Some (incomplete) EFS fixes: can now walk directory trees, follow symlinks

and read files that don't have indirect extents.  Unmounting the EFS
partition causes hangs (deadlock with the locking of the superblock, I
think), and it's nothing resembling fast or clean code.  That's for
tomorrow.

1 files changed, 101 insertions, 70 deletions

diff --git a/fs/efs/dir.c b/fs/efs/dir.c
index a89dd304e..0fd4f3187 100644
--- a/fs/efs/dir.c
+++ b/fs/efs/dir.c
@@ -60,78 +60,109 @@ struct inode_operations efs_dir_in_ops = {
 
    return    - 0 ok, <0 error
 */
-static int efs_readdir(struct file *filp,
-		       void *dirent, filldir_t filldir)
+static int
+efs_readdir(struct file *filp,
+	    void *dirent, filldir_t filldir)
 {
-	struct inode *inode = filp->f_dentry->d_inode;
-	struct efs_inode_info *ini = (struct efs_inode_info *)&inode->u.efs_i;
-	struct buffer_head *bh;
-	__u8  *rawdirblk;
-	__u32  iteminode;
-	__u16 namelen;
-	__u8  *nameptr;
-	__u32  numitems;
-	__u16 itemnum;
-	__u32  block;
-	__u16 rawdepos;  
-
-	/* some checks */
-	if(!inode || !inode->i_sb || !S_ISDIR(inode->i_mode)) 
-		return -EBADF;
-  
-	/* Warnings */
-	if(ini->tot!=1) {
-		printk("EFS: directory %s has more than one extent.\n", 
-		       filp->f_dentry->d_name.name);
-		printk("EFS: Mike is lazy, so we can't handle this yet.  Sorry =(\n");
-		return 0;
-	}
-	if(inode->i_size & (EFS_BLOCK_SIZE-1))
-		printk("efs_readdir: dirsize != blocksize*n\n");
-
-	/* f_pos contains: dirblock<<BLOCK_SIZE | # of item in dirblock */
-	block   = filp->f_pos >> EFS_BLOCK_SIZE_BITS;
-	itemnum = filp->f_pos & 0xff; 
-  
-	/* We found the last entry -> ready */
-	if(block == (inode->i_size>>EFS_BLOCK_SIZE_BITS))
-		return 0;
-
-	/* get disc block number from dir block num: 0..i_size/BLOCK_SIZE */ 
-	bh = bread(inode->i_dev,efs_bmap(inode,block),EFS_BLOCK_SIZE);
-	if(!bh) return 0;
-
-	/* dirblock */
-	rawdirblk = (__u8 *)bh->b_data; 
-	/* number of entries stored in this dirblock */
-	numitems = rawdirblk[EFS_DB_ENTRIES]; 
-	/* offset in block of #off diritem */
-	rawdepos = (__u16)rawdirblk[EFS_DB_FIRST+itemnum]<<1;
-
-	/* diritem first contains the inode number, the namelen and the name */
-	iteminode = ConvertLong(rawdirblk,rawdepos);
-	namelen = (__u16)rawdirblk[rawdepos+EFS_DI_NAMELEN];
-	nameptr = rawdirblk + rawdepos + EFS_DI_NAME;  
-
-#ifdef DEBUG_EFS
-	printk("efs: dir #%d @ %0#3x - inode %lx %s namelen %u\n",
-	       itemnum,rawdepos,iteminode,nameptr,namelen);
+    struct inode *inode = filp->f_dentry->d_inode;
+    struct efs_inode_info *ini = (struct efs_inode_info *)&inode->u.efs_i;
+    struct buffer_head *bh;
+    struct efs_dirblk *dirblk;
+    __u32  iteminode;
+    __u16 namelen;
+    char *nameptr;
+    __u16 itemnum;
+    __u32  block;
+    int db_offset;
+    int error = 0;
+    struct efs_dent *de = NULL;
+    
