f2fs: fix inconsistent comments

Lack of maintenance on comments may mislead developers, fix them.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/checkpoint.c

@@ -50,9 +50,6 @@ struct page *f2fs_grab_meta_page(struct f2fs_sb_info *sbi, pgoff_t index)
 	return page;
 }
 
-/*
- * We guarantee no failure on the returned page.
- */
 static struct page *__get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index,
 							bool is_meta)
 {
@@ -206,7 +203,7 @@ bool f2fs_is_valid_blkaddr(struct f2fs_sb_info *sbi,
 }
 
 /*
- * Readahead CP/NAT/SIT/SSA pages
+ * Readahead CP/NAT/SIT/SSA/POR pages
  */
 int f2fs_ra_meta_pages(struct f2fs_sb_info *sbi, block_t start, int nrpages,
 							int type, bool sync)
@@ -898,7 +895,7 @@ int f2fs_get_valid_checkpoint(struct f2fs_sb_info *sbi)
 		return -ENOMEM;
 	/*
 	 * Finding out valid cp block involves read both
-	 * sets( cp pack1 and cp pack 2)
+	 * sets( cp pack 1 and cp pack 2)
 	 */
 	cp_start_blk_no = le32_to_cpu(fsb->cp_blkaddr);
 	cp1 = validate_checkpoint(sbi, cp_start_blk_no, &cp1_version);
@@ -1385,10 +1382,7 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	/* Flush all the NAT/SIT pages */
 	f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO);
 
-	/*
-	 * modify checkpoint
-	 * version number is already updated
-	 */
+	/* start to update checkpoint, cp ver is already updated previously */
 	ckpt->elapsed_time = cpu_to_le64(get_mtime(sbi, true));
 	ckpt->free_segment_count = cpu_to_le32(free_segments(sbi));
 	for (i = 0; i < NR_CURSEG_NODE_TYPE; i++) {
@@ -1541,9 +1535,6 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	return unlikely(f2fs_cp_error(sbi)) ? -EIO : 0;
 }
 
-/*
- * We guarantee that this checkpoint procedure will not fail.
- */
 int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 {
 	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
@@ -1611,7 +1602,6 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 
 	f2fs_flush_sit_entries(sbi, cpc);
 
-	/* unlock all the fs_lock[] in do_checkpoint() */
 	err = do_checkpoint(sbi, cpc);
 	if (err)
 		f2fs_release_discard_addrs(sbi);
@@ -1624,7 +1614,7 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	if (cpc->reason & CP_RECOVERY)
 		f2fs_notice(sbi, "checkpoint: version = %llx", ckpt_ver);
 
-	/* do checkpoint periodically */
+	/* update CP_TIME to trigger checkpoint periodically */
 	f2fs_update_time(sbi, CP_TIME);
 	trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, "finish checkpoint");
 out:

fs/f2fs/data.c

@@ -364,9 +364,6 @@ static void f2fs_write_end_io(struct bio *bio)
 	bio_put(bio);
 }
 
-/*
- * Return true, if pre_bio's bdev is same as its target device.
- */
 struct block_device *f2fs_target_device(struct f2fs_sb_info *sbi,
 				block_t blk_addr, struct bio *bio)
 {
@@ -403,6 +400,9 @@ int f2fs_target_device_index(struct f2fs_sb_info *sbi, block_t blkaddr)
 	return 0;
 }
 
+/*
+ * Return true, if pre_bio's bdev is same as its target device.
+ */
 static bool __same_bdev(struct f2fs_sb_info *sbi,
 				block_t blk_addr, struct bio *bio)
 {
@@ -410,9 +410,6 @@ static bool __same_bdev(struct f2fs_sb_info *sbi,
 	return bio->bi_disk == b->bd_disk && bio->bi_partno == b->bd_partno;
 }
 
-/*
- * Low-level block read/write IO operations.
- */
 static struct bio *__bio_alloc(struct f2fs_io_info *fio, int npages)
 {
 	struct f2fs_sb_info *sbi = fio->sbi;
@@ -1388,13 +1385,9 @@ void __do_map_lock(struct f2fs_sb_info *sbi, int flag, bool lock)
 }
 
