On Sonntag, 20. Februar 2022 17:50:49 CET Will Cohen wrote:
> From: Keno Fischer <k...@juliacomputing.com>
>
> On darwin d_seekoff exists, but is optional and does not seem to
> be commonly used by file systems. Use `telldir` instead to obtain
> the seek offset and inject it into d_seekoff, and create a
> qemu_dirent_off helper to call it appropriately when appropriate.
>
> Signed-off-by: Keno Fischer <k...@juliacomputing.com>
> [Michael Roitzsch: - Rebase for NixOS]
> Signed-off-by: Michael Roitzsch <reactorcont...@icloud.com>
> [Will Cohen: - Adjust to pass testing
> - Ensure that d_seekoff is filled using telldir
> on darwin, and create qemu_dirent_off helper
> to decide which to access]
> [Fabian Franz: - Add telldir error handling for darwin]
> Signed-off-by: Fabian Franz <fabianfranz....@gmail.com>
> [Will Cohen: - Ensure that telldir error handling uses
> signed int
> - Cleanup of telldir error handling
> - Remove superfluous error handling for
> qemu_dirent_off
> - Adjust formatting
> - Use qemu_dirent_off in codir.c]
> Signed-off-by: Will Cohen <wwco...@gmail.com>
> ---
This patch does not compile on Linux ...
> hw/9pfs/9p-local.c | 9 +++++++++
> hw/9pfs/9p-proxy.c | 16 +++++++++++++++-
> hw/9pfs/9p-synth.c | 4 ++++
> hw/9pfs/9p-util.h | 16 ++++++++++++++++
> hw/9pfs/9p.c | 7 +++++--
> hw/9pfs/codir.c | 4 +++-
> 6 files changed, 52 insertions(+), 4 deletions(-)
>
> diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
> index 1a5e3eed73..f3272f0b43 100644
> --- a/hw/9pfs/9p-local.c
> +++ b/hw/9pfs/9p-local.c
> @@ -562,6 +562,15 @@ again:
> if (!entry) {
> return NULL;
> }
> +#ifdef CONFIG_DARWIN
> + int off;
> + off = telldir(fs->dir.stream);
> + /* If telldir fails, fail the entire readdir call */
> + if (off < 0) {
> + return NULL;
> + }
> + entry->d_seekoff = off;
> +#endif
>
> if (ctx->export_flags & V9FS_SM_MAPPED) {
> entry->d_type = DT_UNKNOWN;
> diff --git a/hw/9pfs/9p-proxy.c b/hw/9pfs/9p-proxy.c
> index b1664080d8..8b4b5cf7dc 100644
> --- a/hw/9pfs/9p-proxy.c
> +++ b/hw/9pfs/9p-proxy.c
> @@ -706,7 +706,21 @@ static off_t proxy_telldir(FsContext *ctx,
> V9fsFidOpenState *fs)
>
> static struct dirent *proxy_readdir(FsContext *ctx, V9fsFidOpenState *fs)
> {
> - return readdir(fs->dir.stream);
> + struct dirent *entry;
> + entry = readdir(fs->dir.stream);
> +#ifdef CONFIG_DARWIN
> + if (!entry) {
> + return NULL;
> + }
> + int td;
> + td = telldir(fs->dir.stream);
> + /* If telldir fails, fail the entire readdir call */
> + if (td < 0) {
> + return NULL;
> + }
> + entry->d_seekoff = td;
> +#endif
> + return entry;
> }
>
> static void proxy_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
> diff --git a/hw/9pfs/9p-synth.c b/hw/9pfs/9p-synth.c
> index bf9b0c5ddd..b3080e415b 100644
> --- a/hw/9pfs/9p-synth.c
> +++ b/hw/9pfs/9p-synth.c
> @@ -234,7 +234,11 @@ static void synth_direntry(V9fsSynthNode *node,
> offsetof(struct dirent, d_name) + sz);
> memcpy(entry->d_name, node->name, sz);
> entry->d_ino = node->attr->inode;
> +#ifdef CONFIG_DARWIN
> + entry->d_seekoff = off + 1;
> +#else
> entry->d_off = off + 1;
> +#endif
> }
>
> static struct dirent *synth_get_dentry(V9fsSynthNode *dir,
> diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
> index 546f46dc7d..d41f37f085 100644
> --- a/hw/9pfs/9p-util.h
> +++ b/hw/9pfs/9p-util.h
> @@ -79,3 +79,19 @@ ssize_t fremovexattrat_nofollow(int dirfd, const char
> *filename, const char *name);
>
> #endif
... ^- this is the end of file #endif, so qemu_dirent_off() should be above
that #endif, and ...
