zonefs: Separate zone information from inode information

In preparation for adding dynamic inode allocation, separate an inode
zone information from the zonefs inode structure. The new data structure
zonefs_zone is introduced to store in memory information about a zone
that must be kept throughout the lifetime of the device mount.

Linking between a zone file inode and its zone information is done by
setting the inode i_private field to point to a struct zonefs_zone.
Using the i_private pointer avoids the need for adding a pointer in
struct zonefs_inode_info. Beside the vfs inode, this structure is
reduced to a mutex and a write open counter.

One struct zonefs_zone is created per file inode on mount. These
structures are organized in an array using the new struct
zonefs_zone_group data structure to represent zone groups. The
zonefs_zone arrays are indexed per file number (the index of a struct
zonefs_zone in its array directly gives the file number/name for that
zone file inode).
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

fs/zonefs/trace.h

@@ -20,8 +20,9 @@
 #define show_dev(dev) MAJOR(dev), MINOR(dev)
 
 TRACE_EVENT(zonefs_zone_mgmt,
-	    TP_PROTO(struct inode *inode, enum req_op op),
-	    TP_ARGS(inode, op),
+	    TP_PROTO(struct super_block *sb, struct zonefs_zone *z,
+		     enum req_op op),
+	    TP_ARGS(sb, z, op),
 	    TP_STRUCT__entry(
 			     __field(dev_t, dev)
 			     __field(ino_t, ino)
@@ -30,12 +31,12 @@ TRACE_EVENT(zonefs_zone_mgmt,
 			     __field(sector_t, nr_sectors)
 	    ),
 	    TP_fast_assign(
-			   __entry->dev = inode->i_sb->s_dev;
-			   __entry->ino = inode->i_ino;
+			   __entry->dev = sb->s_dev;
+			   __entry->ino =
+				z->z_sector >> ZONEFS_SB(sb)->s_zone_sectors_shift;
 			   __entry->op = op;
-			   __entry->sector = ZONEFS_I(inode)->i_zsector;
-			   __entry->nr_sectors =
-				   ZONEFS_I(inode)->i_zone_size >> SECTOR_SHIFT;
+			   __entry->sector = z->z_sector;
+			   __entry->nr_sectors = z->z_size >> SECTOR_SHIFT;
 	    ),
 	    TP_printk("bdev=(%d,%d), ino=%lu op=%s, sector=%llu, nr_sectors=%llu",
 		      show_dev(__entry->dev), (unsigned long)__entry->ino,
@@ -58,9 +59,10 @@ TRACE_EVENT(zonefs_file_dio_append,
 	    TP_fast_assign(
 			   __entry->dev = inode->i_sb->s_dev;
 			   __entry->ino = inode->i_ino;
-			   __entry->sector = ZONEFS_I(inode)->i_zsector;
+			   __entry->sector = zonefs_inode_zone(inode)->z_sector;
 			   __entry->size = size;
-			   __entry->wpoffset = ZONEFS_I(inode)->i_wpoffset;
+			   __entry->wpoffset =
+				zonefs_inode_zone(inode)->z_wpoffset;
 			   __entry->ret = ret;
 	    ),
 	    TP_printk("bdev=(%d, %d), ino=%lu, sector=%llu, size=%zu, wpoffset=%llu, ret=%zu",

fs/zonefs/zonefs.h

@@ -47,22 +47,39 @@ static inline enum zonefs_ztype zonefs_zone_type(struct blk_zone *zone)
 #define ZONEFS_ZONE_CNV		(1U << 31)
 
 /*
- * In-memory inode data.
+ * In-memory per-file inode zone data.
  */
-struct zonefs_inode_info {
-	struct inode		i_vnode;
+struct zonefs_zone {
+	/* Zone state flags */
+	unsigned int		z_flags;
 
-	/* File zone start sector (512B unit) */
-	sector_t		i_zsector;
+	/* Zone start sector (512B unit) */
+	sector_t		z_sector;
 
