[PATCH v3 18/19] fat: Replace fat_sync_inode() with sync_inode_metadata()

[Jan Kara <jack@suse.cz>]

Use generic sync_inode_metadata() instead of fat_sync_inode() for
persisting inode metadata changes for DIRSYNC inodes. This slightly
simplifies code and also addresses a theoretical race where
fat_sync_inode() could return before all metadata buffers associated
with the inode were properly written out when racing with fsync(2).

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/fat/dir.c         |  5 ++---
 fs/fat/fat.h         |  1 -
 fs/fat/file.c        |  6 +++---
 fs/fat/inode.c       | 15 ---------------
 fs/fat/misc.c        |  7 ++++---
 fs/fat/namei_msdos.c | 28 +++++++++++++---------------
 fs/fat/namei_vfat.c  | 16 +++++++---------
 7 files changed, 29 insertions(+), 49 deletions(-)

diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index a54e6d125794..d33bf34bdce7 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -1080,10 +1080,9 @@ int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
 	}
 
 	fat_truncate_time(dir, NULL, FAT_UPDATE_ATIME | FAT_UPDATE_CMTIME);
+	mark_inode_dirty(dir);
 	if (IS_DIRSYNC(dir))
-		(void)fat_sync_inode(dir);
-	else
-		mark_inode_dirty(dir);
+		sync_inode_metadata(dir, 1);
 
 	return 0;
 }
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 99ed9228a677..dcb5ba757073 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -421,7 +421,6 @@ extern void fat_detach(struct inode *inode);
 extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
 extern struct inode *fat_build_inode(struct super_block *sb,
 			struct msdos_dir_entry *de, loff_t i_pos);
-extern int fat_sync_inode(struct inode *inode);
 extern int fat_fill_super(struct super_block *sb, struct fs_context *fc,
 			  void (*setup)(struct super_block *));
 extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
diff --git a/fs/fat/file.c b/fs/fat/file.c
index 8a7585c25207..1c835ca5f21a 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -331,15 +331,15 @@ static int fat_free(struct inode *inode, int skip)
 	}
 	MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
 	fat_truncate_time(inode, NULL, FAT_UPDATE_CMTIME);
+	mark_inode_dirty(inode);
 	if (wait) {
-		err = fat_sync_inode(inode);
+		err = sync_inode_metadata(inode, 1);
 		if (err) {
 			MSDOS_I(inode)->i_start = i_start;
 			MSDOS_I(inode)->i_logstart = i_logstart;
 			return err;
 		}
-	} else
-		mark_inode_dirty(inode);
+	}
 
 	/* Write a new EOF, and get the remaining cluster chain for freeing. */
 	if (skip) {
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index c4d8ca8736fb..c4b4ccaa091a 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -964,21 +964,6 @@ static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
 	return err;
 }
 
-int fat_sync_inode(struct inode *inode)
-{
-	int err;
-	struct writeback_control wbc = {
-		.sync_mode = WB_SYNC_ALL,
-	};
-
-	err = __fat_write_inode(inode);
-	if (err)
-		return err;
-	return fat_sync_inode_metadata(inode, &wbc);
-}
-
-EXPORT_SYMBOL_GPL(fat_sync_inode);
-
 static int fat_show_options(struct seq_file *m, struct dentry *root);
 static const struct super_operations fat_sops = {
 	.alloc_inode	= fat_alloc_inode,
diff --git a/fs/fat/misc.c b/fs/fat/misc.c
index 3027ef53af21..be18f6b5819b 100644
--- a/fs/fat/misc.c
+++ b/fs/fat/misc.c
@@ -146,16 +146,17 @@ int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
 	} else {
 		MSDOS_I(inode)->i_start = new_dclus;
 		MSDOS_I(inode)->i_logstart = new_dclus;
+		mark_inode_dirty(inode);
 		/*
 		 * Since generic_write_sync() synchronizes regular files later,
 		 * we sync here only directories.
 		 */
 		if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
-			ret = fat_sync_inode(inode);
+			ret = sync_inode_metadata(inode, 1);
 			if (ret)
 				return ret;
-		} else
-			mark_inode_dirty(inode);
+		}
+
 	}
 	if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
 		fat_fs_error_ratelimit(
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index 4e20f8498938..472bd847ef9c 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -252,10 +252,9 @@ static int msdos_add_entry(struct inode *dir, const unsigned char *name,
 		return err;
 
