diff options
Diffstat (limited to 'fs/btrfs/extent_io.c')
| -rw-r--r-- | fs/btrfs/extent_io.c | 69 |
1 files changed, 62 insertions, 7 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index d3819dde8952..e498d496560b 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -24,6 +24,7 @@ #include "rcu-string.h" #include "backref.h" #include "disk-io.h" +#include "subpage.h" static struct kmem_cache *extent_state_cache; static struct kmem_cache *extent_buffer_cache; @@ -3141,9 +3142,13 @@ static int submit_extent_page(unsigned int opf, return ret; } -static void attach_extent_buffer_page(struct extent_buffer *eb, - struct page *page) +static int attach_extent_buffer_page(struct extent_buffer *eb, + struct page *page, + struct btrfs_subpage *prealloc) { + struct btrfs_fs_info *fs_info = eb->fs_info; + int ret = 0; + /* * If the page is mapped to btree inode, we should hold the private * lock to prevent race. @@ -3153,10 +3158,28 @@ static void attach_extent_buffer_page(struct extent_buffer *eb, if (page->mapping) lockdep_assert_held(&page->mapping->private_lock); - if (!PagePrivate(page)) - attach_page_private(page, eb); + if (fs_info->sectorsize == PAGE_SIZE) { + if (!PagePrivate(page)) + attach_page_private(page, eb); + else + WARN_ON(page->private != (unsigned long)eb); + return 0; + } + + /* Already mapped, just free prealloc */ + if (PagePrivate(page)) { + btrfs_free_subpage(prealloc); + return 0; + } + + if (prealloc) + /* Has preallocated memory for subpage */ + attach_page_private(page, prealloc); else - WARN_ON(page->private != (unsigned long)eb); + /* Do new allocation to attach subpage */ + ret = btrfs_attach_subpage(fs_info, page, + BTRFS_SUBPAGE_METADATA); + return ret; } void set_page_extent_mapped(struct page *page) @@ -5072,12 +5095,19 @@ struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src) set_bit(EXTENT_BUFFER_UNMAPPED, &new->bflags); for (i = 0; i < num_pages; i++) { + int ret; + p = alloc_page(GFP_NOFS); if (!p) { btrfs_release_extent_buffer(new); return NULL; } - attach_extent_buffer_page(new, p); + ret = attach_extent_buffer_page(new, p, NULL); + if (ret < 0) { + put_page(p); + btrfs_release_extent_buffer(new); + return NULL; + } WARN_ON(PageDirty(p)); SetPageUptodate(p); new->pages[i] = p; @@ -5315,12 +5345,33 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info, num_pages = num_extent_pages(eb); for (i = 0; i < num_pages; i++, index++) { + struct btrfs_subpage *prealloc = NULL; + p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL); if (!p) { exists = ERR_PTR(-ENOMEM); goto free_eb; } + /* + * Preallocate page->private for subpage case, so that we won't + * allocate memory with private_lock hold. The memory will be + * freed by attach_extent_buffer_page() or freed manually if + * we exit earlier. + * + * Although we have ensured one subpage eb can only have one + * 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; + } + spin_lock(&mapping->private_lock); exists = grab_extent_buffer(p); if (exists) { @@ -5328,10 +5379,14 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info, unlock_page(p); put_page(p); mark_extent_buffer_accessed(exists, p); + btrfs_free_subpage(prealloc); goto free_eb; } - attach_extent_buffer_page(eb, p); + /* Should not fail, as we have preallocated the memory */ + ret = attach_extent_buffer_page(eb, p, prealloc); + ASSERT(!ret); spin_unlock(&mapping->private_lock); + WARN_ON(PageDirty(p)); eb->pages[i] = p; if (!PageUptodate(p)) |