udf: Use of s_alloc_mutex to serialize udf_relocate_blocks() execution

This work was supported by a hardware donation from the CE Linux Forum.

Signed-off-by: Alessio Igor Bogani <abogani@texware.it>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 19 insertions, 8 deletions

diff --git a/fs/udf/partition.c b/fs/udf/partition.c
index 745eb209be0c..a71090ea0e07 100644
--- a/fs/udf/partition.c
+++ b/fs/udf/partition.c
@@ -25,6 +25,7 @@
 #include <linux/fs.h>
 #include <linux/string.h>
 #include <linux/buffer_head.h>
+#include <linux/mutex.h>
 
 uint32_t udf_get_pblock(struct super_block *sb, uint32_t block,
                         uint16_t partition, uint32_t offset)
@@ -159,7 +160,9 @@ int udf_relocate_blocks(struct super_block *sb, long old_block, long *new_block)
         struct udf_sb_info *sbi = UDF_SB(sb);
         u16 reallocationTableLen;
         struct buffer_head *bh;
+        int ret = 0;
 
+        mutex_lock(&sbi->s_alloc_mutex);
         for (i = 0; i < sbi->s_partitions; i++) {
                 struct udf_part_map *map = &sbi->s_partmaps[i];
                 if (old_block > map->s_partition_root &&
@@ -175,8 +178,10 @@ int udf_relocate_blocks(struct super_block *sb, long old_block, long *new_block)
                                         break;
                                 }
 
-                        if (!st)
-                                return 1;
+                        if (!st) {
+                                ret = 1;
+                                goto out;
+                        }
 
                         reallocationTableLen =
                                         le16_to_cpu(st->reallocationTableLen);
@@ -207,14 +212,16 @@ int udf_relocate_blocks(struct super_block *sb, long old_block, long *new_block)
                                                      ((old_block -
                                                         map->s_partition_root) &
                                                      (sdata->s_packet_len - 1));
-                                        return 0;
+                                        ret = 0;
+                                        goto out;
                                 } else if (origLoc == packet) {
                                         *new_block = le32_to_cpu(
                                                         entry->mappedLocation) +
                                                      ((old_block -
                                                         map->s_partition_root) &
                                                      (sdata->s_packet_len - 1));
-                                        return 0;
+                                        ret = 0;
+                                        goto out;
                                 } else if (origLoc > packet)
                                         break;
                         }
@@ -251,20 +258,24 @@ int udf_relocate_blocks(struct super_block *sb, long old_block, long *new_block)
                                               st->mapEntry[k].mappedLocation) +
                                         ((old_block - map->s_partition_root) &
                                          (sdata->s_packet_len - 1));
-                                return 0;
+                                ret = 0;
+                                goto out;
                         }
 
-                        return 1;
+                        ret = 1;
+                        goto out;
                 } /* if old_block */
         }
 
         if (i == sbi->s_partitions) {
                 /* outside of partitions */
                 /* for now, fail =) */
-                return 1;
+                ret = 1;
         }
 
-        return 0;
+out:
+        mutex_unlock(&sbi->s_alloc_mutex);
+        return ret;
 }
 
 static uint32_t udf_try_read_meta(struct inode *inode, uint32_t block,