X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;ds=sidebyside;f=fs%2Flibfs.c;h=ae51481e45e5f679e240d64e5f8e1f39e7c0e2c7;hb=d85f50d5e1aa99ab082035f94265847521819e58;hp=7d487047dbb8814ea1d5f0a01c9e30c630d9a322;hpb=ebaf0c6032f525ddb0158fb59848d41899dce8cd;p=powerpc.git

diff --git a/fs/libfs.c b/fs/libfs.c
index 7d487047db..ae51481e45 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -159,7 +159,10 @@ int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
 					continue;
 
 				spin_unlock(&dcache_lock);
-				if (filldir(dirent, next->d_name.name, next->d_name.len, filp->f_pos, next->d_inode->i_ino, dt_type(next->d_inode)) < 0)
+				if (filldir(dirent, next->d_name.name, 
+					    next->d_name.len, filp->f_pos, 
+					    next->d_inode->i_ino, 
+					    dt_type(next->d_inode)) < 0)
 					return 0;
 				spin_lock(&dcache_lock);
 				/* next is still alive */
@@ -190,6 +193,10 @@ const struct inode_operations simple_dir_inode_operations = {
 	.lookup		= simple_lookup,
 };
 
+static const struct super_operations simple_super_operations = {
+	.statfs		= simple_statfs,
+};
+
 /*
  * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
  * will never be mountable)
@@ -199,7 +206,6 @@ int get_sb_pseudo(struct file_system_type *fs_type, char *name,
 	struct vfsmount *mnt)
 {
 	struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
-	static const struct super_operations default_ops = {.statfs = simple_statfs};
 	struct dentry *dentry;
 	struct inode *root;
 	struct qstr d_name = {.name = name, .len = strlen(name)};
@@ -212,11 +218,17 @@ int get_sb_pseudo(struct file_system_type *fs_type, char *name,
 	s->s_blocksize = 1024;
 	s->s_blocksize_bits = 10;
 	s->s_magic = magic;
-	s->s_op = ops ? ops : &default_ops;
+	s->s_op = ops ? ops : &simple_super_operations;
 	s->s_time_gran = 1;
 	root = new_inode(s);
 	if (!root)
 		goto Enomem;
+	/*
+	 * since this is the first inode, make it number 1. New inodes created
+	 * after this must take care not to collide with it (by passing
+	 * max_reserved of 1 to iunique).
+	 */
+	root->i_ino = 1;
 	root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
 	root->i_uid = root->i_gid = 0;
 	root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
@@ -335,17 +347,38 @@ int simple_prepare_write(struct file *file, struct page *page,
 			flush_dcache_page(page);
 			kunmap_atomic(kaddr, KM_USER0);
 		}
-		SetPageUptodate(page);
 	}
 	return 0;
 }
 
-int simple_commit_write(struct file *file, struct page *page,
-			unsigned offset, unsigned to)
+int simple_write_begin(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned flags,
+			struct page **pagep, void **fsdata)
+{
+	struct page *page;
+	pgoff_t index;
+	unsigned from;
+
+	index = pos >> PAGE_CACHE_SHIFT;
+	from = pos & (PAGE_CACHE_SIZE - 1);
+
+	page = __grab_cache_page(mapping, index);
+	if (!page)
+		return -ENOMEM;
+
+	*pagep = page;
+
+	return simple_prepare_write(file, page, from, from+len);
+}
+
+static int simple_commit_write(struct file *file, struct page *page,
+			       unsigned from, unsigned to)
 {
 	struct inode *inode = page->mapping->host;
 	loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
 
+	if (!PageUptodate(page))
+		SetPageUptodate(page);
 	/*
 	 * No need to use i_size_read() here, the i_size
 	 * cannot change under us because we hold the i_mutex.
@@ -356,9 +389,35 @@ int simple_commit_write(struct file *file, struct page *page,
 	return 0;
 }
 
+int simple_write_end(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *page, void *fsdata)
+{
+	unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+
+	/* zero the stale part of the page if we did a short copy */
+	if (copied < len) {
+		void *kaddr = kmap_atomic(page, KM_USER0);
+		memset(kaddr + from + copied, 0, len - copied);
+		flush_dcache_page(page);
+		kunmap_atomic(kaddr, KM_USER0);
+	}
+
+	simple_commit_write(file, page, from, from+copied);
+
+	unlock_page(page);
+	page_cache_release(page);
+
+	return copied;
+}
+
+/*
+ * the inodes created here are not hashed. If you use iunique to generate
+ * unique inode values later for this filesystem, then you must take care
+ * to pass it an appropriate max_reserved value to avoid collisions.
+ */
 int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files)
 {
-	static struct super_operations s_ops = {.statfs = simple_statfs};
 	struct inode *inode;
 	struct dentry *root;
 	struct dentry *dentry;
@@ -367,12 +426,17 @@ int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files
 	s->s_blocksize = PAGE_CACHE_SIZE;
 	s->s_blocksize_bits = PAGE_CACHE_SHIFT;
 	s->s_magic = magic;
-	s->s_op = &s_ops;
+	s->s_op = &simple_super_operations;
 	s->s_time_gran = 1;
 
 	inode = new_inode(s);
 	if (!inode)
 		return -ENOMEM;
+	/*
+	 * because the root inode is 1, the files array must not contain an
+	 * entry at index 1
+	 */
+	inode->i_ino = 1;
 	inode->i_mode = S_IFDIR | 0755;
 	inode->i_uid = inode->i_gid = 0;
 	inode->i_blocks = 0;
@@ -388,6 +452,13 @@ int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files
 	for (i = 0; !files->name || files->name[0]; i++, files++) {
 		if (!files->name)
 			continue;
+
+		/* warn if it tries to conflict with the root inode */
+		if (unlikely(i == 1))
+			printk(KERN_WARNING "%s: %s passed in a files array"
+				"with an index of 1!\n", __func__,
+				s->s_type->name);
+
 		dentry = d_alloc_name(root, files->name);
 		if (!dentry)
 			goto out;
@@ -613,7 +684,8 @@ EXPORT_SYMBOL(dcache_dir_open);
 EXPORT_SYMBOL(dcache_readdir);
 EXPORT_SYMBOL(generic_read_dir);
 EXPORT_SYMBOL(get_sb_pseudo);
-EXPORT_SYMBOL(simple_commit_write);
+EXPORT_SYMBOL(simple_write_begin);
+EXPORT_SYMBOL(simple_write_end);
 EXPORT_SYMBOL(simple_dir_inode_operations);
 EXPORT_SYMBOL(simple_dir_operations);
 EXPORT_SYMBOL(simple_empty);