1 files changed, 92 insertions, 72 deletions

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index b660435978d2..23341c1063bc 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -55,6 +55,7 @@
 #include <linux/security.h>
 #endif /* CONFIG_NFSD_V4 */
 #include <linux/jhash.h>
+#include <linux/ima.h>
 
 #include <asm/uaccess.h>
 
@@ -100,36 +101,35 @@ nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
 {
 	struct svc_export *exp = *expp, *exp2 = NULL;
 	struct dentry *dentry = *dpp;
-	struct vfsmount *mnt = mntget(exp->ex_path.mnt);
-	struct dentry *mounts = dget(dentry);
+	struct path path = {.mnt = mntget(exp->ex_path.mnt),
+			    .dentry = dget(dentry)};
 	int err = 0;
 
-	while (follow_down(&mnt,&mounts)&&d_mountpoint(mounts));
+	while (d_mountpoint(path.dentry) && follow_down(&path))
+		;
 
-	exp2 = rqst_exp_get_by_name(rqstp, mnt, mounts);
+	exp2 = rqst_exp_get_by_name(rqstp, &path);
 	if (IS_ERR(exp2)) {
 		if (PTR_ERR(exp2) != -ENOENT)
 			err = PTR_ERR(exp2);
-		dput(mounts);
-		mntput(mnt);
+		path_put(&path);
 		goto out;
 	}
 	if ((exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
 		/* successfully crossed mount point */
 		/*
-		 * This is subtle: dentry is *not* under mnt at this point.
-		 * The only reason we are safe is that original mnt is pinned
-		 * down by exp, so we should dput before putting exp.
+		 * This is subtle: path.dentry is *not* on path.mnt
+		 * at this point.  The only reason we are safe is that
+		 * original mnt is pinned down by exp, so we should
+		 * put path *before* putting exp
 		 */
-		dput(dentry);
-		*dpp = mounts;
-		exp_put(exp);
+		*dpp = path.dentry;
+		path.dentry = dentry;
 		*expp = exp2;
-	} else {
-		exp_put(exp2);
-		dput(mounts);
+		exp2 = exp;
 	}
-	mntput(mnt);
+	path_put(&path);
+	exp_put(exp2);
 out:
 	return err;
 }
@@ -168,28 +168,29 @@ nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
 			/* checking mountpoint crossing is very different when stepping up */
 			struct svc_export *exp2 = NULL;
 			struct dentry *dp;
-			struct vfsmount *mnt = mntget(exp->ex_path.mnt);
-			dentry = dget(dparent);
-			while(dentry == mnt->mnt_root && follow_up(&mnt, &dentry))
+			struct path path = {.mnt = mntget(exp->ex_path.mnt),
+					    .dentry = dget(dparent)};
+
+			while (path.dentry == path.mnt->mnt_root &&
+			       follow_up(&path))
 				;
-			dp = dget_parent(dentry);
-			dput(dentry);
-			dentry = dp;
+			dp = dget_parent(path.dentry);
+			dput(path.dentry);
+			path.dentry = dp;
 
-			exp2 = rqst_exp_parent(rqstp, mnt, dentry);
+			exp2 = rqst_exp_parent(rqstp, &path);
 			if (PTR_ERR(exp2) == -ENOENT) {
-				dput(dentry);
 				dentry = dget(dparent);
 			} else if (IS_ERR(exp2)) {
 				host_err = PTR_ERR(exp2);
-				dput(dentry);
-				mntput(mnt);
+				path_put(&path);
 				goto out_nfserr;
 			} else {
+				dentry = dget(path.dentry);
 				exp_put(exp);
 				exp = exp2;
 			}
-			mntput(mnt);
+			path_put(&path);
 		}
 	} else {
 		fh_lock(fhp);
@@ -677,7 +678,6 @@ __be32
 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 			int access, struct file **filp)
 {
-	const struct cred *cred = current_cred();
 	struct dentry	*dentry;
 	struct inode	*inode;
 	int		flags = O_RDONLY|O_LARGEFILE;
@@ -732,9 +732,11 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 		vfs_dq_init(inode);
 	}
 	*filp = dentry_open(dget(dentry), mntget(fhp->fh_export->ex_path.mnt),
-			    flags, cred);
+			    flags, current_cred());
 	if (IS_ERR(*filp))
 		host_err = PTR_ERR(*filp);
+	else
+		ima_counts_get(*filp);
 out_nfserr:
 	err = nfserrno(host_err);
 out:
@@ -963,6 +965,43 @@ static void kill_suid(struct dentry *dentry)
 	mutex_unlock(&dentry->d_inode->i_mutex);
 }
 
