From: Miklos Szeredi R/o bind mounts require operations which modify the filesystem to be wrapped in mnt_want_write()/mnt_drop_write(). Create helpers which do this, so callers won't need to bother, and more importantly, cannot forget! Call these path_*, analogous to vfs_*. Where there are no callers of vfs_* left, make them static. This series is a cleanup, as well as fixing several places (mostly in nfsd) where mnt_{want,drop}_write() were missing. It will also help with merging You Know What(*) security module, which needs to know the path within the namespace, and not just within the filesystem. These helpers will allow the security hooks to be in a common place, and need not be repeated in all callers. (*) AppArmor is a swear word in VFS circles, for some reason or other. This patch: Introduce path_create() and path_mknod(). Make vfs_create() and vfs_mknod() static. Signed-off-by: Miklos Szeredi --- fs/ecryptfs/inode.c | 21 +++++++------- fs/namei.c | 75 +++++++++++++++++++++++++++------------------------- fs/nfsd/vfs.c | 19 ++++++------- include/linux/fs.h | 4 +- ipc/mqueue.c | 6 +++- net/unix/af_unix.c | 6 ---- 6 files changed, 68 insertions(+), 63 deletions(-) Index: vfs-2.6/fs/namei.c =================================================================== --- vfs-2.6.orig/fs/namei.c 2008-04-02 21:10:14.000000000 +0200 +++ vfs-2.6/fs/namei.c 2008-04-02 21:10:17.000000000 +0200 @@ -1574,7 +1574,7 @@ void unlock_rename(struct dentry *p1, st } } -int vfs_create(struct inode *dir, struct dentry *dentry, int mode, +static int vfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd) { int error = may_create(dir, dentry, nd); @@ -1596,6 +1596,20 @@ int vfs_create(struct inode *dir, struct return error; } +int path_create(struct path *dir_path, struct dentry *dentry, int mode, + struct nameidata *nd) +{ + int error = mnt_want_write(dir_path->mnt); + + if (!error) { + error = vfs_create(dir_path->dentry->d_inode, dentry, mode, nd); + mnt_drop_write(dir_path->mnt); + } + + return error; +} +EXPORT_SYMBOL(path_create); + int may_open(struct nameidata *nd, int acc_mode, int flag) { struct dentry *dentry = nd->path.dentry; @@ -2015,7 +2029,7 @@ fail: } EXPORT_SYMBOL_GPL(lookup_create); -int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) +static int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) { int error = may_create(dir, dentry, NULL); @@ -2039,22 +2053,19 @@ int vfs_mknod(struct inode *dir, struct return error; } -static int may_mknod(mode_t mode) +int path_mknod(struct path *dir_path, struct dentry *dentry, int mode, + dev_t dev) { - switch (mode & S_IFMT) { - case S_IFREG: - case S_IFCHR: - case S_IFBLK: - case S_IFIFO: - case S_IFSOCK: - case 0: /* zero mode translates to S_IFREG */ - return 0; - case S_IFDIR: - return -EPERM; - default: - return -EINVAL; + int error = mnt_want_write(dir_path->mnt); + + if (!error) { + error = vfs_mknod(dir_path->dentry->d_inode, dentry, mode, dev); + mnt_drop_write(dir_path->mnt); } + + return error; } +EXPORT_SYMBOL(path_mknod); asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, unsigned dev) @@ -2080,26 +2091,22 @@ asmlinkage long sys_mknodat(int dfd, con } if (!IS_POSIXACL(nd.path.dentry->d_inode)) mode &= ~current->fs->umask; - error = may_mknod(mode); - if (error) - goto out_dput; - error = mnt_want_write(nd.path.mnt); - if (error) - goto out_dput; switch (mode & S_IFMT) { - case 0: case S_IFREG: - error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd); - break; - case S_IFCHR: case S_IFBLK: - error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode, - new_decode_dev(dev)); - break; - case S_IFIFO: case S_IFSOCK: - error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0); - break; + case 