On Tuesday, March 11, 2025 6:28:06 PM CET Greg Kurz wrote:
> Add an ftruncate operation to the fs driver and use if when a fid has
> a valid file descriptor. This is required to support more cases where
> the client wants to do an action on an unlinked file which it still
> has an open file decriptor for.
>
> Only 9P2000.L was considered.
>
> Reviewed-by: Christian Schoenebeck <qemu_...@crudebyte.com>
> Signed-off-by: Greg Kurz <gr...@kaod.org>
>
> v2: - moved v9fs_co_ftruncate() near v9fs_co_truncate() in coth.h
> - similar change in file-op-9p.h
> ---
> fsdev/file-op-9p.h | 2 ++
> hw/9pfs/9p-local.c | 9 +++++++++
> hw/9pfs/9p-synth.c | 8 ++++++++
> hw/9pfs/9p.c | 6 +++++-
> hw/9pfs/cofs.c | 18 ++++++++++++++++++
> hw/9pfs/coth.h | 2 ++
> 6 files changed, 44 insertions(+), 1 deletion(-)
>
> diff --git a/fsdev/file-op-9p.h b/fsdev/file-op-9p.h
> index b815cea44e85..26ba1438c0ed 100644
> --- a/fsdev/file-op-9p.h
> +++ b/fsdev/file-op-9p.h
> @@ -152,6 +152,8 @@ struct FileOperations {
> int (*fstat)(FsContext *, int, V9fsFidOpenState *, struct stat *);
> int (*rename)(FsContext *, const char *, const char *);
> int (*truncate)(FsContext *, V9fsPath *, off_t);
> + int (*ftruncate)(FsContext *ctx, int fid_type, V9fsFidOpenState *fs,
> + off_t size);
> int (*fsync)(FsContext *, int, V9fsFidOpenState *, int);
> int (*statfs)(FsContext *s, V9fsPath *path, struct statfs *stbuf);
> ssize_t (*lgetxattr)(FsContext *, V9fsPath *,
> diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
> index b16132299f2c..0b33da8d2a46 100644
> --- a/hw/9pfs/9p-local.c
> +++ b/hw/9pfs/9p-local.c
> @@ -1042,6 +1042,14 @@ static int local_truncate(FsContext *ctx, V9fsPath
> *fs_path, off_t size)
> return ret;
> }
>
> +static int local_ftruncate(FsContext *ctx, int fid_type, V9fsFidOpenState
> *fs,
> + off_t size)
> +{
> + int fd = local_fid_fd(fid_type, fs);
> +
> + return ftruncate(fd, size);
> +}
> +
> static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
> {
> char *dirpath = g_path_get_dirname(fs_path->data);
> @@ -1617,4 +1625,5 @@ FileOperations local_ops = {
> .renameat = local_renameat,
> .unlinkat = local_unlinkat,
> .has_valid_file_handle = local_has_valid_file_handle,
> + .ftruncate = local_ftruncate,
> };
> diff --git a/hw/9pfs/9p-synth.c b/hw/9pfs/9p-synth.c
> index be0492b400e1..3d28afc4d03d 100644
> --- a/hw/9pfs/9p-synth.c
> +++ b/hw/9pfs/9p-synth.c
> @@ -356,6 +356,13 @@ static int synth_truncate(FsContext *ctx, V9fsPath
> *path, off_t offset)
> return -1;
> }
>
> +static int synth_ftruncate(FsContext *ctx, int fid_type, V9fsFidOpenState
> *fs,
> + off_t size)
> +{
> + errno = ENOSYS;
> + return -1;
> +}
> +
> static int synth_chmod(FsContext *fs_ctx, V9fsPath *path, FsCred *credp)
> {
> errno = EPERM;
> @@ -656,4 +663,5 @@ FileOperations synth_ops = {
> .renameat = synth_renameat,
> .unlinkat = synth_unlinkat,
> .has_valid_file_handle = synth_has_valid_file_handle,
> + .ftruncate = synth_ftruncate,
> };
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index 10363f1a1df8..4616bd763012 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -1733,7 +1733,11 @@ static void coroutine_fn v9fs_setattr(void *opaque)
> }
> }
> if (v9iattr.valid & (P9_ATTR_SIZE)) {
> - err = v9fs_co_truncate(pdu, &fidp->path, v9iattr.size);
> + if (fid_has_valid_handle(pdu->s, fidp)) {
> + err = v9fs_co_ftruncate(pdu, fidp, v9iattr.size);
> + } else {
> + err = v9fs_co_truncate(pdu, &fidp->path, v9iattr.size);
> + }
Like with previous patch, s/fid_has_valid_handle/fid_has_valid_file_handle/,
the rest is fine.
Reviewed-by: Christian Schoenebeck <qemu_...@crudebyte.com>
> if (err < 0) {
> goto out;
> }
> diff --git a/hw/9pfs/cofs.c b/hw/9pfs/cofs.c
> index 67e3ae5c5ccd..893466fb1a44 100644
> --- a/hw/9pfs/cofs.c
> +++ b/hw/9pfs/cofs.c
> @@ -184,6 +184,24 @@ int coroutine_fn v9fs_co_truncate(V9fsPDU *pdu, V9fsPath
> *path, off_t size)
> return err;
> }
>
> +int coroutine_fn v9fs_co_ftruncate(V9fsPDU *pdu, V9fsFidState *fidp, off_t
> size)
> +{
> + int err;
> + V9fsState *s = pdu->s;
> +
> + if (v9fs_request_cancelled(pdu)) {
> + return -EINTR;
> + }
> + v9fs_co_run_in_worker(
> + {
> + err = s->ops->ftruncate(&s->ctx, fidp->fid_type, &fidp->fs,
> size);
> + if (err < 0) {
> + err = -errno;
> + }
> + });
> + return err;
> +}
> +
> int coroutine_fn v9fs_co_mknod(V9fsPDU *pdu, V9fsFidState *fidp,
> V9fsString *name, uid_t uid, gid_t gid,
> dev_t dev, mode_t mode, struct stat *stbuf)
> diff --git a/hw/9pfs/coth.h b/hw/9pfs/coth.h
> index 2c54249b3577..62e922dc12e3 100644
> --- a/hw/9pfs/coth.h
> +++ b/hw/9pfs/coth.h
> @@ -73,6 +73,8 @@ int coroutine_fn v9fs_co_chmod(V9fsPDU *, V9fsPath *,
> mode_t);
> int coroutine_fn v9fs_co_utimensat(V9fsPDU *, V9fsPath *, struct timespec
> [2]);
> int coroutine_fn v9fs_co_chown(V9fsPDU *, V9fsPath *, uid_t, gid_t);
> int coroutine_fn v9fs_co_truncate(V9fsPDU *, V9fsPath *, off_t);
> +int coroutine_fn v9fs_co_ftruncate(V9fsPDU *pdu, V9fsFidState *fidp,
> + off_t size);
> int coroutine_fn v9fs_co_llistxattr(V9fsPDU *, V9fsPath *, void *, size_t);
> int coroutine_fn v9fs_co_lgetxattr(V9fsPDU *, V9fsPath *,
> V9fsString *, void *, size_t);
>
