@@ -35,13 +35,18 @@ static int exfat_cont_expand(struct inode *inode, loff_t size)
if (new_num_clusters == num_clusters)
goto out;
- exfat_chain_set(&clu, ei->start_clu, num_clusters, ei->flags);
- ret = exfat_find_last_cluster(sb, &clu, &last_clu);
- if (ret)
- return ret;
+ if (num_clusters) {
+ exfat_chain_set(&clu, ei->start_clu, num_clusters, ei->flags);
+ ret = exfat_find_last_cluster(sb, &clu, &last_clu);
+ if (ret)
+ return ret;
+
+ clu.dir = last_clu + 1;
+ } else {
+ last_clu = EXFAT_EOF_CLUSTER;
+ clu.dir = EXFAT_EOF_CLUSTER;
+ }
- clu.dir = (last_clu == EXFAT_EOF_CLUSTER) ?
- EXFAT_EOF_CLUSTER : last_clu + 1;
clu.size = 0;
clu.flags = ei->flags;
@@ -51,17 +56,19 @@ static int exfat_cont_expand(struct inode *inode, loff_t size)
return ret;
/* Append new clusters to chain */
- if (clu.flags != ei->flags) {
- exfat_chain_cont_cluster(sb, ei->start_clu, num_clusters);
- ei->flags = ALLOC_FAT_CHAIN;
- }
- if (clu.flags == ALLOC_FAT_CHAIN)
- if (exfat_ent_set(sb, last_clu, clu.dir))
- goto free_clu;
-
- if (num_clusters == 0)
+ if (num_clusters) {
+ if (clu.flags != ei->flags)
+ if (exfat_chain_cont_cluster(sb, ei->start_clu, num_clusters))
+ goto free_clu;
+
+ if (clu.flags == ALLOC_FAT_CHAIN)
+ if (exfat_ent_set(sb, last_clu, clu.dir))
+ goto free_clu;
+ } else
ei->start_clu = clu.dir;
+ ei->flags = clu.flags;
+
out:
inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
/* Expanded range not zeroed, do not update valid_size */
Eric Hong found that when using ftruncate to expand an empty file, exfat_ent_set() will fail if discontinuous clusters are allocated. The reason is that the empty file does not have a cluster chain, but exfat_ent_set() attempts to append the newly allocated cluster to the cluster chain. In addition, exfat_find_last_cluster() only supports finding the last cluster in a non-empty file. So this commit adds a check whether the file is empty. If the file is empty, exfat_find_last_cluster() and exfat_ent_set() are no longer called as they do not need to be called. Fixes: f55c096f62f1 ("exfat: do not zero the extended part") Reported-by: Eric Hong <erichong@qnap.com> Closes: https://github.com/namjaejeon/linux-exfat-oot/issues/66 Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com> --- fs/exfat/file.c | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-)