2 files changed, 60 insertions, 14 deletions

diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index a19995c6f6af..5dcd4b0c5533 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -161,7 +161,7 @@ check_partition(struct gendisk *hd, struct block_device *bdev)
         struct parsed_partitions *state;
         int i, res, err;
 
-        state = kmalloc(sizeof(struct parsed_partitions), GFP_KERNEL);
+        state = kzalloc(sizeof(struct parsed_partitions), GFP_KERNEL);
         if (!state)
                 return NULL;
 
@@ -187,6 +187,8 @@ check_partition(struct gendisk *hd, struct block_device *bdev)
         }
         if (res > 0)
                 return state;
+        if (state->access_beyond_eod)
+                err = -ENOSPC;
         if (err)
         /* The partition is unrecognized. So report I/O errors if there were any */
                 res = err;
@@ -539,13 +541,34 @@ exit:
         disk_part_iter_exit(&piter);
 }
 
+static bool disk_unlock_native_capacity(struct gendisk *disk)
+{
+        const struct block_device_operations *bdops = disk->fops;
+
+        if (bdops->unlock_native_capacity &&
+            !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
+                printk(KERN_CONT "enabling native capacity\n");
+                bdops->unlock_native_capacity(disk);
+                disk->flags |= GENHD_FL_NATIVE_CAPACITY;
+                return true;
+        } else {
+                printk(KERN_CONT "truncated\n");
+                return false;
+        }
+}
+
 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 {
+        struct parsed_partitions *state = NULL;
         struct disk_part_iter piter;
         struct hd_struct *part;
-        struct parsed_partitions *state;
         int p, highest, res;
 rescan:
+        if (state && !IS_ERR(state)) {
+                kfree(state);
+                state = NULL;
+        }
+
         if (bdev->bd_part_count)
                 return -EBUSY;
         res = invalidate_partition(disk, 0);
@@ -563,8 +586,32 @@ rescan:
         bdev->bd_invalidated = 0;
         if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
                 return 0;
-        if (IS_ERR(state))      /* I/O error reading the partition table */
+        if (IS_ERR(state)) {
+                /*
+                 * I/O error reading the partition table.  If any
+                 * partition code tried to read beyond EOD, retry
+                 * after unlocking native capacity.
+                 */
+                if (PTR_ERR(state) == -ENOSPC) {
+                        printk(KERN_WARNING "%s: partition table beyond EOD, ",
+                               disk->disk_name);
+                        if (disk_unlock_native_capacity(disk))
+                                goto rescan;
+                }
                 return -EIO;
+        }
+        /*
+         * If any partition code tried to read beyond EOD, try
+         * unlocking native capacity even if partition table is
+         * sucessfully read as we could be missing some partitions.
+         */
+        if (state->access_beyond_eod) {
+                printk(KERN_WARNING
+                       "%s: partition table partially beyond EOD, ",
+                       disk->disk_name);
+                if (disk_unlock_native_capacity(disk))
+                        goto rescan;
+        }
 
         /* tell userspace that the media / partition table may have changed */
         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
@@ -590,25 +637,20 @@ rescan:
                 from = state->parts[p].from;
                 if (from >= get_capacity(disk)) {
                         printk(KERN_WARNING
-                               "%s: p%d ignored, start %llu is behind the end of the disk\n",
+                               "%s: p%d start %llu is beyond EOD, ",
                                disk->disk_name, p, (unsigned long long) from);
+                        if (disk_unlock_native_capacity(disk))
+                                goto rescan;
                         continue;
                 }
 
                 if (from + size > get_capacity(disk)) {
-                        const struct block_device_operations *bdops = disk->fops;
-
                         printk(KERN_WARNING
-                               "%s: p%d size %llu exceeds device capacity, ",
+                               "%s: p%d size %llu extends beyond EOD, ",
                                disk->disk_name, p, (unsigned long long) size);
 
-                        if (bdops->unlock_native_capacity &&
-                            (disk->flags & GENHD_FL_NATIVE_CAPACITY) == 0) {
-                                printk(KERN_CONT "enabling native capacity\n");
-                                bdops->unlock_native_capacity(disk);
-                                disk->flags |= GENHD_FL_NATIVE_CAPACITY;
+                        if (disk_unlock_native_capacity(disk)) {
                                 /* free state and restart */
-                                kfree(state);
                                 goto rescan;
                         } else {
                                 /*
@@ -617,7 +659,6 @@ rescan:
                                  * we limit them to the end of the disk to avoid
                                  * creating invalid block devices
                                  */
-                                printk(KERN_CONT "limited to end of disk\n");
                                 size = get_capacity(disk) - from;
                         }
                 }
diff --git a/fs/partitions/check.h b/fs/partitions/check.h
index 4b31a97775be..52f8bd399396 100644
--- a/fs/partitions/check.h
+++ b/fs/partitions/check.h
@@ -15,11 +15,16 @@ struct parsed_partitions {
         } parts[DISK_MAX_PARTS];
         int next;
         int limit;
+        bool access_beyond_eod;
 };
 
 static inline void *read_part_sector(struct parsed_partitions *state,
                                      sector_t n, Sector *p)
 {
+        if (n >= get_capacity(state->bdev->bd_disk)) {
+                state->access_beyond_eod = true;
+                return NULL;
+        }
         return read_dev_sector(state->bdev, n, p);
 }