Re: [PATCH] tmpfs 2/4 mknod times

Re: [PATCH] tmpfs 2/4 mknod times

[Ryan Cumming]

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On June 11, 2002 20:25, Hugh Dickins wrote:
> On Tue, 11 Jun 2002, Ryan Cumming wrote:
> > On June 11, 2002 19:54, Hugh Dickins wrote:
> > > +               dir->i_ctime = dir->i_mtime = CURRENT_TIME;
> >
> > I'm probably misreading this, but why does shmem_mknod modify the
> > directory's ctime?
>
> Hmmm, good question.  Perhaps I'll have dreamt up an answer by morning.
Well, lets see if the list has any ideas while you're sleeping.

- -Ryan
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Re: [PATCH] tmpfs 2/4 mknod times

[Jan Harkes]

On Tue, Jun 11, 2002 at 08:31:20PM -0700, Ryan Cumming wrote:
> On June 11, 2002 20:25, Hugh Dickins wrote:
> > On Tue, 11 Jun 2002, Ryan Cumming wrote:
> > > On June 11, 2002 19:54, Hugh Dickins wrote:
> > > > +               dir->i_ctime = dir->i_mtime = CURRENT_TIME;
> > >
> > > I'm probably misreading this, but why does shmem_mknod modify the
> > > directory's ctime?
> >
> > Hmmm, good question.  Perhaps I'll have dreamt up an answer by morning.
> Well, lets see if the list has any ideas while you're sleeping.

My guess would be that 'mtime' should be always updated because the
directory contents is changed (a new name is added). And 'ctime' has to
change whenever this new name cause a change in the size of the
directory because the i_size attribute has changed.

As tmpfs doesn't really have on-disk blocks for it's directories, every
create will change the directory size. (as well as every unlink).

Jan

[PATCH] tmpfs 1/4 symlink unwind

[Hugh Dickins]

shmem_symlink error path forgot to unwind.  The failed symlink left
over could be unlinked, but long ones were left on the shmem_inodes
list, causing oops in swapoff at shutdown if not earlier.

--- 2.4.19-pre10/mm/shmem.c	Tue Jun  4 13:54:20 2002
+++ linux/mm/shmem.c	Tue Jun 11 19:02:30 2002
@@ -1123,17 +1123,20 @@
 		return error;
 
 	len = strlen(symname) + 1;
-	if (len > PAGE_CACHE_SIZE)
-		return -ENAMETOOLONG;
-		
 	inode = dentry->d_inode;
 	info = SHMEM_I(inode);
 	inode->i_size = len-1;
+	inode->i_op = &shmem_symlink_inline_operations;
+
 	if (len <= sizeof(struct shmem_inode_info)) {
 		/* do it inline */
 		memcpy(info, symname, len);
-		inode->i_op = &shmem_symlink_inline_operations;
 	} else {
+		if (len > PAGE_CACHE_SIZE) {
+			error = -ENAMETOOLONG;
+			goto rmnod;
+		}
+		inode->i_op = &shmem_symlink_inode_operations;
 		spin_lock (&shmem_ilock);
 		list_add (&info->list, &shmem_inodes);
 		spin_unlock (&shmem_ilock);
@@ -1141,7 +1144,8 @@
 		page = shmem_getpage_locked(info, inode, 0);
 		if (IS_ERR(page)) {
 			up(&info->sem);
-			return PTR_ERR(page);
+			error = PTR_ERR(page);
+			goto rmnod;
 		}
 		kaddr = kmap(page);
 		memcpy(kaddr, symname, len);
@@ -1150,10 +1154,14 @@
 		UnlockPage(page);
 		page_cache_release(page);
 		up(&info->sem);
-		inode->i_op = &shmem_symlink_inode_operations;
 	}
 	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 	return 0;
+
+rmnod:
+	if (!shmem_unlink(dir, dentry))
+		d_delete(dentry);
+	return error;
 }
 
 static int shmem_readlink_inline(struct dentry *dentry, char *buffer, int buflen)

[PATCH] tmpfs 2/4 mknod times

[Hugh Dickins]

shmem_mknod should not update directory times if it cannot get an inode.

--- 2.4.19-pre10/mm/shmem.c	Tue Jun 11 19:02:30 2002
+++ linux/mm/shmem.c	Tue Jun 11 19:02:30 2002
@@ -987,8 +987,8 @@
 	struct inode * inode = shmem_get_inode(dir->i_sb, mode, dev);
 	int error = -ENOSPC;
 
-	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 	if (inode) {
+		dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 		d_instantiate(dentry, inode);
 		dget(dentry); /* Extra count - pin the dentry in core */
 		error = 0;