vfs: add renameat2 syscall

Add new renameat2 syscall, which is the same as renameat with an added
flags argument.

Pass flags to vfs_rename() and to i_op->rename() as well.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Miklos Szeredi 2014-04-01 17:08:42 +02:00
parent bc27027a73
commit 520c8b1650
10 changed files with 58 additions and 15 deletions

View File

@ -47,6 +47,8 @@ prototypes:
int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
int (*rename) (struct inode *, struct dentry *,
struct inode *, struct dentry *);
int (*rename2) (struct inode *, struct dentry *,
struct inode *, struct dentry *, unsigned int);
int (*readlink) (struct dentry *, char __user *,int);
void * (*follow_link) (struct dentry *, struct nameidata *);
void (*put_link) (struct dentry *, struct nameidata *, void *);
@ -78,6 +80,7 @@ mkdir: yes
unlink: yes (both)
rmdir: yes (both) (see below)
rename: yes (all) (see below)
rename2: yes (all) (see below)
readlink: no
follow_link: no
put_link: no
@ -96,7 +99,8 @@ tmpfile: no
Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
victim.
cross-directory ->rename() has (per-superblock) ->s_vfs_rename_sem.
cross-directory ->rename() and rename2() has (per-superblock)
->s_vfs_rename_sem.
See Documentation/filesystems/directory-locking for more detailed discussion
of the locking scheme for directory operations.

View File

@ -347,6 +347,8 @@ struct inode_operations {
int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
int (*rename) (struct inode *, struct dentry *,
struct inode *, struct dentry *);
int (*rename2) (struct inode *, struct dentry *,
struct inode *, struct dentry *, unsigned int);
int (*readlink) (struct dentry *, char __user *,int);
void * (*follow_link) (struct dentry *, struct nameidata *);
void (*put_link) (struct dentry *, struct nameidata *, void *);
@ -414,6 +416,20 @@ otherwise noted.
rename: called by the rename(2) system call to rename the object to
have the parent and name given by the second inode and dentry.
rename2: this has an additional flags argument compared to rename.
If no flags are supported by the filesystem then this method
need not be implemented. If some flags are supported then the
filesystem must return -EINVAL for any unsupported or unknown
flags. Currently the following flags are implemented:
(1) RENAME_NOREPLACE: this flag indicates that if the target
of the rename exists the rename should fail with -EEXIST
instead of replacing the target. The VFS already checks for
existence, so for local filesystems the RENAME_NOREPLACE
implementation is equivalent to plain rename.
(2) RENAME_EXCHANGE: exchange source and target. Both must
exist; this is checked by the VFS. Unlike plain rename,
source and target may be of different type.
readlink: called by the readlink(2) system call. Only required if
you want to support reading symbolic links

View File

@ -322,6 +322,7 @@
313 common finit_module sys_finit_module
314 common sched_setattr sys_sched_setattr
315 common sched_getattr sys_sched_getattr
316 common renameat2 sys_renameat2
#
# x32-specific system call numbers start at 512 to avoid cache impact

View File

@ -105,8 +105,8 @@ static inline void ll_set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt,
#define ll_vfs_unlink(inode,entry,mnt) vfs_unlink(inode,entry)
#define ll_vfs_mknod(dir,entry,mnt,mode,dev) vfs_mknod(dir,entry,mode,dev)
#define ll_security_inode_unlink(dir,entry,mnt) security_inode_unlink(dir,entry)
#define ll_vfs_rename(old,old_dir,mnt,new,new_dir,mnt1,delegated_inode) \
vfs_rename(old,old_dir,new,new_dir,delegated_inode)
#define ll_vfs_rename(old, old_dir, mnt, new, new_dir, mnt1) \
vfs_rename(old, old_dir, new, new_dir, NULL, 0)
#define cfs_bio_io_error(a,b) bio_io_error((a))
#define cfs_bio_endio(a,b,c) bio_endio((a),(c))

