path: root/fs/ext4/ext4_write.c
diff options
authorƁukasz Majewski <>2014-05-06 09:36:05 +0200
committerTom Rini <>2014-05-12 16:31:50 -0400
commit8b454eeeea0ba021ee27f3e103daf1f8fa87bd16 (patch)
tree7aea0d65b3a11b11181e700b1a4053189209a819 /fs/ext4/ext4_write.c
parent35dd055b94eb3ed8c21595eedd740431866b2f26 (diff)
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 <>
Diffstat (limited to 'fs/ext4/ext4_write.c')
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/ext4/ext4_write.c b/fs/ext4/ext4_write.c
index 3db22f8f93..c42add9a7e 100644
--- a/fs/ext4/ext4_write.c
+++ b/fs/ext4/ext4_write.c
@@ -562,6 +562,7 @@ static int ext4fs_delete_file(int inodeno)
+ ext4fs_reinit_global();
if (ext4fs_init() != 0) {
printf("error in File System init\n");