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>

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 @@ xfs_ioc_space(
 	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;

fs/xfs/xfs_ioctl.h

@@ -77,4 +77,9 @@ xfs_set_dmattrs(
 	uint			evmask,
 	uint16_t		state);
 
+struct xfs_ibulk;
+struct xfs_bstat;
+
+int xfs_bulkstat_one_fmt(struct xfs_ibulk *breq, const struct xfs_bstat *bstat);
+
 #endif

fs/xfs/xfs_ioctl32.c

@@ -13,6 +13,7 @@
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
 #include "xfs_inode.h"
+#include "xfs_iwalk.h"
 #include "xfs_itable.h"
 #include "xfs_fsops.h"
 #include "xfs_rtalloc.h"
@@ -167,15 +168,10 @@ xfs_bstime_store_compat(
 /* Return 0 on success or positive error (to xfs_bulkstat()) */
 STATIC int
 xfs_bulkstat_one_fmt_compat(
-	void			__user *ubuffer,
-	int			ubsize,
-	int			*ubused,
-	const xfs_bstat_t	*buffer)
+	struct xfs_ibulk	*breq,
+	const struct xfs_bstat	*buffer)
 {
-	compat_xfs_bstat_t	__user *p32 = ubuffer;
-
-	if (ubsize < sizeof(*p32))
-		return -ENOMEM;
+	struct compat_xfs_bstat	__user *p32 = breq->ubuffer;
 
 	if (put_user(buffer->bs_ino,	  &p32->bs_ino)		||
 	    put_user(buffer->bs_mode,	  &p32->bs_mode)	||
@@ -200,23 +196,8 @@ xfs_bulkstat_one_fmt_compat(
 	    put_user(buffer->bs_dmstate,  &p32->bs_dmstate)	||
 	    put_user(buffer->bs_aextents, &p32->bs_aextents))
 		return -EFAULT;
-	if (ubused)
-		*ubused = sizeof(*p32);
-	return 0;
-}
 
-STATIC int
-xfs_bulkstat_one_compat(
-	xfs_mount_t	*mp,		/* mount point for filesystem */
-	xfs_ino_t	ino,		/* inode number to get data for */
-	void		__user *buffer,	/* buffer to place output in */
-	int		ubsize,		/* size of buffer */
-	int		*ubused,	/* bytes used by me */
-	int		*stat)		/* BULKSTAT_RV_... */
-{
-	return xfs_bulkstat_one_int(mp, ino, buffer, ubsize,
-				    xfs_bulkstat_one_fmt_compat,
-				    ubused, stat);
+	return xfs_ibulk_advance(breq, sizeof(struct compat_xfs_bstat));
 }
 
 /* copied from xfs_ioctl.c */
@@ -227,10 +208,12 @@ xfs_compat_ioc_bulkstat(
 	compat_xfs_fsop_bulkreq_t __user *p32)
 {
 	u32			addr;
-	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;
 
 	/*
@@ -240,8 +223,7 @@ xfs_compat_ioc_bulkstat(
 	 * functions and structure size are the correct ones to use ...
 	 */
 	inumbers_fmt_pf inumbers_func = xfs_inumbers_fmt_compat;
-	bulkstat_one_pf	bs_one_func = xfs_bulkstat_one_compat;
-	size_t bs_one_size = sizeof(struct compat_xfs_bstat);
+	bulkstat_one_fmt_pf	bs_one_func = xfs_bulkstat_one_fmt_compat;
 
 #ifdef CONFIG_X86_X32
 	if (in_x32_syscall()) {
@@ -254,8 +236,7 @@ xfs_compat_ioc_bulkstat(
 		 * x32 userspace expects.
 		 */
 		inumbers_func = xfs_inumbers_fmt;
-		bs_one_func = xfs_bulkstat_one;
-		bs_one_size = sizeof(struct xfs_bstat);
+		bs_one_func = xfs_bulkstat_one_fmt;
 	}
 #endif
 
@@ -279,38 +260,58 @@ xfs_compat_ioc_bulkstat(
 		return -EFAULT;
 	bulkreq.ocount = compat_ptr(addr);
 
-	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;
 
