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SubjectRe: [PATCH] UDF: check for allocated memory for inode data
On Thu, May 10, 2007 at 03:46:40PM -0700, Andrew Morton wrote:
> On Thu, 10 May 2007 18:00:00 +0400
> Cyrill Gorcunov <gorcunov@gmail.com> wrote:
>
> > This patch adds cheking for granted memory while
> > filling up inode data to prevent possible NULL
> > pointer usage. If there is not enough memory to
> > fill inode data we just mark it as "bad".
> >
> > Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
> >
> > Please check the patch, maybe just marking inode as
> > "bad" is not a good solution.
> >
>
> yes, make_bad_inode() is appropriate here.
>
> >
> > diff --git a/fs/udf/inode.c b/fs/udf/inode.c
> > index c846155..91cddae 100644
> > --- a/fs/udf/inode.c
> > +++ b/fs/udf/inode.c
> > @@ -1144,6 +1144,13 @@ static void udf_fill_inode(struct inode *inode, struct buffer_head *bh)
> > UDF_I_EFE(inode) = 1;
> > UDF_I_USE(inode) = 0;
> > UDF_I_DATA(inode) = kmalloc(inode->i_sb->s_blocksize - sizeof(struct extendedFileEntry), GFP_KERNEL);
> > + if (!UDF_I_DATA(inode))
> > + {
> > + printk(KERN_ERR "udf: udf_fill_inode(ino %ld) no free memory\n",
> > + inode->i_ino);
> > + make_bad_inode(inode);
> > + return;
> > + }
>
> But please let's not add three copies of identical code. Do something like:
>
> static int udf_check_inode(struct inode *inode)
> {
> if (!UDF_I_DATA(inode)) {
> printk(KERN_ERR "udf: udf_fill_inode(ino %ld) no free memory\n",
> inode->i_ino);
> make_bad_inode(inode);
> return -1;
> }
> return 0;
> }
>
>
> if (udf_check_inode(inode))
> return;
>
> In fact you can also do the kmalloc in that helper function too:
>
> static int udf_alloc_i_data(struct inode *inode, size_t size)
> {
> UDF_I_DATA(inode) = kmalloc(...);
> ...
> }

And please get rid of the UDF_I_* macro for everything you touch, just
put a

struct udf_inode_info *uip = UDF_I(inode);

at the beginning of the function and use the fields directly.
-
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