In the case of subpagesize-blocksize, this patch makes it possible to read only a single metadata block from the disk instead of all the metadata blocks that map into a page.
Signed-off-by: Chandan Rajendra <[email protected]> --- fs/btrfs/disk-io.c | 65 +++++++++++++++++++------------ fs/btrfs/disk-io.h | 3 ++ fs/btrfs/extent_io.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++---- 3 files changed, 144 insertions(+), 32 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 51fe2ec..b794e33 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -597,28 +597,41 @@ static noinline int check_leaf(struct btrfs_root *root, return 0; } -static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio, - u64 phy_offset, struct page *page, - u64 start, u64 end, int mirror) +int verify_extent_buffer_read(struct btrfs_io_bio *io_bio, + struct page *page, + u64 start, u64 end, int mirror) { - u64 found_start; - int found_level; + struct address_space *mapping = (io_bio->bio).bi_io_vec->bv_page->mapping; + struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree; + struct extent_buffer_head *ebh; struct extent_buffer *eb; struct btrfs_root *root = BTRFS_I(page->mapping->host)->root; - int ret = 0; + unsigned long num_pages; + unsigned long i; + u64 found_start; + int found_level; int reads_done; + int ret = 0; if (!page->private) goto out; eb = (struct extent_buffer *)page->private; + do { + if ((eb->start <= start) && (eb->start + eb->len - 1 > start)) + break; + } while ((eb = eb->eb_next) != NULL); + + BUG_ON(!eb); + + ebh = eb_head(eb); /* the pending IO might have been the only thing that kept this buffer * in memory. Make sure we have a ref for all this other checks */ extent_buffer_get(eb); - reads_done = atomic_dec_and_test(&eb->io_pages); + reads_done = atomic_dec_and_test(&ebh->io_bvecs); if (!reads_done) goto err; @@ -683,28 +696,34 @@ err: * again, we have to make sure it has something * to decrement */ - atomic_inc(&eb->io_pages); + atomic_inc(&eb_head(eb)->io_bvecs); clear_extent_buffer_uptodate(eb); } + + /* + We never read more than one extent buffer from a page at a time. + So unlocking the page here should be fine. + */ + if (reads_done) { + num_pages = num_extent_pages(eb->start, eb->len); + for (i = 0; i < num_pages; i++) { + page = eb_head(eb)->pages[i]; + unlock_page(page); + } + + /* + We don't need to add a check to see if + extent_io_tree->track_uptodate is set or not, Since + this function only deals with extent buffers. + */ + unlock_extent(tree, eb->start, eb->start + eb->len - 1); + } + free_extent_buffer(eb); out: return ret; } -static int btree_io_failed_hook(struct page *page, int failed_mirror) -{ - struct extent_buffer *eb; - struct btrfs_root *root = BTRFS_I(page->mapping->host)->root; - - eb = (struct extent_buffer *)page->private; - set_bit(EXTENT_BUFFER_READ_ERR, &eb->ebflags); - eb->read_mirror = failed_mirror; - atomic_dec(&eb->io_pages); - if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->ebflags)) - btree_readahead_hook(root, eb, eb->start, -EIO); - return -EIO; /* we fixed nothing */ -} - static void end_workqueue_bio(struct bio *bio, int err) { struct btrfs_end_io_wq *end_io_wq = bio->bi_private; @@ -4349,8 +4368,6 @@ static int btrfs_cleanup_transaction(struct btrfs_root *root) } static const struct extent_io_ops btree_extent_io_ops = { - .readpage_end_io_hook = btree_readpage_end_io_hook, - .readpage_io_failed_hook = btree_io_failed_hook, .submit_bio_hook = btree_submit_bio_hook, /* note we're sharing with inode.c for the merge bio hook */ .merge_bio_hook = btrfs_merge_bio_hook, diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h index d4cbfee..c69076c 100644 --- a/fs/btrfs/disk-io.h +++ b/fs/btrfs/disk-io.h @@ -111,6 +111,9 @@ static inline void btrfs_put_fs_root(struct btrfs_root *root) kfree(root); } +int verify_extent_buffer_read(struct btrfs_io_bio *io_bio, + struct page *page, + u64 start, u64 end, int mirror); void btrfs_mark_buffer_dirty(struct extent_buffer *buf); int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid, int atomic); diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index a7e715a..76a6e39 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -14,6 +14,7 @@ #include "extent_io.h" #include "extent_map.h" #include "ctree.h" +#include "disk-io.h" #include "btrfs_inode.h" #include "volumes.h" #include "check-integrity.h" @@ -2179,7 +2180,7 @@ int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb, struct page *p = eb_head(eb)->pages[i]; ret = repair_io_failure(root->fs_info->btree_inode, start, - PAGE_CACHE_SIZE, start, p, + eb->len, start, p, start - page_offset(p), mirror_num); if (ret) break; @@ -3706,6 +3707,77 @@ lock_extent_buffer_for_io(struct extent_buffer *eb, return ret; } +static void end_bio_extent_buffer_readpage(struct bio *bio, int err) +{ + struct address_space *mapping = bio->bi_io_vec->bv_page->mapping; + struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree; + struct btrfs_io_bio *io_bio = btrfs_io_bio(bio); + struct extent_buffer *eb; + struct btrfs_root *root; + struct bio_vec *bvec; + struct page *page; + int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + u64 start; + u64 end; + int mirror; + int ret; + int i; + + if (err) + uptodate = 0; + + bio_for_each_segment_all(bvec, bio, i) { + page = bvec->bv_page; + root = BTRFS_I(page->mapping->host)->root; + + start = page_offset(page) + bvec->bv_offset; + end = start + bvec->bv_len - 1; + + if (!page->private) { + unlock_page(page); + unlock_extent(tree, start, end); + continue; + } + + eb = (struct extent_buffer *)page->private; + + do { + /* + read_extent_buffer_pages() does not start + I/O on PG_uptodate pages. Hence the bio may + map only part of the extent buffer. + */ + if ((eb->start <= start) && (eb->start + eb->len - 1 > start)) + break; + } while ((eb = eb->eb_next) != NULL); + + BUG_ON(!eb); + + mirror = io_bio->mirror_num; + + if (uptodate) { + ret = verify_extent_buffer_read(io_bio, page, start, + end, mirror); + if (ret) + uptodate = 0; + } + + if (!uptodate) { + set_bit(EXTENT_BUFFER_READ_ERR, &eb->ebflags); + eb->read_mirror = mirror; + atomic_dec(&eb_head(eb)->io_bvecs); + if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, + &eb->ebflags)) + btree_readahead_hook(root, eb, eb->start, + -EIO); + ClearPageUptodate(page); + SetPageError(page); + } + } + + bio_put(bio); +} + static void end_extent_buffer_writeback(struct extent_buffer *eb) { clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->ebflags); @@ -5330,6 +5402,9 @@ int read_extent_buffer_pages(struct extent_io_tree *tree, struct extent_buffer *eb, u64 start, int wait, get_extent_t *get_extent, int mirror_num) { + struct inode *inode = tree->mapping->host; + struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info; + struct extent_state *cached_state = NULL; unsigned long i; unsigned long start_i; struct page *page; @@ -5376,15 +5451,31 @@ int read_extent_buffer_pages(struct extent_io_tree *tree, clear_bit(EXTENT_BUFFER_READ_ERR, &eb->ebflags); eb->read_mirror = 0; - atomic_set(&eb->io_pages, num_reads); + atomic_set(&eb_head(eb)->io_bvecs, num_reads); for (i = start_i; i < num_pages; i++) { page = eb_head(eb)->pages[i]; if (!PageUptodate(page)) { ClearPageError(page); - err = __extent_read_full_page(tree, page, - get_extent, &bio, - mirror_num, &bio_flags, - READ | REQ_META); + if (eb->len < PAGE_CACHE_SIZE) { + lock_extent_bits(tree, eb->start, eb->start + eb->len - 1, 0, + &cached_state); + err = submit_extent_page(READ | REQ_META, tree, + page, eb->start >> 9, + eb->len, eb->start - page_offset(page), + fs_info->fs_devices->latest_bdev, + &bio, -1, end_bio_extent_buffer_readpage, + mirror_num, bio_flags, bio_flags); + } else { + lock_extent_bits(tree, page_offset(page), + page_offset(page) + PAGE_CACHE_SIZE - 1, + 0, &cached_state); + err = submit_extent_page(READ | REQ_META, tree, + page, page_offset(page) >> 9, + PAGE_CACHE_SIZE, 0, + fs_info->fs_devices->latest_bdev, + &bio, -1, end_bio_extent_buffer_readpage, + mirror_num, bio_flags, bio_flags); + } if (err) ret = err; } else { @@ -5405,10 +5496,11 @@ int read_extent_buffer_pages(struct extent_io_tree *tree, for (i = start_i; i < num_pages; i++) { page = eb_head(eb)->pages[i]; wait_on_page_locked(page); - if (!PageUptodate(page)) - ret = -EIO; } + if (!extent_buffer_uptodate(eb)) + ret = -EIO; + return ret; unlock_exit: -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
