f2fs: readahead encrypted block during GC

During GC, for each encrypted block, we will read block synchronously
into meta page, and then submit it into current cold data log area.

So this block read model with 4k granularity can make poor performance,
like migrating non-encrypted block, let's readahead encrypted block
as well to improve migration performance.

To implement this, we choose meta page that its index is old block
address of the encrypted block, and readahead ciphertext into this
page, later, if readaheaded page is still updated, we will load its
data into target meta page, and submit the write IO.

Note that for OPU, truncation, deletion, we need to invalid meta
page after we invalid old block address, to make sure we won't load
invalid data from target meta page during encrypted block migration.

for ((i = 0; i < 1000; i++))
do {
        xfs_io -f /mnt/f2fs/dir/$i -c "pwrite 0 128k" -c "fsync";
} done

for ((i = 0; i < 1000; i+=2))
do {
        rm /mnt/f2fs/dir/$i;
} done

ret = ioctl(fd, F2FS_IOC_GARBAGE_COLLECT, 0);

Before:
              gc-6549  [001] d..1 214682.212797: block_rq_insert: 8,32 RA 32768 () 786400 + 64 [gc]
              gc-6549  [001] d..1 214682.212802: block_unplug: [gc] 1
              gc-6549  [001] .... 214682.213892: block_bio_queue: 8,32 R 67494144 + 8 [gc]
              gc-6549  [001] .... 214682.213899: block_getrq: 8,32 R 67494144 + 8 [gc]
              gc-6549  [001] .... 214682.213902: block_plug: [gc]
              gc-6549  [001] d..1 214682.213905: block_rq_insert: 8,32 R 4096 () 67494144 + 8 [gc]
              gc-6549  [001] d..1 214682.213908: block_unplug: [gc] 1
              gc-6549  [001] .... 214682.226405: block_bio_queue: 8,32 R 67494152 + 8 [gc]
              gc-6549  [001] .... 214682.226412: block_getrq: 8,32 R 67494152 + 8 [gc]
              gc-6549  [001] .... 214682.226414: block_plug: [gc]
              gc-6549  [001] d..1 214682.226417: block_rq_insert: 8,32 R 4096 () 67494152 + 8 [gc]
              gc-6549  [001] d..1 214682.226420: block_unplug: [gc] 1
              gc-6549  [001] .... 214682.226904: block_bio_queue: 8,32 R 67494160 + 8 [gc]
              gc-6549  [001] .... 214682.226910: block_getrq: 8,32 R 67494160 + 8 [gc]
              gc-6549  [001] .... 214682.226911: block_plug: [gc]
              gc-6549  [001] d..1 214682.226914: block_rq_insert: 8,32 R 4096 () 67494160 + 8 [gc]
              gc-6549  [001] d..1 214682.226916: block_unplug: [gc] 1

After:
              gc-5678  [003] .... 214327.025906: block_bio_queue: 8,32 R 67493824 + 8 [gc]
              gc-5678  [003] .... 214327.025908: block_bio_backmerge: 8,32 R 67493824 + 8 [gc]
              gc-5678  [003] .... 214327.025915: block_bio_queue: 8,32 R 67493832 + 8 [gc]
              gc-5678  [003] .... 214327.025917: block_bio_backmerge: 8,32 R 67493832 + 8 [gc]
              gc-5678  [003] .... 214327.025923: block_bio_queue: 8,32 R 67493840 + 8 [gc]
              gc-5678  [003] .... 214327.025925: block_bio_backmerge: 8,32 R 67493840 + 8 [gc]
              gc-5678  [003] .... 214327.025932: block_bio_queue: 8,32 R 67493848 + 8 [gc]
              gc-5678  [003] .... 214327.025934: block_bio_backmerge: 8,32 R 67493848 + 8 [gc]
              gc-5678  [003] .... 214327.025941: block_bio_queue: 8,32 R 67493856 + 8 [gc]
              gc-5678  [003] .... 214327.025943: block_bio_backmerge: 8,32 R 67493856 + 8 [gc]
              gc-5678  [003] .... 214327.025953: block_bio_queue: 8,32 R 67493864 + 8 [gc]
              gc-5678  [003] .... 214327.025955: block_bio_backmerge: 8,32 R 67493864 + 8 [gc]
              gc-5678  [003] .... 214327.025962: block_bio_queue: 8,32 R 67493872 + 8 [gc]
              gc-5678  [003] .... 214327.025964: block_bio_backmerge: 8,32 R 67493872 + 8 [gc]
              gc-5678  [003] .... 214327.025970: block_bio_queue: 8,32 R 67493880 + 8 [gc]
              gc-5678  [003] .... 214327.025972: block_bio_backmerge: 8,32 R 67493880 + 8 [gc]
              gc-5678  [003] .... 214327.026000: block_bio_queue: 8,32 WS 34123776 + 2048 [gc]
              gc-5678  [003] .... 214327.026019: block_getrq: 8,32 WS 34123776 + 2048 [gc]
              gc-5678  [003] d..1 214327.026021: block_rq_insert: 8,32 R 131072 () 67493632 + 256 [gc]
              gc-5678  [003] d..1 214327.026023: block_unplug: [gc] 1
              gc-5678  [003] d..1 214327.026026: block_rq_issue: 8,32 R 131072 () 67493632 + 256 [gc]
              gc-5678  [003] .... 214327.026046: block_plug: [gc]
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -875,6 +875,7 @@ static int __allocate_data_block(struct dnode_of_data *dn, int seg_type)
 	struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
 	struct f2fs_summary sum;
 	struct node_info ni;
+	block_t old_blkaddr;
 	pgoff_t fofs;
 	blkcnt_t count = 1;
 	int err;
@@ -896,9 +897,12 @@ static int __allocate_data_block(struct dnode_of_data *dn, int seg_type)
 