+	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_32) {
-		error = xfs_inumbers(mp, &inlast, &count,
+		int	count = breq.icount;
+
+		breq.startino = lastino;
+		error = xfs_inumbers(mp, &breq.startino, &count,
 				bulkreq.ubuffer, inumbers_func);
+		breq.ocount = count;
+		lastino = breq.startino;
 	} else if (cmd == XFS_IOC_FSBULKSTAT_SINGLE_32) {
-		int res;
-
-		error = bs_one_func(mp, inlast, bulkreq.ubuffer,
-				bs_one_size, NULL, &res);
+		breq.startino = lastino;
+		breq.icount = 1;
+		error = xfs_bulkstat_one(&breq, bs_one_func);
+		lastino = breq.startino;
 	} else if (cmd == XFS_IOC_FSBULKSTAT_32) {
-		error = xfs_bulkstat(mp, &inlast, &count,
-			bs_one_func, bs_one_size,
-			bulkreq.ubuffer, &done);
-	} else
+		breq.startino = lastino ? lastino + 1 : 0;
+		error = xfs_bulkstat(&breq, bs_one_func);
+		lastino = breq.startino - 1;
+	} else {
 		error = -EINVAL;
+	}
 	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;

fs/xfs/xfs_itable.h

@@ -5,63 +5,43 @@
 #ifndef __XFS_ITABLE_H__
 #define	__XFS_ITABLE_H__
 
-/*
- * xfs_bulkstat() is used to fill in xfs_bstat structures as well as dm_stat
- * structures (by the dmi library). This is a pointer to a formatter function
- * that will iget the inode and fill in the appropriate structure.
- * see xfs_bulkstat_one() and xfs_dm_bulkstat_one() in dmapi_xfs.c
- */
-typedef int (*bulkstat_one_pf)(struct xfs_mount	*mp,
-			       xfs_ino_t	ino,
-			       void		__user *buffer,
-			       int		ubsize,
-			       int		*ubused,
-			       int		*stat);
+/* In-memory representation of a userspace request for batch inode data. */
+struct xfs_ibulk {
+	struct xfs_mount	*mp;
+	void __user		*ubuffer; /* user output buffer */
+	xfs_ino_t		startino; /* start with this inode */
+	unsigned int		icount;   /* number of elements in ubuffer */
+	unsigned int		ocount;   /* number of records returned */
+};
+
+/* Return value that means we want to abort the walk. */
+#define XFS_IBULK_ABORT		(XFS_IWALK_ABORT)
 
 /*
- * Values for stat return value.
+ * Advance the user buffer pointer by one record of the given size.  If the
+ * buffer is now full, return the appropriate error code.
  */
-#define BULKSTAT_RV_NOTHING	0
-#define BULKSTAT_RV_DIDONE	1
-#define BULKSTAT_RV_GIVEUP	2
+static inline int
+xfs_ibulk_advance(
+	struct xfs_ibulk	*breq,
+	size_t			bytes)
+{
+	char __user		*b = breq->ubuffer;
+
+	breq->ubuffer = b + bytes;
+	breq->ocount++;
+	return breq->ocount == breq->icount ? XFS_IBULK_ABORT : 0;
+}
 
 /*
  * Return stat information in bulk (by-inode) for the filesystem.
  */
-int					/* error status */
-xfs_bulkstat(
-	xfs_mount_t	*mp,		/* mount point for filesystem */
-	xfs_ino_t	*lastino,	/* last inode returned */
-	int		*count,		/* size of buffer/count returned */
-	bulkstat_one_pf formatter,	/* func that'd fill a single buf */
-	size_t		statstruct_size,/* sizeof struct that we're filling */
-	char		__user *ubuffer,/* buffer with inode stats */
-	int		*done);		/* 1 if there are more stats to get */
 
-typedef int (*bulkstat_one_fmt_pf)(  /* used size in bytes or negative error */
-	void			__user *ubuffer, /* buffer to write to */
-	int			ubsize,		 /* remaining user buffer sz */
-	int			*ubused,	 /* bytes used by formatter */
-	const xfs_bstat_t	*buffer);        /* buffer to read from */
+typedef int (*bulkstat_one_fmt_pf)(struct xfs_ibulk *breq,
+		const struct xfs_bstat *bstat);
 
-int
-xfs_bulkstat_one_int(
-	xfs_mount_t		*mp,
-	xfs_ino_t		ino,
-	void			__user *buffer,
-	int			ubsize,
-	bulkstat_one_fmt_pf	formatter,
-	int			*ubused,
-	int			*stat);
-
-int
-xfs_bulkstat_one(
-	xfs_mount_t		*mp,
-	xfs_ino_t		ino,
-	void			__user *buffer,
-	int			ubsize,
-	int			*ubused,
-	int			*stat);
+int xfs_bulkstat_one(struct xfs_ibulk *breq, bulkstat_one_fmt_pf formatter);
+int xfs_bulkstat(struct xfs_ibulk *breq, bulkstat_one_fmt_pf formatter);
 
 typedef int (*inumbers_fmt_pf)(
 	void			__user *ubuffer, /* buffer to write to */