Re: nfs MAP_SHARED corruption fix

From: Trond Myklebust (trond.myklebust@fys.uio.no)
Date: Wed May 09 2001 - 02:30:18 EST


In addition to the two changes I proposed to Andrea's new patch, I
also realized we might want to do a fdatasync() when locking files. If
we don't, then locking won't be atomic on mmap()...

Here therefore is Andrea's patch with the changes I propose. Opinions?

Cheers,
  Trond

diff -u --recursive --new-file linux-2.4.4-fixes/fs/nfs/file.c linux-2.4.4-mmap/fs/nfs/file.c
--- linux-2.4.4/fs/nfs/file.c Fri Feb 9 20:29:44 2001
+++ linux-2.4.4-mmap/fs/nfs/file.c Wed May 9 09:18:45 2001
@@ -39,6 +39,7 @@
 static ssize_t nfs_file_write(struct file *, const char *, size_t, loff_t *);
 static int nfs_file_flush(struct file *);
 static int nfs_fsync(struct file *, struct dentry *dentry, int datasync);
+static void nfs_file_close_vma(struct vm_area_struct *);
 
 struct file_operations nfs_file_operations = {
         read: nfs_file_read,
@@ -57,6 +58,11 @@
         setattr: nfs_notify_change,
 };
 
+static struct vm_operations_struct nfs_file_vm_ops = {
+ nopage: filemap_nopage,
+ close: nfs_file_close_vma,
+};
+
 /* Hack for future NFS swap support */
 #ifndef IS_SWAPFILE
 # define IS_SWAPFILE(inode) (0)
@@ -104,6 +110,20 @@
         return result;
 }
 
+static void nfs_file_close_vma(struct vm_area_struct * vma)
+{
+ struct inode * inode;
+
+ inode = vma->vm_file->f_dentry->d_inode;
+
+ if (inode->i_state & I_DIRTY_PAGES) {
+ down(&inode->i_sem);
+ filemap_fdatasync(inode->i_mapping);
+ nfs_wb_all(inode);
+ up(&inode->i_sem);
+ }
+}
+
 static int
 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
 {
@@ -115,8 +135,11 @@
                 dentry->d_parent->d_name.name, dentry->d_name.name);
 
         status = nfs_revalidate_inode(NFS_SERVER(inode), inode);
- if (!status)
+ if (!status) {
                 status = generic_file_mmap(file, vma);
+ if (!status)
+ vma->vm_ops = &nfs_file_vm_ops;
+ }
         return status;
 }
 
@@ -283,9 +306,10 @@
          * Flush all pending writes before doing anything
          * with locks..
          */
- down(&filp->f_dentry->d_inode->i_sem);
+ down(&inode->i_sem);
+ filemap_fdatasync(inode->i_mapping);
         status = nfs_wb_all(inode);
- up(&filp->f_dentry->d_inode->i_sem);
+ up(&inode->i_sem);
         if (status < 0)
                 return status;
 
@@ -300,10 +324,11 @@
          */
  out_ok:
         if ((cmd == F_SETLK || cmd == F_SETLKW) && fl->fl_type != F_UNLCK) {
- down(&filp->f_dentry->d_inode->i_sem);
+ down(&inode->i_sem);
+ filemap_fdatasync(inode->i_mapping);
                 nfs_wb_all(inode); /* we may have slept */
                 nfs_zap_caches(inode);
- up(&filp->f_dentry->d_inode->i_sem);
+ up(&inode->i_sem);
         }
         return status;
 }
-
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This archive was generated by hypermail 2b29 : Tue May 15 2001 - 21:00:15 EST