palo: fix IPL overlap with ext2/ext3 resize_inode

PATCH In review James Bottomley 2 participants 5 messages Jul 3, 2019

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James Bottomley

author

2019-07-03 05:22 UTC #0 lore raw

PATCH 1/1 palo: fix IPL overlap with ext2/ext3 resize_inode

palo is producing corrupt filesystems because ext2 can't cope with any of the resize_inode, which is traditionally placed at blocks 3-258, being in the badblocks list. If this happens, mke2fs silently produces a corrupt filesystem image and the palo partition will eventually trigger a filesystem error. The fix is to force palo to specify -O^resize_inode to mke2fs which prevents ext2/3 from allocating a resize_inode (and thus prevents the filesystem from being resized).

Signed-off-by James Bottomley <[email protected]>

---
 palo/palo.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

palo/palo.c +6 -2

index 68b85cf..e088993 100644
@@ -443,7 +443,11 @@ do_cdrom(int media, int kernel32, int kernel64,
 #define EXT2_HOLE	((MAXBLSIZE + 1) / EXT2_BLOCKSIZE)
 
 /* offset in bytes before start of hole,  ext2 doesn't allow holes at
- * to cover the first four blocks of the filesystem */
+ * to cover the first four blocks of the filesystem
+ *
+ * Note: modern ext2/3 has a resize_inode covering blocks 3-258 so you
+ * must either always include the -O^resize_inode when creating the
+ * filesystem or define EXT2_OFFSET to (259*EXT2_BLOCKSIZE)*/
 #define EXT2_OFFSET	(4*EXT2_BLOCKSIZE)
 
 int

@@ -502,7 +506,7 @@ do_formatted(int init, int media, const char *medianame, int partition,
 	    }
 	}
 
-	sprintf(cmd, "mke2fs %s -b %d -l %s %s", do_format == 3 ? "-j" : "",
+	sprintf(cmd, "mke2fs %s -O^resize_inode -b %d -l %s %s", do_format == 3 ? "-j" : "",
 		EXT2_BLOCKSIZE, badblockfilename, partitionname);
 
 	if (verbose)

Signature · 1 line

2.16.4

Helge Deller

2019-07-03 05:53 UTC #1 lore raw

Quoted 32 lines · James Bottomley

palo is producing corrupt filesystems because ext2 can't cope with any of the resize_inode, which is traditionally placed at blocks 3-258, being in the badblocks list. If this happens, mke2fs silently produces a corrupt filesystem image and the palo partition will eventually trigger a filesystem error. The fix is to force palo to specify -O^resize_inode to mke2fs which prevents ext2/3 from allocating a resize_inode (and thus prevents the filesystem from being resized).
Signed-off-by James Bottomley <[email protected]>
---
  palo/palo.c | 8 ++++++--
  1 file changed, 6 insertions(+), 2 deletions(-)
palo/palo.c +5 -1
index 68b85cf..e088993 100644
@@ -443,7 +443,11 @@ do_cdrom(int media, int kernel32, int kernel64,
  #define EXT2_HOLE	((MAXBLSIZE + 1) / EXT2_BLOCKSIZE)
 
  /* offset in bytes before start of hole,  ext2 doesn't allow holes at
- * to cover the first four blocks of the filesystem */
+ * to cover the first four blocks of the filesystem
+ *
+ * Note: modern ext2/3 has a resize_inode covering blocks 3-258 so you
+ * must either always include the -O^resize_inode when creating the
+ * filesystem or define EXT2_OFFSET to (259*EXT2_BLOCKSIZE)*/
  #define EXT2_OFFSET	(4*EXT2_BLOCKSIZE)
 
  int

palo/palo.c do_formatted(int init, int media, const char *medianame, int partition, · line 509

Quoted 5 lines

palo/palo.c +1 -1

@@ -502,7 +506,7 @@ do_formatted(int init, int media, const char *medianame, int partition,
  	    }
  	}
 
-	sprintf(cmd, "mke2fs %s -b %d -l %s %s", do_format == 3 ? "-j" : "",
+	sprintf(cmd, "mke2fs %s -O^resize_inode -b %d -l %s %s", do_format == 3 ? "-j" : "",

What happens if we face an "old" mke2fs binary which doesn't know about this feature and thus fails? I wonder if it makes sense to add a fallback path?

