When handling long file names directory entries may be split over multiple clusters. We must make sure that new clusters are zero filled on disk.
When allocating a new cluster for a directory flush it.
The flushing should be executed before updating the FAT. This way if flushing fails, we still have a valid directory structure.
Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de --- fs/fat/fat_write.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-)
diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c index 0746d73f8d..941f8789ab 100644 --- a/fs/fat/fat_write.c +++ b/fs/fat/fat_write.c @@ -738,17 +738,32 @@ static int find_empty_cluster(fsdata *mydata) return entry; }
-/* - * Allocate a cluster for additional directory entries +/** + * new_dir_table() - allocate a cluster for additional directory entries + * + * @itr: directory iterator + * Return: 0 on success, -EIO otherwise */ static int new_dir_table(fat_itr *itr) { fsdata *mydata = itr->fsdata; int dir_newclust = 0; + int dir_oldclust = itr->clust; unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
dir_newclust = find_empty_cluster(mydata); - set_fatent_value(mydata, itr->clust, dir_newclust); + + /* + * Flush before updating FAT to ensure valid directory structure + * in case of failure. + */ + itr->clust = dir_newclust; + itr->next_clust = dir_newclust; + memset(itr->block, 0x00, bytesperclust); + if (flush_dir(itr)) + return -EIO; + + set_fatent_value(mydata, dir_oldclust, dir_newclust); if (mydata->fatsize == 32) set_fatent_value(mydata, dir_newclust, 0xffffff8); else if (mydata->fatsize == 16) @@ -756,13 +771,8 @@ static int new_dir_table(fat_itr *itr) else if (mydata->fatsize == 12) set_fatent_value(mydata, dir_newclust, 0xff8);
- itr->clust = dir_newclust; - itr->next_clust = dir_newclust; - if (flush_dirty_fat_buffer(mydata) < 0) - return -1; - - memset(itr->block, 0x00, bytesperclust); + return -EIO;
itr->dent = (dir_entry *)itr->block; itr->last_cluster = 1; -- 2.29.2