f2fs: reduce unncessary locking pages during read
This patch reduces redundant locking and unlocking pages during read operations. In f2fs_readpage, let's use wait_on_page_locked() instead of lock_page. And then, when we need to modify any data finally, let's lock the page so that we can avoid lock contention. [readpage rule] - The f2fs_readpage returns unlocked page, or released page too in error cases. - Its caller should handle read error, -EIO, after locking the page, which indicates read completion. - Its caller should check PageUptodate after grab_cache_page. Signed-off-by: Changman Lee <cm224.lee@samsung.com> Reviewed-by: Namjae Jeon <namjae.jeon@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
This commit is contained in:
Jaegeuk Kim
parent
25c0a6e529
commit
393ff91f57
@ -57,13 +57,15 @@ repeat:
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cond_resched();
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goto repeat;
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}
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if (f2fs_readpage(sbi, page, index, READ_SYNC)) {
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f2fs_put_page(page, 1);
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goto repeat;
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}
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mark_page_accessed(page);
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if (PageUptodate(page))
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goto out;
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/* We do not allow returning an errorneous page */
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if (f2fs_readpage(sbi, page, index, READ_SYNC))
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goto repeat;
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lock_page(page);
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out:
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mark_page_accessed(page);
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return page;
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}
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@ -199,12 +199,17 @@ struct page *find_data_page(struct inode *inode, pgoff_t index)
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if (!page)
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return ERR_PTR(-ENOMEM);
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err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
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if (err) {
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f2fs_put_page(page, 1);
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return ERR_PTR(err);
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if (PageUptodate(page)) {
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unlock_page(page);
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return page;
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}
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err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
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wait_on_page_locked(page);
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if (!PageUptodate(page)) {
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f2fs_put_page(page, 0);
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return ERR_PTR(-EIO);
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}
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unlock_page(page);
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return page;
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}
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@ -241,9 +246,13 @@ struct page *get_lock_data_page(struct inode *inode, pgoff_t index)
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BUG_ON(dn.data_blkaddr == NULL_ADDR);
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err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
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if (err) {
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f2fs_put_page(page, 1);
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if (err)
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return ERR_PTR(err);
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lock_page(page);
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if (!PageUptodate(page)) {
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f2fs_put_page(page, 1);
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return ERR_PTR(-EIO);
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}
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return page;
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}
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@ -283,14 +292,17 @@ struct page *get_new_data_page(struct inode *inode, pgoff_t index,
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if (dn.data_blkaddr == NEW_ADDR) {
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zero_user_segment(page, 0, PAGE_CACHE_SIZE);
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SetPageUptodate(page);
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} else {
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err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
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if (err) {
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f2fs_put_page(page, 1);
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if (err)
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return ERR_PTR(err);
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lock_page(page);
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if (!PageUptodate(page)) {
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f2fs_put_page(page, 1);
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return ERR_PTR(-EIO);
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}
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}
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SetPageUptodate(page);
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if (new_i_size &&
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i_size_read(inode) < ((index + 1) << PAGE_CACHE_SHIFT)) {
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@ -325,22 +337,14 @@ static void read_end_io(struct bio *bio, int err)
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/*
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* Fill the locked page with data located in the block address.
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* Read operation is synchronous, and caller must unlock the page.
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* Return unlocked page.
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*/
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int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
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block_t blk_addr, int type)
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{
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struct block_device *bdev = sbi->sb->s_bdev;
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bool sync = (type == READ_SYNC);
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struct bio *bio;
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/* This page can be already read by other threads */
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if (PageUptodate(page)) {
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if (!sync)
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unlock_page(page);
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return 0;
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}
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down_read(&sbi->bio_sem);
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/* Allocate a new bio */
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@ -354,18 +358,12 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
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kfree(bio->bi_private);
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bio_put(bio);
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up_read(&sbi->bio_sem);
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f2fs_put_page(page, 1);
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return -EFAULT;
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}
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submit_bio(type, bio);
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up_read(&sbi->bio_sem);
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/* wait for read completion if sync */
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if (sync) {
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lock_page(page);
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if (PageError(page))
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return -EIO;
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}
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return 0;
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}
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@ -636,18 +634,22 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
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/* Reading beyond i_size is simple: memset to zero */
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zero_user_segments(page, 0, start, end, PAGE_CACHE_SIZE);
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return 0;
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goto out;
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}
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if (dn.data_blkaddr == NEW_ADDR) {
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zero_user_segment(page, 0, PAGE_CACHE_SIZE);
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} else {
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err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
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if (err) {
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f2fs_put_page(page, 1);
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if (err)
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return err;
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lock_page(page);
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if (!PageUptodate(page)) {
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f2fs_put_page(page, 1);
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return -EIO;
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}
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}
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out:
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SetPageUptodate(page);
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clear_cold_data(page);
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return 0;
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@ -100,10 +100,13 @@ static void ra_nat_pages(struct f2fs_sb_info *sbi, int nid)
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page = grab_cache_page(mapping, index);
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if (!page)
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continue;
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if (f2fs_readpage(sbi, page, index, READ)) {
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if (PageUptodate(page)) {
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f2fs_put_page(page, 1);
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continue;
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}
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if (f2fs_readpage(sbi, page, index, READ))
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continue;
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f2fs_put_page(page, 0);
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}
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}
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@ -851,8 +854,16 @@ static int read_node_page(struct page *page, int type)
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get_node_info(sbi, page->index, &ni);
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if (ni.blk_addr == NULL_ADDR)
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if (ni.blk_addr == NULL_ADDR) {
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f2fs_put_page(page, 1);
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return -ENOENT;
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}
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if (PageUptodate(page)) {
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unlock_page(page);
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return 0;
