[PATCH RFC 1/2] btrfs: remove the unnecessary path parameter for scrub_raid56_parity()

Qu Wenruo
2021-12-07T07:44:30Z

In function scrub_stripe() we allocated two btrfs_path, one @path for
extent tree search and another @ppath for full stripe extent tree search
for RAID56.

This is totally uncessary, as the @ppath usage is completely inside
scrub_raid56_parity(), thus we can move the path allocation into
scrub_raid56_parity() completely.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/scrub.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 15a123e67108..a3bd3dfd5e8b 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2892,7 +2892,6 @@ static void scrub_parity_put(struct scrub_parity *sparity)
static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
struct map_lookup *map,
struct btrfs_device *sdev,
- struct btrfs_path *path,
u64 logic_start,
u64 logic_end)
{
@@ -2901,6 +2900,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
struct btrfs_root *csum_root;
struct btrfs_extent_item *extent;
struct btrfs_io_context *bioc = NULL;
+ struct btrfs_path *path;
u64 flags;
int ret;
int slot;
@@ -2919,6 +2919,14 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
int extent_mirror_num;
int stop_loop = 0;

+ path = btrfs_alloc_path();
+ if (!path) {
+ spin_lock(&sctx->stat_lock);
+ sctx->stat.malloc_errors++;
+ spin_unlock(&sctx->stat_lock);
+ return -ENOMEM;
+ }
+
ASSERT(map->stripe_len <= U32_MAX);
nsectors = map->stripe_len >> fs_info->sectorsize_bits;
bitmap_len = scrub_calc_parity_bitmap_len(nsectors);
@@ -2928,6 +2936,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
spin_lock(&sctx->stat_lock);
sctx->stat.malloc_errors++;
spin_unlock(&sctx->stat_lock);
+ btrfs_free_path(path);
return -ENOMEM;
}

@@ -3117,7 +3126,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
scrub_wr_submit(sctx);
mutex_unlock(&sctx->wr_lock);

- btrfs_release_path(path);
+ btrfs_free_path(path);
return ret < 0 ? ret : 0;
}

@@ -3167,7 +3176,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
int num, u64 base, u64 length,
struct btrfs_block_group *cache)
{
- struct btrfs_path *path, *ppath;
+ struct btrfs_path *path;
struct btrfs_fs_info *fs_info = sctx->fs_info;
struct btrfs_root *root;
struct btrfs_root *csum_root;
@@ -3229,12 +3238,6 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
if (!path)
return -ENOMEM;

- ppath = btrfs_alloc_path();
- if (!ppath) {
- btrfs_free_path(path);
- return -ENOMEM;
- }
-
/*
* work on commit root. The related disk blocks are static as
* long as COW is applied. This means, it is save to rewrite
@@ -3243,8 +3246,6 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
path->search_commit_root = 1;
path->skip_locking = 1;

- ppath->search_commit_root = 1;
- ppath->skip_locking = 1;
/*
* trigger the readahead for extent tree csum tree and wait for
* completion. During readahead, the scrub is officially paused
@@ -3347,7 +3348,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
stripe_logical += base;
stripe_end = stripe_logical + increment;
ret = scrub_raid56_parity(sctx, map, scrub_dev,
- ppath, stripe_logical,
+ stripe_logical,
stripe_end);
if (ret)
goto out;
@@ -3518,7 +3519,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
stripe_end = stripe_logical +
increment;
ret = scrub_raid56_parity(sctx,
- map, scrub_dev, ppath,
+ map, scrub_dev,
stripe_logical,
stripe_end);
if (ret)
@@ -3565,7 +3566,6 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,

blk_finish_plug(&plug);
btrfs_free_path(path);
- btrfs_free_path(ppath);

if (sctx->is_dev_replace && ret >= 0) {
int ret2;
--
2.34.1