From 3ab2fb5a8cb003897016b6eb38ddad916226c1b2 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Thu, 8 Nov 2007 10:59:22 -0500 Subject: [PATCH] Btrfs: Add readpages support Signed-off-by: Chris Mason --- fs/btrfs/extent_map.c | 70 ++++++++++++++++++++++++++++++++++++++----- fs/btrfs/extent_map.h | 4 +++ fs/btrfs/inode.c | 12 +++++++- 3 files changed, 78 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 754bc42c162a..0077c6c1d9f9 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -11,6 +11,7 @@ #include #include #include +#include #include "extent_map.h" /* temporary define until extent_map moves out of btrfs */ @@ -1503,7 +1504,7 @@ static int submit_extent_page(int rw, struct extent_map_tree *tree, size_t size, unsigned long offset, struct block_device *bdev, struct bio **bio_ret, - int max_pages, + unsigned long max_pages, bio_end_io_t end_io_func) { int ret = 0; @@ -1520,7 +1521,7 @@ static int submit_extent_page(int rw, struct extent_map_tree *tree, return 0; } } - nr = min(max_pages, bio_get_nr_vecs(bdev)); + nr = min_t(int, max_pages, bio_get_nr_vecs(bdev)); bio = extent_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH); if (!bio) { printk("failed to allocate bio nr %d\n", nr); @@ -1552,8 +1553,10 @@ void set_page_extent_mapped(struct page *page) * into the tree that are removed when the IO is done (by the end_io * handlers) */ -int extent_read_full_page(struct extent_map_tree *tree, struct page *page, - get_extent_t *get_extent) +static int __extent_read_full_page(struct extent_map_tree *tree, + struct page *page, + get_extent_t *get_extent, + struct bio **bio) { struct inode *inode = page->mapping->host; u64 start = (u64)page->index << PAGE_CACHE_SHIFT; @@ -1631,10 +1634,12 @@ int extent_read_full_page(struct extent_map_tree *tree, struct page *page, cur + iosize - 1); } if (!ret) { + unsigned long nr = (last_byte >> PAGE_CACHE_SHIFT) + 1; + nr -= page->index; ret = submit_extent_page(READ, tree, page, - sector, iosize, page_offset, - bdev, NULL, 1, - end_bio_extent_readpage); + sector, iosize, page_offset, + bdev, bio, nr, + end_bio_extent_readpage); } if (ret) SetPageError(page); @@ -1649,6 +1654,18 @@ int extent_read_full_page(struct extent_map_tree *tree, struct page *page, } return 0; } + +int extent_read_full_page(struct extent_map_tree *tree, struct page *page, + get_extent_t *get_extent) +{ + struct bio *bio = NULL; + int ret; + + ret = __extent_read_full_page(tree, page, get_extent, &bio); + if (bio) + submit_one_bio(READ, bio); + return ret; +} EXPORT_SYMBOL(extent_read_full_page); /* @@ -1836,6 +1853,45 @@ int extent_writepages(struct extent_map_tree *tree, } EXPORT_SYMBOL(extent_writepages); +int extent_readpages(struct extent_map_tree *tree, + struct address_space *mapping, + struct list_head *pages, unsigned nr_pages, + get_extent_t get_extent) +{ + struct bio *bio = NULL; + unsigned page_idx; + struct pagevec pvec; + + pagevec_init(&pvec, 0); + for (page_idx = 0; page_idx < nr_pages; page_idx++) { + struct page *page = list_entry(pages->prev, struct page, lru); + + prefetchw(&page->flags); + list_del(&page->lru); + /* + * what we want to do here is call add_to_page_cache_lru, + * but that isn't exported, so we reproduce it here + */ + if (!add_to_page_cache(page, mapping, + page->index, GFP_KERNEL)) { + + /* open coding of lru_cache_add, also not exported */ + page_cache_get(page); + if (!pagevec_add(&pvec, page)) + __pagevec_lru_add(&pvec); + __extent_read_full_page(tree, page, get_extent, &bio); + } + page_cache_release(page); + } + if (pagevec_count(&pvec)) + __pagevec_lru_add(&pvec); + BUG_ON(!list_empty(pages)); + if (bio) + submit_one_bio(READ, bio); + return 0; +} +EXPORT_SYMBOL(extent_readpages); + /* * basic invalidatepage code, this waits on any locked or writeback * ranges corresponding to the page, and then deletes any extent state diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h index 0b0dcf19fe45..fbd23a72f53b 100644 --- a/fs/btrfs/extent_map.h +++ b/fs/btrfs/extent_map.h @@ -140,6 +140,10 @@ int extent_writepages(struct extent_map_tree *tree, struct address_space *mapping, get_extent_t *get_extent, struct writeback_control *wbc); +int extent_readpages(struct extent_map_tree *tree, + struct address_space *mapping, + struct list_head *pages, unsigned nr_pages, + get_extent_t get_extent); int extent_prepare_write(struct extent_map_tree *tree, struct inode *inode, struct page *page, unsigned from, unsigned to, get_extent_t *get_extent); diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 90cb71d68294..d6d32465bc9a 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1748,7 +1748,6 @@ static int btrfs_writepage(struct page *page, struct writeback_control *wbc) return extent_write_full_page(tree, page, btrfs_get_extent, wbc); } - static int btrfs_writepages(struct address_space *mapping, struct writeback_control *wbc) { @@ -1757,6 +1756,16 @@ static int btrfs_writepages(struct address_space *mapping, return extent_writepages(tree, mapping, btrfs_get_extent, wbc); } +static int +btrfs_readpages(struct file *file, struct address_space *mapping, + struct list_head *pages, unsigned nr_pages) +{ + struct extent_map_tree *tree; + tree = &BTRFS_I(mapping->host)->extent_tree; + return extent_readpages(tree, mapping, pages, nr_pages, + btrfs_get_extent); +} + static int btrfs_releasepage(struct page *page, gfp_t unused_gfp_flags) { struct extent_map_tree *tree; @@ -2537,6 +2546,7 @@ static struct address_space_operations btrfs_aops = { .readpage = btrfs_readpage, .writepage = btrfs_writepage, .writepages = btrfs_writepages, + .readpages = btrfs_readpages, .sync_page = block_sync_page, .prepare_write = btrfs_prepare_write, .commit_write = btrfs_commit_write, -- 2.20.1