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authorChris Mason <clm@fb.com>2014-09-02 12:12:52 +1000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-09-17 09:22:18 -0700
commit2f3219f6e413ee5f9690876f3e8fa9bb0213d9ad (patch)
tree008080476fb09697704bc413c5ce68e626bcb605 /fs
parentd2f8462e2213eb237eca50b5c12bc75037f06b87 (diff)
xfs: don't zero partial page cache pages during O_DIRECT writes
commit 85e584da3212140ee80fd047f9058bbee0bc00d5 upstream. xfs is using truncate_pagecache_range to invalidate the page cache during DIO reads. This is different from the other filesystems who only invalidate pages during DIO writes. truncate_pagecache_range is meant to be used when we are freeing the underlying data structs from disk, so it will zero any partial ranges in the page. This means a DIO read can zero out part of the page cache page, and it is possible the page will stay in cache. buffered reads will find an up to date page with zeros instead of the data actually on disk. This patch fixes things by using invalidate_inode_pages2_range instead. It preserves the page cache invalidation, but won't zero any pages. [dchinner: catch error and warn if it fails. Comment.] Signed-off-by: Chris Mason <clm@fb.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/xfs/xfs_file.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index a9814050714b..055459999660 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -295,7 +295,16 @@ xfs_file_read_iter(
xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL);
return ret;
}
- truncate_pagecache_range(VFS_I(ip), pos, -1);
+
+ /*
+ * Invalidate whole pages. This can return an error if
+ * we fail to invalidate a page, but this should never
+ * happen on XFS. Warn if it does fail.
+ */
+ ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping,
+ pos >> PAGE_CACHE_SHIFT, -1);
+ WARN_ON_ONCE(ret);
+ ret = 0;
}
xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
}