Calculate st_nlink for each node, via a small but n^2 algorithm.

diff --git a/toys/mke2fs.c b/toys/mke2fs.c
index 7fb45e8..64d65eb 100644 (file)
--- a/toys/mke2fs.c
+++ b/toys/mke2fs.c
@@ -76,6 +76,32 @@ long check_treesize(struct dirtree *this, off_t *size)
        return blocks;
 }
 
+// Use the parent pointer to iterate through the tree non-recursively.
+static struct dirtree *treenext(struct dirtree *this)
+{
+       while (this && !this->next) this = this->parent;
+       if (this) this = this->next;
+
+       return this;
+}
+
+// To do this right I need to copy the tree and sort it, but here's a really
+// ugly n^2 way of dealing with the problem that doesn't scale well to large
+// numbers of files but can be done in very little code.
+
+static void check_treelinks(void)
+{
+       struct dirtree *this, *that;
+
+       for (this = TT.dt; this; this = treenext(this)) {
+               this->st.st_nlink = 0;
+               for (that = TT.dt; that; that = treenext(that))
+                       if (this->st.st_ino == that->st.st_ino)
+                               if (this->st.st_dev == that->st.st_dev)
+                                       this->st.st_nlink++;
+       }
+}
+
 // According to http://www.opengroup.org/onlinepubs/9629399/apdxa.htm
 // we should generate a uuid structure by reading a clock with 100 nanosecond
 // precision, normalizing it to the start of the gregorian calendar in 1582,
@@ -172,9 +198,7 @@ static void init_superblock(struct ext2_superblock *sb)
        // TODO If we're called as mke3fs or mkfs.ext3, do a journal.
 
        //if (strchr(toys.which->name,'3'))
-       //      sb->feature_compat = SWAP_LE32(EXT3_FEATURE_COMPAT_HAS_JOURNAL);
-
-       // TODO fill out free_blocks, free_inodes, first_ino
+       //      sb->feature_compat |= SWAP_LE32(EXT3_FEATURE_COMPAT_HAS_JOURNAL);
 }
 
 // Number of blocks used in this group by superblock/group list backup.
@@ -253,7 +277,7 @@ static void fill_inode(struct ext2_inode *in, struct dirtree *this)
        in->ctime = this->st.st_ctime;
        in->mtime = this->st.st_mtime;
 
-       in->links_count = this->st.st_nlink;    // TODO
+       in->links_count = this->st.st_nlink;
        in->blocks = this->st.st_blocks;
 }
 
@@ -281,8 +305,6 @@ int mke2fs_main(void)
                TT.dt->st.st_ctime = TT.dt->st.st_mtime = time(NULL);
        }
 
-       // TODO: Calculate st_nlink for each node in tree.
-
        // TODO: Check if filesystem is mounted here
 
        // For mke?fs, open file.  For gene?fs, create file.
@@ -313,7 +335,9 @@ int mke2fs_main(void)
        TT.sb.free_inodes_count = SWAP_LE32(TT.inodespg*TT.groups - INODES_RESERVED
                                        - TT.treeinodes);
 
-       // Figure out how many inodes are used
+       // Calculate st_nlink for each node in tree.
+
+       check_treelinks();
 
        // Loop through block groups.