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nfsd: make V4ROOT exports read-only
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I can't see any use for writeable V4ROOT exports.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
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J. Bruce Fields committed Dec 15, 2009
1 parent 03a816b commit 774b147
Showing 1 changed file with 11 additions and 4 deletions.
15 changes: 11 additions & 4 deletions fs/nfsd/export.c
Original file line number Diff line number Diff line change
Expand Up @@ -355,7 +355,7 @@ static struct svc_export *svc_export_update(struct svc_export *new,
struct svc_export *old);
static struct svc_export *svc_export_lookup(struct svc_export *);

static int check_export(struct inode *inode, int flags, unsigned char *uuid)
static int check_export(struct inode *inode, int *flags, unsigned char *uuid)
{

/*
Expand All @@ -367,6 +367,13 @@ static int check_export(struct inode *inode, int flags, unsigned char *uuid)
!S_ISREG(inode->i_mode))
return -ENOTDIR;

/*
* Mountd should never pass down a writeable V4ROOT export, but,
* just to make sure:
*/
if (*flags & NFSEXP_V4ROOT)
*flags |= NFSEXP_READONLY;

/* There are two requirements on a filesystem to be exportable.
* 1: We must be able to identify the filesystem from a number.
* either a device number (so FS_REQUIRES_DEV needed)
Expand All @@ -375,7 +382,7 @@ static int check_export(struct inode *inode, int flags, unsigned char *uuid)
* This means that s_export_op must be set.
*/
if (!(inode->i_sb->s_type->fs_flags & FS_REQUIRES_DEV) &&
!(flags & NFSEXP_FSID) &&
!(*flags & NFSEXP_FSID) &&
uuid == NULL) {
dprintk("exp_export: export of non-dev fs without fsid\n");
return -EINVAL;
Expand Down Expand Up @@ -590,7 +597,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
goto out4;
}

err = check_export(exp.ex_path.dentry->d_inode, exp.ex_flags,
err = check_export(exp.ex_path.dentry->d_inode, &exp.ex_flags,
exp.ex_uuid);
if (err)
goto out4;
Expand Down Expand Up @@ -1029,7 +1036,7 @@ exp_export(struct nfsctl_export *nxp)
goto finish;
}

err = check_export(path.dentry->d_inode, nxp->ex_flags, NULL);
err = check_export(path.dentry->d_inode, &nxp->ex_flags, NULL);
if (err) goto finish;

err = -ENOMEM;
Expand Down

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