Re: [Stable-10.0.11 79/86] hw/9pfs: consolidate name validation with check_name()

[Christian Schoenebeck <qemu_oss@crudebyte.com>]

Hi Michael,

On Wednesday, 24 June 2026 07:02:50 CEST Michael Tokarev wrote:
> From: Christian Schoenebeck <qemu_oss@crudebyte.com>
> 
> Add a new, shared helper function check_name() that consolidates the name
> validation logic (illegal name check and "." / ".." rejection) currently
> spread over multiple 9p handlers, unnecessarily duplicating code.
> 
> This is pure refactoring with no behavior change. The existing error code
> semantics are preserved: rename operations return -EISDIR, create
> operations return -EEXIST.

Note that this particular patch is actually not a fix. It is just code 
deduplication. So my expecation was that this patch would not go to the stable 
branches, therefore I intentionally omitted to CC qemu-stable on this patch.

/Christian
 
> Note: These current error codes actually differ from native Linux system
> calls (e.g. rename() returns -EBUSY, open(O_CREAT) returns -EISDIR). The 9P
> protocol does not mandate specific error codes for these validation errors.
> Hence consolidating to a single error code (e.g., -EINVAL) for all cases
> could be considered in the future for simplicity reason.
> 
> This change reduces code duplication across 9 functions:
> 
> - v9fs_lcreate
> - v9fs_create
> - v9fs_symlink
> - v9fs_link
> - v9fs_rename
> - v9fs_renameat
> - v9fs_wstat
> - v9fs_mknod
> - v9fs_mkdir
> 
> Link:
> https://lore.kernel.org/qemu-devel/0573103880129eb543f07b68c77e86f2f572f6bf
> .1780072238.git.qemu_oss@crudebyte.com Signed-off-by: Christian Schoenebeck
> <qemu_oss@crudebyte.com>
> (cherry picked from commit 116db2986b11c914217bbd1547815b6c7efb944a)
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>