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[PATCH 02/14] xfs: fix rounding in xfs_free_file_space

To: xfs@xxxxxxxxxxx
Subject: [PATCH 02/14] xfs: fix rounding in xfs_free_file_space
From: Dave Chinner <david@xxxxxxxxxxxxx>
Date: Mon, 20 May 2013 09:51:09 +1000
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <1369007481-15185-1-git-send-email-david@xxxxxxxxxxxxx>
References: <1369007481-15185-1-git-send-email-david@xxxxxxxxxxxxx>
From: Dave Chinner <dchinner@xxxxxxxxxx>

The offset passed into xfs_free_file_space() needs to be rounded
down to a certain size, but the rounding mask is built by a 32 bit
variable. Hence the mask will always mask off the upper 32 bits of
the offset and lead to incorrect writeback and invalidation ranges.

This is not actually exposed as a bug because we writeback and
invalidate from the rounded offset to the end of the file, and hence
the offset we are actually punching a hole out of will always be
covered by the code. This needs fixing, however, if we ever want to
use exact ranges for writeback/invalidation here...

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
 fs/xfs/xfs_vnodeops.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 1501f4f..0176bb2 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -1453,7 +1453,7 @@ xfs_free_file_space(
        xfs_mount_t             *mp;
        int                     nimap;
        uint                    resblks;
-       uint                    rounding;
+       xfs_off_t               rounding;
        int                     rt;
        xfs_fileoff_t           startoffset_fsb;
        xfs_trans_t             *tp;
@@ -1482,7 +1482,7 @@ xfs_free_file_space(
-       rounding = max_t(uint, 1 << mp->m_sb.sb_blocklog, PAGE_CACHE_SIZE);
+       rounding = max_t(xfs_off_t, 1 << mp->m_sb.sb_blocklog, PAGE_CACHE_SIZE);
        ioffset = offset & ~(rounding - 1);
        error = -filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
                                              ioffset, -1);

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