diff mbox series

[3/4] xfs: allow setting xattrs on special files

Message ID 20240509151459.3622910-5-aalbersh@redhat.com (mailing list archive)
State Superseded, archived
Headers show
Series Introduce XFS_IOC_SETFSXATTRAT/XFS_IOC_GETFSXATTRAT ioctls | expand

Commit Message

Andrey Albershteyn May 9, 2024, 3:14 p.m. UTC
As XFS didn't have ioctls for special files setting an inode
extended attributes was rejected for them in xfs_fileattr_set().
Same applies for reading.

With XFS's project quota directories this is necessary. When project
is setup, xfs_quota opens and calls FS_IOC_SETFSXATTR on every inode
in the directory. However, special files are skipped due to open()
returning a special inode for them. So, they don't even get to this
check.

The further patch introduces XFS_IOC_SETFSXATTRAT which will call
xfs_fileattr_set/get() on a special file. This patch add handling of
setting xflags and project ID for special files.

Signed-off-by: Andrey Albershteyn <aalbersh@redhat.com>
---
 fs/xfs/xfs_ioctl.c | 96 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 92 insertions(+), 4 deletions(-)

Comments

Darrick J. Wong May 9, 2024, 11:34 p.m. UTC | #1
On Thu, May 09, 2024 at 05:14:59PM +0200, Andrey Albershteyn wrote:
> As XFS didn't have ioctls for special files setting an inode
> extended attributes was rejected for them in xfs_fileattr_set().
> Same applies for reading.
> 
> With XFS's project quota directories this is necessary. When project
> is setup, xfs_quota opens and calls FS_IOC_SETFSXATTR on every inode
> in the directory. However, special files are skipped due to open()
> returning a special inode for them. So, they don't even get to this
> check.
> 
> The further patch introduces XFS_IOC_SETFSXATTRAT which will call
> xfs_fileattr_set/get() on a special file. This patch add handling of
> setting xflags and project ID for special files.
> 
> Signed-off-by: Andrey Albershteyn <aalbersh@redhat.com>
> ---
>  fs/xfs/xfs_ioctl.c | 96 ++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 92 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index f0117188f302..515c9b4b862d 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -459,9 +459,6 @@ xfs_fileattr_get(
>  {
>  	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
>  
> -	if (d_is_special(dentry))
> -		return -ENOTTY;
> -
>  	xfs_ilock(ip, XFS_ILOCK_SHARED);
>  	xfs_fill_fsxattr(ip, XFS_DATA_FORK, fa);
>  	xfs_iunlock(ip, XFS_ILOCK_SHARED);
> @@ -721,6 +718,97 @@ xfs_ioctl_setattr_check_projid(
>  	return 0;
>  }
>  
> +static int
> +xfs_fileattr_spec_set(
> +	struct mnt_idmap	*idmap,
> +	struct dentry		*dentry,
> +	struct fileattr		*fa)
> +{
> +	struct xfs_inode *ip = XFS_I(d_inode(dentry));
> +	struct xfs_mount *mp = ip->i_mount;
> +	struct xfs_trans *tp;
> +	struct xfs_dquot *pdqp = NULL;
> +	struct xfs_dquot *olddquot = NULL;
> +	int error;
> +
> +	if (!fa->fsx_valid)
> +		return -EOPNOTSUPP;
> +
> +	if (fa->fsx_extsize ||
> +	    fa->fsx_nextents ||
> +	    fa->fsx_cowextsize)
> +		return -EOPNOTSUPP;
> +
> +	error = xfs_ioctl_setattr_check_projid(ip, fa);
> +	if (error)
> +		return error;
> +
> +	/*
> +	 * If disk quotas is on, we make sure that the dquots do exist on disk,
> +	 * before we start any other transactions. Trying to do this later
> +	 * is messy. We don't care to take a readlock to look at the ids
> +	 * in inode here, because we can't hold it across the trans_reserve.
> +	 * If the IDs do change before we take the ilock, we're covered
> +	 * because the i_*dquot fields will get updated anyway.
> +	 */
> +	if (fa->fsx_valid && XFS_IS_QUOTA_ON(mp)) {

Didn't we already check fsx_valid?

Also, what's different about the behavior of setxattr on special files
(vs. directories and regular files) such that we need a separate function?
Is it to disable the ability to set the extent size hints or the xflags?

