direct-io: do not merge logically non-contiguous requests

[net-next-2.6.git] / fs / direct-io.c

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 5949947b060a839327f9b7ff27a915d30e6e7894..da111aacb46eed8e0ba2d94ffcba137d4fcb009a 100644 (file)
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -632,10 +632,26 @@ static int dio_send_cur_page(struct dio *dio)
        int ret = 0;
 
        if (dio->bio) {
+               loff_t cur_offset = dio->block_in_file << dio->blkbits;
+               loff_t bio_next_offset = dio->logical_offset_in_bio +
+                       dio->bio->bi_size;
+
                /*
-                * See whether this new request is contiguous with the old
+                * See whether this new request is contiguous with the old.
+                *
+                * Btrfs cannot handl having logically non-contiguous requests
+                * submitted.  For exmple if you have
+                *
+                * Logical:  [0-4095][HOLE][8192-12287]
+                * Phyiscal: [0-4095]      [4096-8181]
+                *
+                * We cannot submit those pages together as one BIO.  So if our
+                * current logical offset in the file does not equal what would
+                * be the next logical offset in the bio, submit the bio we
+                * have.
                 */
-               if (dio->final_block_in_bio != dio->cur_page_block)
+               if (dio->final_block_in_bio != dio->cur_page_block ||
+                   cur_offset != bio_next_offset)
                        dio_bio_submit(dio);
                /*
                 * Submit now if the underlying fs is about to perform a