X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=fs%2Ffile_table.c;h=664e3f2309b89811b028603da0f17a6e266ee9fd;hb=49ba87811f34a0219dc7a373cd24aa68450f2058;hp=d17fd691b8325c8dab7c4ab086bfb1900687b1e0;hpb=18062a91d2ddc40e19fc674afeb7cad58cfa23ab;p=~andy%2Flinux

diff --git a/fs/file_table.c b/fs/file_table.c
index d17fd691b83..664e3f2309b 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -98,16 +98,15 @@ struct file *get_empty_filp(void)
 		 * percpu_counters are inaccurate.  Do an expensive check before
 		 * we go and fail.
 		 */
-		if (percpu_counter_sum(&nr_files) >= files_stat.max_files)
+		if (percpu_counter_sum_positive(&nr_files) >= files_stat.max_files)
 			goto over;
 	}
 
-	f = kmem_cache_alloc(filp_cachep, GFP_KERNEL);
+	f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
 	if (f == NULL)
 		goto fail;
 
 	percpu_counter_inc(&nr_files);
-	memset(f, 0, sizeof(*f));
 	if (security_file_alloc(f))
 		goto fail_sec;
 
@@ -138,6 +137,66 @@ fail:
 
 EXPORT_SYMBOL(get_empty_filp);
 
+/**
+ * alloc_file - allocate and initialize a 'struct file'
+ * @mnt: the vfsmount on which the file will reside
+ * @dentry: the dentry representing the new file
+ * @mode: the mode with which the new file will be opened
+ * @fop: the 'struct file_operations' for the new file
+ *
+ * Use this instead of get_empty_filp() to get a new
+ * 'struct file'.  Do so because of the same initialization
+ * pitfalls reasons listed for init_file().  This is a
+ * preferred interface to using init_file().
+ *
+ * If all the callers of init_file() are eliminated, its
+ * code should be moved into this function.
+ */
+struct file *alloc_file(struct vfsmount *mnt, struct dentry *dentry,
+		mode_t mode, const struct file_operations *fop)
+{
+	struct file *file;
+	struct path;
+
+	file = get_empty_filp();
+	if (!file)
+		return NULL;
+
+	init_file(file, mnt, dentry, mode, fop);
+	return file;
+}
+EXPORT_SYMBOL(alloc_file);
+
+/**
+ * init_file - initialize a 'struct file'
+ * @file: the already allocated 'struct file' to initialized
+ * @mnt: the vfsmount on which the file resides
+ * @dentry: the dentry representing this file
+ * @mode: the mode the file is opened with
+ * @fop: the 'struct file_operations' for this file
+ *
+ * Use this instead of setting the members directly.  Doing so
+ * avoids making mistakes like forgetting the mntget() or
+ * forgetting to take a write on the mnt.
+ *
+ * Note: This is a crappy interface.  It is here to make
+ * merging with the existing users of get_empty_filp()
+ * who have complex failure logic easier.  All users
+ * of this should be moving to alloc_file().
+ */
+int init_file(struct file *file, struct vfsmount *mnt, struct dentry *dentry,
+	   mode_t mode, const struct file_operations *fop)
+{
+	int error = 0;
+	file->f_path.dentry = dentry;
+	file->f_path.mnt = mntget(mnt);
+	file->f_mapping = dentry->d_inode->i_mapping;
+	file->f_mode = mode;
+	file->f_op = fop;
+	return error;
+}
+EXPORT_SYMBOL(init_file);
+
 void fastcall fput(struct file *file)
 {
 	if (atomic_dec_and_test(&file->f_count))
@@ -264,12 +323,11 @@ void file_kill(struct file *file)
 
 int fs_may_remount_ro(struct super_block *sb)
 {
-	struct list_head *p;
+	struct file *file;
 
 	/* Check that no files are currently opened for writing. */
 	file_list_lock();
-	list_for_each(p, &sb->s_files) {
-		struct file *file = list_entry(p, struct file, f_u.fu_list);
+	list_for_each_entry(file, &sb->s_files, f_u.fu_list) {
 		struct inode *inode = file->f_path.dentry->d_inode;
 
 		/* File with pending delete? */