| Message ID | 20191128155940.17530-13-mszeredi@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | various vfs patches | expand |
On Thu, Nov 28, 2019 at 04:59:40PM +0100, Miklos Szeredi wrote: > While this is a standard option as documented in mount(8), it is ignored by > most filesystems. So reject, unless filesystem explicitly wants to handle > it. > > The exception is unconverted filesystems, where it is unknown if the > filesystem handles this or not. > > Any implementation, such as mount(8), that needs to parse this option > without failing can simply ignore the return value from fsconfig(). Unless I'm missing something, that will mean that having it in /etc/fstab for a converted filesystem (xfs, for example) will fail when booting new kernel with existing /sbin/mount. Doesn't sound like a good idea...
On Tue, Dec 17, 2019 at 4:37 AM Al Viro <viro@zeniv.linux.org.uk> wrote: > > On Thu, Nov 28, 2019 at 04:59:40PM +0100, Miklos Szeredi wrote: > > While this is a standard option as documented in mount(8), it is ignored by > > most filesystems. So reject, unless filesystem explicitly wants to handle > > it. > > > > The exception is unconverted filesystems, where it is unknown if the > > filesystem handles this or not. > > > > Any implementation, such as mount(8), that needs to parse this option > > without failing can simply ignore the return value from fsconfig(). > > Unless I'm missing something, that will mean that having it in /etc/fstab > for a converted filesystem (xfs, for example) will fail when booting > new kernel with existing /sbin/mount. Doesn't sound like a good idea... Nope, the mount(2) case is not changed (see second hunk). When mount(8) is converted to the new API, it can just handle such back compat issues (ignore error from fconfig()) in that case. Thanks, Miklos
On Tue, Dec 17, 2019 at 5:12 AM Miklos Szeredi <miklos@szeredi.hu> wrote: > > On Tue, Dec 17, 2019 at 4:37 AM Al Viro <viro@zeniv.linux.org.uk> wrote: > > > > On Thu, Nov 28, 2019 at 04:59:40PM +0100, Miklos Szeredi wrote: > > > While this is a standard option as documented in mount(8), it is ignored by > > > most filesystems. So reject, unless filesystem explicitly wants to handle > > > it. > > > > > > The exception is unconverted filesystems, where it is unknown if the > > > filesystem handles this or not. > > > > > > Any implementation, such as mount(8), that needs to parse this option > > > without failing can simply ignore the return value from fsconfig(). > > > > Unless I'm missing something, that will mean that having it in /etc/fstab > > for a converted filesystem (xfs, for example) will fail when booting > > new kernel with existing /sbin/mount. Doesn't sound like a good idea... > > Nope, the mount(2) case is not changed (see second hunk). Wrong, this has nothing to do with mount(2). The second hunk is about unconverted filesystems... When a filesystem that really needs to handle "silent" is converted, it can handle that option itself. Thanks, Miklos
On Tue, Dec 17, 2019 at 05:12:05AM +0100, Miklos Szeredi wrote: > On Tue, Dec 17, 2019 at 4:37 AM Al Viro <viro@zeniv.linux.org.uk> wrote: > > > > On Thu, Nov 28, 2019 at 04:59:40PM +0100, Miklos Szeredi wrote: > > > While this is a standard option as documented in mount(8), it is ignored by > > > most filesystems. So reject, unless filesystem explicitly wants to handle > > > it. > > > > > > The exception is unconverted filesystems, where it is unknown if the > > > filesystem handles this or not. > > > > > > Any implementation, such as mount(8), that needs to parse this option > > > without failing can simply ignore the return value from fsconfig(). > > > > Unless I'm missing something, that will mean that having it in /etc/fstab > > for a converted filesystem (xfs, for example) will fail when booting > > new kernel with existing /sbin/mount. Doesn't sound like a good idea... > > Nope, the mount(2) case is not changed (see second hunk). How would mounting XFS end up calling legacy_parse_param(), rather than the expected generic_parse_monolithic() -> vfs_parse_fs_string() -> vfs_parse_fs_param() -> xfs_fc_parse_param()?
On Tue, Dec 17, 2019 at 05:16:58AM +0100, Miklos Szeredi wrote: > On Tue, Dec 17, 2019 at 5:12 AM Miklos Szeredi <miklos@szeredi.hu> wrote: > > > > On Tue, Dec 17, 2019 at 4:37 AM Al Viro <viro@zeniv.linux.org.uk> wrote: > > > > > > On Thu, Nov 28, 2019 at 04:59:40PM +0100, Miklos Szeredi wrote: > > > > While this is a standard option as documented in mount(8), it is ignored by > > > > most filesystems. So reject, unless filesystem explicitly wants to handle > > > > it. > > > > > > > > The exception is unconverted filesystems, where it is unknown if the > > > > filesystem handles this or not. > > > > > > > > Any implementation, such as mount(8), that needs to parse this option > > > > without failing can simply ignore the return value from fsconfig(). > > > > > > Unless I'm missing something, that will mean that having it in /etc/fstab > > > for a converted filesystem (xfs, for example) will fail when booting > > > new kernel with existing /sbin/mount. Doesn't sound like a good idea... > > > > Nope, the mount(2) case is not changed (see second hunk). > > Wrong, this has nothing to do with mount(2). The second hunk is about > unconverted filesystems... > > When a filesystem that really needs to handle "silent" is converted, > it can handle that option itself. You know, I had a specific reason to mention XFS...
