From 965fb88611d6c4267ff6bdcd7b777a8048bb8060 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 26 Jan 2021 16:33:47 +0800 Subject: [PATCH] btrfs: introduce the skeleton of btrfs_subpage structure For sectorsize < page size support, we need a structure to record extra status info for each sector of a page. Introduce the skeleton structure, all subpage related code would go to subpage.[ch]. Reviewed-by: Josef Bacik Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/Makefile | 3 ++- fs/btrfs/subpage.c | 43 +++++++++++++++++++++++++++++++++++++++++++ fs/btrfs/subpage.h | 33 +++++++++++++++++++++++++++++++++ fs/btrfs/super.c | 1 - 4 files changed, 78 insertions(+), 2 deletions(-) create mode 100644 fs/btrfs/subpage.c create mode 100644 fs/btrfs/subpage.h diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile index e459573194249..b634c42115ead 100644 --- a/fs/btrfs/Makefile +++ b/fs/btrfs/Makefile @@ -27,7 +27,8 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \ compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \ reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \ uuid-tree.o props.o free-space-tree.o tree-checker.o space-info.o \ - block-rsv.o delalloc-space.o block-group.o discard.o reflink.o + block-rsv.o delalloc-space.o block-group.o discard.o reflink.o \ + subpage.o btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c new file mode 100644 index 0000000000000..a3e5b6a13d545 --- /dev/null +++ b/fs/btrfs/subpage.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include "ctree.h" +#include "subpage.h" + +int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info, + struct page *page, enum btrfs_subpage_type type) +{ + struct btrfs_subpage *subpage; + + /* + * We have cases like a dummy extent buffer page, which is not mappped + * and doesn't need to be locked. + */ + if (page->mapping) + ASSERT(PageLocked(page)); + /* Either not subpage, or the page already has private attached */ + if (fs_info->sectorsize == PAGE_SIZE || PagePrivate(page)) + return 0; + + subpage = kzalloc(sizeof(struct btrfs_subpage), GFP_NOFS); + if (!subpage) + return -ENOMEM; + + spin_lock_init(&subpage->lock); + attach_page_private(page, subpage); + return 0; +} + +void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, + struct page *page) +{ + struct btrfs_subpage *subpage; + + /* Either not subpage, or already detached */ + if (fs_info->sectorsize == PAGE_SIZE || !PagePrivate(page)) + return; + + subpage = (struct btrfs_subpage *)detach_page_private(page); + ASSERT(subpage); + kfree(subpage); +} diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h new file mode 100644 index 0000000000000..676280bc75621 --- /dev/null +++ b/fs/btrfs/subpage.h @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef BTRFS_SUBPAGE_H +#define BTRFS_SUBPAGE_H + +#include + +/* + * Maximum page size we support is 64K, minimum sector size is 4K, u16 bitmap + * is sufficient. Regular bitmap_* is not used due to size reasons. + */ +#define BTRFS_SUBPAGE_BITMAP_SIZE 16 + +/* + * Structure to trace status of each sector inside a page, attached to + * page::private for both data and metadata inodes. + */ +struct btrfs_subpage { + /* Common members for both data and metadata pages */ + spinlock_t lock; +}; + +enum btrfs_subpage_type { + BTRFS_SUBPAGE_METADATA, + BTRFS_SUBPAGE_DATA, +}; + +int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info, + struct page *page, enum btrfs_subpage_type type); +void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, + struct page *page); + +#endif diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 12d7d3be7cd45..919ed5c357e92 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -48,7 +48,6 @@ #include "tests/btrfs-tests.h" #include "block-group.h" #include "discard.h" - #include "qgroup.h" #define CREATE_TRACE_POINTS #include -- 2.39.5