[PATCH v2 1/4] btrfs: only call btrfs_alloc_subpage() when sectorsize is smaller than PAGE_SIZE
From: Qu Wenruo <hidden>
Date: 2021-08-17 09:39:03
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
There are two call sites of btrfs_alloc_subpage(): - btrfs_attach_subpage() We have ensured sectorsize is smaller than PAGE_SIZE - alloc_extent_buffer() We call btrfs_alloc_subpage() unconditionally. The alloc_extent_buffer() forces us to check the sectorsize size against page size inside btrfs_alloc_subpage(). Since the function name, btrfs_alloc_subpage(), already indicates it should only get called for subpage cases, do the check in alloc_extent_buffer() and add an ASSERT() in btrfs_alloc_subpage(). Signed-off-by: Qu Wenruo <redacted> --- fs/btrfs/extent_io.c | 16 +++++++++------- fs/btrfs/subpage.c | 3 +-- 2 files changed, 10 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index aaddd7225348..19889dbfcf15 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c@@ -6137,13 +6137,15 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info, * page, but it may change in the future for 16K page size * support, so we still preallocate the memory in the loop. */ - ret = btrfs_alloc_subpage(fs_info, &prealloc, - BTRFS_SUBPAGE_METADATA); - if (ret < 0) { - unlock_page(p); - put_page(p); - exists = ERR_PTR(ret); - goto free_eb; + if (fs_info->sectorsize < PAGE_SIZE) { + ret = btrfs_alloc_subpage(fs_info, &prealloc, + BTRFS_SUBPAGE_METADATA); + if (ret < 0) { + unlock_page(p); + put_page(p); + exists = ERR_PTR(ret); + goto free_eb; + } } spin_lock(&mapping->private_lock);
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c
index cb10e56ee31e..ff1c6ba34a4d 100644
--- a/fs/btrfs/subpage.c
+++ b/fs/btrfs/subpage.c@@ -104,8 +104,7 @@ int btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info, struct btrfs_subpage **ret, enum btrfs_subpage_type type) { - if (fs_info->sectorsize == PAGE_SIZE) - return 0; + ASSERT(fs_info->sectorsize < PAGE_SIZE); *ret = kzalloc(sizeof(struct btrfs_subpage), GFP_NOFS); if (!*ret)
--
2.32.0