[patch 21/22] sys_mknodat(): elevate write count for
vfs_mknod/create()
Cedric Le Goater
clg at fr.ibm.com
Thu Jun 7 08:25:48 PDT 2007
From: Dave Hansen <hansendc at us.ibm.com>
This takes care of all of the direct callers of vfs_mknod().
Since a few of these cases also handle normal file creation
as well, this also covers some calls to vfs_create().
Signed-off-by: Dave Hansen <hansendc at us.ibm.com>
---
fs/namei.c | 12 ++++++++++++
fs/nfsd/vfs.c | 8 ++++++--
net/unix/af_unix.c | 4 ++++
3 files changed, 22 insertions(+), 2 deletions(-)
Index: 2.6.22-rc4-mm2-robindmount/fs/namei.c
===================================================================
--- 2.6.22-rc4-mm2-robindmount.orig/fs/namei.c
+++ 2.6.22-rc4-mm2-robindmount/fs/namei.c
@@ -1949,14 +1949,26 @@ asmlinkage long sys_mknodat(int dfd, con
if (!IS_ERR(dentry)) {
switch (mode & S_IFMT) {
case 0: case S_IFREG:
+ error = mnt_want_write(nd.mnt);
+ if (error)
+ break;
error = vfs_create(nd.dentry->d_inode,dentry,mode,&nd);
+ mnt_drop_write(nd.mnt);
break;
case S_IFCHR: case S_IFBLK:
+ error = mnt_want_write(nd.mnt);
+ if (error)
+ break;
error = vfs_mknod(nd.dentry->d_inode,dentry,mode,
new_decode_dev(dev));
+ mnt_drop_write(nd.mnt);
break;
case S_IFIFO: case S_IFSOCK:
+ error = mnt_want_write(nd.mnt);
+ if (error)
+ break;
error = vfs_mknod(nd.dentry->d_inode,dentry,mode,0);
+ mnt_drop_write(nd.mnt);
break;
case S_IFDIR:
error = -EPERM;
Index: 2.6.22-rc4-mm2-robindmount/fs/nfsd/vfs.c
===================================================================
--- 2.6.22-rc4-mm2-robindmount.orig/fs/nfsd/vfs.c
+++ 2.6.22-rc4-mm2-robindmount/fs/nfsd/vfs.c
@@ -1192,7 +1192,11 @@ 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_mnt);
+ if (host_err)
+ break;
host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev);
+ mnt_drop_write(fhp->fh_export->ex_mnt);
break;
default:
printk("nfsd: bad file type %o in nfsd_create\n", type);
@@ -1811,7 +1815,7 @@ nfsd_permission(struct svc_export *exp,
inode->i_mode,
IS_IMMUTABLE(inode)? " immut" : "",
IS_APPEND(inode)? " append" : "",
- __mnt_is_readonly(exp->mnt)? " ro" : "");
+ __mnt_is_readonly(exp->ex_mnt)? " ro" : "");
dprintk(" owner %d/%d user %d/%d\n",
inode->i_uid, inode->i_gid, current->fsuid, current->fsgid);
#endif
@@ -1822,7 +1826,7 @@ nfsd_permission(struct svc_export *exp,
*/
if (!(acc & MAY_LOCAL_ACCESS))
if (acc & (MAY_WRITE | MAY_SATTR | MAY_TRUNC)) {
- if (EX_RDONLY(exp) || __mnt_is_readonly(exp->mnt))
+ if (EX_RDONLY(exp) || __mnt_is_readonly(exp->ex_mnt))
return nfserr_rofs;
if (/* (acc & MAY_WRITE) && */ IS_IMMUTABLE(inode))
return nfserr_perm;
Index: 2.6.22-rc4-mm2-robindmount/net/unix/af_unix.c
===================================================================
--- 2.6.22-rc4-mm2-robindmount.orig/net/unix/af_unix.c
+++ 2.6.22-rc4-mm2-robindmount/net/unix/af_unix.c
@@ -815,7 +815,11 @@ static int unix_bind(struct socket *sock
*/
mode = S_IFSOCK |
(SOCK_INODE(sock)->i_mode & ~current->fs->umask);
+ err = mnt_want_write(nd.mnt);
+ if (err)
+ goto out_mknod_dput;
err = vfs_mknod(nd.dentry->d_inode, dentry, mode, 0);
+ mnt_drop_write(nd.mnt);
if (err)
goto out_mknod_dput;
mutex_unlock(&nd.dentry->d_inode->i_mutex);
--
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