+/*
+ * Gathered writes: If another process is currently writing to the file,
+ * there's a high chance this is another nfsd (triggered by a bulk write
+ * from a client's biod). Rather than syncing the file with each write
+ * request, we sleep for 10 msec.
+ *
+ * I don't know if this roughly approximates C. Juszak's idea of
+ * gathered writes, but it's a nice and simple solution (IMHO), and it
+ * seems to work:-)
+ *
+ * Note: we do this only in the NFSv2 case, since v3 and higher have a
+ * better tool (separate unstable writes and commits) for solving this
+ * problem.
+ */
+static int wait_for_concurrent_writes(struct file *file)
+{
+	struct inode *inode = file->f_path.dentry->d_inode;
+	static ino_t last_ino;
+	static dev_t last_dev;
+	int err = 0;
+
+	if (atomic_read(&inode->i_writecount) > 1
+	    || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
+		dprintk("nfsd: write defer %d\n", task_pid_nr(current));
+		msleep(10);
+		dprintk("nfsd: write resume %d\n", task_pid_nr(current));
+	}
+
+	if (inode->i_state & I_DIRTY) {
+		dprintk("nfsd: write sync %d\n", task_pid_nr(current));
+		err = nfsd_sync(file);
+	}
+	last_ino = inode->i_ino;
+	last_dev = inode->i_sb->s_dev;
+	return err;
+}
+
 static __be32
 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 				loff_t offset, struct kvec *vec, int vlen,
@@ -975,6 +1014,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	__be32			err = 0;
 	int			host_err;
 	int			stable = *stablep;
+	int			use_wgather;
 
 #ifdef MSNFS
 	err = nfserr_perm;
@@ -993,9 +1033,10 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	 *  -	the sync export option has been set, or
 	 *  -	the client requested O_SYNC behavior (NFSv3 feature).
 	 *  -   The file system doesn't support fsync().
-	 * When gathered writes have been configured for this volume,
+	 * When NFSv2 gathered writes have been configured for this volume,
 	 * flushing the data to disk is handled separately below.
 	 */
+	use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
 
 	if (!file->f_op->fsync) {/* COMMIT3 cannot work */
 	       stable = 2;
@@ -1004,7 +1045,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 
 	if (!EX_ISSYNC(exp))
 		stable = 0;
-	if (stable && !EX_WGATHER(exp)) {
+	if (stable && !use_wgather) {
 		spin_lock(&file->f_lock);
 		file->f_flags |= O_SYNC;
 		spin_unlock(&file->f_lock);
@@ -1014,52 +1055,20 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	oldfs = get_fs(); set_fs(KERNEL_DS);
 	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset);
 	set_fs(oldfs);
-	if (host_err >= 0) {
-		*cnt = host_err;
-		nfsdstats.io_write += host_err;
-		fsnotify_modify(file->f_path.dentry);
-	}
+	if (host_err < 0)
+		goto out_nfserr;
+	*cnt = host_err;
+	nfsdstats.io_write += host_err;
+	fsnotify_modify(file->f_path.dentry);
 
 	/* clear setuid/setgid flag after write */
-	if (host_err >= 0 && (inode->i_mode & (S_ISUID | S_ISGID)))
+	if (inode->i_mode & (S_ISUID | S_ISGID))
 		kill_suid(dentry);
 
-	if (host_err >= 0 && stable) {
-		static ino_t	last_ino;
-		static dev_t	last_dev;
-
-		/*
-		 * Gathered writes: If another process is currently
-		 * writing to the file, there's a high chance
-		 * this is another nfsd (triggered by a bulk write
-		 * from a client's biod). Rather than syncing the
-		 * file with each write request, we sleep for 10 msec.
-		 *
-		 * I don't know if this roughly approximates
-		 * C. Juszak's idea of gathered writes, but it's a
-		 * nice and simple solution (IMHO), and it seems to
-		 * work:-)
-		 */
-		if (EX_WGATHER(exp)) {
-			if (atomic_read(&inode->i_writecount) > 1
-			    || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
-				dprintk("nfsd: write defer %d\n", task_pid_nr(current));
-				msleep(10);
-				dprintk("nfsd: write resume %d\n", task_pid_nr(current));
-			}
-
-			if (inode->i_state & I_DIRTY) {
-				dprintk("nfsd: write sync %d\n", task_pid_nr(current));
-				host_err=nfsd_sync(file);
-			}
-#if 0
-			wake_up(&inode->i_wait);
-#endif
-		}
-		last_ino = inode->i_ino;
-		last_dev = inode->i_sb->s_dev;
-	}
+	if (stable && use_wgather)
+		host_err = wait_for_concurrent_writes(file);
 
+out_nfserr:
 	dprintk("nfsd: write complete host_err=%d\n", host_err);
 	if (host_err >= 0)
 		err = 0;
@@ -2024,6 +2033,7 @@ nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
 					struct dentry *dentry, int acc)
 {
 	struct inode	*inode = dentry->d_inode;
+	struct path	path;
 	int		err;
 
 	if (acc == NFSD_MAY_NOP)
@@ -2096,7 +2106,17 @@ nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
 	if (err == -EACCES && S_ISREG(inode->i_mode) &&
 	    acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE))
 		err = inode_permission(inode, MAY_EXEC);
+	if (err)
+		goto nfsd_out;
 
+	/* Do integrity (permission) checking now, but defer incrementing
+	 * IMA counts to the actual file open.
+	 */
+	path.mnt = exp->ex_path.mnt;
+	path.dentry = dentry;
+	err = ima_path_check(&path, acc & (MAY_READ | MAY_WRITE | MAY_EXEC),
+			     IMA_COUNT_LEAVE);
+nfsd_out:
 	return err? nfserrno(err) : 0;
 }