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Re: [Qemu-devel] [PATCH v3 2/2] qga/commands-posix: Return per path fstr
From: |
Thomas Huth |
Subject: |
Re: [Qemu-devel] [PATCH v3 2/2] qga/commands-posix: Return per path fstrim result |
Date: |
Thu, 30 Apr 2015 18:35:40 +0200 |
On Thu, 30 Apr 2015 16:29:58 +0200
Justin Ossevoort <address@hidden> wrote:
> The current guest-fstrim support only returns an error if some
> mountpoint was unable to be trimmed, skipping any possible additional
> mountpoints. The result of the TRIM operation itself is also discarded.
>
> This change returns a per mountpoint result of the TRIM operation. If an
> error occurs on some mountpoints that error is returned and the
> guest-fstrim continue with any additional mountpoints.
>
> Signed-off-by: Justin Ossevoort <address@hidden>
> ---
> qga/commands-posix.c | 54
> ++++++++++++++++++++++++++++++++++++++--------------
> qga/qapi-schema.json | 32 ++++++++++++++++++++++++++++---
> 2 files changed, 69 insertions(+), 17 deletions(-)
>
> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> index 4449628..ec0d69e 100644
> --- a/qga/commands-posix.c
> +++ b/qga/commands-posix.c
> @@ -1325,8 +1325,12 @@ static void guest_fsfreeze_cleanup(void)
> /*
> * Walk list of mounted file systems in the guest, and trim them.
> */
> -void qmp_guest_fstrim(bool has_minimum, int64_t minimum, Error **errp)
> +GuestFilesystemTrimResponse *
> +qmp_guest_fstrim(bool has_minimum, int64_t minimum, Error **errp)
> {
> + GuestFilesystemTrimResponse *response;
> + GuestFilesystemTrimResultList *list;
> + GuestFilesystemTrimResult *result;
> int ret = 0;
> FsMountList mounts;
> struct FsMount *mount;
> @@ -1340,39 +1344,59 @@ void qmp_guest_fstrim(bool has_minimum, int64_t
> minimum, Error **errp)
> build_fs_mount_list(&mounts, &local_err);
> if (local_err) {
> error_propagate(errp, local_err);
> - return;
> + return NULL;
> }
>
> + response = g_malloc0(sizeof(*response));
> +
> QTAILQ_FOREACH(mount, &mounts, next) {
> + result = g_malloc0(sizeof(*result));
> + result->path = g_strdup(mount->dirname);
> +
> + list = g_malloc0(sizeof(*list));
> + list->value = result;
> + list->next = response->paths;
> + response->paths = list;
> +
> fd = qemu_open(mount->dirname, O_RDONLY);
> if (fd == -1) {
> - error_setg_errno(errp, errno, "failed to open %s",
> mount->dirname);
> - goto error;
> + result->error = g_strdup_printf("failed to open: %s",
> + strerror(errno));
> + result->has_error = true;
> + continue;
> }
>
> /* We try to cull filesytems we know won't work in advance, but other
> * filesytems may not implement fstrim for less obvious reasons.
> These
> - * will report EOPNOTSUPP; we simply ignore these errors. Any other
> - * error means an unexpected error, so return it in those cases. In
> - * some other cases ENOTTY will be reported (e.g. CD-ROMs).
> + * will report EOPNOTSUPP; while in some other cases ENOTTY will be
> + * reported (e.g. CD-ROMs).
> + * Any other error means an unexpected error.
> */
> r.start = 0;
> r.len = -1;
> r.minlen = has_minimum ? minimum : 0;
> ret = ioctl(fd, FITRIM, &r);
> if (ret == -1) {
> - if (errno != ENOTTY && errno != EOPNOTSUPP) {
> - error_setg_errno(errp, errno, "failed to trim %s",
> - mount->dirname);
> - close(fd);
> - goto error;
> + result->has_error = true;
> + if (errno == ENOTTY || errno == EOPNOTSUPP) {
> + result->error = g_strdup("trim not supported");
> + } else {
> + result->error = g_strdup_printf("failed to trim: %s",
> + strerror(errno));
> }
> + close(fd);
> + continue;
> }
> +
> + result->has_minimum = true;
> + result->minimum = r.minlen;
I'm not sure, but does this "minimum" result make sense at all? What's
the kernel supposed to return in this field? I had a quick look at some
file system implementations in the kernel, but to me it seems like only
the .len field is updated with a return value.
> + result->has_trimmed = true;
> + result->trimmed = r.len;
> close(fd);
> }
>
> -error:
> free_fs_mount_list(&mounts);
> + return response;
> }
> #endif /* CONFIG_FSTRIM */
I just also had a quick test of this patch and got this behaviour:
{"execute":"guest-fstrim"}
{"return": {"paths": [{"minimum": 4096, "path": "/mnt", "trimmed": 2040348672},
{"minimum": 4096, "path": "/mnt2", "trimmed": 2040348672}, {"minimum": 0,
"path": "/boot", "trimmed": 388968448}, {"minimum": 0, "path": "/", "trimmed":
17699807232}]}}
{"execute":"guest-fstrim"}
{"return": {"paths": [{"minimum": 4096, "path": "/mnt", "trimmed": 0},
{"minimum": 4096, "path": "/mnt2", "trimmed": 0}, {"minimum": 0, "path":
"/boot", "trimmed": 388968448}, {"minimum": 0, "path": "/", "trimmed":
17699799040}]}}
{"execute":"guest-fstrim"}
{"return": {"paths": [{"minimum": 4096, "path": "/mnt", "trimmed": 0},
{"minimum": 4096, "path": "/mnt2", "trimmed": 0}, {"minimum": 0, "path":
"/boot", "trimmed": 388968448}, {"minimum": 0, "path": "/", "trimmed":
17699799040}]}}
{"execute":"guest-fstrim"}
{"return": {"paths": [{"minimum": 4096, "path": "/mnt", "trimmed": 0},
{"minimum": 4096, "path": "/mnt2", "trimmed": 0}, {"minimum": 0, "path":
"/boot", "trimmed": 388968448}, {"minimum": 0, "path": "/", "trimmed":
17699799040}]}}
{"execute":"guest-fstrim"}
{"return": {"paths": [{"minimum": 4096, "path": "/mnt", "trimmed": 0},
{"minimum": 4096, "path": "/mnt2", "trimmed": 0}, {"minimum": 0, "path":
"/boot", "trimmed": 388968448}, {"minimum": 0, "path": "/", "trimmed":
17699799040}]}}
/mnt and /mnt2 got successfully trimmed and consecutive calls then
reported "trimmed: 0". But the values for "/boot" and "/" do not make
sense to me, why does it claim to have always trimmed the same amount
of bytes here? (I only touched the /mnt and /mnt2 file systems before
doing the trim calls, so I wonder why there are bytes trimmed on /
and /boot at all?)
Also, I think you need to adjust the stub of qmp_guest_fstrim() in
commands-win32.c, too, so that you don't break the compilation of the
windows target.
Thomas