diff options
Diffstat (limited to 'fs/buffer.c')
-rw-r--r-- | fs/buffer.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index 3dc712f29d2..5e4a90ee103 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1022,6 +1022,7 @@ try_again: bh->b_state = 0; atomic_set(&bh->b_count, 0); + bh->b_private = NULL; bh->b_size = size; /* Link the buffer to its page */ @@ -3050,6 +3051,66 @@ asmlinkage long sys_bdflush(int func, long data) } /* + * Migration function for pages with buffers. This function can only be used + * if the underlying filesystem guarantees that no other references to "page" + * exist. + */ +#ifdef CONFIG_MIGRATION +int buffer_migrate_page(struct page *newpage, struct page *page) +{ + struct address_space *mapping = page->mapping; + struct buffer_head *bh, *head; + + if (!mapping) + return -EAGAIN; + + if (!page_has_buffers(page)) + return migrate_page(newpage, page); + + head = page_buffers(page); + + if (migrate_page_remove_references(newpage, page, 3)) + return -EAGAIN; + + bh = head; + do { + get_bh(bh); + lock_buffer(bh); + bh = bh->b_this_page; + + } while (bh != head); + + ClearPagePrivate(page); + set_page_private(newpage, page_private(page)); + set_page_private(page, 0); + put_page(page); + get_page(newpage); + + bh = head; + do { + set_bh_page(bh, newpage, bh_offset(bh)); + bh = bh->b_this_page; + + } while (bh != head); + + SetPagePrivate(newpage); + + migrate_page_copy(newpage, page); + + bh = head; + do { + unlock_buffer(bh); + put_bh(bh); + bh = bh->b_this_page; + + } while (bh != head); + + return 0; +} +EXPORT_SYMBOL(buffer_migrate_page); +#endif + +/* * Buffer-head allocation */ static kmem_cache_t *bh_cachep; |