Patchwork FILO: parse old ext2 revisions correctly

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Submitter Daniel Mack
Date 2009-09-23 10:31:01
Message ID <20090923103101.GN9410@buzzloop.caiaq.de>
Download mbox | patch
Permalink /patch/281/
State Accepted
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Comments

Daniel Mack - 2009-09-23 10:31:01
This patch applies against r104 of filo and allows older versions of
ext2 file systems to be accessed. The problem with the current code is
that EXT2_INODE_SIZE() returns 0 for these file systems and the
EXT2_INODES_PER_BLOCK() uses that value in a calculation which causes a
div0 and sends the machine to reboot.

Below is a fix for that.

Signed-off-by: Daniel Mack <daniel@caiaq.de>


----- End forwarded message -----
Peter Stuge - 2009-09-23 14:12:44
Daniel Mack wrote:
> This patch applies against r104 of filo and allows older versions of
> ext2 file systems to be accessed. The problem with the current code is
> that EXT2_INODE_SIZE() returns 0 for these file systems and the
> EXT2_INODES_PER_BLOCK() uses that value in a calculation which causes a
> div0 and sends the machine to reboot.
> 
> Below is a fix for that.
> 
> Signed-off-by: Daniel Mack <daniel@caiaq.de>

Thanks. r106

Patch

Index: fs/fsys_ext2fs.c
===================================================================
--- fs/fsys_ext2fs.c	(revision 105)
+++ fs/fsys_ext2fs.c	(working copy)
@@ -253,10 +253,18 @@ 
     ((char *)((char *)DATABLOCK1 + EXT2_BLOCK_SIZE(SUPERBLOCK)))
 
 /* linux/ext2_fs.h */
+
+#define EXT2_OLD_REV		0	/* The good old (original) format */
+#define EXT2_DYNAMIC_REV	1	/* V2 format w/ dynamic inode sizes */
+
+#define EXT2_OLD_INODE_SIZE	128
+
 #define EXT2_ADDR_PER_BLOCK(s)          (EXT2_BLOCK_SIZE(s) / sizeof (__u32))
 #define EXT2_ADDR_PER_BLOCK_BITS(s)	(log2(EXT2_ADDR_PER_BLOCK(s)))
 
-#define EXT2_INODE_SIZE(s)             (SUPERBLOCK->s_inode_size)
+#define EXT2_INODE_SIZE(s)		(((s)->s_rev_level == EXT2_OLD_REV) ? \
+					EXT2_OLD_INODE_SIZE : (s)->s_inode_size)
+
 #define EXT2_INODES_PER_BLOCK(s)       (EXT2_BLOCK_SIZE(s)/EXT2_INODE_SIZE(s))
 
 /* linux/ext2_fs.h */
@@ -287,6 +295,7 @@ 
     printf("  b_free=%d\n", le32_to_cpu(s->s_free_blocks_count));
     printf("  first=%d\n", le32_to_cpu(s->s_first_data_block));
     printf("  log_b_size=%d, b_size=%d\n", le32_to_cpu(s->s_log_block_size), EXT2_BLOCK_SIZE(s));
+    printf("  inode_size=%d\n", le32_to_cpu(EXT2_INODE_SIZE(s)));
     printf("  log_f_size=%d\n", le32_to_cpu(s->s_log_frag_size));
     printf("  bpg=%d\n", le32_to_cpu(s->s_blocks_per_group));
     printf("  fpg=%d\n", le32_to_cpu(s->s_frags_per_group));