btrfs: sink the failed_start parameter to set_extent_bit

The @failed_start parameter is only paired with @exclusive_bits, and
those parameters are only used for EXTENT_LOCKED bit, which have their
own wrappers lock_extent_bits().

Thus for regular set_extent_bit() calls, the failed_start makes no
sense, just sink the parameter.

Also, since @failed_start and @exclusive_bits are used in pairs, add
an assert to make it obvious.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: adam900710

fs/btrfs/extent-io-tree.h

@@ -154,15 +154,14 @@ static inline int clear_extent_bits(struct extent_io_tree *tree, u64 start,
 int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
 			   unsigned bits, struct extent_changeset *changeset);
 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
-		   unsigned bits, u64 *failed_start,
-		   struct extent_state **cached_state, gfp_t mask);
+		   unsigned bits, struct extent_state **cached_state, gfp_t mask);
 int set_extent_bits_nowait(struct extent_io_tree *tree, u64 start, u64 end,
 			   unsigned bits);
 
 static inline int set_extent_bits(struct extent_io_tree *tree, u64 start,
 		u64 end, unsigned bits)
 {
-	return set_extent_bit(tree, start, end, bits, NULL, NULL, GFP_NOFS);
+	return set_extent_bit(tree, start, end, bits, NULL, GFP_NOFS);
 }
 
 static inline int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
@@ -175,8 +174,7 @@ static inline int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
 static inline int set_extent_dirty(struct extent_io_tree *tree, u64 start,
 		u64 end, gfp_t mask)
 {
-	return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL,
-			      NULL, mask);
+	return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL, mask);
 }
 
 static inline int clear_extent_dirty(struct extent_io_tree *tree, u64 start,
@@ -197,28 +195,27 @@ static inline int set_extent_delalloc(struct extent_io_tree *tree, u64 start,
 {
 	return set_extent_bit(tree, start, end,
 			      EXTENT_DELALLOC | EXTENT_UPTODATE | extra_bits,
-			      NULL, cached_state, GFP_NOFS);
+			      cached_state, GFP_NOFS);
 }
 
 static inline int set_extent_defrag(struct extent_io_tree *tree, u64 start,
 		u64 end, struct extent_state **cached_state)
 {
 	return set_extent_bit(tree, start, end,
 			      EXTENT_DELALLOC | EXTENT_UPTODATE | EXTENT_DEFRAG,
-			      NULL, cached_state, GFP_NOFS);
+			      cached_state, GFP_NOFS);
 }
 
 static inline int set_extent_new(struct extent_io_tree *tree, u64 start,
 		u64 end)
 {
-	return set_extent_bit(tree, start, end, EXTENT_NEW, NULL, NULL,
-			GFP_NOFS);
+	return set_extent_bit(tree, start, end, EXTENT_NEW, NULL, GFP_NOFS);
 }
 
 static inline int set_extent_uptodate(struct extent_io_tree *tree, u64 start,
 		u64 end, struct extent_state **cached_state, gfp_t mask)
 {
-	return set_extent_bit(tree, start, end, EXTENT_UPTODATE, NULL,
+	return set_extent_bit(tree, start, end, EXTENT_UPTODATE,
 			      cached_state, mask);
 }
 

fs/btrfs/extent_io.c

@@ -980,6 +980,10 @@ __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 	btrfs_debug_check_extent_io_range(tree, start, end);
 	trace_btrfs_set_extent_bit(tree, start, end - start + 1, bits);
 
+	if (exclusive_bits)
+		ASSERT(failed_start);
+	else
+		ASSERT(failed_start == NULL);
 again:
 	if (!prealloc && gfpflags_allow_blocking(mask)) {
 		/*
@@ -1180,11 +1184,10 @@ __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 }
 
 int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
-		   unsigned bits, u64 * failed_start,
-		   struct extent_state **cached_state, gfp_t mask)
+		   unsigned bits, struct extent_state **cached_state, gfp_t mask)
 {
-	return __set_extent_bit(tree, start, end, bits, 0, failed_start,
-				cached_state, mask, NULL);
+	return __set_extent_bit(tree, start, end, bits, 0, NULL, cached_state,
+			        mask, NULL);
 }
 
 

fs/btrfs/inode.c

@@ -4717,8 +4717,7 @@ int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,
 
 	if (only_release_metadata)
 		set_extent_bit(&BTRFS_I(inode)->io_tree, block_start,
-				block_end, EXTENT_NORESERVE, NULL, NULL,
-				GFP_NOFS);
+			       block_end, EXTENT_NORESERVE, NULL, GFP_NOFS);
 
 out_unlock:
 	if (ret) {