 /*
- * f2fs_map_blocks() now supported readahead/bmap/rw direct_IO with
- * f2fs_map_blocks structure.
- * If original data blocks are allocated, then give them to blockdev.
- * Otherwise,
- *     a. preallocate requested block addresses
- *     b. do not use extent cache for better performance
- *     c. give the block addresses to blockdev
+ * f2fs_map_blocks() tries to find or build mapping relationship which
+ * maps continuous logical blocks to physical blocks, and return such
+ * info via f2fs_map_blocks structure.
  */
 int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
 						int create, int flag)

fs/f2fs/f2fs.h

@@ -2388,9 +2388,9 @@ static inline block_t datablock_addr(struct inode *inode,
 
 	raw_node = F2FS_NODE(node_page);
 
-	/* from GC path only */
 	if (is_inode) {
 		if (!inode)
+			/* from GC path only */
 			base = offset_in_addr(&raw_node->i);
 		else if (f2fs_has_extra_attr(inode))
 			base = get_extra_isize(inode);

fs/f2fs/file.c

@@ -112,7 +112,6 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf)
 		}
 	}
 
-	/* fill the page */
 	f2fs_wait_on_page_writeback(page, DATA, false, true);
 
 	/* wait for GCed page writeback via META_MAPPING */

fs/f2fs/gc.c

@@ -192,7 +192,10 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
 		p->ofs_unit = sbi->segs_per_sec;
 	}
 
-	/* we need to check every dirty segments in the FG_GC case */
+	/*
+	 * adjust candidates range, should select all dirty segments for
+	 * foreground GC and urgent GC cases.
+	 */
 	if (gc_type != FG_GC &&
 			(sbi->gc_mode != GC_URGENT) &&
 			p->max_search > sbi->max_victim_search)

fs/f2fs/inode.c

@@ -776,7 +776,7 @@ void f2fs_evict_inode(struct inode *inode)
 	else
 		f2fs_inode_synced(inode);
 
-	/* ino == 0, if f2fs_new_inode() was failed t*/
+	/* for the case f2fs_new_inode() was failed, .i_ino is zero, skip it */
 	if (inode->i_ino)
 		invalidate_mapping_pages(NODE_MAPPING(sbi), inode->i_ino,
 							inode->i_ino);

fs/f2fs/namei.c

@@ -177,7 +177,7 @@ static inline int is_extension_exist(const unsigned char *s, const char *sub)
 }
 
 /*
- * Set multimedia files as cold files for hot/cold data separation
+ * Set file's temperature for hot/cold data separation
  */
 static inline void set_file_temperature(struct f2fs_sb_info *sbi, struct inode *inode,
 		const unsigned char *name)

fs/f2fs/node.c

@@ -510,9 +510,6 @@ int f2fs_try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
 	return nr - nr_shrink;
 }
 
-/*
- * This function always returns success
- */
 int f2fs_get_node_info(struct f2fs_sb_info *sbi, nid_t nid,
 						struct node_info *ni)
 {
@@ -716,8 +713,7 @@ static int get_node_path(struct inode *inode, long block,
 /*
  * Caller should call f2fs_put_dnode(dn).
  * Also, it should grab and release a rwsem by calling f2fs_lock_op() and
- * f2fs_unlock_op() only if ro is not set RDONLY_NODE.
- * In the case of RDONLY_NODE, we don't need to care about mutex.
+ * f2fs_unlock_op() only if mode is set with ALLOC_NODE.
  */
 int f2fs_get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int mode)
 {

fs/f2fs/shrinker.c

@@ -58,7 +58,7 @@ unsigned long f2fs_shrink_count(struct shrinker *shrink,
 		/* count extent cache entries */
 		count += __count_extent_cache(sbi);
 
-		/* shrink clean nat cache entries */
+		/* count clean nat cache entries */
 		count += __count_nat_entries(sbi);
 
 		/* count free nids cache entries */

fs/f2fs/super.c

@@ -1658,7 +1658,7 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
 out_unlock:
 	up_write(&sbi->gc_lock);
 restore_flag:
-	sbi->sb->s_flags = s_flags;	/* Restore MS_RDONLY status */
+	sbi->sb->s_flags = s_flags;	/* Restore SB_RDONLY status */
 	return err;
 }
 
@@ -3590,7 +3590,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 			f2fs_err(sbi, "Cannot turn on quotas: error %d", err);
 	}
 #endif
-	/* if there are nt orphan nodes free them */
+	/* if there are any orphan inodes, free them */
 	err = f2fs_recover_orphan_inodes(sbi);
 	if (err)
 		goto free_meta;