On Thu, Oct 08, 2009 at 06:13:16PM -0700, Mingming wrote: > ext4: Direct IO return value fix for holes/fallocate > > When direct IO complete, ext4 will convert unwritten extents to written, > for > writes over preallocated space, or holes. > > ext4_direct_IO should returns the number of bytes read/write on success. > However there is a bug that cause ext4_direct_IO returns the number of > bytes converted to written extents, which is 0 on success. This bug > causes > direct IO falls back to buffered IO even on sucessful rewrites or > preallocated space. > > Signed-off-by: Mingming Cao <cmm@xxxxxxxxxx> I fixed up some white space issues, and rewrote the patch descriptions as follows: ext4: fix ext4_ext_direct_IO()'s return value after converting uninit extents After a direct I/O request covering an uninitalized extent (i.e., created using the fallocate system call) or a hole in a file, ext4 will convert the uninitialized extent so it is marked as initialized by calling ext4_convert_unwritten_extents(). This function returns zero on success. This return value was getting returned by ext4_direct_IO(); however the file system's direct_IO function is supposed to return the number of bytes read or written on a success. By returning zero, it confused the direct I/O code into falling back to buffered I/O unnecessarily. Signed-off-by: Mingming Cao <cmm@xxxxxxxxxx> Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx> Added to the patch queue. - Ted -- 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
