ext4: Avoid corruption of directories with hash tree indexes

While directories can be read using the old linear scan method, adding a
new file would require updating the index tree (alternatively, the whole
tree could be removed).

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>

diff --git a/fs/ext4/ext4_write.c b/fs/ext4/ext4_write.c
index a52804e8e1d76e939f16e44bbad60530b063bd2d..8554793f4f7da0c1c794c09c2761aff25de1d404 100644 (file)
--- a/fs/ext4/ext4_write.c
+++ b/fs/ext4/ext4_write.c
@@ -881,6 +881,11 @@ int ext4fs_write(const char *fname, unsigned char *buffer,
                goto fail;
        if (ext4fs_iget(parent_inodeno, g_parent_inode))
                goto fail;
+       /* do not mess up a directory using hash trees */
+       if (le32_to_cpu(g_parent_inode->flags) & EXT4_INDEX_FL) {
+               printf("hash tree directory\n");
+               goto fail;
+       }
        /* check if the filename is already present in root */
        existing_file_inodeno = ext4fs_filename_unlink(filename);
        if (existing_file_inodeno != -1) {

diff --git a/include/ext4fs.h b/include/ext4fs.h
index e3f6216fa91f695423de93a4a84c0c766b26d20e..6e31c738123434fc499b9704068d26d563e07a0d 100644 (file)
--- a/include/ext4fs.h
+++ b/include/ext4fs.h
@@ -28,6 +28,7 @@
 #define __EXT4__
 #include <ext_common.h>
 
+#define EXT4_INDEX_FL          0x00001000 /* Inode uses hash tree index */
 #define EXT4_EXTENTS_FL                0x00080000 /* Inode uses extents */
 #define EXT4_EXT_MAGIC                 0xf30a
 #define EXT4_FEATURE_RO_COMPAT_GDT_CSUM        0x0010