xfs: convert bulkstat to new iwalk infrastructure

Create a new ibulk structure incore to help us deal with bulk inode stat
state tracking and then convert the bulkstat code to use the new iwalk
iterator.  This disentangles inode walking from bulk stat control for
simpler code and enables us to isolate the formatter functions to the
ioctl handling code.

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

1 files changed, 53 insertions, 17 deletions

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 8bc74ae3b72a..7299e3f01c42 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -12,6 +12,7 @@
 #include "xfs_mount.h"
 #include "xfs_inode.h"
 #include "xfs_rtalloc.h"
+#include "xfs_iwalk.h"
 #include "xfs_itable.h"
 #include "xfs_error.h"
 #include "xfs_attr.h"
@@ -712,16 +713,29 @@ out_unlock:
 	return error;
 }
 
+/* Return 0 on success or positive error */
+int
+xfs_bulkstat_one_fmt(
+	struct xfs_ibulk	*breq,
+	const struct xfs_bstat	*bstat)
+{
+	if (copy_to_user(breq->ubuffer, bstat, sizeof(*bstat)))
+		return -EFAULT;
+	return xfs_ibulk_advance(breq, sizeof(struct xfs_bstat));
+}
+
 STATIC int
 xfs_ioc_bulkstat(
 	xfs_mount_t		*mp,
 	unsigned int		cmd,
 	void			__user *arg)
 {
-	xfs_fsop_bulkreq_t	bulkreq;
-	int			count;	/* # of records returned */
-	xfs_ino_t		inlast;	/* last inode number */
-	int			done;
+	struct xfs_fsop_bulkreq	bulkreq;
+	struct xfs_ibulk	breq = {
+		.mp		= mp,
+		.ocount		= 0,
+	};
+	xfs_ino_t		lastino;
 	int			error;
 
 	/* done = 1 if there are more stats to get and if bulkstat */
@@ -736,35 +750,57 @@ xfs_ioc_bulkstat(
 	if (copy_from_user(&bulkreq, arg, sizeof(xfs_fsop_bulkreq_t)))
 		return -EFAULT;
 
-	if (copy_from_user(&inlast, bulkreq.lastip, sizeof(__s64)))
+	if (copy_from_user(&lastino, bulkreq.lastip, sizeof(__s64)))
 		return -EFAULT;
 
-	if ((count = bulkreq.icount) <= 0)
+	if (bulkreq.icount <= 0)
 		return -EINVAL;
 
 	if (bulkreq.ubuffer == NULL)
 		return -EINVAL;
 
-	if (cmd == XFS_IOC_FSINUMBERS)
-		error = xfs_inumbers(mp, &inlast, &count,
+	breq.ubuffer = bulkreq.ubuffer;
+	breq.icount = bulkreq.icount;
+
+	/*
+	 * FSBULKSTAT_SINGLE expects that *lastip contains the inode number
+	 * that we want to stat.  However, FSINUMBERS and FSBULKSTAT expect
+	 * that *lastip contains either zero or the number of the last inode to
+	 * be examined by the previous call and return results starting with
+	 * the next inode after that.  The new bulk request back end functions
+	 * take the inode to start with, so we have to compute the startino
+	 * parameter from lastino to maintain correct function.  lastino == 0
+	 * is a special case because it has traditionally meant "first inode
+	 * in filesystem".
+	 */
+	if (cmd == XFS_IOC_FSINUMBERS) {
+		int	count = breq.icount;
+
+		breq.startino = lastino;
+		error = xfs_inumbers(mp, &breq.startino, &count,
 					bulkreq.ubuffer, xfs_inumbers_fmt);
-	else if (cmd == XFS_IOC_FSBULKSTAT_SINGLE)
-		error = xfs_bulkstat_one(mp, inlast, bulkreq.ubuffer,
-					sizeof(xfs_bstat_t), NULL, &done);
-	else	/* XFS_IOC_FSBULKSTAT */
-		error = xfs_bulkstat(mp, &inlast, &count, xfs_bulkstat_one,
-				     sizeof(xfs_bstat_t), bulkreq.ubuffer,
-				     &done);
+		breq.ocount = count;
+		lastino = breq.startino;
+	} else if (cmd == XFS_IOC_FSBULKSTAT_SINGLE) {
+		breq.startino = lastino;
+		breq.icount = 1;
+		error = xfs_bulkstat_one(&breq, xfs_bulkstat_one_fmt);
+		lastino = breq.startino;
+	} else {	/* XFS_IOC_FSBULKSTAT */
+		breq.startino = lastino ? lastino + 1 : 0;
+		error = xfs_bulkstat(&breq, xfs_bulkstat_one_fmt);
+		lastino = breq.startino - 1;
+	}
 
 	if (error)
 		return error;
 
 	if (bulkreq.lastip != NULL &&
-	    copy_to_user(bulkreq.lastip, &inlast, sizeof(xfs_ino_t)))
+	    copy_to_user(bulkreq.lastip, &lastino, sizeof(xfs_ino_t)))
 		return -EFAULT;
 
 	if (bulkreq.ocount != NULL &&
-	    copy_to_user(bulkreq.ocount, &count, sizeof(count)))
+	    copy_to_user(bulkreq.ocount, &breq.ocount, sizeof(__s32)))
 		return -EFAULT;
 
 	return 0;