From 4c5b479975212065ef39786e115fde42847e95a9 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Wed, 7 Apr 2021 14:36:42 +0200 Subject: vfs: add fileattr ops There's a substantial amount of boilerplate in filesystems handling FS_IOC_[GS]ETFLAGS/ FS_IOC_FS[GS]ETXATTR ioctls. Also due to userspace buffers being involved in the ioctl API this is difficult to stack, as shown by overlayfs issues related to these ioctls. Introduce a new internal API named "fileattr" (fsxattr can be confused with xattr, xflags is inappropriate, since this is more than just flags). There's significant overlap between flags and xflags and this API handles the conversions automatically, so filesystems may choose which one to use. In ->fileattr_get() a hint is provided to the filesystem whether flags or xattr are being requested by userspace, but in this series this hint is ignored by all filesystems, since generating all the attributes is cheap. If a filesystem doesn't implemement the fileattr API, just fall back to f_op->ioctl(). When all filesystems are converted, the fallback can be removed. 32bit compat ioctls are now handled by the generic code as well. Signed-off-by: Miklos Szeredi --- Documentation/filesystems/locking.rst | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'Documentation/filesystems/locking.rst') diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index b7dcc86c92a4..729ce492b662 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -80,13 +80,16 @@ prototypes:: struct file *, unsigned open_flag, umode_t create_mode); int (*tmpfile) (struct inode *, struct dentry *, umode_t); + int (*fileattr_set)(struct user_namespace *mnt_userns, + struct dentry *dentry, struct fileattr *fa); + int (*fileattr_get)(struct dentry *dentry, struct fileattr *fa); locking rules: all may block -============ ============================================= +============= ============================================= ops i_rwsem(inode) -============ ============================================= +============= ============================================= lookup: shared create: exclusive link: exclusive (both) @@ -107,7 +110,9 @@ fiemap: no update_time: no atomic_open: shared (exclusive if O_CREAT is set in open flags) tmpfile: no -============ ============================================= +fileattr_get: no or exclusive +fileattr_set: exclusive +============= ============================================= Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_rwsem -- cgit