+       f = JFFS2_INODE_INFO(child->d_inode);
+
+       pino = f->inocache->pino_nlink;
+
+       JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
+                   f->inocache->ino, pino);
+
+       return d_obtain_alias(jffs2_iget(child->d_inode->i_sb, pino));
+}
+
+static const struct export_operations jffs2_export_ops = {
+       .get_parent = jffs2_get_parent,
+       .fh_to_dentry = jffs2_fh_to_dentry,
+       .fh_to_parent = jffs2_fh_to_parent,
+};
+
 static const struct super_operations jffs2_super_operations =
 {
        .alloc_inode =  jffs2_alloc_inode,
        .destroy_inode =jffs2_destroy_inode,
-       .read_inode =   jffs2_read_inode,
        .put_super =    jffs2_put_super,
        .write_super =  jffs2_write_super,
        .statfs =       jffs2_statfs,
@@ -77,204 +140,50 @@ 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;
-       }
+       c->mtd = sb->s_mtd;
+       c->os_priv = sb;
+       sb->s_fs_info = c;
 
-       D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): New superblock for device %d (\"%s\")\n",
-                 mtd->index, mtd->name));
-
-       /* Initialize JFFS2 superblock locks, the further initialization will be
-        * done later */
-       init_MUTEX(&c->alloc_sem);
-       init_MUTEX(&c->erase_free_sem);
+       /* Initialize JFFS2 superblock locks, the further initialization will
+        * be done later */
+       mutex_init(&c->alloc_sem);
+       mutex_init(&c->erase_free_sem);
        init_waitqueue_head(&c->erase_wait);
        init_waitqueue_head(&c->inocache_wq);
        spin_lock_init(&c->erase_completion_lock);
        spin_lock_init(&c->inocache_lock);
 
        sb->s_op = &jffs2_super_operations;
-       sb->s_flags = flags | MS_NOATIME;
+       sb->s_export_op = &jffs2_export_ops;
+       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)
@@ -283,9 +192,14 @@ static void jffs2_put_super (struct super_block *sb)
 
        D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
 
-       down(&c->alloc_sem);
+       lock_kernel();
+
+       if (sb->s_dirt)
+               jffs2_write_super(sb);
+
+       mutex_lock(&c->alloc_sem);
        jffs2_flush_wbuf_pad(c);
-       up(&c->alloc_sem);
+       mutex_unlock(&c->alloc_sem);
 
        jffs2_sum_exit(c);
 
@@ -301,6 +215,8 @@ static void jffs2_put_super (struct super_block *sb)
        if (c->mtd->sync)
                c->mtd->sync(c->mtd);
 
+       unlock_kernel();
+
        D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
 }
 
@@ -309,8 +225,7 @@ 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);
 }
 
@@ -350,7 +265,7 @@ static int __init init_jffs2_fs(void)
                                             sizeof(struct jffs2_inode_info),
                                             0, (SLAB_RECLAIM_ACCOUNT|
                                                SLAB_MEM_SPREAD),
-                                            jffs2_i_init_once, NULL);
+                                            jffs2_i_init_once);
        if (!jffs2_inode_cachep) {
                printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
                return -ENOMEM;