From 2c56547272e43b483d560a61692f1e24926a82fb Mon Sep 17 00:00:00 2001
From: Robert Morris <rtm@csail.mit.edu>
Date: Mon, 4 Aug 2014 13:06:48 -0400
Subject: every iput() and namei() must be inside a transaction

---
 sysfile.c | 35 ++++++++++++++++++++++++++---------
 1 file changed, 26 insertions(+), 9 deletions(-)

(limited to 'sysfile.c')

diff --git a/sysfile.c b/sysfile.c
index 64f2b33..095fca7 100644
--- a/sysfile.c
+++ b/sysfile.c
@@ -120,10 +120,12 @@ sys_link(void)
 
   if(argstr(0, &old) < 0 || argstr(1, &new) < 0)
     return -1;
-  if((ip = namei(old)) == 0)
-    return -1;
 
   begin_trans();
+  if((ip = namei(old)) == 0){
+    commit_trans();
+    return -1;
+  }
 
   ilock(ip);
   if(ip->type == T_DIR){
@@ -186,10 +188,12 @@ sys_unlink(void)
 
   if(argstr(0, &path) < 0)
     return -1;
-  if((dp = nameiparent(path, name)) == 0)
-    return -1;
 
   begin_trans();
+  if((dp = nameiparent(path, name)) == 0){
+    commit_trans();
+    return -1;
+  }
 
   ilock(dp);
 
@@ -286,18 +290,24 @@ sys_open(void)
 
   if(argstr(0, &path) < 0 || argint(1, &omode) < 0)
     return -1;
+
+  begin_trans();
+
   if(omode & O_CREATE){
-    begin_trans();
     ip = create(path, T_FILE, 0, 0);
-    commit_trans();
-    if(ip == 0)
+    if(ip == 0){
+      commit_trans();
       return -1;
+    }
   } else {
-    if((ip = namei(path)) == 0)
+    if((ip = namei(path)) == 0){
+      commit_trans();
       return -1;
+    }
     ilock(ip);
     if(ip->type == T_DIR && omode != O_RDONLY){
       iunlockput(ip);
+      commit_trans();
       return -1;
     }
   }
@@ -306,9 +316,11 @@ sys_open(void)
     if(f)
       fileclose(f);
     iunlockput(ip);
+    commit_trans();
     return -1;
   }
   iunlock(ip);
+  commit_trans();
 
   f->type = FD_INODE;
   f->ip = ip;
@@ -361,15 +373,20 @@ sys_chdir(void)
   char *path;
   struct inode *ip;
 
-  if(argstr(0, &path) < 0 || (ip = namei(path)) == 0)
+  begin_trans();
+  if(argstr(0, &path) < 0 || (ip = namei(path)) == 0){
+    commit_trans();
     return -1;
+  }
   ilock(ip);
   if(ip->type != T_DIR){
     iunlockput(ip);
+    commit_trans();
     return -1;
   }
   iunlock(ip);
   iput(proc->cwd);
+  commit_trans();
   proc->cwd = ip;
   return 0;
 }
-- 
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