| Message ID | 20230830181519.2964941-2-bschubert@ddn.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Use exclusive lock for file_remove_privs | expand |
On Wed, Aug 30, 2023 at 08:15:18PM +0200, Bernd Schubert wrote: > File systems want to hold a shared lock for DIO writes, > but may need to drop file priveliges - that a requires an > exclusive lock. The new export function file_needs_remove_privs() > is added in order to first check if that is needed. As said last time - the existing file systems with shared locking for direct I/O just do the much more pessimistic IS_SEC check here. I'd suggest to just do that for btrfs first step. If we then have numbers justifying the finer grained check we should update veryone and not just do it for one place.
diff --git a/fs/inode.c b/fs/inode.c index 67611a360031..9b05db602e41 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -2013,6 +2013,14 @@ int dentry_needs_remove_privs(struct mnt_idmap *idmap, return mask; } +int file_needs_remove_privs(struct file *file) +{ + struct dentry *dentry = file_dentry(file); + + return dentry_needs_remove_privs(file_mnt_idmap(file), dentry); +} +EXPORT_SYMBOL_GPL(file_needs_remove_privs); + static int __remove_privs(struct mnt_idmap *idmap, struct dentry *dentry, int kill) { diff --git a/include/linux/fs.h b/include/linux/fs.h index 562f2623c9c9..9245f0de00bc 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2721,6 +2721,7 @@ extern struct inode *new_inode_pseudo(struct super_block *sb); extern struct inode *new_inode(struct super_block *sb); extern void free_inode_nonrcu(struct inode *inode); extern int setattr_should_drop_suidgid(struct mnt_idmap *, struct inode *); +int file_needs_remove_privs(struct file *); extern int file_remove_privs(struct file *); int setattr_should_drop_sgid(struct mnt_idmap *idmap, const struct inode *inode);
File systems want to hold a shared lock for DIO writes, but may need to drop file priveliges - that a requires an exclusive lock. The new export function file_needs_remove_privs() is added in order to first check if that is needed. Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Dharmendra Singh <dsingh@ddn.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: linux-btrfs@vger.kernel.org Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Bernd Schubert <bschubert@ddn.com> --- fs/inode.c | 8 ++++++++ include/linux/fs.h | 1 + 2 files changed, 9 insertions(+)