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}
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return f2fs_readpage(sbi, page, ni.blk_addr, type);
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}
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@ -865,19 +876,18 @@ void ra_node_page(struct f2fs_sb_info *sbi, nid_t nid)
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struct page *apage;
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apage = find_get_page(mapping, nid);
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if (apage && PageUptodate(apage))
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goto release_out;
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if (apage && PageUptodate(apage)) {
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f2fs_put_page(apage, 0);
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return;
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}
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f2fs_put_page(apage, 0);
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apage = grab_cache_page(mapping, nid);
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if (!apage)
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return;
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if (read_node_page(apage, READA))
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unlock_page(apage);
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release_out:
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f2fs_put_page(apage, 0);
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if (read_node_page(apage, READA) == 0)
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f2fs_put_page(apage, 0);
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return;
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}
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@ -892,11 +902,14 @@ struct page *get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid)
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return ERR_PTR(-ENOMEM);
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err = read_node_page(page, READ_SYNC);
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if (err) {
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f2fs_put_page(page, 1);
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if (err)
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return ERR_PTR(err);
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}
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lock_page(page);
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if (!PageUptodate(page)) {
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f2fs_put_page(page, 1);
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return ERR_PTR(-EIO);
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}
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BUG_ON(nid != nid_of_node(page));
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mark_page_accessed(page);
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return page;
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@ -928,11 +941,8 @@ repeat:
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goto page_hit;
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err = read_node_page(page, READ_SYNC);
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unlock_page(page);
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if (err) {
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f2fs_put_page(page, 0);
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if (err)
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return ERR_PTR(err);
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}
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/* Then, try readahead for siblings of the desired node */
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end = start + MAX_RA_NODE;
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@ -957,6 +967,7 @@ page_hit:
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f2fs_put_page(page, 1);
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goto repeat;
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}
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mark_page_accessed(page);
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return page;
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}
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@ -1473,23 +1484,24 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
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sum_entry = &sum->entries[0];
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for (i = 0; i < last_offset; i++, sum_entry++) {
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if (f2fs_readpage(sbi, page, addr, READ_SYNC))
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goto out;
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rn = (struct f2fs_node *)page_address(page);
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sum_entry->nid = rn->footer.nid;
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sum_entry->version = 0;
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sum_entry->ofs_in_node = 0;
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addr++;
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/*
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* In order to read next node page,
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* we must clear PageUptodate flag.
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*/
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ClearPageUptodate(page);
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if (f2fs_readpage(sbi, page, addr, READ_SYNC))
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goto out;
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lock_page(page);
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rn = (struct f2fs_node *)page_address(page);
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sum_entry->nid = rn->footer.nid;
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sum_entry->version = 0;
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sum_entry->ofs_in_node = 0;
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addr++;
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}
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out:
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unlock_page(page);
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out:
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__free_pages(page, 0);
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return 0;
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}
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@ -112,11 +112,16 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head)
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while (1) {
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struct fsync_inode_entry *entry;
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if (f2fs_readpage(sbi, page, blkaddr, READ_SYNC))
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err = f2fs_readpage(sbi, page, blkaddr, READ_SYNC);
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if (err)
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goto out;
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if (cp_ver != cpver_of_node(page))
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goto out;
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lock_page(page);
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if (cp_ver != cpver_of_node(page)) {
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err = -EINVAL;
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goto unlock_out;
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}
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if (!is_fsync_dnode(page))
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goto next;
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@ -131,7 +136,7 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head)
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if (IS_INODE(page) && is_dent_dnode(page)) {
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if (recover_inode_page(sbi, page)) {
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err = -ENOMEM;
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goto out;
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goto unlock_out;
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}
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}
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@ -139,14 +144,14 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head)
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entry = kmem_cache_alloc(fsync_entry_slab, GFP_NOFS);
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if (!entry) {
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err = -ENOMEM;
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goto out;
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goto unlock_out;
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}
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entry->inode = f2fs_iget(sbi->sb, ino_of_node(page));
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if (IS_ERR(entry->inode)) {
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err = PTR_ERR(entry->inode);
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kmem_cache_free(fsync_entry_slab, entry);
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goto out;
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goto unlock_out;
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}
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list_add_tail(&entry->list, head);
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@ -155,15 +160,15 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head)
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if (IS_INODE(page)) {
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err = recover_inode(entry->inode, page);
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if (err)
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goto out;
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goto unlock_out;
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}
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next:
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/* check next segment */
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blkaddr = next_blkaddr_of_node(page);
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ClearPageUptodate(page);
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}
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out:
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unlock_out:
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unlock_page(page);
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out:
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__free_pages(page, 0);
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return err;
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}
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@ -319,8 +324,10 @@ static void recover_data(struct f2fs_sb_info *sbi,
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if (f2fs_readpage(sbi, page, blkaddr, READ_SYNC))
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goto out;
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lock_page(page);
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if (cp_ver != cpver_of_node(page))
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goto out;
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goto unlock_out;
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entry = get_fsync_inode(head, ino_of_node(page));
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if (!entry)
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@ -336,10 +343,10 @@ static void recover_data(struct f2fs_sb_info *sbi,
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next:
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/* check next segment */
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blkaddr = next_blkaddr_of_node(page);
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ClearPageUptodate(page);
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}
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out:
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unlock_out:
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unlock_page(page);
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out:
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__free_pages(page, 0);
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allocate_new_segments(sbi);
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