Replace get_ext_path macro with an inline function,
since this macro looks like a function call but its arguments
get modified. Ted pointed this out, thanks.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This function means moving extents every page, so change its name from
move_exgtent_par_page().
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.co.jp>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The ext4_move_extents() functions checks with BUG_ON() whether the
exchanged blocks count accords with request blocks count.  But, if the
target range (orig_start + len) includes sparse block(s), 'moved_len'
(exchanged blocks count) does not agree with 'len' (request blocks
count), since sparse block is not counted in 'moved_len'.  This causes
us to hit the BUG_ON(), even though the function succeeded.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The mext_check_arguments() function in move_extents.c has wrong
comparisons.  orig_start which is passed from user-space is block
unit, but i_size of inode is byte unit, therefore the checks do not
work fine.  This mis-check leads to the overflow of 'len' and then
hits BUG_ON() in ext4_move_extents().  The patch fixes this issue.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Reviewed-by: NGreg Freemyer <greg.freemyer@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

move_extent_par_page calls a_ops->write_begin() to increase journal
handler's reference count. However, if either mext_replace_branches()
or ext4_get_block fails, the increased reference count isn't
decreased. This will cause a later attempt to umount of the fs to hang
forever. The patch addresses the issue by calling ext4_journal_stop()
if page is not NULL (which means a_ops->write_end() isn't invoked).
Signed-off-by: NPeng Tao <bergwolf@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The EXT4_IOC_MOVE_EXT exchanges the blocks between orig_fd and donor_fd,
and then write the file data of orig_fd to donor_fd.
ext4_mext_move_extent() is the main fucntion of ext4 online defrag,
and this patch includes all functions related to ext4 online defrag.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: NTakashi Sato <t-sato@yk.jp.nec.com>
Signed-off-by: NKazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>