On 12/03/2012 09:48 AM, Theodore Ts'o wrote: > On Wed, Oct 24, 2012 at 10:55:18AM +0800, Tao Ma wrote: >> + EXT4_STATE_MAY_INLINE_DATA, /* may have in-inode data */ > > Can you write a paragraph or two about exactly what the semantics are > of this state flag --- what it means, when it should be set, and when > it should be cleared, etc.? > > I'm not entirely sure I understand why you test > EXT4_STATE_MAY_INLINE_DATA versus simply calling > ext4_has_inline_data() in various places. OK, so in general, EXT4_STATE_MAY_INLINE_DATA is a flag that show that the file has a potential to be inlined, but there is no guarantee it is inlined. So when the inode is created and the volume has inline-data support, this flag is set. And when the write_begin comes, we have no idea whether it is OK or not to create an inline file, so if this flag is set, we just try to call the inline-data stuff to see whether it works. If it succeeds, that is cool. But if not, this flag is cleared and we will not trap to inline-data stuff for the future write_begin. The reason why ext4_has_inline_data() doesn't work here is that a new file has no inline data but has the potential to be inlined. Thanks Tao -- 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