 alloc:
 	set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version);
-
-	f2fs_allocate_data_block(sbi, NULL, dn->data_blkaddr, &dn->data_blkaddr,
+	old_blkaddr = dn->data_blkaddr;
+	f2fs_allocate_data_block(sbi, NULL, old_blkaddr, &dn->data_blkaddr,
 					&sum, seg_type, NULL, false);
+	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO)
+		invalidate_mapping_pages(META_MAPPING(sbi),
+					old_blkaddr, old_blkaddr);
 	f2fs_set_data_blkaddr(dn);
 
 	/* update i_size */
@@ -1614,6 +1618,7 @@ static int f2fs_read_data_pages(struct file *file,
 static int encrypt_one_page(struct f2fs_io_info *fio)
 {
 	struct inode *inode = fio->page->mapping->host;
+	struct page *mpage;
 	gfp_t gfp_flags = GFP_NOFS;
 
 	if (!f2fs_encrypted_file(inode))
@@ -1625,17 +1630,25 @@ static int encrypt_one_page(struct f2fs_io_info *fio)
 retry_encrypt:
 	fio->encrypted_page = fscrypt_encrypt_page(inode, fio->page,
 			PAGE_SIZE, 0, fio->page->index, gfp_flags);
-	if (!IS_ERR(fio->encrypted_page))
-		return 0;
+	if (IS_ERR(fio->encrypted_page)) {
+		/* flush pending IOs and wait for a while in the ENOMEM case */
+		if (PTR_ERR(fio->encrypted_page) == -ENOMEM) {
+			f2fs_flush_merged_writes(fio->sbi);
+			congestion_wait(BLK_RW_ASYNC, HZ/50);
+			gfp_flags |= __GFP_NOFAIL;
+			goto retry_encrypt;
+		}
+		return PTR_ERR(fio->encrypted_page);
+	}
 
-	/* flush pending IOs and wait for a while in the ENOMEM case */
-	if (PTR_ERR(fio->encrypted_page) == -ENOMEM) {
-		f2fs_flush_merged_writes(fio->sbi);
-		congestion_wait(BLK_RW_ASYNC, HZ/50);
-		gfp_flags |= __GFP_NOFAIL;
-		goto retry_encrypt;
+	mpage = find_lock_page(META_MAPPING(fio->sbi), fio->old_blkaddr);
+	if (mpage) {
+		if (PageUptodate(mpage))
+			memcpy(page_address(mpage),
+				page_address(fio->encrypted_page), PAGE_SIZE);
+		f2fs_put_page(mpage, 1);
 	}
-	return PTR_ERR(fio->encrypted_page);
+	return 0;
 }
 
 static inline bool check_inplace_update_policy(struct inode *inode,

fs/f2fs/gc.c

@@ -599,6 +599,72 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 	return true;
 }
 