> +
> +
> +/**
> + * Darwin has d_seekoff, which appears to function similarly to d_off.
> + * However, it does not appear to be supported on all file systems,
> + * so ensure it is manually injected earlier and call here when
> + * needed.
> + */
> +inline off_t qemu_dirent_off(struct dirent *dent)
... this function declaration misses the 'static' keyword, which is mandatory
to prevent a linker error.
Best regards,
Christian Schoenebeck
> +{
> +#ifdef CONFIG_DARWIN
> + return dent->d_seekoff;
> +#else
> + return dent->d_off;
> +#endif
> +}
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index 1563d7b7c6..caf3b240fe 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -27,6 +27,7 @@
> #include "virtio-9p.h"
> #include "fsdev/qemu-fsdev.h"
> #include "9p-xattr.h"
> +#include "9p-util.h"
> #include "coth.h"
> #include "trace.h"
> #include "migration/blocker.h"
> @@ -2281,7 +2282,7 @@ static int coroutine_fn
> v9fs_do_readdir_with_stat(V9fsPDU *pdu, count += len;
> v9fs_stat_free(&v9stat);
> v9fs_path_free(&path);
> - saved_dir_pos = dent->d_off;
> + saved_dir_pos = qemu_dirent_off(dent);
> }
>
> v9fs_readdir_unlock(&fidp->fs.dir);
> @@ -2420,6 +2421,7 @@ static int coroutine_fn v9fs_do_readdir(V9fsPDU *pdu,
> V9fsFidState *fidp, V9fsString name;
> int len, err = 0;
> int32_t count = 0;
> + off_t off;
> struct dirent *dent;
> struct stat *st;
> struct V9fsDirEnt *entries = NULL;
> @@ -2480,12 +2482,13 @@ static int coroutine_fn v9fs_do_readdir(V9fsPDU
> *pdu, V9fsFidState *fidp, qid.version = 0;
> }
>
> + off = qemu_dirent_off(dent);
> v9fs_string_init(&name);
> v9fs_string_sprintf(&name, "%s", dent->d_name);
>
> /* 11 = 7 + 4 (7 = start offset, 4 = space for storing count) */
> len = pdu_marshal(pdu, 11 + count, "Qqbs",
> - &qid, dent->d_off,
> + &qid, off,
> dent->d_type, &name);
>
> v9fs_string_free(&name);
> diff --git a/hw/9pfs/codir.c b/hw/9pfs/codir.c
> index c0873bde16..f96d8ac4e6 100644
> --- a/hw/9pfs/codir.c
> +++ b/hw/9pfs/codir.c
> @@ -22,6 +22,8 @@
> #include "qemu/coroutine.h"
> #include "qemu/main-loop.h"
> #include "coth.h"
> +#include "9p-xattr.h"
> +#include "9p-util.h"
>
> /*
> * Intended to be called from bottom-half (e.g. background I/O thread)
> @@ -166,7 +168,7 @@ static int do_readdir_many(V9fsPDU *pdu, V9fsFidState
> *fidp, }
>
> size += len;
> - saved_dir_pos = dent->d_off;
> + saved_dir_pos = qemu_dirent_off(dent);
> }
>
> /* restore (last) saved position */
