ext2 large_file

[Brian Bergstrand]

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I ported the FreeBSD driver to Mac OS X / Darwin a few years ago and  
added large file support in the process. Here's the patch, as you can  
see it's a rather simple patch (as long as the in core i_size member  
is 64bit which I think is true for FreeBSD):

I doubt this patch will apply cleanly as my tree has diverged from  
FreeBSD in a non-compatible way quite a while ago -- but it should  
give you a start:

The first part of the patch (@@ -98,7 +128,9 @@) is to ext2_ei2i()  
and the second part (@@ -182,6 +214,31 @@) is to ext2_i2ei()

$ cvs diff -r 1.6 -r 1.7 ext2_inode_cnv.c
Index: ext2_inode_cnv.c
===================================================================
RCS file: /cvsroot/ext2fsx/src/gnu/ext2fs/ext2_inode_cnv.c,v
retrieving revision 1.6
retrieving revision 1.7
diff -u -b -r1.6 -r1.7
- --- ext2_inode_cnv.c    3 May 2003 23:54:39 -0000       1.6
+++ ext2_inode_cnv.c    9 Jul 2003 23:09:24 -0000       1.7
@@ -98,7 +128,9 @@
                 ip->i_uid |= le16_to_cpu(ei->i_uid_high) << 16;
                 ip->i_gid |= le16_to_cpu(ei->i_gid_high) << 16;
         /*}*/
- -       /* XXX use memcpy */
+   if (S_ISREG(ip->i_mode))
+      ip->i_size |= ((u_int64_t)le32_to_cpu(ei->i_size_high)) << 32;
+   /* TBD: Otherwise, setup the dir acl */

     #if BYTE_ORDER == BIG_ENDIAN
     /* We don't want to swap the block addr's for a short symlink  
because
@@ -182,6 +214,31 @@
                 raw_inode->i_uid_high = 0;
                 raw_inode->i_gid_high = 0;
         }*/
+   if (S_ISREG(ip->i_mode)) {
+      ei->i_size_high = cpu_to_le32(ip->i_size >> 32);
+      if (ip->i_size > 0x7fffffffULL) {
+         struct ext2_sb_info *sb = ip->i_e2fs;
+         if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
+            EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
+            EXT2_SB(sb)->s_es->s_rev_level == cpu_to_le32 
(EXT2_GOOD_OLD_REV)) {
+            /* First large file, add the flag to the superblock. */
+            lock_super (VFSTOEXT2(ip->i_vnode->v_mount)->um_devvp);
+
+            if (EXT2_SB(sb)->s_es->s_rev_level == cpu_to_le32 
(EXT2_GOOD_OLD_REV)) {
+               log(LOG_WARNING,
+                  "ext2: updating to rev %d because of new feature  
flag, "
+                  "running e2fsck is recommended", EXT2_DYNAMIC_REV);
+               sb->s_es->s_first_ino = cpu_to_le32 
(EXT2_GOOD_OLD_FIRST_INO);
+               sb->s_es->s_inode_size = cpu_to_le16 
(EXT2_GOOD_OLD_INODE_SIZE);
+               sb->s_es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
+            }
+
+            EXT2_SET_RO_COMPAT_FEATURE(sb,  
EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
+            sb->s_dirt = 1;
+            unlock_super (VFSTOEXT2(ip->i_vnode->v_mount)->um_devvp);
+         }
+      }
+   }



On Oct 30, 2005, at 11:37 AM, Ivan Voras wrote:

> I recently tried to use ext2 on FreeBSD but have decided not to  
> when I saw that the support for large files is missing (and went  
> with msdosfs instead).
>
> Now I accidentaly noticed that large_file support is present in  
> latest NetBSD (and maybe OpenBSD). Is anyone interested in porting  
> the support to FreeBSD? :)
>

Brian Bergstrand
<http://www.bergstrand.org/brian/>   PGP Key ID: 0xB6C7B6A2

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