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. 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
