On 5/24/11 5:06 PM, Jiaying Zhang wrote: > On Tue, May 24, 2011 at 7:30 AM, Eric Sandeen <sandeen@xxxxxxxxxx> wrote: >> On 5/23/11 2:19 PM, Theodore Ts'o wrote: >>> In commit c8d46e41 (ext4: Add flag to files with blocks intentionally >>> past EOF), if the EOFBLOCKS_FL flag is set, we call ext4_truncate() >>> before calling vmtruncate(). This caused any allocated but unwritten >>> blocks created by calling fallocate() with the FALLOC_FL_KEEP_SIZE >>> flag to be dropped. This was done to make to make sure that >>> EOFBLOCKS_FL would not be cleared while still leaving blocks past >>> i_size allocated. This was not necessary, since ext4_truncate() >>> guarantees that blocks past i_size will be dropped, even in the case >>> where truncate() has increased i_size before calling ext4_truncate(). >>> >>> So fix this by removing the EOFBLOCKS_FL special case treatment in >>> ext4_setattr(). In addition, use truncate_setsize() followed by a >>> call to ext4_truncate() instead of using vmtruncate(). This is more >>> efficient since it skips the call to inode_newsize_ok(), which has >>> been checked already by inode_change_ok(). This is also in a win in >>> the case where EOFBLOCKS_FL is set since it avoids calling >>> ext4_truncate() twice. >>> >>> Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx> >>> --- >>> Jiayingz pointed out that in the case where we fallocate 12k, write 4k, and >>> then truncate to 4k, we should discard the excess fallocate'd blocks. So if >>> attr->ia_size == inode.i_size, we can skip the truncate_setsize() call, but >>> if the EOFBLOCKS_FL flag is set, we should still call ext4_truncate(). >> >> are there xfstests which cover this explicitly? It should be simple to write. >> > Vivek has written a xfstest to cover this and more fallocate/truncate cases: > http://old.nabble.com/-PATCH--xfstests%3A-test-fallocate%2C-write%2C-ftruncate-combinations.-to31666685.html#a31666685 ah, right - ok, thanks! Sorry for not keeping up. -Eric > Jiaying > >> If filesystem behavior differs we can always make ext4-only tests. >> >> -Eric >> -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
