Re: [PATCH v3 09/25] fs: add is_userns_visible() helper
From: "Serge E. Hallyn" <serge@hallyn.com>
Date: 2020-02-19 02:42:39
Also in:
linux-api, linux-fsdevel, lkml
On Tue, Feb 18, 2020 at 03:33:55PM +0100, Christian Brauner wrote:
Introduce a helper which makes it possible to detect fileystems whose superblock is visible in multiple user namespace. This currently only means proc and sys. Such filesystems usually have special semantics so their behavior will not be changed with the introduction of fsid mappings.
Hi, I'm afraid I've got a bit of a hangup about the terminology here. I *think* what you mean is that SB_I_USERNS_VISIBLE is an fs whose uids are always translated per the id mappings, not fsid mappings. But when I see the name it seems to imply that !SB_I_USERNS_VISIBLE filesystems can't be seen by other namespaces at all. Am I right in my first interpretation? If so, can we talk about the naming?
quoted hunk ↗ jump to hunk
Signed-off-by: Christian Brauner <redacted> --- /* v2 */ unchanged /* v3 */ unchanged --- include/linux/fs.h | 5 +++++ 1 file changed, 5 insertions(+)diff --git a/include/linux/fs.h b/include/linux/fs.h index 3cd4fe6b845e..fdc8fb2d786b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h@@ -3651,4 +3651,9 @@ static inline int inode_drain_writes(struct inode *inode) return filemap_write_and_wait(inode->i_mapping); } +static inline bool is_userns_visible(unsigned long iflags) +{ + return (iflags & SB_I_USERNS_VISIBLE); +} + #endif /* _LINUX_FS_H */-- 2.25.0