xfs: support caching rtgroup metadata inodes

Create the necessary per-rtgroup infrastructure that we need to load
metadata inodes into memory.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/libxfs/xfs_rtgroup.c

@@ -30,6 +30,8 @@
 #include "xfs_icache.h"
 #include "xfs_rtgroup.h"
 #include "xfs_rtbitmap.h"
+#include "xfs_metafile.h"
+#include "xfs_metadir.h"
 
 int
 xfs_rtgroup_alloc(
@@ -250,3 +252,124 @@ xfs_rtginode_lockdep_setup(
 #else
 #define xfs_rtginode_lockdep_setup(ip, rgno, type)	do { } while (0)
 #endif /* CONFIG_PROVE_LOCKING */
+
+struct xfs_rtginode_ops {
+	const char		*name;	/* short name */
+
+	enum xfs_metafile_type	metafile_type;
+
+	/* Does the fs have this feature? */
+	bool			(*enabled)(struct xfs_mount *mp);
+};
+
+static const struct xfs_rtginode_ops xfs_rtginode_ops[XFS_RTGI_MAX] = {
+};
+
+/* Return the shortname of this rtgroup inode. */
+const char *
+xfs_rtginode_name(
+	enum xfs_rtg_inodes	type)
+{
+	return xfs_rtginode_ops[type].name;
+}
+
+/* Return the metafile type of this rtgroup inode. */
+enum xfs_metafile_type
+xfs_rtginode_metafile_type(
+	enum xfs_rtg_inodes	type)
+{
+	return xfs_rtginode_ops[type].metafile_type;
+}
+
+/* Should this rtgroup inode be present? */
+bool
+xfs_rtginode_enabled(
+	struct xfs_rtgroup	*rtg,
+	enum xfs_rtg_inodes	type)
+{
+	const struct xfs_rtginode_ops *ops = &xfs_rtginode_ops[type];
+
+	if (!ops->enabled)
+		return true;
+	return ops->enabled(rtg_mount(rtg));
+}
+
+/* Load and existing rtgroup inode into the rtgroup structure. */
+int
+xfs_rtginode_load(
+	struct xfs_rtgroup	*rtg,
+	enum xfs_rtg_inodes	type,
+	struct xfs_trans	*tp)
+{
+	struct xfs_mount	*mp = tp->t_mountp;
+	const char		*path;
+	struct xfs_inode	*ip;
+	const struct xfs_rtginode_ops *ops = &xfs_rtginode_ops[type];
+	int			error;
+
+	if (!xfs_rtginode_enabled(rtg, type))
+		return 0;
+
+	if (!mp->m_rtdirip)
+		return -EFSCORRUPTED;
+
+	path = xfs_rtginode_path(rtg_rgno(rtg), type);
+	if (!path)
+		return -ENOMEM;
+	error = xfs_metadir_load(tp, mp->m_rtdirip, path, ops->metafile_type,
+			&ip);
+	kfree(path);
+
+	if (error)
+		return error;
+
+	if (XFS_IS_CORRUPT(mp, ip->i_df.if_format != XFS_DINODE_FMT_EXTENTS &&
+			       ip->i_df.if_format != XFS_DINODE_FMT_BTREE)) {
+		xfs_irele(ip);
+		return -EFSCORRUPTED;
+	}
+
+	if (XFS_IS_CORRUPT(mp, ip->i_projid != rtg_rgno(rtg))) {
+		xfs_irele(ip);
+		return -EFSCORRUPTED;
+	}
+
+	xfs_rtginode_lockdep_setup(ip, rtg_rgno(rtg), type);
+	rtg->rtg_inodes[type] = ip;
+	return 0;
+}
+
+/* Release an rtgroup metadata inode. */
+void
+xfs_rtginode_irele(
+	struct xfs_inode	**ipp)
+{
+	if (*ipp)
+		xfs_irele(*ipp);
+	*ipp = NULL;
+}
+
+/* Create the parent directory for all rtgroup inodes and load it. */
+int
+xfs_rtginode_mkdir_parent(
+	struct xfs_mount	*mp)
+{
+	if (!mp->m_metadirip)
+		return -EFSCORRUPTED;
+
+	return xfs_metadir_mkdir(mp->m_metadirip, "rtgroups", &mp->m_rtdirip);
+}
+
+/* Load the parent directory of all rtgroup inodes. */
+int
+xfs_rtginode_load_parent(
+	struct xfs_trans	*tp)
+{
+	struct xfs_mount	*mp = tp->t_mountp;
+
+	if (!mp->m_metadirip)
+		return -EFSCORRUPTED;
+
+	return xfs_metadir_load(tp, mp->m_metadirip, "rtgroups",
+			XFS_METAFILE_DIR, &mp->m_rtdirip);
+}

fs/xfs/libxfs/xfs_rtgroup.h

@@ -11,12 +11,23 @@
 struct xfs_mount;
 struct xfs_trans;
 
+enum xfs_rtg_inodes {
+	XFS_RTGI_MAX,
+};
+
+#ifdef MAX_LOCKDEP_SUBCLASSES
+static_assert(XFS_RTGI_MAX <= MAX_LOCKDEP_SUBCLASSES);
+#endif
+
 /*
  * Realtime group incore structure, similar to the per-AG structure.
  */
 struct xfs_rtgroup {
 	struct xfs_group	rtg_group;
 
