ext4: propagate flags to ext4_convert_unwritten_extents_endio()

ext4: propagate flags to ext4_convert_unwritten_extents_endio()

Currently, callers like ext4_convert_unwritten_extents() pass
EXT4_EX_NOCACHE flag to avoid caching extents however this is not
respected by ext4_convert_unwritten_extents_endio(). Hence, modify it to
accept flags from the caller and to pass the flags on to other extent
manipulation functions it calls. This makes sure the NOCACHE flag is
respected throughout the code path.

Also, since the caller already passes METADATA_NOFAIL and CONVERT flags
we don't need to explicitly pass it anymore.

Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://patch.msgid.link/7c2139e0ad32c49c19b194f72219e15d613de284.1769149131.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>