ext2fs_extent_open: If the inode is empty, initialize the extent tree

If the inode's i_block[] array is completely empty, create an empty
extent tree in the in-core inode and set the EXT4_EXTENT_FL inode
flag.  This makes it easy to create a new inode using extents.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/lib/ext2fs/extent.c b/lib/ext2fs/extent.c
index b669e29..18e9aca 100644 (file)
--- a/lib/ext2fs/extent.c
+++ b/lib/ext2fs/extent.c
@@ -176,6 +176,7 @@ extern errcode_t ext2fs_extent_open(ext2_filsys fs, ext2_ino_t ino,
        struct ext2_extent_handle       *handle;
        errcode_t                       retval;
        int                             isize = EXT2_INODE_SIZE(fs->super);
+       int                             i;
        struct ext3_extent_header       *eh;
 
        EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
@@ -199,11 +200,24 @@ extern errcode_t ext2fs_extent_open(ext2_filsys fs, ext2_ino_t ino,
        if (retval)
                goto errout;
 
+       eh = (struct ext3_extent_header *) &handle->inode->i_block[0];
+
+       for (i=0; i < EXT2_N_BLOCKS; i++)
+               if (handle->inode->i_block[i])
+                       break;
+       if (i >= EXT2_N_BLOCKS) {
+               eh->eh_magic = ext2fs_cpu_to_le16(EXT3_EXT_MAGIC);
+               eh->eh_depth = 0;
+               eh->eh_entries = 0;
+               i = (sizeof(handle->inode->i_block) - sizeof(*eh)) /
+                       sizeof(struct ext3_extent);
+               eh->eh_max = ext2fs_cpu_to_le16(i);
+               handle->inode->i_flags |= EXT4_EXTENTS_FL;
+       }
+
        if (!(handle->inode->i_flags & EXT4_EXTENTS_FL))
                return EXT2_ET_INODE_NOT_EXTENT;
 
-       eh = (struct ext3_extent_header *) &handle->inode->i_block[0];
-
        retval = ext2fs_extent_header_verify(eh, sizeof(handle->inode->i_block));
        if (retval)
                return (retval);
@@ -967,7 +981,8 @@ void do_delete_node(int argc, char *argv[])
                com_err(argv[0], retval, 0);
                return;
        }
-       do_current_node(argc, argv);
+       if (current_handle->path && current_handle->path[0].curr)
+               do_current_node(argc, argv);
 }
 
 void do_replace_node(int argc, char *argv[])