f2fs: change the current atomic write way

Current atomic write has three major issues like below.
 - keeps the updates in non-reclaimable memory space and they are even
   hard to be migrated, which is not good for contiguous memory
   allocation.
 - disk spaces used for atomic files cannot be garbage collected, so
   this makes it difficult for the filesystem to be defragmented.
 - If atomic write operations hit the threshold of either memory usage
   or garbage collection failure count, All the atomic write operations
   will fail immediately.

To resolve the issues, I will keep a COW inode internally for all the
updates to be flushed from memory, when we need to flush them out in a
situation like high memory pressure. These COW inodes will be tagged
as orphan inodes to be reclaimed in case of sudden power-cut or system
failure during atomic writes.

Signed-off-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 7 insertions, 26 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index efe5e80163a8..68d299b54820 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -716,7 +716,6 @@ enum {
 
 enum {
 	GC_FAILURE_PIN,
-	GC_FAILURE_ATOMIC,
 	MAX_GC_FAILURE
 };
 
@@ -738,7 +737,6 @@ enum {
 	FI_UPDATE_WRITE,	/* inode has in-place-update data */
 	FI_NEED_IPU,		/* used for ipu per file */
 	FI_ATOMIC_FILE,		/* indicate atomic file */
-	FI_ATOMIC_COMMIT,	/* indicate the state of atomical committing */
 	FI_VOLATILE_FILE,	/* indicate volatile file */
 	FI_FIRST_BLOCK_WRITTEN,	/* indicate #0 data block was written */
 	FI_DROP_CACHE,		/* drop dirty page cache */
@@ -752,7 +750,6 @@ enum {
 	FI_EXTRA_ATTR,		/* indicate file has extra attribute */
 	FI_PROJ_INHERIT,	/* indicate file inherits projectid */
 	FI_PIN_FILE,		/* indicate file should not be gced */
-	FI_ATOMIC_REVOKE_REQUEST, /* request to drop atomic data */
 	FI_VERITY_IN_PROGRESS,	/* building fs-verity Merkle tree */
 	FI_COMPRESSED_FILE,	/* indicate file's data can be compressed */
 	FI_COMPRESS_CORRUPT,	/* indicate compressed cluster is corrupted */
@@ -794,11 +791,9 @@ struct f2fs_inode_info {
 #endif
 	struct list_head dirty_list;	/* dirty list for dirs and files */
 	struct list_head gdirty_list;	/* linked in global dirty list */
-	struct list_head inmem_ilist;	/* list for inmem inodes */
-	struct list_head inmem_pages;	/* inmemory pages managed by f2fs */
-	struct task_struct *inmem_task;	/* store inmemory task */
-	struct mutex inmem_lock;	/* lock for inmemory pages */
+	struct task_struct *atomic_write_task;	/* store atomic write task */
 	struct extent_tree *extent_tree;	/* cached extent_tree entry */
+	struct inode *cow_inode;	/* copy-on-write inode for atomic write */
 
 	/* avoid racing between foreground op and gc */
 	struct f2fs_rwsem i_gc_rwsem[2];
@@ -1092,7 +1087,6 @@ enum count_type {
 	F2FS_DIRTY_QDATA,
 	F2FS_DIRTY_NODES,
 	F2FS_DIRTY_META,
-	F2FS_INMEM_PAGES,
 	F2FS_DIRTY_IMETA,
 	F2FS_WB_CP_DATA,
 	F2FS_WB_DATA,
@@ -1122,11 +1116,7 @@ enum page_type {
 	META,
 	NR_PAGE_TYPE,
 	META_FLUSH,
-	INMEM,		/* the below types are used by tracepoints only. */
-	INMEM_DROP,
-	INMEM_INVALIDATE,
-	INMEM_REVOKE,
-	IPU,
+	IPU,		/* the below types are used by tracepoints only. */
 	OPU,
 };
 
@@ -1718,7 +1708,6 @@ struct f2fs_sb_info {
 
 	/* for skip statistic */
 	unsigned int atomic_files;		/* # of opened atomic file */
-	unsigned long long skipped_atomic_files[2];	/* FG_GC and BG_GC */
 	unsigned long long skipped_gc_rwsem;		/* FG_GC only */
 
 	/* threshold for gc trials on pinned files */
@@ -3202,11 +3191,6 @@ static inline bool f2fs_is_atomic_file(struct inode *inode)
 	return is_inode_flag_set(inode, FI_ATOMIC_FILE);
 }
 
-static inline bool f2fs_is_commit_atomic_write(struct inode *inode)
-{
-	return is_inode_flag_set(inode, FI_ATOMIC_COMMIT);
-}
-
 static inline bool f2fs_is_volatile_file(struct inode *inode)
 {
 	return is_inode_flag_set(inode, FI_VOLATILE_FILE);
@@ -3444,6 +3428,8 @@ void f2fs_handle_failed_inode(struct inode *inode);
 int f2fs_update_extension_list(struct f2fs_sb_info *sbi, const char *name,
 							bool hot, bool set);
 struct dentry *f2fs_get_parent(struct dentry *child);
+int f2fs_get_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
+		     struct inode **new_inode);
 
 /*
  * dir.c
@@ -3579,11 +3565,8 @@ void f2fs_destroy_node_manager_caches(void);
  * segment.c
  */
 bool f2fs_need_SSR(struct f2fs_sb_info *sbi);
-void f2fs_register_inmem_page(struct inode *inode, struct page *page);
-void f2fs_drop_inmem_pages_all(struct f2fs_sb_info *sbi, bool gc_failure);
-void f2fs_drop_inmem_pages(struct inode *inode);
-void f2fs_drop_inmem_page(struct inode *inode, struct page *page);
-int f2fs_commit_inmem_pages(struct inode *inode);
+int f2fs_commit_atomic_write(struct inode *inode);
+void f2fs_abort_atomic_write(struct inode *inode, bool clean);
 void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need);
 void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi, bool from_bg);
 int f2fs_issue_flush(struct f2fs_sb_info *sbi, nid_t ino);
@@ -3815,7 +3798,6 @@ struct f2fs_stat_info {
 	int ext_tree, zombie_tree, ext_node;
 	int ndirty_node, ndirty_dent, ndirty_meta, ndirty_imeta;
 	int ndirty_data, ndirty_qdata;
-	int inmem_pages;
 	unsigned int ndirty_dirs, ndirty_files, nquota_files, ndirty_all;
 	int nats, dirty_nats, sits, dirty_sits;
 	int free_nids, avail_nids, alloc_nids;
@@ -3845,7 +3827,6 @@ struct f2fs_stat_info {
 	int bg_node_segs, bg_data_segs;
 	int tot_blks, data_blks, node_blks;
 	int bg_data_blks, bg_node_blks;
-	unsigned long long skipped_atomic_files[2];
 	int curseg[NR_CURSEG_TYPE];
 	int cursec[NR_CURSEG_TYPE];
 	int curzone[NR_CURSEG_TYPE];