[PATCH 1/2] btrfs: Remove EXTENT_WRITEBACK

[PATCH 1/2] btrfs: Remove EXTENT_WRITEBACK

[Nikolay Borisov]

This flag was introduced in a52d9a8033c4 ("Btrfs: Extent based page
cache code.") and subsequently it's usage effectively was removed by
1edbb734b4e0 ("Btrfs: reduce CPU usage in the extent_state tree") and
f2a97a9dbd86 ("btrfs: remove all unused functions"). Just remove it,
no functional changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/extent_io.c |  3 +--
 fs/btrfs/extent_io.h | 31 +++++++++++++++----------------
 2 files changed, 16 insertions(+), 18 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index a958cbd8b11a..d3cd6cb6c1d8 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4289,8 +4289,7 @@ int try_release_extent_mapping(struct page *page, gfp_t mask)
 			}
 			if (!test_range_bit(tree, em->start,
 					    extent_map_end(em) - 1,
-					    EXTENT_LOCKED | EXTENT_WRITEBACK,
-					    0, NULL)) {
+					    EXTENT_LOCKED, 0, NULL)) {
 				set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
 					&btrfs_inode->runtime_flags);
 				remove_extent_mapping(map, em);
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 7012ff27da82..0ed7a572673d 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -9,22 +9,21 @@
 
 /* bits for the extent state */
 #define EXTENT_DIRTY		(1U << 0)
-#define EXTENT_WRITEBACK	(1U << 1)
-#define EXTENT_UPTODATE		(1U << 2)
-#define EXTENT_LOCKED		(1U << 3)
-#define EXTENT_NEW		(1U << 4)
-#define EXTENT_DELALLOC		(1U << 5)
-#define EXTENT_DEFRAG		(1U << 6)
-#define EXTENT_BOUNDARY		(1U << 9)
-#define EXTENT_NODATASUM	(1U << 10)
-#define EXTENT_CLEAR_META_RESV	(1U << 11)
-#define EXTENT_NEED_WAIT	(1U << 12)
-#define EXTENT_DAMAGED		(1U << 13)
-#define EXTENT_NORESERVE	(1U << 14)
-#define EXTENT_QGROUP_RESERVED	(1U << 15)
-#define EXTENT_CLEAR_DATA_RESV	(1U << 16)
-#define EXTENT_DELALLOC_NEW	(1U << 17)
-#define EXTENT_IOBITS		(EXTENT_LOCKED | EXTENT_WRITEBACK)
+#define EXTENT_UPTODATE		(1U << 1)
+#define EXTENT_LOCKED		(1U << 2)
+#define EXTENT_NEW		(1U << 3)
+#define EXTENT_DELALLOC		(1U << 4)
+#define EXTENT_DEFRAG		(1U << 5)
+#define EXTENT_BOUNDARY		(1U << 6)
+#define EXTENT_NODATASUM	(1U << 7)
+#define EXTENT_CLEAR_META_RESV	(1U << 8)
+#define EXTENT_NEED_WAIT	(1U << 9)
+#define EXTENT_DAMAGED		(1U << 10)
+#define EXTENT_NORESERVE	(1U << 11)
+#define EXTENT_QGROUP_RESERVED	(1U << 12)
+#define EXTENT_CLEAR_DATA_RESV	(1U << 13)
+#define EXTENT_DELALLOC_NEW	(1U << 14)
+#define EXTENT_IOBITS		(EXTENT_LOCKED)
 #define EXTENT_DO_ACCOUNTING    (EXTENT_CLEAR_META_RESV | \
 				 EXTENT_CLEAR_DATA_RESV)
 #define EXTENT_CTLBITS		(EXTENT_DO_ACCOUNTING)
-- 
2.17.1

[PATCH 2/2] btrfs: Remove EXTENT_IOBITS

[Nikolay Borisov]

This flag just became synonymous to EXTENT_LOCKED, so just remove it and
used EXTENT_LOCKED directly. No functional changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/extent_io.c | 11 +++++------
 fs/btrfs/extent_io.h |  1 -
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index d3cd6cb6c1d8..a04e0328f1bb 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -427,7 +427,7 @@ static void merge_state(struct extent_io_tree *tree,
 	struct extent_state *other;
 	struct rb_node *other_node;
 
-	if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
+	if (state->state & (EXTENT_LOCKED | EXTENT_BOUNDARY))
 		return;
 
 	other_node = rb_prev(&state->rb_node);
@@ -645,7 +645,7 @@ int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 	if (delete)
 		bits |= ~EXTENT_CTLBITS;
 
-	if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
+	if (bits & (EXTENT_LOCKED | EXTENT_BOUNDARY))
 		clear = 1;
 again:
 	if (!prealloc && gfpflags_allow_blocking(mask)) {
@@ -877,7 +877,7 @@ static void cache_state(struct extent_state *state,
 			struct extent_state **cached_ptr)
 {
 	return cache_state_if_flags(state, cached_ptr,
-				    EXTENT_IOBITS | EXTENT_BOUNDARY);
+				    EXTENT_LOCKED | EXTENT_BOUNDARY);
 }
 
 /*
@@ -4233,10 +4233,9 @@ static int try_release_extent_state(struct extent_io_tree *tree,
 	u64 end = start + PAGE_SIZE - 1;
 	int ret = 1;
 
-	if (test_range_bit(tree, start, end,
-			   EXTENT_IOBITS, 0, NULL))
+	if (test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL)) {
 		ret = 0;
-	else {
+	} else {
 		/*
 		 * at this point we can safely clear everything except the
 		 * locked bit and the nodatasum bit
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 0ed7a572673d..f41797690839 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -23,7 +23,6 @@
 #define EXTENT_QGROUP_RESERVED	(1U << 12)
 #define EXTENT_CLEAR_DATA_RESV	(1U << 13)
 #define EXTENT_DELALLOC_NEW	(1U << 14)
-#define EXTENT_IOBITS		(EXTENT_LOCKED)
 #define EXTENT_DO_ACCOUNTING    (EXTENT_CLEAR_META_RESV | \
 				 EXTENT_CLEAR_DATA_RESV)
 #define EXTENT_CTLBITS		(EXTENT_DO_ACCOUNTING)
-- 
2.17.1

Re: [PATCH 2/2] btrfs: Remove EXTENT_IOBITS

[David Sterba]

On Thu, Mar 14, 2019 at 03:28:31PM +0200, Nikolay Borisov wrote:
> This flag just became synonymous to EXTENT_LOCKED, so just remove it and
> used EXTENT_LOCKED directly. No functional changes.

Ok. The only reason to have an alias would be to make it explicit that
it's for IO, but _LOCKED is used in that context too in other places so
I don't think we're losing any information here.

Reviewed-by: David Sterba <dsterba@suse.com>

1 and 2 added to misc-next, thanks.