[U-Boot] [U-Boot, v2, 2/2] fs:ext4:write:fix: Reinitialize global variables after updating a file

[Tom Rini]

On Tue, May 06, 2014 at 09:36:05AM +0200, Łukasz Majewski wrote:

> 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 <l.majewski at samsung.com>

Applied to u-boot/master, thanks!

-- 
Tom
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