0: case S_IFREG: + error = path_create(&nd.path, dentry, mode, &nd); + break; + case S_IFCHR: case S_IFBLK: + error = path_mknod(&nd.path, dentry, mode, new_decode_dev(dev)); + break; + case S_IFIFO: case S_IFSOCK: + error = path_mknod(&nd.path, dentry, mode, 0); + break; + case S_IFDIR: + error = -EPERM; + break; + default: + error = -EINVAL; } - mnt_drop_write(nd.path.mnt); -out_dput: dput(dentry); out_unlock: mutex_unlock(&nd.path.dentry->d_inode->i_mutex); @@ -2966,11 +2973,9 @@ EXPORT_SYMBOL(permission); EXPORT_SYMBOL(vfs_permission); EXPORT_SYMBOL(file_permission); EXPORT_SYMBOL(unlock_rename); -EXPORT_SYMBOL(vfs_create); EXPORT_SYMBOL(vfs_follow_link); EXPORT_SYMBOL(vfs_link); EXPORT_SYMBOL(vfs_mkdir); -EXPORT_SYMBOL(vfs_mknod); EXPORT_SYMBOL(generic_permission); EXPORT_SYMBOL(vfs_readlink); EXPORT_SYMBOL(vfs_rename); Index: vfs-2.6/include/linux/fs.h =================================================================== --- vfs-2.6.orig/include/linux/fs.h 2008-04-02 21:10:14.000000000 +0200 +++ vfs-2.6/include/linux/fs.h 2008-04-02 21:10:17.000000000 +0200 @@ -1123,9 +1123,9 @@ extern void unlock_super(struct super_bl * VFS helper functions.. */ extern int vfs_permission(struct nameidata *, int); -extern int vfs_create(struct inode *, struct dentry *, int, struct nameidata *); +extern int path_create(struct path *, struct dentry *, int, struct nameidata *); extern int vfs_mkdir(struct inode *, struct dentry *, int); -extern int vfs_mknod(struct inode *, struct dentry *, int, dev_t); +extern int path_mknod(struct path *, struct dentry *, int, dev_t); extern int vfs_symlink(struct inode *, struct dentry *, const char *, int); extern int vfs_link(struct dentry *, struct inode *, struct dentry *); extern int vfs_rmdir(struct inode *, struct dentry *); Index: vfs-2.6/fs/ecryptfs/inode.c =================================================================== --- vfs-2.6.orig/fs/ecryptfs/inode.c 2008-04-02 21:10:15.000000000 +0200 +++ vfs-2.6/fs/ecryptfs/inode.c 2008-04-02 21:10:17.000000000 +0200 @@ -67,7 +67,7 @@ static void unlock_dir(struct dentry *di * Returns zero on success; non-zero on error condition */ static int -ecryptfs_create_underlying_file(struct inode *lower_dir_inode, +ecryptfs_create_underlying_file(struct dentry *lower_dir_dentry, struct dentry *dentry, int mode, struct nameidata *nd) { @@ -79,9 +79,9 @@ ecryptfs_create_underlying_file(struct i dentry_save = nd->path.dentry; vfsmount_save = nd->path.mnt; - nd->path.dentry = lower_dentry; + nd->path.dentry = lower_dir_dentry; nd->path.mnt = lower_mnt; - rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd); + rc = path_create(&nd->path, lower_dentry, mode, nd); nd->path.dentry = dentry_save; nd->path.mnt = vfsmount_save; return rc; @@ -117,7 +117,7 @@ ecryptfs_do_create(struct inode *directo rc = PTR_ERR(lower_dir_dentry); goto out; } - rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode, + rc = ecryptfs_create_underlying_file(lower_dir_dentry, ecryptfs_dentry, mode, nd); if (rc) { printk(KERN_ERR "%s: Failure to create dentry in lower fs; " @@ -535,20 +535,21 @@ ecryptfs_mknod(struct inode *dir, struct { int rc; struct dentry *lower_dentry; - struct dentry *lower_dir_dentry; + struct path lower_dir; lower_dentry = ecryptfs_dentry_to_lower(dentry); - lower_dir_dentry = lock_parent(lower_dentry); - rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev); + lower_dir.mnt = ecryptfs_dentry_to_lower_mnt(dentry); + lower_dir.dentry = lock_parent(lower_dentry); + rc = path_mknod(&lower_dir, lower_dentry, mode, dev); if (rc || !lower_dentry->d_inode) goto out; rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); if (rc) goto out; - fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); - fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); + fsstack_copy_attr_times(dir, lower_dir.dentry->d_inode); + fsstack_copy_inode_size(dir, lower_dir.dentry->d_inode); out: - unlock_dir(lower_dir_dentry); + unlock_dir(lower_dir.dentry); if (!dentry->d_inode) d_drop(dentry); return rc; Index: vfs-2.6/fs/nfsd/vfs.c =================================================================== --- vfs-2.6.orig/fs/nfsd/vfs.c 2008-04-02 21:10:14.000000000 +0200 +++ vfs-2.6/fs/nfsd/vfs.c 2008-04-02 21:10:17.000000000 +0200 @@ -1185,6 +1185,7 @@ nfsd_create(struct svc_rqst *rqstp, stru char *fname, int flen, struct iattr *iap, int type, dev_t rdev, struct svc_fh *resfhp) { + struct path dir_path; struct dentry *dentry, *dchild = NULL; struct inode *dirp; __be32 err; @@ -1249,13 +1250,12 @@ nfsd_create(struct svc_rqst *rqstp, stru iap->ia_mode = 0; iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type; - /* - * Get the dir op function pointer. - */ + dir_path.mnt = fhp->fh_export->ex_path.mnt; + dir_path.dentry = dentry; err = 0; switch (type) { case S_IFREG: - host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL); + host_err = path_create(&dir_path, dchild, iap->ia_mode, NULL); break; case S_IFDIR: host_err = vfs_mkdir(dirp, dchild, iap->ia_mode); @@ -1264,11 +1264,7 @@ nfsd_create(struct svc_rqst *rqstp, stru case S_IFBLK: case S_IFIFO: case S_IFSOCK: - host_err = mnt_want_write(fhp->fh_export->ex_path.mnt); - if (host_err) - break; - host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev); - mnt_drop_write(fhp->fh_export->ex_path.mnt); + host_err = path_mknod(&dir_path, dchild, iap->ia_mode, rdev); break; default: printk("nfsd: bad file type %o in nfsd_create\n", type); @@ -1311,6 +1307,7 @@ nfsd_create_v3(struct svc_rqst *rqstp, s struct svc_fh *resfhp, int createmode, u32 *verifier, int *truncp, int *created) { + struct path dir_path; struct dentry *dentry, *dchild = NULL; struct inode *dirp; __be32 err; @@ -1397,7 +1394,9 @@ nfsd_create_v3(struct svc_rqst *rqstp, s goto out; } - host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL); + dir_path.mnt = fhp->fh_export->ex_path.mnt; + dir_path.dentry = dentry; + host_err = path_create(&dir_path, dchild, iap->ia_mode, NULL); if (host_err < 0) goto out_nfserr; if (created) Index: vfs-2.6/ipc/mqueue.c =================================================================== --- vfs-2.6.orig/ipc/mqueue.c 2008-04-02 21:10:14.000000000 +0200 +++ vfs-2.6/ipc/mqueue.c 2008-04-02 21:10:17.000000000 +0200 @@ -599,6 +599,7 @@ static struct file *do_create(struct den { struct mq_attr attr; struct file *result; + struct path dir_path; int ret; if (u_attr) { @@ -616,7 +617,10 @@ static struct file *do_create(struct den ret = mnt_want_write(mqueue_mnt); if (ret) goto out; - ret = vfs_create(dir->d_inode, dentry, mode, NULL); + + dir_path.mnt = mqueue_mnt; + dir_path.dentry = dir; + ret = path_create(&dir_path, dentry, mode, NULL); dentry->d_fsdata = NULL; if (ret) goto out_drop_write; Index: vfs-2.6/net/unix/af_unix.c =================================================================== --- vfs-2.6.orig/net/unix/af_unix.c 2008-04-02 21:10:14.000000000 +0200 +++ vfs-2.6/net/unix/af_unix.c 2008-04-02 21:10:17.000000000 +0200 @@ -819,11 +819,7 @@ static int unix_bind(struct socket *sock */ mode = S_IFSOCK | (SOCK_INODE(sock)->i_mode & ~current->fs->umask); - err = mnt_want_write(nd.path.mnt); - if (err) - goto out_mknod_dput; - err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0); - mnt_drop_write(nd.path.mnt); + err = path_mknod(&nd.path, dentry, mode, 0); if (err) goto out_mknod_dput; mutex_unlock(&nd.path.dentry->d_inode->i_mutex); -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/