Josef Bacik
2013-Aug-30 18:38 UTC
[PATCH] Btrfs: actually limit the size of delalloc range
So forever we have had this thing to limit the amount of delalloc pages
we''ll
setup to be written out to 128mb. This is because we have to lock all the pages
in this range, so anything above this gets a bit unweildly, and also without a
limit we''ll happily allocate gigantic chunks of disk space. Turns out
our check
for this wasn''t quite right, we wouldn''t actually limit the
chunk we wanted to
write out, we''d just stop looking for more space after we went over the
limit.
So if you do a giant 20gb dd on my box with lots of ram I could get 2gig
extents. This is fine normally, except when you go to relocate these extents
and we can''t find enough space to relocate these moster extents, since
we have
to be able to allocate exactly the same sized extent to move it around. So fix
this by actually enforcing the limit. With this patch I''m no longer
seeing
giant 1.5gb extents. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
---
fs/btrfs/extent_io.c | 8 +++++---
1 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 4068d40..bf6e526 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1481,10 +1481,12 @@ static noinline u64 find_delalloc_range(struct
extent_io_tree *tree,
*end = state->end;
cur_start = state->end + 1;
node = rb_next(node);
- if (!node)
- break;
total_bytes += state->end - state->start + 1;
- if (total_bytes >= max_bytes)
+ if (total_bytes >= max_bytes) {
+ *end = *start + max_bytes - 1;
+ break;
+ }
+ if (!node)
break;
}
out:
--
1.7.7.6
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html