f2fs: introduce mode=lfs mount option

This mount option is to enable original log-structured filesystem forcefully.
So, there should be no random writes for main area.

Especially, this supports host-managed SMR device.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

9 files changed, 74 insertions, 4 deletions

diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index e1c9f0849da6..3a5ce24021d9 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -151,6 +151,9 @@ noinline_data          Disable the inline data feature, inline data feature is
                        enabled by default.
 data_flush             Enable data flushing before checkpoint in order to
                        persist data of regular and symlink.
+mode=%s                Control block allocation mode which supports "adaptive"
+                       and "lfs". In "lfs" mode, there should be no random
+                       writes towards main area.
 
 ================================================================================
 DEBUGFS ENTRIES
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 4179c7b971fc..837e6bcad5ce 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -981,7 +981,7 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
          * This avoids to conduct wrong roll-forward operations and uses
          * metapages, so should be called prior to sync_meta_pages below.
          */
-        if (discard_next_dnode(sbi, discard_blk))
+        if (!test_opt(sbi, LFS) && discard_next_dnode(sbi, discard_blk))
                 invalidate = true;
 
         /* Flush all the NAT/SIT pages */
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 5f655d0c5b1f..607ef4397330 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1710,6 +1710,8 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 
         if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
                 return 0;
+        if (test_opt(F2FS_I_SB(inode), LFS))
+                return 0;
 
         trace_f2fs_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
 
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 24c7cde84905..82acdec022ef 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -111,6 +111,8 @@ static inline bool time_to_inject(int type)
 #define F2FS_MOUNT_FORCE_FG_GC          0x00004000
 #define F2FS_MOUNT_DATA_FLUSH           0x00008000
 #define F2FS_MOUNT_FAULT_INJECTION      0x00010000
+#define F2FS_MOUNT_ADAPTIVE             0x00020000
+#define F2FS_MOUNT_LFS                  0x00040000
 
 #define clear_opt(sbi, option)  (sbi->mount_opt.opt &= ~F2FS_MOUNT_##option)
 #define set_opt(sbi, option)    (sbi->mount_opt.opt |= F2FS_MOUNT_##option)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 7a8d262bc488..b9d745ef5b08 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -878,9 +878,15 @@ static int __exchange_data_block(struct inode *inode, pgoff_t src,
                 return full ? truncate_hole(inode, dst, dst + 1) : 0;
 
         if (do_replace) {
-                struct page *ipage = get_node_page(sbi, inode->i_ino);
+                struct page *ipage;
                 struct node_info ni;
 
+                if (test_opt(sbi, LFS)) {
+                        ret = -ENOTSUPP;
+                        goto err_out;
+                }
+
+                ipage = get_node_page(sbi, inode->i_ino);
                 if (IS_ERR(ipage)) {
                         ret = PTR_ERR(ipage);
                         goto err_out;
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index b568b28c74f2..a39d84ab66b2 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -624,8 +624,12 @@ out:
         if (err) {
                 bool invalidate = false;
 
-                if (discard_next_dnode(sbi, blkaddr))
+                if (test_opt(sbi, LFS)) {
+                        update_meta_page(sbi, NULL, blkaddr);
                         invalidate = true;
+                } else if (discard_next_dnode(sbi, blkaddr)) {
+                        invalidate = true;
+                }
 
                 /* Flush all the NAT/SIT pages */
                 while (get_pages(sbi, F2FS_DIRTY_META))
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index eff046a792ad..4792f94089f7 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -707,6 +707,7 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
         unsigned long *prefree_map = dirty_i->dirty_segmap[PRE];
         unsigned int start = 0, end = -1;
+        unsigned int secno, start_segno;
 
         mutex_lock(&dirty_i->seglist_lock);
 
@@ -726,8 +727,22 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
                 if (!test_opt(sbi, DISCARD))
                         continue;
 
