nfsd: fix race in nfsd_nrthreads()

[safe/jmp/linux-2.6] / fs / nfsd / vfs.c

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 18a4cc9..a3a291f 100644 (file)
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -264,7 +264,6 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
        struct inode    *inode;
        int             accmode = MAY_SATTR;
        int             ftype = 0;
-       int             imode;
        __be32          err;
        int             host_err;
        int             size_change = 0;
@@ -360,25 +359,25 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
                DQUOT_INIT(inode);
        }
 
-       imode = inode->i_mode;
+       /* sanitize the mode change */
        if (iap->ia_valid & ATTR_MODE) {
                iap->ia_mode &= S_IALLUGO;
-               imode = iap->ia_mode |= (imode & ~S_IALLUGO);
-               /* if changing uid/gid revoke setuid/setgid in mode */
-               if ((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid) {
-                       iap->ia_valid |= ATTR_KILL_PRIV;
+               iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
+       }
+
+       /* Revoke setuid/setgid on chown */
+       if (((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid) ||
+           ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid)) {
+               iap->ia_valid |= ATTR_KILL_PRIV;
+               if (iap->ia_valid & ATTR_MODE) {
+                       /* we're setting mode too, just clear the s*id bits */
                        iap->ia_mode &= ~S_ISUID;
+                       if (iap->ia_mode & S_IXGRP)
+                               iap->ia_mode &= ~S_ISGID;
+               } else {
+                       /* set ATTR_KILL_* bits and let VFS handle it */
+                       iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
                }
-               if ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid)
-                       iap->ia_mode &= ~S_ISGID;
-       } else {
-               /*
-                * Revoke setuid/setgid bit on chown/chgrp
-                */
-               if ((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid)
-                       iap->ia_valid |= ATTR_KILL_SUID | ATTR_KILL_PRIV;
-               if ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid)
-                       iap->ia_valid |= ATTR_KILL_SGID;
        }
 
        /* Change the attributes. */
@@ -988,7 +987,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
         * flushing the data to disk is handled separately below.
         */
 
-       if (file->f_op->fsync == 0) {/* COMMIT3 cannot work */
+       if (!file->f_op->fsync) {/* COMMIT3 cannot work */
               stable = 2;
               *stablep = 2; /* FILE_SYNC */
        }
@@ -1152,7 +1151,7 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
 }
 #endif /* CONFIG_NFSD_V3 */
 
-__be32
+static __be32
 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
                        struct iattr *iap)
 {
@@ -1912,7 +1911,7 @@ nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
                inode->i_mode,
                IS_IMMUTABLE(inode)?    " immut" : "",
                IS_APPEND(inode)?       " append" : "",
-               IS_RDONLY(inode)?       " ro" : "");
+               __mnt_is_readonly(exp->ex_path.mnt)?    " ro" : "");
        dprintk("      owner %d/%d user %d/%d\n",
                inode->i_uid, inode->i_gid, current->fsuid, current->fsgid);
 #endif
@@ -1923,7 +1922,8 @@ nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
         */
        if (!(acc & MAY_LOCAL_ACCESS))
                if (acc & (MAY_WRITE | MAY_SATTR | MAY_TRUNC)) {
-                       if (exp_rdonly(rqstp, exp) || IS_RDONLY(inode))
+                       if (exp_rdonly(rqstp, exp) ||
+                           __mnt_is_readonly(exp->ex_path.mnt))
                                return nfserr_rofs;
                        if (/* (acc & MAY_WRITE) && */ IS_IMMUTABLE(inode))
                                return nfserr_perm;
@@ -2086,6 +2086,9 @@ nfsd_set_posix_acl(struct svc_fh *fhp, int type, struct posix_acl *acl)
        } else
                size = 0;
 
+       error = mnt_want_write(fhp->fh_export->ex_path.mnt);
+       if (error)
+               goto getout;
        if (size)
                error = vfs_setxattr(fhp->fh_dentry, name, value, size, 0);
        else {
@@ -2097,6 +2100,7 @@ nfsd_set_posix_acl(struct svc_fh *fhp, int type, struct posix_acl *acl)
                                error = 0;
                }
        }
+       mnt_drop_write(fhp->fh_export->ex_path.mnt);
 
 getout:
        kfree(value);