xfs: move xfs_ioc_getfsmap out of xfs_ioctl.c

Move this function out of xfs_ioctl.c to reduce the clutter in there,
and make the entire getfsmap implementation self-contained in a single
file.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 132 insertions, 2 deletions

diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
index 615253406fde..ae18ab86e608 100644
--- a/fs/xfs/xfs_fsmap.c
+++ b/fs/xfs/xfs_fsmap.c
@@ -44,7 +44,7 @@ xfs_fsmap_from_internal(
 }
 
 /* Convert an fsmap to an xfs_fsmap. */
-void
+static void
 xfs_fsmap_to_internal(
 	struct xfs_fsmap	*dest,
 	struct fsmap		*src)
@@ -889,7 +889,7 @@ xfs_getfsmap_check_keys(
  * xfs_getfsmap_info.low/high	-- per-AG low/high keys computed from
  *				   dkeys; used to query the metadata.
  */
-int
+STATIC int
 xfs_getfsmap(
 	struct xfs_mount		*mp,
 	struct xfs_fsmap_head		*head,
@@ -1019,3 +1019,133 @@ xfs_getfsmap(
 	head->fmh_oflags = FMH_OF_DEV_T;
 	return error;
 }
+
+int
+xfs_ioc_getfsmap(
+	struct xfs_inode	*ip,
+	struct fsmap_head	__user *arg)
+{
+	struct xfs_fsmap_head	xhead = {0};
+	struct fsmap_head	head;
+	struct fsmap		*recs;
+	unsigned int		count;
+	__u32			last_flags = 0;
+	bool			done = false;
+	int			error;
+
+	if (copy_from_user(&head, arg, sizeof(struct fsmap_head)))
+		return -EFAULT;
+	if (memchr_inv(head.fmh_reserved, 0, sizeof(head.fmh_reserved)) ||
+	    memchr_inv(head.fmh_keys[0].fmr_reserved, 0,
+		       sizeof(head.fmh_keys[0].fmr_reserved)) ||
+	    memchr_inv(head.fmh_keys[1].fmr_reserved, 0,
+		       sizeof(head.fmh_keys[1].fmr_reserved)))
+		return -EINVAL;
+
+	/*
+	 * Use an internal memory buffer so that we don't have to copy fsmap
+	 * data to userspace while holding locks.  Start by trying to allocate
+	 * up to 128k for the buffer, but fall back to a single page if needed.
+	 */
+	count = min_t(unsigned int, head.fmh_count,
+			131072 / sizeof(struct fsmap));
+	recs = kvcalloc(count, sizeof(struct fsmap), GFP_KERNEL);
+	if (!recs) {
+		count = min_t(unsigned int, head.fmh_count,
+				PAGE_SIZE / sizeof(struct fsmap));
+		recs = kvcalloc(count, sizeof(struct fsmap), GFP_KERNEL);
+		if (!recs)
+			return -ENOMEM;
+	}
+
+	xhead.fmh_iflags = head.fmh_iflags;
+	xfs_fsmap_to_internal(&xhead.fmh_keys[0], &head.fmh_keys[0]);
+	xfs_fsmap_to_internal(&xhead.fmh_keys[1], &head.fmh_keys[1]);
+
+	trace_xfs_getfsmap_low_key(ip->i_mount, &xhead.fmh_keys[0]);
+	trace_xfs_getfsmap_high_key(ip->i_mount, &xhead.fmh_keys[1]);
+
+	head.fmh_entries = 0;
+	do {
+		struct fsmap __user	*user_recs;
+		struct fsmap		*last_rec;
+
+		user_recs = &arg->fmh_recs[head.fmh_entries];
+		xhead.fmh_entries = 0;
+		xhead.fmh_count = min_t(unsigned int, count,
+					head.fmh_count - head.fmh_entries);
+
+		/* Run query, record how many entries we got. */
+		error = xfs_getfsmap(ip->i_mount, &xhead, recs);
+		switch (error) {
+		case 0:
+			/*
+			 * There are no more records in the result set.  Copy
+			 * whatever we got to userspace and break out.
+			 */
+			done = true;
+			break;
+		case -ECANCELED:
+			/*
+			 * The internal memory buffer is full.  Copy whatever
+			 * records we got to userspace and go again if we have
+			 * not yet filled the userspace buffer.
+			 */
+			error = 0;
+			break;
+		default:
+			goto out_free;
+		}
+		head.fmh_entries += xhead.fmh_entries;
+		head.fmh_oflags = xhead.fmh_oflags;
+
+		/*
+		 * If the caller wanted a record count or there aren't any
+		 * new records to return, we're done.
+		 */
+		if (head.fmh_count == 0 || xhead.fmh_entries == 0)
+			break;
+
+		/* Copy all the records we got out to userspace. */
+		if (copy_to_user(user_recs, recs,
+				 xhead.fmh_entries * sizeof(struct fsmap))) {
+			error = -EFAULT;
+			goto out_free;
+		}
+
+		/* Remember the last record flags we copied to userspace. */
+		last_rec = &recs[xhead.fmh_entries - 1];
+		last_flags = last_rec->fmr_flags;
+
+		/* Set up the low key for the next iteration. */
+		xfs_fsmap_to_internal(&xhead.fmh_keys[0], last_rec);
+		trace_xfs_getfsmap_low_key(ip->i_mount, &xhead.fmh_keys[0]);
+	} while (!done && head.fmh_entries < head.fmh_count);
+
+	/*
+	 * If there are no more records in the query result set and we're not
+	 * in counting mode, mark the last record returned with the LAST flag.
+	 */
+	if (done && head.fmh_count > 0 && head.fmh_entries > 0) {
+		struct fsmap __user	*user_rec;
+
+		last_flags |= FMR_OF_LAST;
+		user_rec = &arg->fmh_recs[head.fmh_entries - 1];
+
+		if (copy_to_user(&user_rec->fmr_flags, &last_flags,
+					sizeof(last_flags))) {
+			error = -EFAULT;
+			goto out_free;
+		}
+	}
+
+	/* copy back header */
+	if (copy_to_user(arg, &head, sizeof(struct fsmap_head))) {
+		error = -EFAULT;
+		goto out_free;
+	}
+
+out_free:
+	kvfree(recs);
+	return error;
+}