+	/* per-rtgroup metadata inodes */
+	struct xfs_inode	*rtg_inodes[1 /* hack */];
+
 	/* Number of blocks in this group */
 	xfs_rtxnum_t		rtg_extents;
 };
@@ -210,6 +221,22 @@ void xfs_rtgroup_lock(struct xfs_rtgroup *rtg, unsigned int rtglock_flags);
 void xfs_rtgroup_unlock(struct xfs_rtgroup *rtg, unsigned int rtglock_flags);
 void xfs_rtgroup_trans_join(struct xfs_trans *tp, struct xfs_rtgroup *rtg,
 		unsigned int rtglock_flags);
+
+int xfs_rtginode_mkdir_parent(struct xfs_mount *mp);
+int xfs_rtginode_load_parent(struct xfs_trans *tp);
+
+const char *xfs_rtginode_name(enum xfs_rtg_inodes type);
+enum xfs_metafile_type xfs_rtginode_metafile_type(enum xfs_rtg_inodes type);
+bool xfs_rtginode_enabled(struct xfs_rtgroup *rtg, enum xfs_rtg_inodes type);
+int xfs_rtginode_load(struct xfs_rtgroup *rtg, enum xfs_rtg_inodes type,
+		struct xfs_trans *tp);
+void xfs_rtginode_irele(struct xfs_inode **ipp);
+
+static inline const char *xfs_rtginode_path(xfs_rgnumber_t rgno,
+		enum xfs_rtg_inodes type)
+{
+	return kasprintf(GFP_KERNEL, "%u.%s", rgno, xfs_rtginode_name(type));
+}
 #else
 static inline void xfs_free_rtgroups(struct xfs_mount *mp,
 		xfs_rgnumber_t first_rgno, xfs_rgnumber_t end_rgno)

fs/xfs/xfs_mount.h

@@ -128,6 +128,7 @@ typedef struct xfs_mount {
 	struct xfs_inode	*m_rsumip;	/* pointer to summary inode */
 	struct xfs_inode	*m_rootip;	/* pointer to root directory */
 	struct xfs_inode	*m_metadirip;	/* ptr to metadata directory */
+	struct xfs_inode	*m_rtdirip;	/* ptr to realtime metadir */
 	struct xfs_quotainfo	*m_quotainfo;	/* disk quota information */
 	struct xfs_buftarg	*m_ddev_targp;	/* data device */
 	struct xfs_buftarg	*m_logdev_targp;/* log device */

fs/xfs/xfs_rtalloc.c

@@ -28,6 +28,7 @@
 #include "xfs_da_format.h"
 #include "xfs_metafile.h"
 #include "xfs_rtgroup.h"
+#include "xfs_error.h"
 
 /*
  * Return whether there are any free extents in the size range given
@@ -652,6 +653,16 @@ xfs_rtallocate_extent_size(
 	return -ENOSPC;
 }
 
+static void
+xfs_rtunmount_rtg(
+	struct xfs_rtgroup	*rtg)
+{
+	int			i;
+
+	for (i = 0; i < XFS_RTGI_MAX; i++)
+		xfs_rtginode_irele(&rtg->rtg_inodes[i]);
+}
+
 static int
 xfs_alloc_rsum_cache(
 	struct xfs_mount	*mp,
@@ -1127,6 +1138,43 @@ xfs_rtmount_iread_extents(
 	return error;
 }
 
+static void
+xfs_rtgroup_unmount_inodes(
+	struct xfs_mount	*mp)
+{
+	struct xfs_rtgroup	*rtg = NULL;
+
+	while ((rtg = xfs_rtgroup_next(mp, rtg)))
+		xfs_rtunmount_rtg(rtg);
+	xfs_rtginode_irele(&mp->m_rtdirip);
+}
+
+static int
+xfs_rtmount_rtg(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	struct xfs_rtgroup	*rtg)
+{
+	int			error, i;
+
+	rtg->rtg_extents = xfs_rtgroup_extents(mp, rtg_rgno(rtg));
+
+	for (i = 0; i < XFS_RTGI_MAX; i++) {
+		error = xfs_rtginode_load(rtg, i, tp);
+		if (error)
+			return error;
+
+		if (rtg->rtg_inodes[i]) {
+			error = xfs_rtmount_iread_extents(tp,
+					rtg->rtg_inodes[i], 0);
+			if (error)
+				return error;
+		}
+	}
+
+	return 0;
+}
+
 /*
  * Get the bitmap and summary inodes and the summary cache into the mount
  * structure at mount time.
@@ -1168,15 +1216,28 @@ xfs_rtmount_inodes(
 	if (error)
 		goto out_rele_summary;
 
-	while ((rtg = xfs_rtgroup_next(mp, rtg)))
-		rtg->rtg_extents = xfs_rtgroup_extents(mp, rtg_rgno(rtg));
+	if (xfs_has_rtgroups(mp) && mp->m_sb.sb_rgcount > 0) {
+		error = xfs_rtginode_load_parent(tp);
+		if (error)
+			goto out_rele_summary;
+	}
+
+	while ((rtg = xfs_rtgroup_next(mp, rtg))) {
+		error = xfs_rtmount_rtg(mp, tp, rtg);
+		if (error) {
+			xfs_rtgroup_rele(rtg);
+			goto out_rele_inodes;
+		}
+	}
 
 	error = xfs_alloc_rsum_cache(mp, sbp->sb_rbmblocks);
 	if (error)
-		goto out_rele_summary;
+		goto out_rele_inodes;
 	xfs_trans_cancel(tp);
 	return 0;
 
+out_rele_inodes:
+	xfs_rtgroup_unmount_inodes(mp);
 out_rele_summary:
 	xfs_irele(mp->m_rsumip);
 out_rele_bitmap:
@@ -1191,6 +1252,8 @@ xfs_rtunmount_inodes(
 	struct xfs_mount	*mp)
 {
 	kvfree(mp->m_rsum_cache);
+
+	xfs_rtgroup_unmount_inodes(mp);
 	if (mp->m_rbmip)
 		xfs_irele(mp->m_rbmip);
 	if (mp->m_rsumip)