-                f2fs_issue_discard(sbi, START_BLOCK(sbi, start),
+                if (!test_opt(sbi, LFS) || sbi->segs_per_sec == 1) {
+                        f2fs_issue_discard(sbi, START_BLOCK(sbi, start),
                                 (end - start) << sbi->log_blocks_per_seg);
+                        continue;
+                }
+next:
+                secno = GET_SECNO(sbi, start);
+                start_segno = secno * sbi->segs_per_sec;
+                if (!IS_CURSEC(sbi, secno) &&
+                        !get_valid_blocks(sbi, start, sbi->segs_per_sec))
+                        f2fs_issue_discard(sbi, START_BLOCK(sbi, start_segno),
+                                sbi->segs_per_sec << sbi->log_blocks_per_seg);
+
+                start = start_segno + sbi->segs_per_sec;
+                if (start < end)
+                        goto next;
         }
         mutex_unlock(&dirty_i->seglist_lock);
 
@@ -1221,6 +1236,9 @@ void allocate_new_segments(struct f2fs_sb_info *sbi)
 {
         int i;
 
+        if (test_opt(sbi, LFS))
+                return;
+
         for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++)
                 __allocate_new_segments(sbi, i);
 }
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 890bb28d2082..d74cc330ae13 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -470,6 +470,10 @@ static inline bool need_SSR(struct f2fs_sb_info *sbi)
 {
         int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES);
         int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS);
+
+        if (test_opt(sbi, LFS))
+                return false;
+
         return free_sections(sbi) <= (node_secs + 2 * dent_secs +
                                                 reserved_sections(sbi) + 1);
 }
@@ -533,6 +537,9 @@ static inline bool need_inplace_update(struct inode *inode)
         if (S_ISDIR(inode->i_mode) || f2fs_is_atomic_file(inode))
                 return false;
 
+        if (test_opt(sbi, LFS))
+                return false;
+
         if (policy & (0x1 << F2FS_IPU_FORCE))
                 return true;
         if (policy & (0x1 << F2FS_IPU_SSR) && need_SSR(sbi))
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index dc66f1623e06..edc736de8ee9 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -94,6 +94,7 @@ enum {
         Opt_noextent_cache,
         Opt_noinline_data,
         Opt_data_flush,
+        Opt_mode,
         Opt_fault_injection,
         Opt_lazytime,
         Opt_nolazytime,
@@ -123,6 +124,7 @@ static match_table_t f2fs_tokens = {
         {Opt_noextent_cache, "noextent_cache"},
         {Opt_noinline_data, "noinline_data"},
         {Opt_data_flush, "data_flush"},
+        {Opt_mode, "mode=%s"},
         {Opt_fault_injection, "fault_injection=%u"},
         {Opt_lazytime, "lazytime"},
         {Opt_nolazytime, "nolazytime"},
@@ -506,6 +508,25 @@ static int parse_options(struct super_block *sb, char *options)
                 case Opt_data_flush:
                         set_opt(sbi, DATA_FLUSH);
                         break;
+                case Opt_mode:
+                        name = match_strdup(&args[0]);
+
+                        if (!name)
+                                return -ENOMEM;
+                        if (strlen(name) == 8 &&
+                                        !strncmp(name, "adaptive", 8)) {
+                                set_opt(sbi, ADAPTIVE);
+                                clear_opt(sbi, LFS);
+                        } else if (strlen(name) == 3 &&
+                                        !strncmp(name, "lfs", 3)) {
+                                clear_opt(sbi, ADAPTIVE);
+                                set_opt(sbi, LFS);
+                        } else {
+                                kfree(name);
+                                return -EINVAL;
+                        }
+                        kfree(name);
+                        break;
                 case Opt_fault_injection:
                         if (args->from && match_int(args, &arg))
                                 return -EINVAL;
@@ -870,6 +891,12 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
                 seq_puts(seq, ",noextent_cache");
         if (test_opt(sbi, DATA_FLUSH))
                 seq_puts(seq, ",data_flush");
+
+        seq_puts(seq, ",mode=");
+        if (test_opt(sbi, ADAPTIVE))
+                seq_puts(seq, "adaptive");
+        else if (test_opt(sbi, LFS))
+                seq_puts(seq, "lfs");
         seq_printf(seq, ",active_logs=%u", sbi->active_logs);
 
         return 0;
@@ -953,6 +980,7 @@ static void default_options(struct f2fs_sb_info *sbi)
         set_opt(sbi, EXTENT_CACHE);
         sbi->sb->s_flags |= MS_LAZYTIME;
         set_opt(sbi, FLUSH_MERGE);
+        set_opt(sbi, ADAPTIVE);
 
 #ifdef CONFIG_F2FS_FS_XATTR
         set_opt(sbi, XATTR_USER);