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btrfs: allocate backref_ctx on stack in find_extent_clone

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Instead of using kmalloc() to allocate backref_ctx, allocate backref_ctx
on stack. The size is reasonably small.

sizeof(backref_ctx) = 48

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Goldwyn Rodrigues 2021-07-27 16:17:31 -05:00 committed by David Sterba
parent c853a5783e
commit dce2815039
1 changed files with 11 additions and 18 deletions
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29
fs/btrfs/send.c
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@ -1307,7 +1307,7 @@ static int find_extent_clone(struct send_ctx *sctx,
u64 flags = 0;
struct btrfs_file_extent_item *fi;
struct extent_buffer *eb = path->nodes[0];
struct backref_ctx *backref_ctx = NULL;
struct backref_ctx backref_ctx = {0};
struct clone_root *cur_clone_root;
struct btrfs_key found_key;
struct btrfs_path *tmp_path;
@ -1322,12 +1322,6 @@ static int find_extent_clone(struct send_ctx *sctx,
/* We only use this path under the commit sem */
tmp_path->need_commit_sem = 0;
backref_ctx = kmalloc(sizeof(*backref_ctx), GFP_KERNEL);
if (!backref_ctx) {
ret = -ENOMEM;
goto out;
}
if (data_offset >= ino_size) {
/*
* There may be extents that lie behind the file's size.
@ -1392,12 +1386,12 @@ static int find_extent_clone(struct send_ctx *sctx,
cur_clone_root->found_refs = 0;
}
backref_ctx->sctx = sctx;
backref_ctx->found = 0;
backref_ctx->cur_objectid = ino;
backref_ctx->cur_offset = data_offset;
backref_ctx->found_itself = 0;
backref_ctx->extent_len = num_bytes;
backref_ctx.sctx = sctx;
backref_ctx.found = 0;
backref_ctx.cur_objectid = ino;
backref_ctx.cur_offset = data_offset;
backref_ctx.found_itself = 0;
backref_ctx.extent_len = num_bytes;
/*
* The last extent of a file may be too large due to page alignment.
@ -1405,7 +1399,7 @@ static int find_extent_clone(struct send_ctx *sctx,
* __iterate_backrefs work.
*/
if (data_offset + num_bytes >= ino_size)
backref_ctx->extent_len = ino_size - data_offset;
backref_ctx.extent_len = ino_size - data_offset;
/*
* Now collect all backrefs.
@ -1416,12 +1410,12 @@ static int find_extent_clone(struct send_ctx *sctx,
extent_item_pos = 0;
ret = iterate_extent_inodes(fs_info, found_key.objectid,
extent_item_pos, 1, __iterate_backrefs,
backref_ctx, false);
&backref_ctx, false);
if (ret < 0)
goto out;
if (!backref_ctx->found_itself) {
if (!backref_ctx.found_itself) {
/* found a bug in backref code? */
ret = -EIO;
btrfs_err(fs_info,
@ -1434,7 +1428,7 @@ static int find_extent_clone(struct send_ctx *sctx,
"find_extent_clone: data_offset=%llu, ino=%llu, num_bytes=%llu, logical=%llu",
data_offset, ino, num_bytes, logical);
if (!backref_ctx->found)
if (!backref_ctx.found)
btrfs_debug(fs_info, "no clones found");
cur_clone_root = NULL;
@ -1458,7 +1452,6 @@ static int find_extent_clone(struct send_ctx *sctx,
out:
btrfs_free_path(tmp_path);
kfree(backref_ctx);
return ret;
}