[PATCH v2 06/10] btrfs: defrag: introduce a helper to defrag a range
From: Qu Wenruo <hidden>
Date: 2021-06-02 02:15:45
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
A new helper, defrag_one_range(), is introduced to defrag one range. This function will mostly prepare the needed pages and extent status for defrag_one_locked_target(). As we can only have a consistent view of extent map with page and extent bits locked, we need to re-check the range passed in to get a real target list for defrag_one_locked_target(). Signed-off-by: Qu Wenruo <redacted> --- fs/btrfs/ioctl.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 26957cd91ea6..a5ca752bcda8 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c@@ -1548,6 +1548,77 @@ static int defrag_one_locked_target(struct btrfs_inode *inode, return ret; } +static int defrag_one_range(struct btrfs_inode *inode, + u64 start, u32 len, + u32 extent_thresh, u64 newer_than, + bool do_compress) +{ + struct extent_state *cached_state = NULL; + struct defrag_target_range *entry; + struct defrag_target_range *tmp; + LIST_HEAD(target_list); + struct page **pages; + const u32 sectorsize = inode->root->fs_info->sectorsize; + unsigned long last_index = (start + len - 1) >> PAGE_SHIFT; + unsigned long start_index = start >> PAGE_SHIFT; + unsigned int nr_pages = last_index - start_index + 1; + int ret = 0; + int i; + + ASSERT(nr_pages <= CLUSTER_SIZE / PAGE_SIZE); + ASSERT(IS_ALIGNED(start, sectorsize) && IS_ALIGNED(len, sectorsize)); + + pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS); + if (!pages) + return -ENOMEM; + + /* Prepare all pages */ + for (i = 0; i < nr_pages; i++) { + pages[i] = defrag_prepare_one_page(inode, start_index + i); + if (IS_ERR(pages[i])) { + ret = PTR_ERR(pages[i]); + pages[i] = NULL; + goto free_pages; + } + } + /* Also lock the pages range */ + lock_extent_bits(&inode->io_tree, start_index << PAGE_SHIFT, + (last_index << PAGE_SHIFT) + PAGE_SIZE - 1, + &cached_state); + /* + * Now we have a consistent view about the extent map, re-check + * which range really need to be defraged. + */ + ret = defrag_collect_targets(inode, start, len, extent_thresh, + newer_than, do_compress, &target_list); + if (ret < 0) + goto unlock_extent; + + list_for_each_entry(entry, &target_list, list) { + ret = defrag_one_locked_target(inode, entry, pages, nr_pages); + if (ret < 0) + break; + } + + list_for_each_entry_safe(entry, tmp, &target_list, list) { + list_del_init(&entry->list); + kfree(entry); + } +unlock_extent: + unlock_extent_cached(&inode->io_tree, start_index << PAGE_SHIFT, + (last_index << PAGE_SHIFT) + PAGE_SIZE - 1, + &cached_state); +free_pages: + for (i = 0; i < nr_pages; i++) { + if (pages[i]) { + unlock_page(pages[i]); + put_page(pages[i]); + } + } + kfree(pages); + return ret; +} + /* * Btrfs entrace for defrag. *
--
2.31.1