* [PATCH] ext4: Trim allocation requests to group size
@ 2017-01-10 9:32 Jan Kara
2017-02-01 19:07 ` Theodore Ts'o
0 siblings, 1 reply; 2+ messages in thread
From: Jan Kara @ 2017-01-10 9:32 UTC (permalink / raw)
To: Ted Tso; +Cc: linux-ext4, Kirill A. Shutemov, Jan Kara
If filesystem groups are artifically small (using parameter -g to
mkfs.ext4), ext4_mb_normalize_request() can result in a request that is
larger than a block group. Trim the request size to not confuse
allocation code.
Reported-by: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/ext4/mballoc.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 7ae43c59bc79..2e9fc7a61048 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3123,6 +3123,13 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
if (ar->pright && start + size - 1 >= ar->lright)
size -= start + size - ar->lright;
+ /*
+ * Trim allocation request for filesystems with artificially small
+ * groups.
+ */
+ if (size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb))
+ size = EXT4_BLOCKS_PER_GROUP(ac->ac_sb);
+
end = start + size;
/* check we don't cross already preallocated blocks */
--
2.10.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] ext4: Trim allocation requests to group size
2017-01-10 9:32 [PATCH] ext4: Trim allocation requests to group size Jan Kara
@ 2017-02-01 19:07 ` Theodore Ts'o
0 siblings, 0 replies; 2+ messages in thread
From: Theodore Ts'o @ 2017-02-01 19:07 UTC (permalink / raw)
To: Jan Kara; +Cc: linux-ext4, Kirill A. Shutemov
On Tue, Jan 10, 2017 at 10:32:01AM +0100, Jan Kara wrote:
> If filesystem groups are artifically small (using parameter -g to
> mkfs.ext4), ext4_mb_normalize_request() can result in a request that is
> larger than a block group. Trim the request size to not confuse
> allocation code.
>
> Reported-by: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Signed-off-by: Jan Kara <jack@suse.cz>
Thanks, applied.
- Ted
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