xfs: add a new ioctl to describe allocation group geometry

Add a new ioctl to describe an allocation group's geometry.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

5 files changed, 93 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
index 1ef8acf35e7d..1c0f2a6c10b4 100644
--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -19,6 +19,7 @@
 #include "xfs_ialloc.h"
 #include "xfs_rmap.h"
 #include "xfs_ag.h"
+#include "xfs_ag_resv.h"
 
 static struct xfs_buf *
 xfs_get_aghdr_buf(
@@ -461,3 +462,54 @@ xfs_ag_extend_space(
                                 len, &XFS_RMAP_OINFO_SKIP_UPDATE,
                                 XFS_AG_RESV_NONE);
 }
+
+/* Retrieve AG geometry. */
+int
+xfs_ag_get_geometry(
+        struct xfs_mount        *mp,
+        xfs_agnumber_t          agno,
+        struct xfs_ag_geometry  *ageo)
+{
+        struct xfs_buf          *agi_bp;
+        struct xfs_buf          *agf_bp;
+        struct xfs_agi          *agi;
+        struct xfs_agf          *agf;
+        struct xfs_perag        *pag;
+        unsigned int            freeblks;
+        int                     error;
+
+        if (agno >= mp->m_sb.sb_agcount)
+                return -EINVAL;
+
+        /* Lock the AG headers. */
+        error = xfs_ialloc_read_agi(mp, NULL, agno, &agi_bp);
+        if (error)
+                return error;
+        error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agf_bp);
+        if (error)
+                goto out_agi;
+        pag = xfs_perag_get(mp, agno);
+
+        /* Fill out form. */
+        memset(ageo, 0, sizeof(*ageo));
+        ageo->ag_number = agno;
+
+        agi = XFS_BUF_TO_AGI(agi_bp);
+        ageo->ag_icount = be32_to_cpu(agi->agi_count);
+        ageo->ag_ifree = be32_to_cpu(agi->agi_freecount);
+
+        agf = XFS_BUF_TO_AGF(agf_bp);
+        ageo->ag_length = be32_to_cpu(agf->agf_length);
+        freeblks = pag->pagf_freeblks +
+                   pag->pagf_flcount +
+                   pag->pagf_btreeblks -
+                   xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE);
+        ageo->ag_freeblks = freeblks;
+
+        /* Release resources. */
+        xfs_perag_put(pag);
+        xfs_buf_relse(agf_bp);
+out_agi:
+        xfs_buf_relse(agi_bp);
+        return error;
+}
diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h
index 412702e23f61..5166322807e7 100644
--- a/fs/xfs/libxfs/xfs_ag.h
+++ b/fs/xfs/libxfs/xfs_ag.h
@@ -26,5 +26,7 @@ struct aghdr_init_data {
 int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id);
 int xfs_ag_extend_space(struct xfs_mount *mp, struct xfs_trans *tp,
                         struct aghdr_init_data *id, xfs_extlen_t len);
+int xfs_ag_get_geometry(struct xfs_mount *mp, xfs_agnumber_t agno,
+                        struct xfs_ag_geometry *ageo);
 
 #endif /* __LIBXFS_AG_H */
diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index cb7d0b1453cd..ee33d628a240 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -268,6 +268,19 @@ typedef struct xfs_fsop_resblks {
                          (s)->sb_agblocks + XFS_MIN_AG_BLOCKS)
 
 /*
+ * Output for XFS_IOC_AG_GEOMETRY
+ */
+struct xfs_ag_geometry {
+        uint32_t        ag_number;      /* i/o: AG number */
+        uint32_t        ag_length;      /* o: length in blocks */
+        uint32_t        ag_freeblks;    /* o: free space */
+        uint32_t        ag_icount;      /* o: inodes allocated */
+        uint32_t        ag_ifree;       /* o: inodes free */
+        uint32_t        ag_reserved32;  /* o: zero */
+        uint64_t        ag_reserved[13];/* o: zero */
+};
+
+/*
  * Structures for XFS_IOC_FSGROWFSDATA, XFS_IOC_FSGROWFSLOG & XFS_IOC_FSGROWFSRT
  */
 typedef struct xfs_growfs_data {
@@ -620,6 +633,7 @@ struct xfs_scrub_metadata {
 #define XFS_IOC_FREE_EOFBLOCKS  _IOR ('X', 58, struct xfs_fs_eofblocks)
 /*      XFS_IOC_GETFSMAP ------ hoisted 59         */
 #define XFS_IOC_SCRUB_METADATA  _IOWR('X', 60, struct xfs_scrub_metadata)
+#define XFS_IOC_AG_GEOMETRY     _IOWR('X', 61, struct xfs_ag_geometry)
 
 /*
  * ioctl commands that replace IRIX syssgi()'s
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index ec3c6c401ee7..b36abd453709 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -33,6 +33,7 @@
 #include "xfs_fsmap.h"
 #include "scrub/xfs_scrub.h"
 #include "xfs_sb.h"
+#include "xfs_ag.h"
 
 #include <linux/capability.h>
 #include <linux/cred.h>
@@ -804,6 +805,26 @@ xfs_ioc_fsgeometry(
         return 0;
 }
 
+STATIC int
+xfs_ioc_ag_geometry(
+        struct xfs_mount        *mp,
+        void                    __user *arg)
+{
+        struct xfs_ag_geometry  ageo;
+        int                     error;
+
+        if (copy_from_user(&ageo, arg, sizeof(ageo)))
+                return -EFAULT;
+
+        error = xfs_ag_get_geometry(mp, ageo.ag_number, &ageo);
+        if (error)
+                return error;
+
+        if (copy_to_user(arg, &ageo, sizeof(ageo)))
+                return -EFAULT;
+        return 0;
+}
+
 /*
  * Linux extended inode flags interface.
  */
@@ -1930,6 +1951,9 @@ xfs_file_ioctl(
         case XFS_IOC_FSGEOMETRY:
                 return xfs_ioc_fsgeometry(mp, arg, 5);
 
+        case XFS_IOC_AG_GEOMETRY:
+                return xfs_ioc_ag_geometry(mp, arg);
+
         case XFS_IOC_GETVERSION:
                 return put_user(inode->i_generation, (int __user *)arg);
 
diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index 55ace6308637..65997a6315e9 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -563,6 +563,7 @@ xfs_file_compat_ioctl(
         case XFS_IOC_DIOINFO:
         case XFS_IOC_FSGEOMETRY_V4:
         case XFS_IOC_FSGEOMETRY:
+        case XFS_IOC_AG_GEOMETRY:
         case XFS_IOC_FSGETXATTR:
         case XFS_IOC_FSSETXATTR:
         case XFS_IOC_FSGETXATTRA: