jffs2: some fixes to summary support

This patch fixes some issues with JFFS2 summary support in U-Boot.
1/ Summary support made compilation configurable (as summary support
considered expiremental even in Linux).
2/ Summary code can do unaligned 16-bit and 32-bit memory accesses.
We need to get data byte by byte to exclude data aborts.
3/ Make summary scan in two passes so we can safely fall back to full
scan if we found unsupported entry in the summary.

Signed-off-by: Ilya Yanok <yanok@emcraft.com>

diff --git a/fs/jffs2/jffs2_1pass.c b/fs/jffs2/jffs2_1pass.c
index b61a6f9..1923ed9 100644 (file)
--- a/fs/jffs2/jffs2_1pass.c
+++ b/fs/jffs2/jffs2_1pass.c
@@ -120,6 +120,7 @@
 #include <jffs2/jffs2.h>
 #include <jffs2/jffs2_1pass.h>
 #include <linux/mtd/compat.h>
+#include <asm/errno.h>
 
 #include "jffs2_private.h"
 
@@ -1200,8 +1201,30 @@ jffs2_1pass_rescan_needed(struct part_info *part)
        return 0;
 }
 
+#ifdef CONFIG_JFFS2_SUMMARY
+static u32 sum_get_unaligned32(u32 *ptr)
+{
+       u32 val;
+       u8 *p = (u8 *)ptr;
+
+       val = *p | (*(p + 1) << 8) | (*(p + 2) << 16) | (*(p + 3) << 24);
+
+       return __le32_to_cpu(val);
+}
+
+static u16 sum_get_unaligned16(u16 *ptr)
+{
+       u16 val;
+       u8 *p = (u8 *)ptr;
+
+       val = *p | (*(p + 1) << 8);
+
+       return __le16_to_cpu(val);
+}
+
 #define dbg_summary(...) do {} while (0);
-/* Process the stored summary information - helper function for
+/*
+ * Process the stored summary information - helper function for
  * jffs2_sum_scan_sumnode()
  */
 
@@ -1210,54 +1233,64 @@ static int jffs2_sum_process_sum_data(struct part_info *part, uint32_t offset,
                                struct b_lists *pL)
 {
        void *sp;
-       int i;
+       int i, pass;
+       void *ret;
 
-       sp = summary->sum;
+       for (pass = 0; pass < 2; pass++) {
+               sp = summary->sum;
 
-       for (i = 0; i < summary->sum_num; i++) {
-               dbg_summary("processing summary index %d\n", i);
+               for (i = 0; i < summary->sum_num; i++) {
+                       struct jffs2_sum_unknown_flash *spu = sp;
+                       dbg_summary("processing summary index %d\n", i);
 
-               switch (((struct jffs2_sum_unknown_flash *)sp)->nodetype) {
-                       case JFFS2_NODETYPE_INODE: {
+                       switch (sum_get_unaligned16(&spu->nodetype)) {
+                               case JFFS2_NODETYPE_INODE: {
                                struct jffs2_sum_inode_flash *spi;
-                               spi = sp;
-
-                               dbg_summary("Inode at 0x%08x-0x%08x\n",
-                                           offset + spi->offset,
-                                           offset + spi->offset + spi->totlen);
+                                       if (pass) {
+                                               spi = sp;
 
-                               if (insert_node(&pL->frag, (u32) part->offset +
-                                               offset + spi->offset) == NULL)
-                                       return -1;
+                                               ret = insert_node(&pL->frag,
+                                                       (u32)part->offset +
+                                                       offset +
+                                                       sum_get_unaligned32(
+                                                               &spi->offset));
+                                               if (ret == NULL)
+                                                       return -1;
+                                       }
 
-                               sp += JFFS2_SUMMARY_INODE_SIZE;
+                                       sp += JFFS2_SUMMARY_INODE_SIZE;
 
-                               break;
-                       }
-
-                       case JFFS2_NODETYPE_DIRENT: {
-                               struct jffs2_sum_dirent_flash *spd;
-                               spd = sp;
-
-                               dbg_summary("Dirent at 0x%08x-0x%08x\n",
-                                           offset + spd->offset,
-                                           offset + spd->offset + spd->totlen);
-
-                               if (insert_node(&pL->dir, (u32) part->offset +
-                                               offset + spd->offset) == NULL)
-                                       return -1;
-
-                               sp += JFFS2_SUMMARY_DIRENT_SIZE(spd->nsize);
+                                       break;
+                               }
+                               case JFFS2_NODETYPE_DIRENT: {
+                                       struct jffs2_sum_dirent_flash *spd;
+                                       spd = sp;
+                                       if (pass) {
+                                               ret = insert_node(&pL->dir,
+                                                       (u32) part->offset +
+                                                       offset +
+                                                       sum_get_unaligned32(
+                                                               &spd->offset));
+                                               if (ret == NULL)
+                                                       return -1;
+                                       }
+
+                                       sp += JFFS2_SUMMARY_DIRENT_SIZE(
+                                                       spd->nsize);
 
-                               break;
-                       }
-                       default : {
-                               uint16_t nodetype =
-                                       ((struct jffs2_sum_unknown_flash *)
-                                        sp)->nodetype;
-                               printf("Unsupported node type %x found in "
-                                               "summary!\n", nodetype);
-                               break;
+                                       break;
+                               }
+                               default : {
+                                       uint16_t nodetype = sum_get_unaligned16(
+                                                               &spu->nodetype);
+                                       printf("Unsupported node type %x found"
+                                                       " in summary!\n",
+                                                       nodetype);
+                                       if ((nodetype & JFFS2_COMPAT_MASK) ==
+                                                       JFFS2_FEATURE_INCOMPAT)
+                                               return -EIO;
+                                       return -EBADMSG;
+                               }
                        }
                }
        }
@@ -1315,6 +1348,8 @@ int jffs2_sum_scan_sumnode(struct part_info *part, uint32_t offset,
                dbg_summary("Summary : CLEANMARKER node \n");
 
        ret = jffs2_sum_process_sum_data(part, offset, summary, pL);
+       if (ret == -EBADMSG)
+               return 0;
        if (ret)
                return ret;             /* real error */
 
@@ -1325,6 +1360,7 @@ crc_err:
 
        return 0;
 }
+#endif /* CONFIG_JFFS2_SUMMARY */
 
 #ifdef DEBUG_FRAGMENTS
 static void
@@ -1430,13 +1466,16 @@ jffs2_1pass_build_lists(struct part_info * part)
                uint32_t buf_ofs = sector_ofs;
                uint32_t buf_len;
                uint32_t ofs, prevofs;
+#ifdef CONFIG_JFFS2_SUMMARY
                struct jffs2_sum_marker *sm;
                void *sumptr = NULL;
                uint32_t sumlen;
                int ret;
+#endif
 
                WATCHDOG_RESET();
 
+#ifdef CONFIG_JFFS2_SUMMARY
                buf_len = sizeof(*sm);
 
                /* Read as much as we want into the _end_ of the preallocated
@@ -1489,6 +1528,7 @@ jffs2_1pass_build_lists(struct part_info * part)
                                continue;
 
                }
+#endif /* CONFIG_JFFS2_SUMMARY */
 
                buf_len = EMPTY_SCAN_SIZE(part->sector_size);