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[PATCH] [XFS] Free buffer pages array unconditionally

To: xfs@xxxxxxxxxxx
Subject: [PATCH] [XFS] Free buffer pages array unconditionally
From: Dave Chinner <david@xxxxxxxxxxxxx>
Date: Wed, 2 Dec 2009 17:12:13 +1100
The code in xfs_free_buf() only attempts to free the b_pages array if the
buffer is a page cache backed or page allocated buffer. The extra log buffer
that is used when the log wraps uses pages that are allocated to a different
log buffer, but it still has a b_pages array allocated when those pages
are associated to with the extra buffer in xfs_buf_associate_memory.

Hence we need to always attempt to free the b_pages array when tearing
down a buffer, not just on buffers that are explicitly marked as page bearing
buffers. This fixes a leak detected by the kernel memory leak code.

Signed-off-by: Dave Chinner <david@xxxxxxxxxxxxx>
---
 fs/xfs/linux-2.6/xfs_buf.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index 4ddc973..4b84bbc 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -316,7 +316,7 @@ STATIC void
 _xfs_buf_free_pages(
        xfs_buf_t       *bp)
 {
-       if (bp->b_pages != bp->b_page_array) {
+       if (bp->b_pages && bp->b_pages != bp->b_page_array) {
                kmem_free(bp->b_pages);
        }
 }
@@ -349,9 +349,9 @@ xfs_buf_free(
                                ASSERT(!PagePrivate(page));
                        page_cache_release(page);
                }
-               _xfs_buf_free_pages(bp);
        }
 
+       _xfs_buf_free_pages(bp);
        xfs_buf_deallocate(bp);
 }
 
-- 
1.6.5

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