Re: Boot failure with ext2 and initrds

[Mingming Cao <cmm@us.ibm.com>]

On Mon, 2006-11-20 at 20:54 +0000, Hugh Dickins wrote:
> Not found anything relevant, but I keep noticing these lines
> in ext2_try_to_allocate_with_rsv(), ext3 and ext4 similar:
> 
> 		} else if (grp_goal > 0 &&
> 				(my_rsv->rsv_end - grp_goal + 1) < *count)
> 			try_to_extend_reservation(my_rsv, sb,
> 					*count-my_rsv->rsv_end + grp_goal - 1);
> 
> They're wrong, a no-op in most groups, aren't they?  rsv_end is an
> absolute block number, whereas grp_goal is group-relative, so the
> calculation ought to bring in group_first_block?  Or I'm confused.
> 

You are right, thanks. Here are two patches, to fix this bug in ext3/4
and ext2 correspondingly.


Signed-Off-By: Mingming Cao <cmm@us.ibm.com>

---

 linux-2.6.19-rc5-cmm/fs/ext3/balloc.c |   12 ++++++++----
 linux-2.6.19-rc5-cmm/fs/ext4/balloc.c |   12 ++++++++----
 2 files changed, 16 insertions(+), 8 deletions(-)

diff -puN fs/ext3/balloc.c~ext34_extend_reservation_window_fix fs/ext3/balloc.c
--- linux-2.6.19-rc5/fs/ext3/balloc.c~ext34_extend_reservation_window_fix	2006-11-20 15:58:11.000000000 -0800
+++ linux-2.6.19-rc5-cmm/fs/ext3/balloc.c	2006-11-20 15:58:11.000000000 -0800
@@ -1307,10 +1307,14 @@ ext3_try_to_allocate_with_rsv(struct sup
 			if (!goal_in_my_reservation(&my_rsv->rsv_window,
 							grp_goal, group, sb))
 				grp_goal = -1;
-		} else if (grp_goal > 0 &&
-			  (my_rsv->rsv_end-grp_goal+1) < *count)
-			try_to_extend_reservation(my_rsv, sb,
-					*count-my_rsv->rsv_end + grp_goal - 1);
+		} else if (grp_goal > 0) {
+			int curr = my_rsv->rsv_end -
+					(grp_goal + group_first_block) + 1;
+
+			if (curr < *count)
+				try_to_extend_reservation(my_rsv, sb,
+							*count - curr);
+			}
 
 		if ((my_rsv->rsv_start > group_last_block) ||
 				(my_rsv->rsv_end < group_first_block)) {
diff -puN fs/ext4/balloc.c~ext34_extend_reservation_window_fix fs/ext4/balloc.c
--- linux-2.6.19-rc5/fs/ext4/balloc.c~ext34_extend_reservation_window_fix	2006-11-20 15:58:11.000000000 -0800
+++ linux-2.6.19-rc5-cmm/fs/ext4/balloc.c	2006-11-20 15:58:11.000000000 -0800
@@ -1324,10 +1324,14 @@ ext4_try_to_allocate_with_rsv(struct sup
 			if (!goal_in_my_reservation(&my_rsv->rsv_window,
 							grp_goal, group, sb))
 				grp_goal = -1;
-		} else if (grp_goal > 0 &&
-			  (my_rsv->rsv_end-grp_goal+1) < *count)
-			try_to_extend_reservation(my_rsv, sb,
-					*count-my_rsv->rsv_end + grp_goal - 1);
+		} else if (grp_goal > 0) {
+			int curr = my_rsv->rsv_end -
+					(grp_goal + group_first_block) + 1;
+
+			if (curr < *count)
+				try_to_extend_reservation(my_rsv, sb,
+							*count - curr);
+			}
 
 		if ((my_rsv->rsv_start > group_last_block) ||
 				(my_rsv->rsv_end < group_first_block)) {


Sync up ext2 with ext3/4 for the extend reservation window bug.

Signed-Off-By: Mingming Cao <cmm@us.ibm.com>



---

 linux-2.6.19-rc5-cmm/fs/ext2/balloc.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff -puN fs/ext2/balloc.c~ext2_reservation_extend_window_fix fs/ext2/balloc.c
--- linux-2.6.19-rc5/fs/ext2/balloc.c~ext2_reservation_extend_window_fix	2006-11-20 16:05:36.000000000 -0800
+++ linux-2.6.19-rc5-cmm/fs/ext2/balloc.c	2006-11-20 16:05:36.000000000 -0800
@@ -1091,10 +1091,14 @@ ext2_try_to_allocate_with_rsv(struct sup
 			if (!goal_in_my_reservation(&my_rsv->rsv_window,
 							grp_goal, group, sb))
 				grp_goal = -1;
-		} else if (grp_goal > 0 &&
-				(my_rsv->rsv_end - grp_goal + 1) < *count)
-			try_to_extend_reservation(my_rsv, sb,
-					*count-my_rsv->rsv_end + grp_goal - 1);
+		} else if (grp_goal > 0) {
+			int curr = my_rsv->rsv_end -
+					(grp_goal + group_first_block) + 1;
+
+			if (curr < *count)
+				try_to_extend_reservation(my_rsv, sb,
+							*count - curr);
+			}
 
 		if ((my_rsv->rsv_start >=
 			group_first_block + EXT2_BLOCKS_PER_GROUP(sb))

_


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