ext4: get rid of EXT4_GET_BLOCKS_NO_LOCK flag

When dioread_nolock mode is enabled, we grab i_data_sem in
ext4_ext_direct_IO() and therefore we need to instruct _ext4_get_block()
not to grab i_data_sem again using EXT4_GET_BLOCKS_NO_LOCK. However
holding i_data_sem over overwrite direct IO isn't needed these days. We
have exclusion against truncate / hole punching because we increase
i_dio_count under i_mutex in ext4_ext_direct_IO() so once
ext4_file_write_iter() verifies blocks are allocated & written, they are
guaranteed to stay so during the whole direct IO even after we drop
i_mutex.

So we can just remove this locking abuse and the no longer necessary
EXT4_GET_BLOCKS_NO_LOCK flag.

Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 594b4b2..5f2ace5 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -42,8 +42,7 @@
 	{ EXT4_GET_BLOCKS_CONVERT,		"CONVERT" },		\
 	{ EXT4_GET_BLOCKS_METADATA_NOFAIL,	"METADATA_NOFAIL" },	\
 	{ EXT4_GET_BLOCKS_NO_NORMALIZE,		"NO_NORMALIZE" },	\
-	{ EXT4_GET_BLOCKS_KEEP_SIZE,		"KEEP_SIZE" },		\
-	{ EXT4_GET_BLOCKS_NO_LOCK,		"NO_LOCK" })
+	{ EXT4_GET_BLOCKS_KEEP_SIZE,		"KEEP_SIZE" })
 
 #define show_mflags(flags) __print_flags(flags, "",	\
 	{ EXT4_MAP_NEW,		"N" },			\