On Tue, Dec 17, 2019 at 5:19 AM Al Viro <viro@zeniv.linux.org.uk> wrote: > > On Tue, Dec 17, 2019 at 05:16:58AM +0100, Miklos Szeredi wrote: > > On Tue, Dec 17, 2019 at 5:12 AM Miklos Szeredi <miklos@szeredi.hu> wrote: > > > > > > On Tue, Dec 17, 2019 at 4:37 AM Al Viro <viro@zeniv.linux.org.uk> wrote: > > > > > > > > On Thu, Nov 28, 2019 at 04:59:40PM +0100, Miklos Szeredi wrote: > > > > > While this is a standard option as documented in mount(8), it is ignored by > > > > > most filesystems. So reject, unless filesystem explicitly wants to handle > > > > > it. > > > > > > > > > > The exception is unconverted filesystems, where it is unknown if the > > > > > filesystem handles this or not. > > > > > > > > > > Any implementation, such as mount(8), that needs to parse this option > > > > > without failing can simply ignore the return value from fsconfig(). > > > > > > > > Unless I'm missing something, that will mean that having it in /etc/fstab > > > > for a converted filesystem (xfs, for example) will fail when booting > > > > new kernel with existing /sbin/mount. Doesn't sound like a good idea... > > > > > > Nope, the mount(2) case is not changed (see second hunk). > > > > Wrong, this has nothing to do with mount(2). The second hunk is about > > unconverted filesystems... > > > > When a filesystem that really needs to handle "silent" is converted, > > it can handle that option itself. > > You know, I had a specific reason to mention XFS... Will fix. My bad, I did check filesystems at the time of writing the patch, but not when resending... Thanks, Miklos
On Tue, Dec 17, 2019 at 5:23 AM Miklos Szeredi <miklos@szeredi.hu> wrote: > > On Tue, Dec 17, 2019 at 5:19 AM Al Viro <viro@zeniv.linux.org.uk> wrote: > > > > On Tue, Dec 17, 2019 at 05:16:58AM +0100, Miklos Szeredi wrote: > > > On Tue, Dec 17, 2019 at 5:12 AM Miklos Szeredi <miklos@szeredi.hu> wrote: > > > > > > > > On Tue, Dec 17, 2019 at 4:37 AM Al Viro <viro@zeniv.linux.org.uk> wrote: > > > > > > > > > > On Thu, Nov 28, 2019 at 04:59:40PM +0100, Miklos Szeredi wrote: > > > > > > While this is a standard option as documented in mount(8), it is ignored by > > > > > > most filesystems. So reject, unless filesystem explicitly wants to handle > > > > > > it. > > > > > > > > > > > > The exception is unconverted filesystems, where it is unknown if the > > > > > > filesystem handles this or not. > > > > > > > > > > > > Any implementation, such as mount(8), that needs to parse this option > > > > > > without failing can simply ignore the return value from fsconfig(). > > > > > > > > > > Unless I'm missing something, that will mean that having it in /etc/fstab > > > > > for a converted filesystem (xfs, for example) will fail when booting > > > > > new kernel with existing /sbin/mount. Doesn't sound like a good idea... > > > > > > > > Nope, the mount(2) case is not changed (see second hunk). > > > > > > Wrong, this has nothing to do with mount(2). The second hunk is about > > > unconverted filesystems... > > > > > > When a filesystem that really needs to handle "silent" is converted, > > > it can handle that option itself. > > > > You know, I had a specific reason to mention XFS... > > Will fix. My bad, I did check filesystems at the time of writing the > patch, but not when resending... And BTW this is still not breakage of mount(2) since that code path is unaffected. Would need to think how much the "silent" option makes sense on the new interface for individual cases specifically. Thanks, Miklos
diff --git a/fs/fs_context.c b/fs/fs_context.c index 738f59b6c06a..b37ce07ee230 100644 --- a/fs/fs_context.c +++ b/fs/fs_context.c @@ -51,7 +51,6 @@ static const struct constant_table common_clear_sb_flag[] = { { "nolazytime", SB_LAZYTIME }, { "nomand", SB_MANDLOCK }, { "rw", SB_RDONLY }, - { "silent", SB_SILENT }, }; /* @@ -530,6 +529,15 @@ static int legacy_parse_param(struct fs_context *fc, struct fs_parameter *param) unsigned int size = ctx->data_size; size_t len = 0; + if (strcmp(param->key, "silent") == 0) { + if (param->type != fs_value_is_flag) + return invalf(fc, "%s: Unexpected value for '%s'", + fc->fs_type->name, param->key); + + fc->sb_flags |= SB_SILENT; + return 0; + } + if (strcmp(param->key, "source") == 0) { if (param->type != fs_value_is_string) return invalf(fc, "VFS: Legacy: Non-string source");
While this is a standard option as documented in mount(8), it is ignored by most filesystems. So reject, unless filesystem explicitly wants to handle it. The exception is unconverted filesystems, where it is unknown if the filesystem handles this or not. Any implementation, such as mount(8), that needs to parse this option without failing can simply ignore the return value from fsconfig(). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> --- fs/fs_context.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)