[3/5] xfs: enable userspace to hide an AG from allocation

Commit Message

Darrick J. Wong Dec. 27, 2023, 1:38 p.m. UTC

From: Darrick J. Wong <[e-mail]>

Add an administrative interface so that userspace can hide an allocation
group from block allocation.

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 libxfs/xfs_ag.c |   54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/xfs_fs.h |    5 +++++
 2 files changed, 59 insertions(+)

Patch

diff --git a/libxfs/xfs_ag.c b/libxfs/xfs_ag.c
index c639e8e07d7..abc0a9d89c5 100644
--- a/libxfs/xfs_ag.c
+++ b/libxfs/xfs_ag.c
@@ -1073,6 +1073,54 @@  xfs_ag_extend_space(
 	return 0;
 }
 
+/* Compute the AG geometry flags. */
+static inline uint32_t
+xfs_ag_calc_geoflags(
+	struct xfs_perag	*pag)
+{
+	uint32_t		ret = 0;
+
+	if (xfs_perag_prohibits_alloc(pag))
+		ret |= XFS_AG_FLAG_NOALLOC;
+
+	return ret;
+}
+
+/*
+ * Compare the current AG geometry flags against the flags in the AG geometry
+ * structure and update the AG state to reflect any changes, then update the
+ * struct to reflect the current status.
+ */
+static inline int
+xfs_ag_update_geoflags(
+	struct xfs_perag	*pag,
+	struct xfs_ag_geometry	*ageo,
+	uint32_t		new_flags)
+{
+	uint32_t		old_flags = xfs_ag_calc_geoflags(pag);
+	int			error;
+
+	if (!(new_flags & XFS_AG_FLAG_UPDATE)) {
+		ageo->ag_flags = old_flags;
+		return 0;
+	}
+
+	if ((old_flags & XFS_AG_FLAG_NOALLOC) &&
+	    !(new_flags & XFS_AG_FLAG_NOALLOC)) {
+		xfs_ag_clear_noalloc(pag);
+	}
+
+	if (!(old_flags & XFS_AG_FLAG_NOALLOC) &&
+	    (new_flags & XFS_AG_FLAG_NOALLOC)) {
+		error = xfs_ag_set_noalloc(pag);
+		if (error)
+			return error;
+	}
+
+	ageo->ag_flags = xfs_ag_calc_geoflags(pag);
+	return 0;
+}
+
 /* Retrieve AG geometry. */
 int
 xfs_ag_get_geometry(
@@ -1084,6 +1132,7 @@  xfs_ag_get_geometry(
 	struct xfs_agi		*agi;
 	struct xfs_agf		*agf;
 	unsigned int		freeblks;
+	uint32_t		inflags = ageo->ag_flags;
 	int			error;
 
 	/* Lock the AG headers. */
@@ -1094,6 +1143,10 @@  xfs_ag_get_geometry(
 	if (error)
 		goto out_agi;
 
+	error = xfs_ag_update_geoflags(pag, ageo, inflags);
+	if (error)
+		goto out;
+
 	/* Fill out form. */
 	memset(ageo, 0, sizeof(*ageo));
 	ageo->ag_number = pag->pag_agno;
@@ -1111,6 +1164,7 @@  xfs_ag_get_geometry(
 	ageo->ag_freeblks = freeblks;
 	xfs_ag_geom_health(pag, ageo);
 
+out:
 	/* Release resources. */
 	xfs_buf_relse(agf_bp);
 out_agi:
diff --git a/libxfs/xfs_fs.h b/libxfs/xfs_fs.h
index 4159e96d01a..96688f9301e 100644
--- a/libxfs/xfs_fs.h
+++ b/libxfs/xfs_fs.h
@@ -305,6 +305,11 @@  struct xfs_ag_geometry {
 #define XFS_AG_GEOM_SICK_REFCNTBT (1 << 9)  /* reference counts */
 #define XFS_AG_GEOM_SICK_INODES	(1 << 10) /* bad inodes were seen */
 
+#define XFS_AG_FLAG_UPDATE	(1 << 0)  /* update flags */
+#define XFS_AG_FLAG_NOALLOC	(1 << 1)  /* do not allocate from this AG */
+#define XFS_AG_FLAG_ALL		(XFS_AG_FLAG_UPDATE | \
+				 XFS_AG_FLAG_NOALLOC)
+
 /*
  * Structures for XFS_IOC_FSGROWFSDATA, XFS_IOC_FSGROWFSLOG & XFS_IOC_FSGROWFSRT
  */