1 files changed, 47 insertions, 23 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index fcb1dcc6f036..bedc66163176 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -4532,39 +4532,63 @@ xfs_iext_irec_compact_full(
         int             nlists;                 /* number of irec's (ex lists) */
 
         ASSERT(ifp->if_flags & XFS_IFEXTIREC);
+
         nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
         erp = ifp->if_u1.if_ext_irec;
         ep = &erp->er_extbuf[erp->er_extcount];
         erp_next = erp + 1;
         ep_next = erp_next->er_extbuf;
+
         while (erp_idx < nlists - 1) {
+                /*
+                 * Check how many extent records are available in this irec.
+                 * If there is none skip the whole exercise.
+                 */
                 ext_avail = XFS_LINEAR_EXTS - erp->er_extcount;
-                ext_diff = MIN(ext_avail, erp_next->er_extcount);
-                memcpy(ep, ep_next, ext_diff * sizeof(xfs_bmbt_rec_t));
-                erp->er_extcount += ext_diff;
-                erp_next->er_extcount -= ext_diff;
-                /* Remove next page */
-                if (erp_next->er_extcount == 0) {
+                if (ext_avail) {
+
                         /*
-                         * Free page before removing extent record
-                         * so er_extoffs don't get modified in
-                         * xfs_iext_irec_remove.
+                         * Copy over as many as possible extent records into
+                         * the previous page.
                          */
-                        kmem_free(erp_next->er_extbuf);
-                        erp_next->er_extbuf = NULL;
-                        xfs_iext_irec_remove(ifp, erp_idx + 1);
-                        erp = &ifp->if_u1.if_ext_irec[erp_idx];
-                        nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
-                /* Update next page */
-                } else {
-                        /* Move rest of page up to become next new page */
-                        memmove(erp_next->er_extbuf, ep_next,
-                                erp_next->er_extcount * sizeof(xfs_bmbt_rec_t));
-                        ep_next = erp_next->er_extbuf;
-                        memset(&ep_next[erp_next->er_extcount], 0,
-                                (XFS_LINEAR_EXTS - erp_next->er_extcount) *
-                                sizeof(xfs_bmbt_rec_t));
+                        ext_diff = MIN(ext_avail, erp_next->er_extcount);
+                        memcpy(ep, ep_next, ext_diff * sizeof(xfs_bmbt_rec_t));
+                        erp->er_extcount += ext_diff;
+                        erp_next->er_extcount -= ext_diff;
+
+                        /*
+                         * If the next irec is empty now we can simply
+                         * remove it.
+                         */
+                        if (erp_next->er_extcount == 0) {
+                                /*
+                                 * Free page before removing extent record
+                                 * so er_extoffs don't get modified in
+                                 * xfs_iext_irec_remove.
+                                 */
+                                kmem_free(erp_next->er_extbuf);
+                                erp_next->er_extbuf = NULL;
+                                xfs_iext_irec_remove(ifp, erp_idx + 1);
+                                erp = &ifp->if_u1.if_ext_irec[erp_idx];
+                                nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
+
+                        /*
+                         * If the next irec is not empty move up the content
+                         * that has not been copied to the previous page to
+                         * the beggining of this one.
+                         */
+                        } else {
+                                memmove(erp_next->er_extbuf, &ep_next[ext_diff],
+                                        erp_next->er_extcount *
+                                        sizeof(xfs_bmbt_rec_t));
+                                ep_next = erp_next->er_extbuf;
+                                memset(&ep_next[erp_next->er_extcount], 0,
+                                        (XFS_LINEAR_EXTS -
+                                                erp_next->er_extcount) *
+                                        sizeof(xfs_bmbt_rec_t));
+                        }
                 }
+
                 if (erp->er_extcount == XFS_LINEAR_EXTS) {
                         erp_idx++;
                         if (erp_idx < nlists)