-	/* File zone write pointer position (sequential zones only) */
-	loff_t			i_wpoffset;
+	/* Zone size (bytes) */
+	loff_t			z_size;
 
-	/* File maximum size */
-	loff_t			i_max_size;
+	/* Zone capacity (file maximum size, bytes) */
+	loff_t			z_capacity;
 
-	/* File zone size */
-	loff_t			i_zone_size;
+	/* Write pointer offset in the zone (sequential zones only, bytes) */
+	loff_t			z_wpoffset;
+};
+
+/*
+ * In memory zone group information: all zones of a group are exposed
+ * as files, one file per zone.
+ */
+struct zonefs_zone_group {
+	unsigned int		g_nr_zones;
+	struct zonefs_zone	*g_zones;
+};
+
+/*
+ * In-memory inode data.
+ */
+struct zonefs_inode_info {
+	struct inode		i_vnode;
 
 	/*
 	 * To serialise fully against both syscall and mmap based IO and
@@ -81,7 +98,6 @@ struct zonefs_inode_info {
 
 	/* guarded by i_truncate_mutex */
 	unsigned int		i_wr_refcnt;
-	unsigned int		i_flags;
 };
 
 static inline struct zonefs_inode_info *ZONEFS_I(struct inode *inode)
@@ -89,24 +105,29 @@ static inline struct zonefs_inode_info *ZONEFS_I(struct inode *inode)
 	return container_of(inode, struct zonefs_inode_info, i_vnode);
 }
 
-static inline bool zonefs_zone_is_cnv(struct zonefs_inode_info *zi)
+static inline bool zonefs_zone_is_cnv(struct zonefs_zone *z)
+{
+	return z->z_flags & ZONEFS_ZONE_CNV;
+}
+
+static inline bool zonefs_zone_is_seq(struct zonefs_zone *z)
 {
-	return zi->i_flags & ZONEFS_ZONE_CNV;
+	return !zonefs_zone_is_cnv(z);
 }
 
-static inline bool zonefs_zone_is_seq(struct zonefs_inode_info *zi)
+static inline struct zonefs_zone *zonefs_inode_zone(struct inode *inode)
 {
-	return !zonefs_zone_is_cnv(zi);
+	return inode->i_private;
 }
 
 static inline bool zonefs_inode_is_cnv(struct inode *inode)
 {
-	return zonefs_zone_is_cnv(ZONEFS_I(inode));
+	return zonefs_zone_is_cnv(zonefs_inode_zone(inode));
 }
 
 static inline bool zonefs_inode_is_seq(struct inode *inode)
 {
-	return zonefs_zone_is_seq(ZONEFS_I(inode));
+	return zonefs_zone_is_seq(zonefs_inode_zone(inode));
 }
 
 /*
@@ -200,7 +221,7 @@ struct zonefs_sb_info {
 	uuid_t			s_uuid;
 	unsigned int		s_zone_sectors_shift;
 
-	unsigned int		s_nr_files[ZONEFS_ZTYPE_MAX];
+	struct zonefs_zone_group s_zgroup[ZONEFS_ZTYPE_MAX];
 
 	loff_t			s_blocks;
 	loff_t			s_used_blocks;
@@ -229,8 +250,8 @@ static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb)
 	pr_warn("zonefs (%s) WARNING: " format, sb->s_id, ## args)
 
 /* In super.c */
-void zonefs_account_active(struct inode *inode);
-int zonefs_zone_mgmt(struct inode *inode, enum req_op op);
+void zonefs_inode_account_active(struct inode *inode);
+int zonefs_inode_zone_mgmt(struct inode *inode, enum req_op op);
 void zonefs_i_size_write(struct inode *inode, loff_t isize);
 void zonefs_update_stats(struct inode *inode, loff_t new_isize);
 void __zonefs_io_error(struct inode *inode, bool write);