+    /* some checks -- ISDIR should be done by upper layer */
+    if(!inode || !inode->i_sb || !S_ISDIR(inode->i_mode)) {
+	printk("EFS: bad inode for readdir!\n");
+	return -EBADF;
+    }
+    
+    if(ini->tot!=1) {
+	printk("EFS: directory %s has more than one extent.\n", 
+	       filp->f_dentry->d_name.name);
+	printk("EFS: Mike is lazy, so we can't handle this yet.  Sorry =(\n");
+	return -EBADF;
+    }
+
+    /* Warnings */
+    if(inode->i_size & (EFS_BLOCK_SIZE-1)) 
+	printk("efs_readdir: dirsize != blocksize*n\n");
+    
+    /* f_pos contains: dirblock<<BLOCK_SIZE | # of item in dirblock */
+    block   = filp->f_pos >> EFS_BLOCK_SIZE_BITS;
+    itemnum = filp->f_pos & 0xff; 
+    
+    /* We found the last entry -> ready */
+    if(block == (inode->i_size>>EFS_BLOCK_SIZE_BITS)) {
+	printk("EFS: read all entries -- done\n");
+	return 0;
+    }
+    
+    /* get disc block number from dir block num: 0..i_size/BLOCK_SIZE */ 
+    bh = bread(inode->i_dev,efs_bmap(inode,block),EFS_BLOCK_SIZE);
+    if(!bh) {
+	/* XXX try next block? */
+	return -EBADF;
+    }
+
+    /* from here on, we must exit through out: to release bh */
+    
+    /* dirblock */
+    dirblk = (struct efs_dirblk *)bh->b_data;
+    if (dirblk->db_magic != EFS_DIRBLK_MAGIC) {
+	printk("EFS: bad dirblk magic %#xl\n", dirblk->db_magic);
+	error = -EBADF;
+	goto out;
+    }
+    db_offset = ((__u16)dirblk->db_space[itemnum] << 1) 
+	- EFS_DIRBLK_HEADERSIZE;
+    de = (struct efs_dent *)(&dirblk->db_space[db_offset]);
+    if (dirblk->db_slots == 0) {
+	error = 0;
+	goto out;
+    }
+
+#ifdef DEBUG_EFS_DIRS
+    if (itemnum == 0) {
+	printk("efs: readdir: db %d has %d entries, starting at offset %0#x\n",
+	       block, dirblk->db_slots, (__u16)dirblk->db_firstused << 1);
+    }
+#endif
+    
+    /* diritem first contains the inode number, the namelen and the name */
+    iteminode = EFS_DE_GET_INUM(de);
+    namelen = de->d_namelen;
+    nameptr = de->d_name;
+
+#ifdef DEBUG_EFS_DIRS
+    printk("efs: dir #%d @ %0#x - inode %#0x %*s namelen %u\n",
+	   itemnum,db_offset,iteminode, namelen, 
+	   nameptr ? nameptr : "(null)", namelen);
 #endif
 
-	/* copy filename and data in direntry */
-	filldir(dirent,nameptr,namelen,filp->f_pos,iteminode);
-
-	brelse(bh);
-
-  /* store pos of next item */
-	itemnum++;
-	if(itemnum==numitems) {
-		itemnum = 0;
-		block++;
-	}
-	filp->f_pos = (block<<EFS_BLOCK_SIZE_BITS) | itemnum;
-	UPDATE_ATIME(inode);
-  
-	return 0;
+    /* copy filename and data in direntry */
+    error = filldir(dirent,nameptr,namelen,filp->f_pos,iteminode);
+    if (error)
+	goto out;
+
+    /* store pos of next item */
+    itemnum++;
+    if(itemnum == dirblk->db_slots) {
+	itemnum = 0;
+	block++;
+    }
+    filp->f_pos = (block<<EFS_BLOCK_SIZE_BITS) | itemnum;
+    UPDATE_ATIME(inode);
+    
+ out:    
+    brelse(bh);
+
+    return error;
 }