Helge

James Bottomley

author

2019-07-03 14:30 UTC #2 lore raw

Quoted 43 lines · Helge Deller

Quoted 42 lines · James Bottomley
palo is producing corrupt filesystems because ext2 can't cope with any of the resize_inode, which is traditionally placed at blocks 3- 258, being in the badblocks list. If this happens, mke2fs silently produces a corrupt filesystem image and the palo partition will eventually trigger a filesystem error. The fix is to force palo to specify -O^resize_inode to mke2fs which prevents ext2/3 from allocating a resize_inode (and thus prevents the filesystem from being
resized).
Signed-off-by James Bottomley <[email protected]
om>
---
  palo/palo.c | 8 ++++++--
  1 file changed, 6 insertions(+), 2 deletions(-)
palo/palo.c +0 -0
index 68b85cf..e088993 100644
@@ -443,7 +443,11 @@ do_cdrom(int media, int kernel32, int
 kernel64,
  #define EXT2_HOLE	((MAXBLSIZE + 1) / EXT2_BLOCKSIZE)
 
  /* offset in bytes before start of hole,  ext2 doesn't allow
holes at
- * to cover the first four blocks of the filesystem */
+ * to cover the first four blocks of the filesystem
+ *
+ * Note: modern ext2/3 has a resize_inode covering blocks 3-258 so you
+ * must either always include the -O^resize_inode when creating the
+ * filesystem or define EXT2_OFFSET to (259*EXT2_BLOCKSIZE)*/
#define EXT2_OFFSET (4*EXT2_BLOCKSIZE)
int
palo/palo.c +0 -0
@@ -502,7 +506,7 @@ do_formatted(int init, int media, const char
 *medianame, int partition,
  	    }
  	}
 

Quoted 8 lines

palo/palo.c do_formatted(int init, int media, const char · line 512
Quoted 4 lines
palo/palo.c +1 -1
-	sprintf(cmd, "mke2fs %s -b %d -l %s %s", do_format == 3 ?
 "-j" : "",
+	sprintf(cmd, "mke2fs %s -O^resize_inode -b %d -l %s %s",
 do_format == 3 ? "-j" : "",
What happens if we face an "old" mke2fs binary which doesn't know about this feature and thus fails?
I wonder if it makes sense to add a fallback path?

It would fail according to my tests. It's a bit unlikely that anyone who's updating palo is not also updating the rest of their system, and even when parisc fell off debian we had a version of mke2fs recent enough to understand resize inodes because the feature was introduced in 2006.

The other alternative is simply to change EXT2_OFFSET to always not clash with the resize inode ... that would work for all cases.

James

Helge Deller

2019-07-03 14:45 UTC #3 lore raw

Quoted 53 lines · James Bottomley

Quoted 43 lines · Helge Deller
Quoted 42 lines · James Bottomley
palo is producing corrupt filesystems because ext2 can't cope with any of the resize_inode, which is traditionally placed at blocks 3- 258, being in the badblocks list. If this happens, mke2fs silently produces a corrupt filesystem image and the palo partition will eventually trigger a filesystem error. The fix is to force palo to specify -O^resize_inode to mke2fs which prevents ext2/3 from allocating a resize_inode (and thus prevents the filesystem from being
resized).
Signed-off-by James Bottomley <[email protected]
om>
---
   palo/palo.c | 8 ++++++--
   1 file changed, 6 insertions(+), 2 deletions(-)
palo/palo.c +0 -0
index 68b85cf..e088993 100644
@@ -443,7 +443,11 @@ do_cdrom(int media, int kernel32, int
 kernel64,
   #define EXT2_HOLE	((MAXBLSIZE + 1) / EXT2_BLOCKSIZE)
 
