xfs: add XFS_IOC_FREE_EOFBLOCKS ioctl

The XFS_IOC_FREE_EOFBLOCKS ioctl allows users to invoke an EOFBLOCKS
scan. The xfs_eofblocks structure is defined to support the command
parameters (scan mode).
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

fs/xfs/xfs_fs.h

@@ -339,6 +339,22 @@ typedef struct xfs_error_injection {
 } xfs_error_injection_t;
 
 
+/*
+ * Speculative preallocation trimming.
+ */
+#define XFS_EOFBLOCKS_VERSION		1
+struct xfs_eofblocks {
+	__u32		eof_version;
+	__u32		eof_flags;
+	__u64		pad[15];
+};
+
+/* eof_flags values */
+#define XFS_EOF_FLAGS_SYNC		(1 << 0) /* sync/wait mode scan */
+#define XFS_EOF_FLAGS_VALID	\
+	(XFS_EOF_FLAGS_SYNC)
+
+
 /*
  * The user-level Handle Request interface structure.
  */
@@ -457,6 +473,7 @@ typedef struct xfs_handle {
 /*	XFS_IOC_GETBIOSIZE ---- deprecated 47	   */
 #define XFS_IOC_GETBMAPX	_IOWR('X', 56, struct getbmap)
 #define XFS_IOC_ZERO_RANGE	_IOW ('X', 57, struct xfs_flock64)
+#define XFS_IOC_FREE_EOFBLOCKS	_IOR ('X', 58, struct xfs_eofblocks)
 
 /*
  * ioctl commands that replace IRIX syssgi()'s

fs/xfs/xfs_icache.c

@@ -1206,11 +1206,15 @@ xfs_inode_free_eofblocks(
 int
 xfs_icache_free_eofblocks(
 	struct xfs_mount	*mp,
-	int			flags)
+	struct xfs_eofblocks	*eofb)
 {
-	ASSERT((flags & ~(SYNC_TRYLOCK|SYNC_WAIT)) == 0);
+	int flags = SYNC_TRYLOCK;
+
+	if (eofb && (eofb->eof_flags & XFS_EOF_FLAGS_SYNC))
+		flags = SYNC_WAIT;
+
 	return xfs_inode_ag_iterator_tag(mp, xfs_inode_free_eofblocks, flags,
-					 NULL, XFS_ICI_EOFBLOCKS_TAG);
+					 eofb, XFS_ICI_EOFBLOCKS_TAG);
 }
 
 void

fs/xfs/xfs_icache.h

@@ -37,7 +37,7 @@ void xfs_inode_set_reclaim_tag(struct xfs_inode *ip);
 
 void xfs_inode_set_eofblocks_tag(struct xfs_inode *ip);
 void xfs_inode_clear_eofblocks_tag(struct xfs_inode *ip);
-int xfs_icache_free_eofblocks(struct xfs_mount *, int);
+int xfs_icache_free_eofblocks(struct xfs_mount *, struct xfs_eofblocks *);
 
 int xfs_sync_inode_grab(struct xfs_inode *ip);
 int xfs_inode_ag_iterator(struct xfs_mount *mp,

fs/xfs/xfs_ioctl.c

@@ -42,6 +42,7 @@
 #include "xfs_inode_item.h"
 #include "xfs_export.h"
 #include "xfs_trace.h"
+#include "xfs_icache.h"
 
 #include <linux/capability.h>
 #include <linux/dcache.h>
@@ -1602,6 +1603,25 @@ xfs_file_ioctl(
 		error = xfs_errortag_clearall(mp, 1);
 		return -error;
 
+	case XFS_IOC_FREE_EOFBLOCKS: {
+		struct xfs_eofblocks eofb;
+
+		if (copy_from_user(&eofb, arg, sizeof(eofb)))
+			return -XFS_ERROR(EFAULT);
+
+		if (eofb.eof_version != XFS_EOFBLOCKS_VERSION)
+			return -XFS_ERROR(EINVAL);
+
+		if (eofb.eof_flags & ~XFS_EOF_FLAGS_VALID)
+			return -XFS_ERROR(EINVAL);
+
+		if (memchr_inv(eofb.pad, 0, sizeof(eofb.pad)))
+			return -XFS_ERROR(EINVAL);
+
+		error = xfs_icache_free_eofblocks(mp, &eofb);
+		return -error;
+	}
+
 	default:
 		return -ENOTTY;
 	}