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| author | Christian Brauner <brauner@kernel.org> | 2022-02-03 14:14:08 +0100 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2022-02-14 08:37:39 +0100 |
| commit | a26f788b6e7a10d193c4cc6889818e4d625e9461 (patch) | |
| tree | c4fbe3e3f699fdbe95d2bba6a93ce775c58c15b5 | |
| parent | fs: add kernel doc for mnt_{hold,unhold}_writers() (diff) | |
| download | linux-a26f788b6e7a10d193c4cc6889818e4d625e9461.tar.xz linux-a26f788b6e7a10d193c4cc6889818e4d625e9461.zip | |
fs: add mnt_allow_writers() and simplify mount_setattr_prepare()
Add a tiny helper that lets us simplify the control-flow and can be used
in the next patch to avoid adding another condition open-coded into
mount_setattr_prepare(). Instead we can add it into the new helper.
Link: https://lore.kernel.org/r/20220203131411.3093040-5-brauner@kernel.org
Cc: Seth Forshee <seth.forshee@digitalocean.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
| -rw-r--r-- | fs/namespace.c | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index de6fae84f1a1..7e5535ed155d 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3998,6 +3998,22 @@ static int can_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt) return 0; } +/** + * mnt_allow_writers() - check whether the attribute change allows writers + * @kattr: the new mount attributes + * @mnt: the mount to which @kattr will be applied + * + * Check whether thew new mount attributes in @kattr allow concurrent writers. + * + * Return: true if writers need to be held, false if not + */ +static inline bool mnt_allow_writers(const struct mount_kattr *kattr, + const struct mount *mnt) +{ + return !(kattr->attr_set & MNT_READONLY) || + (mnt->mnt.mnt_flags & MNT_READONLY); +} + static struct mount *mount_setattr_prepare(struct mount_kattr *kattr, struct mount *mnt, int *err) { @@ -4028,12 +4044,12 @@ static struct mount *mount_setattr_prepare(struct mount_kattr *kattr, last = m; - if ((kattr->attr_set & MNT_READONLY) && - !(m->mnt.mnt_flags & MNT_READONLY)) { - *err = mnt_hold_writers(m); - if (*err) - goto out; - } + if (mnt_allow_writers(kattr, m)) + continue; + + *err = mnt_hold_writers(m); + if (*err) + goto out; } while (kattr->recurse && (m = next_mnt(m, mnt))); out: |