Re: [PATCH 0/3] fs: return error pointers from ->get_link() on failure

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello Sascha,

On 11/2/26 10:08 AM, Sascha Hauer wrote:
> Like in Linux, the callers of ->get_link() expect an error pointer when
> the link can't be read: readlinkat() checks the result only with
> IS_ERR() before copying from it, and path lookup takes NULL to mean that
> the link has already been followed and continues from the directory
> containing the link. barebox has no nd_jump_link(), so a NULL from
> ->get_link() is never legitimate there.
> 
> 9p and nfs already return error pointers, and the squashfs series posted
> separately converts squashfs_get_link(). This series converts the
> remaining file systems:
> 
> - legacy returned NULL when the driver's readlink failed.

What do you think, is it time we (meaning you, because you said the
l-word) do something about the legacy file systems? :D

Cheers,
Ahmad

> - cramfs and ext4 checked their read helpers for return values these
>   never produce, so a link that couldn't be read was returned as a valid,
>   partly zeroed link and stayed cached in inode->i_link.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
> Sascha Hauer (3):
>       fs: cramfs: return an error pointer from cramfs_get_link()
>       fs: ext4: return an error pointer from ext_get_link()
>       fs: legacy: return an error pointer from legacy_get_link()
> 
>  fs/cramfs/cramfs.c    | 7 +++++--
>  fs/ext4/ext_barebox.c | 3 ++-
>  fs/legacy.c           | 2 +-
>  3 files changed, 8 insertions(+), 4 deletions(-)
> ---
> base-commit: f2e574b9c63c6da07a06179a868cae8a471ec176
> change-id: 20261102-fs-getlink-fixes-d634fd50d1f9
> 
> Best regards,

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