 	fat_truncate_time(dir, ts, FAT_UPDATE_CMTIME);
+	mark_inode_dirty(dir);
 	if (IS_DIRSYNC(dir))
-		(void)fat_sync_inode(dir);
-	else
-		mark_inode_dirty(dir);
+		sync_inode_metadata(dir, 1);
 
 	return 0;
 }
@@ -473,21 +472,21 @@ static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 				MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 			else
 				MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
+			mark_inode_dirty(old_inode);
 			if (IS_DIRSYNC(old_dir)) {
-				err = fat_sync_inode(old_inode);
+				err = sync_inode_metadata(old_inode, 1);
 				if (err) {
 					MSDOS_I(old_inode)->i_attrs = old_attrs;
 					goto out;
 				}
-			} else
-				mark_inode_dirty(old_inode);
+			}
 
 			inode_inc_iversion(old_dir);
 			fat_truncate_time(old_dir, NULL, FAT_UPDATE_CMTIME);
+			mark_inode_dirty(old_dir);
 			if (IS_DIRSYNC(old_dir))
-				(void)fat_sync_inode(old_dir);
+				sync_inode_metadata(old_dir, 1);
 			else
-				mark_inode_dirty(old_dir);
 			goto out;
 		}
 	}
@@ -526,12 +525,12 @@ static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 		if (!new_inode)
 			inc_nlink(new_dir);
 	}
+	mark_inode_dirty(old_inode);
 	if (IS_DIRSYNC(new_dir)) {
-		err = fat_sync_inode(old_inode);
+		err = sync_inode_metadata(old_inode, 1);
 		if (err)
 			goto error_dotdot;
-	} else
-		mark_inode_dirty(old_inode);
+	}
 
 
 	err = fat_remove_entries(old_dir, &old_sinfo);	/* and releases bh */
@@ -540,10 +539,9 @@ static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 		goto error_dotdot;
 	inode_inc_iversion(old_dir);
 	fat_truncate_time(old_dir, &ts, FAT_UPDATE_CMTIME);
+	mark_inode_dirty(old_dir);
 	if (IS_DIRSYNC(old_dir))
-		(void)fat_sync_inode(old_dir);
-	else
-		mark_inode_dirty(old_dir);
+		sync_inode_metadata(old_dir, 1);
 
 	if (new_inode) {
 		drop_nlink(new_inode);
@@ -572,7 +570,7 @@ static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 	if (new_inode) {
 		fat_attach(new_inode, new_i_pos);
 		if (corrupt)
-			corrupt |= fat_sync_inode(new_inode);
+			corrupt |= sync_inode_metadata(new_inode, 1);
 	} else {
 		/*
 		 * If new entry was not sharing the data cluster, it
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index e909447873e3..732abf072fdd 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -678,10 +678,9 @@ static int vfat_add_entry(struct inode *dir, const struct qstr *qname,
 
 	/* update timestamp */
 	fat_truncate_time(dir, ts, FAT_UPDATE_CMTIME);
+	mark_inode_dirty(dir);
 	if (IS_DIRSYNC(dir))
-		(void)fat_sync_inode(dir);
-	else
-		mark_inode_dirty(dir);
+		sync_inode_metadata(dir, 1);
 cleanup:
 	kfree(slots);
 	return err;
@@ -904,9 +903,9 @@ static int vfat_get_dotdot_de(struct inode *inode, struct buffer_head **bh,
 
 static int vfat_sync_ipos(struct inode *dir, struct inode *inode)
 {
-	if (IS_DIRSYNC(dir))
-		return fat_sync_inode(inode);
 	mark_inode_dirty(inode);
+	if (IS_DIRSYNC(dir))
+		return sync_inode_metadata(inode, 1);
 	return 0;
 }
 
@@ -925,10 +924,9 @@ static void vfat_update_dir_metadata(struct inode *dir, struct timespec64 *ts)
 {
 	inode_inc_iversion(dir);
 	fat_truncate_time(dir, ts, FAT_UPDATE_CMTIME);
+	mark_inode_dirty(dir);
 	if (IS_DIRSYNC(dir))
-		(void)fat_sync_inode(dir);
-	else
-		mark_inode_dirty(dir);
+		sync_inode_metadata(dir, 1);
 }
 
 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
@@ -1025,7 +1023,7 @@ static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
 	if (new_inode) {
 		fat_attach(new_inode, new_i_pos);
 		if (corrupt)
-			corrupt |= fat_sync_inode(new_inode);
+			corrupt |= sync_inode_metadata(new_inode, 1);
 	} else {
 		/*
 		 * If new entry was not sharing the data cluster, it
-- 
2.51.0