View File

@ -223,7 +223,7 @@ int lustre_rename(struct dentry *dir, struct vfsmount *mnt,
GOTO(put_old, err = PTR_ERR(dchild_new));
err = ll_vfs_rename(dir->d_inode, dchild_old, mnt,
dir->d_inode, dchild_new, mnt, NULL);
dir->d_inode, dchild_new, mnt);
dput(dchild_new);
put_old:

View File

@ -396,7 +396,7 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache,
cachefiles_io_error(cache, "Rename security error %d", ret);
} else {
ret = vfs_rename(dir->d_inode, rep,
cache->graveyard->d_inode, grave, NULL);
cache->graveyard->d_inode, grave, NULL, 0);
if (ret != 0 && ret != -ENOMEM)
cachefiles_io_error(cache,
"Rename failed with error %d", ret);

View File

@ -641,7 +641,7 @@ ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
}
rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
lower_new_dir_dentry->d_inode, lower_new_dentry,
NULL);
NULL, 0);
if (rc)
goto out_lock;
if (target_inode)

View File

@ -3980,6 +3980,7 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname
* @new_dir: parent of destination
* @new_dentry: destination
* @delegated_inode: returns an inode needing a delegation break
* @flags: rename flags
*
* The caller must hold multiple mutexes--see lock_rename()).
*
@ -4023,7 +4024,7 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname
*/
int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
struct inode **delegated_inode)
struct inode **delegated_inode, unsigned int flags)
{
int error;
bool is_dir = d_is_dir(old_dentry);
@ -4048,6 +4049,9 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
if (!old_dir->i_op->rename)
return -EPERM;
if (flags && !old_dir->i_op->rename2)
return -EINVAL;
/*
* If we are going to change the parent - check write permissions,
* we'll need to flip '..'.
@ -4093,7 +4097,13 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
goto out;
}
}
error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
if (!flags) {
error = old_dir->i_op->rename(old_dir, old_dentry,
new_dir, new_dentry);
} else {
error = old_dir->i_op->rename2(old_dir, old_dentry,
new_dir, new_dentry, flags);
}
if (error)
goto out;
@ -4118,8 +4128,8 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
return error;
}
SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname)
SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname, unsigned int, flags)
{
struct dentry *old_dir, *new_dir;
struct dentry *old_dentry, *new_dentry;
@ -4131,6 +4141,10 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
unsigned int lookup_flags = 0;
bool should_retry = false;
int error;
if (flags)
return -EINVAL;
retry:
from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags);
if (IS_ERR(from)) {
@ -4202,8 +4216,8 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
if (error)
goto exit5;
error = vfs_rename(old_dir->d_inode, old_dentry,
new_dir->d_inode, new_dentry,
&delegated_inode);
new_dir->d_inode, new_dentry,
&delegated_inode, flags);
exit5:
dput(new_dentry);
exit4:
@ -4233,9 +4247,15 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
return error;
}
SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname)
{
return sys_renameat2(olddfd, oldname, newdfd, newname, 0);
}
SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname)
{
return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname);
return sys_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
}
int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link)

View File

@ -1694,7 +1694,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
goto out_dput_new;
host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL);
host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0);
if (!host_err) {
host_err = commit_metadata(tfhp);
if (!host_err)

View File

@ -1460,7 +1460,7 @@ extern int vfs_symlink(struct inode *, struct dentry *, const char *);
extern int vfs_link(struct dentry *, struct inode *, struct dentry *, struct inode **);
extern int vfs_rmdir(struct inode *, struct dentry *);
extern int vfs_unlink(struct inode *, struct dentry *, struct inode **);
extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **);
extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **, unsigned int);
/*
* VFS dentry helper functions.
@ -1571,6 +1571,8 @@ struct inode_operations {
int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
int (*rename) (struct inode *, struct dentry *,
struct inode *, struct dentry *);
int (*rename2) (struct inode *, struct dentry *,
struct inode *, struct dentry *, unsigned int);
int (*setattr) (struct dentry *, struct iattr *);
int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);