+static int ra_data_block(struct inode *inode, pgoff_t index)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct address_space *mapping = inode->i_mapping;
+	struct dnode_of_data dn;
+	struct page *page;
+	struct extent_info ei = {0, 0, 0};
+	struct f2fs_io_info fio = {
+		.sbi = sbi,
+		.ino = inode->i_ino,
+		.type = DATA,
+		.temp = COLD,
+		.op = REQ_OP_READ,
+		.op_flags = 0,
+		.encrypted_page = NULL,
+		.in_list = false,
+		.retry = false,
+	};
+	int err;
+
+	page = f2fs_grab_cache_page(mapping, index, true);
+	if (!page)
+		return -ENOMEM;
+
+	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
+		dn.data_blkaddr = ei.blk + index - ei.fofs;
+		goto got_it;
+	}
+
+	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
+	if (err)
+		goto put_page;
+	f2fs_put_dnode(&dn);
+
+	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
+						DATA_GENERIC))) {
+		err = -EFAULT;
+		goto put_page;
+	}
+got_it:
+	/* read page */
+	fio.page = page;
+	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
+
+	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
+					dn.data_blkaddr,
+					FGP_LOCK | FGP_CREAT, GFP_NOFS);
+	if (!fio.encrypted_page) {
+		err = -ENOMEM;
+		goto put_page;
+	}
+
+	err = f2fs_submit_page_bio(&fio);
+	if (err)
+		goto put_encrypted_page;
+	f2fs_put_page(fio.encrypted_page, 0);
+	f2fs_put_page(page, 1);
+	return 0;
+put_encrypted_page:
+	f2fs_put_page(fio.encrypted_page, 1);
+put_page:
+	f2fs_put_page(page, 1);
+	return err;
+}
+
 /*
  * Move data block via META_MAPPING while keeping locked data page.
  * This can be used to move blocks, aka LBAs, directly on disk.
@@ -620,7 +686,7 @@ static void move_data_block(struct inode *inode, block_t bidx,
 	struct dnode_of_data dn;
 	struct f2fs_summary sum;
 	struct node_info ni;
-	struct page *page;
+	struct page *page, *mpage;
 	block_t newaddr;
 	int err;
 	bool lfs_mode = test_opt(fio.sbi, LFS);
@@ -683,6 +749,23 @@ static void move_data_block(struct inode *inode, block_t bidx,
 		goto recover_block;
 	}
 
+	mpage = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
+					fio.old_blkaddr, FGP_LOCK, GFP_NOFS);
+	if (mpage) {
+		bool updated = false;
+
+		if (PageUptodate(mpage)) {
+			memcpy(page_address(fio.encrypted_page),
+					page_address(mpage), PAGE_SIZE);
+			updated = true;
+		}
+		f2fs_put_page(mpage, 1);
+		invalidate_mapping_pages(META_MAPPING(fio.sbi),
+					fio.old_blkaddr, fio.old_blkaddr);
+		if (updated)
+			goto write_page;
+	}
+
 	err = f2fs_submit_page_bio(&fio);
 	if (err)
 		goto put_page_out;
@@ -699,6 +782,7 @@ static void move_data_block(struct inode *inode, block_t bidx,
 		goto put_page_out;
 	}
 
+write_page:
 	set_page_dirty(fio.encrypted_page);
 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true);
 	if (clear_page_dirty_for_io(fio.encrypted_page))
@@ -873,12 +957,6 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 			if (IS_ERR(inode) || is_bad_inode(inode))
 				continue;
 
-			/* if inode uses special I/O path, let's go phase 3 */
-			if (f2fs_post_read_required(inode)) {
-				add_gc_inode(gc_list, inode);
-				continue;
-			}
-
 			if (!down_write_trylock(
 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
 				iput(inode);
@@ -886,10 +964,23 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 				continue;
 			}
 
-			start_bidx = f2fs_start_bidx_of_node(nofs, inode);
+			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
+								ofs_in_node;
+
+			if (f2fs_post_read_required(inode)) {
+				int err = ra_data_block(inode, start_bidx);
+
+				up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+				if (err) {
+					iput(inode);
+					continue;
+				}
+				add_gc_inode(gc_list, inode);
+				continue;
+			}
+
 			data_page = f2fs_get_read_data_page(inode,
-					start_bidx + ofs_in_node, REQ_RAHEAD,
-					true);
+						start_bidx, REQ_RAHEAD, true);
 			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 			if (IS_ERR(data_page)) {
 				iput(inode);

fs/f2fs/segment.c

@@ -2079,6 +2079,8 @@ void f2fs_invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr)
 	if (addr == NEW_ADDR)
 		return;
 
+	invalidate_mapping_pages(META_MAPPING(sbi), addr, addr);
+
 	/* add it into sit main buffer */
 	down_write(&sit_i->sentry_lock);
 
@@ -2978,6 +2980,9 @@ static void do_write_page(struct f2fs_summary *sum, struct f2fs_io_info *fio)
 reallocate:
 	f2fs_allocate_data_block(fio->sbi, fio->page, fio->old_blkaddr,
 			&fio->new_blkaddr, sum, type, fio, true);
+	if (GET_SEGNO(fio->sbi, fio->old_blkaddr) != NULL_SEGNO)
+		invalidate_mapping_pages(META_MAPPING(fio->sbi),
+					fio->old_blkaddr, fio->old_blkaddr);
 
 	/* writeout dirty page into bdev */
 	f2fs_submit_page_write(fio);
@@ -3132,8 +3137,11 @@ void f2fs_do_replace_block(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 
 	if (!recover_curseg || recover_newaddr)
 		update_sit_entry(sbi, new_blkaddr, 1);
-	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO)
+	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO) {
+		invalidate_mapping_pages(META_MAPPING(sbi),
+					old_blkaddr, old_blkaddr);
 		update_sit_entry(sbi, old_blkaddr, -1);
+	}
 
 	locate_dirty_segment(sbi, GET_SEGNO(sbi, old_blkaddr));
 	locate_dirty_segment(sbi, GET_SEGNO(sbi, new_blkaddr));