   /* offset in bytes before start of hole,  ext2 doesn't allow
holes at
- * to cover the first four blocks of the filesystem */
+ * to cover the first four blocks of the filesystem
+ *
+ * Note: modern ext2/3 has a resize_inode covering blocks 3-258 so you
+ * must either always include the -O^resize_inode when creating the
+ * filesystem or define EXT2_OFFSET to (259*EXT2_BLOCKSIZE)*/
#define EXT2_OFFSET (4*EXT2_BLOCKSIZE)
int
palo/palo.c +0 -0
@@ -502,7 +506,7 @@ do_formatted(int init, int media, const char
 *medianame, int partition,
   	    }
   	}
 
Quoted 8 lines
palo/palo.c do_formatted(int init, int media, const char · line 512
Quoted 4 lines
palo/palo.c +1 -1
-	sprintf(cmd, "mke2fs %s -b %d -l %s %s", do_format == 3 ?
 "-j" : "",
+	sprintf(cmd, "mke2fs %s -O^resize_inode -b %d -l %s %s",
 do_format == 3 ? "-j" : "",
What happens if we face an "old" mke2fs binary which doesn't know about this feature and thus fails?
I wonder if it makes sense to add a fallback path?

Quoted 8 lines

It would fail according to my tests. It's a bit unlikely that anyone who's updating palo is not also updating the rest of their system, and even when parisc fell off debian we had a version of mke2fs recent enough to understand resize inodes because the feature was introduced in 2006.
The other alternative is simply to change EXT2_OFFSET to always not clash with the resize inode ... that would work for all cases.

If mke2fs would be too old to know about the resize_inode, I'd expect it to be able to still handle the old calling syntax (as it did before). So my inital though would be, that if the call with -O^resize_inode fails, we simply call the commmand again without that option.

But given that's 16 years ago when it was introduced, I think we should be fine with your patch as it is. I'll apply it shortly.

Thanks!
Helge

Helge Deller

2019-07-03 17:59 UTC #4 lore raw

Quoted 45 lines · Helge Deller

Quoted 44 lines · James Bottomley
Quoted 43 lines · Helge Deller
Quoted 42 lines · James Bottomley
palo is producing corrupt filesystems because ext2 can't cope with any of the resize_inode, which is traditionally placed at blocks 3- 258, being in the badblocks list. If this happens, mke2fs silently produces a corrupt filesystem image and the palo partition will eventually trigger a filesystem error. The fix is to force palo to specify -O^resize_inode to mke2fs which prevents ext2/3 from allocating a resize_inode (and thus prevents the filesystem from being
resized).
Signed-off-by James Bottomley <[email protected]
om>
---
palo/palo.c | 8 ++++++--
   1 file changed, 6 insertions(+), 2 deletions(-)
palo/palo.c +0 -0
index 68b85cf..e088993 100644
@@ -443,7 +443,11 @@ do_cdrom(int media, int kernel32, int
 kernel64,
    #define EXT2_HOLE    ((MAXBLSIZE + 1) / EXT2_BLOCKSIZE)
 
    /* offset in bytes before start of hole,  ext2 doesn't allow
holes at
- * to cover the first four blocks of the filesystem */
+ * to cover the first four blocks of the filesystem
+ *
+ * Note: modern ext2/3 has a resize_inode covering blocks 3-258 so you
+ * must either always include the -O^resize_inode when creating the
+ * filesystem or define EXT2_OFFSET to (259*EXT2_BLOCKSIZE)*/ #define EXT2_OFFSET (4*EXT2_BLOCKSIZE)
int
palo/palo.c +0 -0
@@ -502,7 +506,7 @@ do_formatted(int init, int media, const char
 *medianame, int partition,
            }
        }
 

Quoted 4 lines

Quoted 4 lines
Quoted 4 lines
palo/palo.c do_formatted(int init, int media, const char · line 512
Quoted 4 lines
palo/palo.c +1 -1
-    sprintf(cmd, "mke2fs %s -b %d -l %s %s", do_format == 3 ?
 "-j" : "",
+    sprintf(cmd, "mke2fs %s -O^resize_inode -b %d -l %s %s",
 do_format == 3 ? "-j" : "",

Now included in the palo v2.01 release...

Helge