fs: move mark_files_ro into file_table.c

This function walks the s_files lock, and operates primarily on the
files in a superblock, so it better belongs here (eg. see also
fs_may_remount_ro).

[AV: ... and it shouldn't be static after that move]

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 38 insertions, 0 deletions

diff --git a/fs/file_table.c b/fs/file_table.c
index 3d66dbcebef..334ce39881f 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -399,6 +399,44 @@ too_bad:
 	return 0;
 }
 
+/**
+ *	mark_files_ro - mark all files read-only
+ *	@sb: superblock in question
+ *
+ *	All files are marked read-only.  We don't care about pending
+ *	delete files so this should be used in 'force' mode only.
+ */
+void mark_files_ro(struct super_block *sb)
+{
+	struct file *f;
+
+retry:
+	file_list_lock();
+	list_for_each_entry(f, &sb->s_files, f_u.fu_list) {
+		struct vfsmount *mnt;
+		if (!S_ISREG(f->f_path.dentry->d_inode->i_mode))
+		       continue;
+		if (!file_count(f))
+			continue;
+		if (!(f->f_mode & FMODE_WRITE))
+			continue;
+		f->f_mode &= ~FMODE_WRITE;
+		if (file_check_writeable(f) != 0)
+			continue;
+		file_release_write(f);
+		mnt = mntget(f->f_path.mnt);
+		file_list_unlock();
+		/*
+		 * This can sleep, so we can't hold
+		 * the file_list_lock() spinlock.
+		 */
+		mnt_drop_write(mnt);
+		mntput(mnt);
+		goto retry;
+	}
+	file_list_unlock();
+}
+
 void __init files_init(unsigned long mempages)
 { 
 	int n;