[PATCH RFC v2 1/6] fs: vfs ioctls for managing project id
From: Konstantin Khlebnikov
Date: Tue Mar 10 2015 - 13:22:18 EST
This patch adds generic vfs interface for project id and
related super-block methods.
Two new ioctls:
int ioctl(fd, FS_IOC_GETPROJECT, unsigned *project);
int ioctl(fd, FS_IOC_SETPROJECT, unsigned *project);
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
---
Documentation/filesystems/Locking | 4 +++
Documentation/filesystems/vfs.txt | 8 +++++
fs/compat_ioctl.c | 2 +
fs/ioctl.c | 58 +++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 2 +
include/uapi/linux/fs.h | 3 ++
6 files changed, 77 insertions(+)
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index f91926f2f482..7a01e2b606d0 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -126,6 +126,8 @@ prototypes:
ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
+ kprojid_t (*get_project) (struct inode *);
+ int (*set_project) (struct inode *, kprojid_t);
locking rules:
All may block [not true, see below]
@@ -147,6 +149,8 @@ show_options: no (namespace_sem)
quota_read: no (see below)
quota_write: no (see below)
bdev_try_to_free_page: no (see below)
+get_project no
+set_project no (i_mutex)
->statfs() has s_umount (shared) when called by ustat(2) (native or
compat), but that's an accident of bad API; s_umount is used to pin
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 966b22829f3b..aeff3c54021b 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -230,6 +230,8 @@ struct super_operations {
ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
int (*nr_cached_objects)(struct super_block *);
void (*free_cached_objects)(struct super_block *, int);
+ kprojid_t (*get_project)(struct inode *);
+ int (*set_project)(struct inode *, kprojid_t);
};
All methods are called without any locks being held, unless otherwise
@@ -319,6 +321,12 @@ or bottom half).
implementations will cause holdoff problems due to large scan batch
sizes.
+ get_project: called by the ioctl and quota code to get project id of an inode.
+ Method should return INVALID_PROJID if feature isn't supported.
+
+ set_project: called by the ioctl to set project id for an inode.
+ This is called with i_mutex held.
+
Whoever sets up the inode is responsible for filling in the "i_op" field. This
is a pointer to a "struct inode_operations" which describes the methods that
can be performed on individual inodes.
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index afec6450450f..9a24e4038377 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -889,6 +889,8 @@ COMPATIBLE_IOCTL(FIOASYNC)
COMPATIBLE_IOCTL(FIONBIO)
COMPATIBLE_IOCTL(FIONREAD) /* This is also TIOCINQ */
COMPATIBLE_IOCTL(FS_IOC_FIEMAP)
+COMPATIBLE_IOCTL(FS_IOC_GETPROJECT)
+COMPATIBLE_IOCTL(FS_IOC_SETPROJECT)
/* 0x00 */
COMPATIBLE_IOCTL(FIBMAP)
COMPATIBLE_IOCTL(FIGETBSZ)
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 5d01d2638ca5..d351576d95c8 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -9,6 +9,7 @@
#include <linux/capability.h>
#include <linux/file.h>
#include <linux/fs.h>
+#include <linux/mount.h>
#include <linux/security.h>
#include <linux/export.h>
#include <linux/uaccess.h>
@@ -545,6 +546,57 @@ static int ioctl_fsthaw(struct file *filp)
return thaw_super(sb);
}
+static int ioctl_getproject(struct file *filp, projid_t __user *argp)
+{
+ struct user_namespace *ns = current_user_ns();
+ struct inode *inode = file_inode(filp);
+ struct super_block *sb = inode->i_sb;
+ kprojid_t kprojid;
+ projid_t projid;
+
+ if (!sb->s_op->get_project)
+ return -EOPNOTSUPP;
+ kprojid = sb->s_op->get_project(inode);
+ if (!projid_valid(kprojid))
+ return -EOPNOTSUPP;
+ projid = from_kprojid(ns, kprojid);
+ if (projid == (projid_t)-1)
+ return -EACCES;
+ return put_user(projid, argp);
+}
+
+static int ioctl_setproject(struct file *filp, projid_t __user *argp)
+{
+ struct user_namespace *ns = current_user_ns();
+ struct inode *inode = file_inode(filp);
+ struct super_block *sb = inode->i_sb;
+ kprojid_t kprojid;
+ projid_t projid;
+ int ret;
+
+ if (!sb->s_op->set_project)
+ return -EOPNOTSUPP;
+ if (ns != &init_user_ns)
+ return -EPERM;
+ ret = get_user(projid, argp);
+ if (ret)
+ return ret;
+ kprojid = make_kprojid(ns, projid);
+ if (!projid_valid(kprojid))
+ return -EACCES;
+ ret = mnt_want_write_file(filp);
+ if (ret)
+ return ret;
+ mutex_lock(&inode->i_mutex);
+ if (inode_owner_or_capable(inode))
+ ret = sb->s_op->set_project(inode, kprojid);
+ else
+ ret = -EPERM;
+ mutex_unlock(&inode->i_mutex);
+ mnt_drop_write_file(filp);
+ return ret;
+}
+
/*
* When you add any new common ioctls to the switches above and below
* please update compat_sys_ioctl() too.
@@ -597,6 +649,12 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
case FS_IOC_FIEMAP:
return ioctl_fiemap(filp, arg);
+ case FS_IOC_GETPROJECT:
+ return ioctl_getproject(filp, argp);
+
+ case FS_IOC_SETPROJECT:
+ return ioctl_setproject(filp, argp);
+
case FIGETBSZ:
return put_user(inode->i_sb->s_blocksize, argp);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b4d71b5e1ff2..42156801739e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1655,6 +1655,8 @@ struct super_operations {
struct shrink_control *);
long (*free_cached_objects)(struct super_block *,
struct shrink_control *);
+ kprojid_t (*get_project)(struct inode *);
+ int (*set_project)(struct inode *, kprojid_t);
};
/*
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 9b964a5920af..144426326e15 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -170,6 +170,9 @@ struct inodes_stat_t {
#define FS_IOC32_GETVERSION _IOR('v', 1, int)
#define FS_IOC32_SETVERSION _IOW('v', 2, int)
+#define FS_IOC_GETPROJECT _IOR('f', 20, unsigned)
+#define FS_IOC_SETPROJECT _IOW('f', 21, unsigned)
+
/*
* Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS)
*/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/