--D

> +		error = xfs_qm_vop_dqalloc(ip, VFS_I(ip)->i_uid,
> +					   VFS_I(ip)->i_gid, fa->fsx_projid,
> +					   XFS_QMOPT_PQUOTA, NULL, NULL, &pdqp);
> +		if (error)
> +			return error;
> +	}
> +
> +	tp = xfs_ioctl_setattr_get_trans(ip, pdqp);
> +	if (IS_ERR(tp)) {
> +		error = PTR_ERR(tp);
> +		goto error_free_dquots;
> +	}
> +
> +	error = xfs_ioctl_setattr_xflags(tp, ip, fa);
> +	if (error)
> +		goto error_trans_cancel;
> +
> +	/*
> +	 * Change file ownership.  Must be the owner or privileged.  CAP_FSETID
> +	 * overrides the following restrictions:
> +	 *
> +	 * The set-user-ID and set-group-ID bits of a file will be cleared upon
> +	 * successful return from chown()
> +	 */
> +
> +	if ((VFS_I(ip)->i_mode & (S_ISUID | S_ISGID)) &&
> +	    !capable_wrt_inode_uidgid(idmap, VFS_I(ip), CAP_FSETID))
> +		VFS_I(ip)->i_mode &= ~(S_ISUID | S_ISGID);
> +
> +	/* Change the ownerships and register project quota modifications */
> +	if (ip->i_projid != fa->fsx_projid) {
> +		if (XFS_IS_PQUOTA_ON(mp)) {
> +			olddquot =
> +				xfs_qm_vop_chown(tp, ip, &ip->i_pdquot, pdqp);
> +		}
> +		ip->i_projid = fa->fsx_projid;
> +	}
> +
> +	error = xfs_trans_commit(tp);
> +
> +	/*
> +	 * Release any dquot(s) the inode had kept before chown.
> +	 */
> +	xfs_qm_dqrele(olddquot);
> +	xfs_qm_dqrele(pdqp);
> +
> +	return error;
> +
> +error_trans_cancel:
> +	xfs_trans_cancel(tp);
> +error_free_dquots:
> +	xfs_qm_dqrele(pdqp);
> +	return error;
> +
> +	return 0;
> +}
> +
>  int
>  xfs_fileattr_set(
>  	struct mnt_idmap	*idmap,
> @@ -737,7 +825,7 @@ xfs_fileattr_set(
>  	trace_xfs_ioctl_setattr(ip);
>  
>  	if (d_is_special(dentry))
> -		return -ENOTTY;
> +		return xfs_fileattr_spec_set(idmap, dentry, fa);
>  
>  	if (!fa->fsx_valid) {
>  		if (fa->flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL |
> -- 
> 2.42.0
> 
>
Andrey Albershteyn May 10, 2024, 9:46 a.m. UTC | #2
On 2024-05-09 16:34:06, Darrick J. Wong wrote:
> On Thu, May 09, 2024 at 05:14:59PM +0200, Andrey Albershteyn wrote:
> > As XFS didn't have ioctls for special files setting an inode
> > extended attributes was rejected for them in xfs_fileattr_set().
> > Same applies for reading.
> > 
> > With XFS's project quota directories this is necessary. When project
> > is setup, xfs_quota opens and calls FS_IOC_SETFSXATTR on every inode
> > in the directory. However, special files are skipped due to open()
> > returning a special inode for them. So, they don't even get to this
> > check.
> > 
> > The further patch introduces XFS_IOC_SETFSXATTRAT which will call
> > xfs_fileattr_set/get() on a special file. This patch add handling of
> > setting xflags and project ID for special files.
> > 
> > Signed-off-by: Andrey Albershteyn <aalbersh@redhat.com>
> > ---
> >  fs/xfs/xfs_ioctl.c | 96 ++++++++++++++++++++++++++++++++++++++++++++--
> >  1 file changed, 92 insertions(+), 4 deletions(-)
> > 
> > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> > index f0117188f302..515c9b4b862d 100644
> > --- a/fs/xfs/xfs_ioctl.c
> > +++ b/fs/xfs/xfs_ioctl.c
> > @@ -459,9 +459,6 @@ xfs_fileattr_get(
> >  {
> >  	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
> >  
> > -	if (d_is_special(dentry))
> > -		return -ENOTTY;
> > -
> >  	xfs_ilock(ip, XFS_ILOCK_SHARED);
> >  	xfs_fill_fsxattr(ip, XFS_DATA_FORK, fa);
> >  	xfs_iunlock(ip, XFS_ILOCK_SHARED);
> > @@ -721,6 +718,97 @@ xfs_ioctl_setattr_check_projid(
> >  	return 0;
> >  }
> >  
> > +static int
> > +xfs_fileattr_spec_set(
> > +	struct mnt_idmap	*idmap,
> > +	struct dentry		*dentry,
> > +	struct fileattr		*fa)
> > +{
> > +	struct xfs_inode *ip = XFS_I(d_inode(dentry));
> > +	struct xfs_mount *mp = ip->i_mount;
> > +	struct xfs_trans *tp;
> > +	struct xfs_dquot *pdqp = NULL;
> > +	struct xfs_dquot *olddquot = NULL;
> > +	int error;
> > +
> > +	if (!fa->fsx_valid)
> > +		return -EOPNOTSUPP;
> > +
> > +	if (fa->fsx_extsize ||
> > +	    fa->fsx_nextents ||
> > +	    fa->fsx_cowextsize)
> > +		return -EOPNOTSUPP;
> > +
> > +	error = xfs_ioctl_setattr_check_projid(ip, fa);
> > +	if (error)
> > +		return error;
> > +
> > +	/*
> > +	 * If disk quotas is on, we make sure that the dquots do exist on disk,
> > +	 * before we start any other transactions. Trying to do this later
> > +	 * is messy. We don't care to take a readlock to look at the ids
> > +	 * in inode here, because we can't hold it across the trans_reserve.
> > +	 * If the IDs do change before we take the ilock, we're covered
> > +	 * because the i_*dquot fields will get updated anyway.
> > +	 */
> > +	if (fa->fsx_valid && XFS_IS_QUOTA_ON(mp)) {
> 
> Didn't we already check fsx_valid?

