ext4: fix overflows in SEEK_HOLE, SEEK_DATA implementations

ext4_lblk_t is just u32 so multiplying it by blocksize can easily
overflow for files larger than 4 GB. Fix that by properly typing the
block offsets before shifting.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index b1b4d51b5d86b4e54c179ddce5f5b574238b3629..b19f0a457f329c5fb0f6974f7afff8dc79f1e31c 100644 (file)
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -312,7 +312,7 @@ static int ext4_find_unwritten_pgoff(struct inode *inode,
        blkbits = inode->i_sb->s_blocksize_bits;
        startoff = *offset;
        lastoff = startoff;
-       endoff = (map->m_lblk + map->m_len) << blkbits;
+       endoff = (loff_t)(map->m_lblk + map->m_len) << blkbits;
 
        index = startoff >> PAGE_CACHE_SHIFT;
        end = endoff >> PAGE_CACHE_SHIFT;
@@ -457,7 +457,7 @@ static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
                ret = ext4_map_blocks(NULL, inode, &map, 0);
                if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
                        if (last != start)
-                               dataoff = last << blkbits;
+                               dataoff = (loff_t)last << blkbits;
                        break;
                }
 
@@ -468,7 +468,7 @@ static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
                ext4_es_find_delayed_extent_range(inode, last, last, &es);
                if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
                        if (last != start)
-                               dataoff = last << blkbits;
+                               dataoff = (loff_t)last << blkbits;
                        break;
                }
 
@@ -486,7 +486,7 @@ static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
                }
 
                last++;
-               dataoff = last << blkbits;
+               dataoff = (loff_t)last << blkbits;
        } while (last <= end);
 
        mutex_unlock(&inode->i_mutex);
@@ -540,7 +540,7 @@ static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
                ret = ext4_map_blocks(NULL, inode, &map, 0);
                if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
                        last += ret;
-                       holeoff = last << blkbits;
+                       holeoff = (loff_t)last << blkbits;
                        continue;
                }
 
@@ -551,7 +551,7 @@ static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
                ext4_es_find_delayed_extent_range(inode, last, last, &es);
                if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
                        last = es.es_lblk + es.es_len;
-                       holeoff = last << blkbits;
+                       holeoff = (loff_t)last << blkbits;
                        continue;
                }
 
@@ -566,7 +566,7 @@ static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
                                                              &map, &holeoff);
                        if (!unwritten) {
                                last += ret;
-                               holeoff = last << blkbits;
+                               holeoff = (loff_t)last << blkbits;
                                continue;
                        }
                }