vfs: Create function for iterating over block devices
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/block_dev.c b/fs/block_dev.c
index c2bbe1f..1e51919 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1710,3 +1710,39 @@
return res;
}
EXPORT_SYMBOL(__invalidate_device);
+
+void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg)
+{
+ struct inode *inode, *old_inode = NULL;
+
+ spin_lock(&inode_sb_list_lock);
+ list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) {
+ struct address_space *mapping = inode->i_mapping;
+
+ spin_lock(&inode->i_lock);
+ if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) ||
+ mapping->nrpages == 0) {
+ spin_unlock(&inode->i_lock);
+ continue;
+ }
+ __iget(inode);
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_sb_list_lock);
+ /*
+ * We hold a reference to 'inode' so it couldn't have been
+ * removed from s_inodes list while we dropped the
+ * inode_sb_list_lock. We cannot iput the inode now as we can
+ * be holding the last reference and we cannot iput it under
+ * inode_sb_list_lock. So we keep the reference and iput it
+ * later.
+ */
+ iput(old_inode);
+ old_inode = inode;
+
+ func(I_BDEV(inode), arg);
+
+ spin_lock(&inode_sb_list_lock);
+ }
+ spin_unlock(&inode_sb_list_lock);
+ iput(old_inode);
+}
