xfs: fix various typos

Signed-off-by: Malcolm Parsons <malcolm.parsons@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 07b7d0d..47a87de 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -2479,7 +2479,7 @@
 	fb_agno = nullfb ? NULLAGNUMBER : XFS_FSB_TO_AGNO(mp, ap->firstblock);
 	/*
 	 * If allocating at eof, and there's a previous real block,
-	 * try to use it's last block as our starting point.
+	 * try to use its last block as our starting point.
 	 */
 	if (ap->eof && ap->prevp->br_startoff != NULLFILEOFF &&
 	    !isnullstartblock(ap->prevp->br_startblock) &&
@@ -4796,7 +4796,7 @@
 	xfs_extlen_t	minlen;		/* min allocation size */
 	xfs_mount_t	*mp;		/* xfs mount structure */
 	int		n;		/* current extent index */
-	int		nallocs;	/* number of extents alloc\'d */
+	int		nallocs;	/* number of extents alloc'd */
 	xfs_extnum_t	nextents;	/* number of extents in file */
 	xfs_fileoff_t	obno;		/* old block number (offset) */
 	xfs_bmbt_irec_t	prev;		/* previous file extent record */
@@ -6486,7 +6486,7 @@
 	block = XFS_BUF_TO_BLOCK(bp);
 
 	if (--level) {
-		/* Not at node above leafs, count this level of nodes */
+		/* Not at node above leaves, count this level of nodes */
 		nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
 		while (nextbno != NULLFSBLOCK) {
 			if ((error = xfs_btree_read_bufl(mp, tp, nextbno,