From 8b454eeeea0ba021ee27f3e103daf1f8fa87bd16 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=C5=81ukasz=20Majewski?= Date: Tue, 6 May 2014 09:36:05 +0200 Subject: fs:ext4:write:fix: Reinitialize global variables after updating a file This bug shows up when file stored on the ext4 file system is updated. The ext4fs_delete_file() is responsible for deleting file's (e.g. uImage) data. However some global data (especially ext4fs_indir2_block), which is used during file deletion are left unchanged. The ext4fs_indir2_block pointer stores reference to old ext4 double indirect allocated blocks. When it is unchanged, after file deletion, ext4fs_write_file() uses the same pointer (since it is already initialized - i.e. not NULL) to return number of blocks to write. This trunks larger file when previous one was smaller. Lets consider following scenario: 1. Flash target with ext4 formatted boot.img (which has uImage [*] on itself) 2. Developer wants to upload their custom uImage [**] - When new uImage [**] is smaller than the [*] - everything works correctly - we are able to store the whole smaller file with corrupted ext4fs_indir2_block pointer - When new uImage [**] is larger than the [*] - theCRC is corrupted, since truncation on data stored at eMMC was done. 3. When uImage CRC error appears, then reboot and LTHOR/DFU reflashing causes proper setting of ext4fs_indir2_block() and after that uImage[**] is successfully stored (correct uImage [*] metadata is stored at an eMMC on the first flashing). Due to above the bug was very difficult to reproduce. This patch sets default values for all ext4fs_indir* pointers/variables. Signed-off-by: Lukasz Majewski --- include/ext4fs.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/ext4fs.h') diff --git a/include/ext4fs.h b/include/ext4fs.h index aacb147..fbbb002 100644 --- a/include/ext4fs.h +++ b/include/ext4fs.h @@ -133,6 +133,7 @@ int ext4fs_open(const char *filename); int ext4fs_read(char *buf, unsigned len); int ext4fs_mount(unsigned part_length); void ext4fs_close(void); +void ext4fs_reinit_global(void); int ext4fs_ls(const char *dirname); int ext4fs_exists(const char *filename); void ext4fs_free_node(struct ext2fs_node *node, struct ext2fs_node *currroot); -- cgit v1.1