From: Jan Kara <jack@suse.cz>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: linux-fsdevel@vger.kernel.org, linux-mtd@lists.infradead.org,
Jan Kara <jack@suse.com>, Richard Weinberger <richard@nod.at>,
kernel@pengutronix.de
Subject: Re: [PATCH 04/10] quota: Allow to pass mount path to quotactl
Date: Fri, 1 Nov 2019 17:07:06 +0100 [thread overview]
Message-ID: <20191101160706.GA23441@quack2.suse.cz> (raw)
In-Reply-To: <20191030152702.14269-5-s.hauer@pengutronix.de>
On Wed 30-10-19 16:26:56, Sascha Hauer wrote:
> This patch introduces the Q_PATH flag to the quotactl cmd argument.
> When given, the path given in the special argument to quotactl will
> be the mount path where the filesystem is mounted, instead of a path
> to the block device.
> This is necessary for filesystems which do not have a block device as
> backing store. Particularly this is done for upcoming UBIFS support.
>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Thanks for the patch! Some smaller comments below...
> ---
> fs/quota/quota.c | 37 ++++++++++++++++++++++++++++---------
> include/uapi/linux/quota.h | 1 +
> 2 files changed, 29 insertions(+), 9 deletions(-)
>
> diff --git a/fs/quota/quota.c b/fs/quota/quota.c
> index cb13fb76dbee..035cdd1b022b 100644
> --- a/fs/quota/quota.c
> +++ b/fs/quota/quota.c
> @@ -19,6 +19,7 @@
> #include <linux/types.h>
> #include <linux/writeback.h>
> #include <linux/nospec.h>
> +#include <linux/mount.h>
>
> static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
> qid_t id)
> @@ -825,12 +826,16 @@ int kernel_quotactl(unsigned int cmd, const char __user *special,
> {
> uint cmds, type;
> struct super_block *sb = NULL;
> - struct path path, *pathp = NULL;
> + struct path path, *pathp = NULL, qpath;
Maybe call these two 'file_path', 'file_pathp', and 'sb_path' to make it
clearer which path is which?
> int ret;
> + bool q_path;
>
> cmds = cmd >> SUBCMDSHIFT;
> type = cmd & SUBCMDMASK;
>
> + q_path = cmds & Q_PATH;
> + cmds &= ~Q_PATH;
> +
> /*
> * As a special case Q_SYNC can be called without a specific device.
> * It will iterate all superblocks that have quota enabled and call
> @@ -855,19 +860,33 @@ int kernel_quotactl(unsigned int cmd, const char __user *special,
> pathp = &path;
> }
>
> - sb = quotactl_block(special, cmds);
> - if (IS_ERR(sb)) {
> - ret = PTR_ERR(sb);
> - goto out;
> + if (q_path) {
> + ret = user_path_at(AT_FDCWD, special, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT,
> + &qpath);
> + if (ret)
> + goto out1;
> +
> + sb = qpath.mnt->mnt_sb;
> + } else {
> + sb = quotactl_block(special, cmds);
> + if (IS_ERR(sb)) {
> + ret = PTR_ERR(sb);
> + goto out;
> + }
> }
>
> ret = do_quotactl(sb, type, cmds, id, addr, pathp);
>
> - if (!quotactl_cmd_onoff(cmds))
> - drop_super(sb);
> - else
> - drop_super_exclusive(sb);
> + if (!q_path) {
> + if (!quotactl_cmd_onoff(cmds))
> + drop_super(sb);
> + else
> + drop_super_exclusive(sb);
> + }
> out:
> + if (q_path)
> + path_put(&qpath);
> +out1:
Why do you need out1? If you leave 'out' as is, things should just work.
And you can also combine the above if like:
if (q_path) {
path_put(&qpath);
} else {
if (!quotactl_cmd_onoff(cmds))
drop_super(sb);
else
drop_super_exclusive(sb);
}
which would then make it more obvious, what's actually going on...
Otherwise the patch looks good to me.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2019-11-01 16:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-30 15:26 [PATCH v2 00/10] Add quota support to UBIFS Sascha Hauer
2019-10-30 15:26 ` [PATCH 01/10] quota: Make inode optional Sascha Hauer
2019-11-01 18:07 ` Jan Kara
2019-11-04 7:48 ` Sascha Hauer
2019-10-30 15:26 ` [PATCH 02/10] quota: Pass sb to vfs_load_quota_inode() Sascha Hauer
2019-10-30 15:26 ` [PATCH 03/10] quota: Introduce dquot_enable_sb() Sascha Hauer
2019-10-30 15:26 ` [PATCH 04/10] quota: Allow to pass mount path to quotactl Sascha Hauer
2019-11-01 16:07 ` Jan Kara [this message]
2019-11-11 10:08 ` Sascha Hauer
2019-11-11 11:05 ` Jan Kara
2019-11-11 11:14 ` Sascha Hauer
2019-10-30 15:26 ` [PATCH 05/10] ubifs: move checks and preparation into setflags() Sascha Hauer
2019-10-30 15:26 ` [PATCH 06/10] ubifs: Add support for FS_IOC_FS[SG]ETXATTR ioctls Sascha Hauer
2019-10-30 15:26 ` [PATCH 07/10] ubifs: do not ubifs_inode() on potentially NULL pointer Sascha Hauer
2019-10-30 15:27 ` [PATCH 08/10] ubifs: Add support for project id Sascha Hauer
2019-10-30 15:27 ` [PATCH 09/10] ubifs: export get_znode Sascha Hauer
2019-10-30 15:27 ` [PATCH 10/10] ubifs: Add quota support Sascha Hauer
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