diff mbox series

[2/2] btrfs: simplify the inline extent map creation

Message ID da18eebca4fdff1e0be286c18aee0359c074d3f8.1712038308.git.wqu@suse.com (mailing list archive)
State New, archived
Headers show
Series btrfs: more explaination on extent_map members | expand

Commit Message

Qu Wenruo April 2, 2024, 6:23 a.m. UTC 
With the tree-checker ensuring all inline file extents starts at file
offset 0 and has a length no larger than sectorsize, we can simplify the
calculation to assigned those fixes values directly.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/file-item.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

Comments

Filipe Manana April 2, 2024, 3:50 p.m. UTC | #1 
On Tue, Apr 2, 2024 at 7:24 AM Qu Wenruo <wqu@suse.com> wrote:
>
> With the tree-checker ensuring all inline file extents starts at file
> offset 0 and has a length no larger than sectorsize, we can simplify the
> calculation to assigned those fixes values directly.
>
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>  fs/btrfs/file-item.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
> index e58fb5347e65..de3ccee38572 100644
> --- a/fs/btrfs/file-item.c
> +++ b/fs/btrfs/file-item.c
> @@ -1265,18 +1265,19 @@ void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
>         struct extent_buffer *leaf = path->nodes[0];
>         const int slot = path->slots[0];
>         struct btrfs_key key;
> -       u64 extent_start, extent_end;
> +       u64 extent_start;
>         u64 bytenr;
>         u8 type = btrfs_file_extent_type(leaf, fi);
>         int compress_type = btrfs_file_extent_compression(leaf, fi);
>
>         btrfs_item_key_to_cpu(leaf, &key, slot);
>         extent_start = key.offset;
> -       extent_end = btrfs_file_extent_end(path);
>         em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
>         em->generation = btrfs_file_extent_generation(leaf, fi);
>         if (type == BTRFS_FILE_EXTENT_REG ||
>             type == BTRFS_FILE_EXTENT_PREALLOC) {
> +               u64 extent_end = btrfs_file_extent_end(path);
> +

This can be made const or better, since it's only used in one place
now and fits within 80 characters, just use the expression directly
instead of using a variable.

>                 em->start = extent_start;
>                 em->len = extent_end - extent_start;

Which is here:   em->len = btrfs_file_extent_end(path) - extent_start;

>                 em->orig_start = extent_start -
> @@ -1299,9 +1300,12 @@ void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
>                                 em->flags |= EXTENT_FLAG_PREALLOC;
>                 }
>         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
> +               /* Tree-checker has ensured this. */
> +               ASSERT(extent_start == 0);
> +
>                 em->block_start = EXTENT_MAP_INLINE;
> -               em->start = extent_start;
> -               em->len = extent_end - extent_start;
> +               em->start = 0;
> +               em->len = fs_info->sectorsize;
>                 /*
>                  * Initialize orig_start and block_len with the same values
>                  * as in inode.c:btrfs_get_extent().
> @@ -1336,7 +1340,7 @@ u64 btrfs_file_extent_end(const struct btrfs_path *path)
>
>         if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
>                 end = btrfs_file_extent_ram_bytes(leaf, fi);
> -               end = ALIGN(key.offset + end, leaf->fs_info->sectorsize);
> +               end = leaf->fs_info->sectorsize;

So both assignments to "end" should be removed, not just the second
one, as the new one doesn't need the previous and makes it pointless.

Thanks.

>         } else {
>                 end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
>         }
> --
> 2.44.0
>
>
diff mbox series

Patch

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index e58fb5347e65..de3ccee38572 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -1265,18 +1265,19 @@  void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
 	struct extent_buffer *leaf = path->nodes[0];
 	const int slot = path->slots[0];
 	struct btrfs_key key;
-	u64 extent_start, extent_end;
+	u64 extent_start;
 	u64 bytenr;
 	u8 type = btrfs_file_extent_type(leaf, fi);
 	int compress_type = btrfs_file_extent_compression(leaf, fi);
 
 	btrfs_item_key_to_cpu(leaf, &key, slot);
 	extent_start = key.offset;
-	extent_end = btrfs_file_extent_end(path);
 	em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
 	em->generation = btrfs_file_extent_generation(leaf, fi);
 	if (type == BTRFS_FILE_EXTENT_REG ||
 	    type == BTRFS_FILE_EXTENT_PREALLOC) {
+		u64 extent_end = btrfs_file_extent_end(path);
+
 		em->start = extent_start;
 		em->len = extent_end - extent_start;
 		em->orig_start = extent_start -
@@ -1299,9 +1300,12 @@  void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
 				em->flags |= EXTENT_FLAG_PREALLOC;
 		}
 	} else if (type == BTRFS_FILE_EXTENT_INLINE) {
+		/* Tree-checker has ensured this. */
+		ASSERT(extent_start == 0);
+
 		em->block_start = EXTENT_MAP_INLINE;
-		em->start = extent_start;
-		em->len = extent_end - extent_start;
+		em->start = 0;
+		em->len = fs_info->sectorsize;
 		/*
 		 * Initialize orig_start and block_len with the same values
 		 * as in inode.c:btrfs_get_extent().
@@ -1336,7 +1340,7 @@  u64 btrfs_file_extent_end(const struct btrfs_path *path)
 
 	if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
 		end = btrfs_file_extent_ram_bytes(leaf, fi);
-		end = ALIGN(key.offset + end, leaf->fs_info->sectorsize);
+		end = leaf->fs_info->sectorsize;
 	} else {
 		end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
 	}