lkml.org 
[lkml]   [2013]   [Sep]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH][RFC] Fix breakage in ffs_fs_mount()
Date
On Fri, Sep 20 2013, Al Viro wrote:
> There's a bunch of failure exits in ffs_fs_mount() with
> seriously broken recovery logics. Most of that appears to stem
> from misunderstanding of the ->kill_sb() semantics;

That sounds likely.

[…]

> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Acked-by: Michal Nazarewicz <mina86@mina86.com>

> --
> diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
> index 1a66c5b..0658908 100644
> --- a/drivers/usb/gadget/f_fs.c
> +++ b/drivers/usb/gadget/f_fs.c
> @@ -1034,37 +1034,19 @@ struct ffs_sb_fill_data {
> struct ffs_file_perms perms;
> umode_t root_mode;
> const char *dev_name;
> - union {
> - /* set by ffs_fs_mount(), read by ffs_sb_fill() */
> - void *private_data;
> - /* set by ffs_sb_fill(), read by ffs_fs_mount */
> - struct ffs_data *ffs_data;
> - };
> + struct ffs_data *ffs_data;
> };
>
> static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
> {
> struct ffs_sb_fill_data *data = _data;
> struct inode *inode;
> - struct ffs_data *ffs;
> + struct ffs_data *ffs = data->ffs_data;
>
> ENTER();
>
> - /* Initialise data */
> - ffs = ffs_data_new();
> - if (unlikely(!ffs))
> - goto Enomem;
> -
> ffs->sb = sb;
> - ffs->dev_name = kstrdup(data->dev_name, GFP_KERNEL);
> - if (unlikely(!ffs->dev_name))
> - goto Enomem;
> - ffs->file_perms = data->perms;
> - ffs->private_data = data->private_data;
> -
> - /* used by the caller of this function */
> - data->ffs_data = ffs;
> -
> + data->ffs_data = NULL;
> sb->s_fs_info = ffs;
> sb->s_blocksize = PAGE_CACHE_SIZE;
> sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
> @@ -1080,17 +1062,14 @@ static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
> &data->perms);
> sb->s_root = d_make_root(inode);
> if (unlikely(!sb->s_root))
> - goto Enomem;
> + return -ENOMEM;
>
> /* EP0 file */
> if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
> &ffs_ep0_operations, NULL)))
> - goto Enomem;
> + return -ENOMEM;
>
> return 0;
> -
> -Enomem:
> - return -ENOMEM;
> }
>
> static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
> @@ -1193,6 +1172,7 @@ ffs_fs_mount(struct file_system_type *t, int flags,
> struct dentry *rv;
> int ret;
> void *ffs_dev;
> + struct ffs_data *ffs;
>
> ENTER();
>
> @@ -1200,18 +1180,30 @@ ffs_fs_mount(struct file_system_type *t, int flags,
> if (unlikely(ret < 0))
> return ERR_PTR(ret);
>
> + ffs = ffs_data_new();
> + if (unlikely(!ffs))
> + return ERR_PTR(-ENOMEM);
> + ffs->file_perms = data.perms;
> +
> + ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
> + if (unlikely(!ffs->dev_name)) {
> + ffs_data_put(ffs);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> ffs_dev = functionfs_acquire_dev_callback(dev_name);
> - if (IS_ERR(ffs_dev))
> - return ffs_dev;
> + if (IS_ERR(ffs_dev)) {
> + ffs_data_put(ffs);
> + return ERR_CAST(ffs_dev);
> + }
> + ffs->private_data = ffs_dev;
> + data.ffs_data = ffs;
>
> - data.dev_name = dev_name;
> - data.private_data = ffs_dev;
> rv = mount_nodev(t, flags, &data, ffs_sb_fill);
> -
> - /* data.ffs_data is set by ffs_sb_fill */
> - if (IS_ERR(rv))
> + if (IS_ERR(rv) && data.ffs_data) {
> functionfs_release_dev_callback(data.ffs_data);
> -
> + ffs_data_put(data.ffs_data);
> + }
> return rv;
> }
>

--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał “mina86” Nazarewicz (o o)
ooo +--<mpn@google.com>--<xmpp:mina86@jabber.org>--ooO--(_)--Ooo--
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2013-09-21 01:41    [W:0.043 / U:7.716 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site