oh, right

> 
> Also, what's different about the behavior of setxattr on special files
> (vs. directories and regular files) such that we need a separate function?
> Is it to disable the ability to set the extent size hints or the xflags?

yes, that's it, and the function looks a bit easier to follow for me
here

> 
> --D
> 
> > +		error = xfs_qm_vop_dqalloc(ip, VFS_I(ip)->i_uid,
> > +					   VFS_I(ip)->i_gid, fa->fsx_projid,
> > +					   XFS_QMOPT_PQUOTA, NULL, NULL, &pdqp);
> > +		if (error)
> > +			return error;
> > +	}
> > +
> > +	tp = xfs_ioctl_setattr_get_trans(ip, pdqp);
> > +	if (IS_ERR(tp)) {
> > +		error = PTR_ERR(tp);
> > +		goto error_free_dquots;
> > +	}
> > +
> > +	error = xfs_ioctl_setattr_xflags(tp, ip, fa);
> > +	if (error)
> > +		goto error_trans_cancel;
> > +
> > +	/*
> > +	 * Change file ownership.  Must be the owner or privileged.  CAP_FSETID
> > +	 * overrides the following restrictions:
> > +	 *
> > +	 * The set-user-ID and set-group-ID bits of a file will be cleared upon
> > +	 * successful return from chown()
> > +	 */
> > +
> > +	if ((VFS_I(ip)->i_mode & (S_ISUID | S_ISGID)) &&
> > +	    !capable_wrt_inode_uidgid(idmap, VFS_I(ip), CAP_FSETID))
> > +		VFS_I(ip)->i_mode &= ~(S_ISUID | S_ISGID);
> > +
> > +	/* Change the ownerships and register project quota modifications */
> > +	if (ip->i_projid != fa->fsx_projid) {
> > +		if (XFS_IS_PQUOTA_ON(mp)) {
> > +			olddquot =
> > +				xfs_qm_vop_chown(tp, ip, &ip->i_pdquot, pdqp);
> > +		}
> > +		ip->i_projid = fa->fsx_projid;
> > +	}
> > +
> > +	error = xfs_trans_commit(tp);
> > +
> > +	/*
> > +	 * Release any dquot(s) the inode had kept before chown.
> > +	 */
> > +	xfs_qm_dqrele(olddquot);
> > +	xfs_qm_dqrele(pdqp);
> > +
> > +	return error;
> > +
> > +error_trans_cancel:
> > +	xfs_trans_cancel(tp);
> > +error_free_dquots:
> > +	xfs_qm_dqrele(pdqp);
> > +	return error;
> > +
> > +	return 0;
> > +}
> > +
> >  int
> >  xfs_fileattr_set(
> >  	struct mnt_idmap	*idmap,
> > @@ -737,7 +825,7 @@ xfs_fileattr_set(
> >  	trace_xfs_ioctl_setattr(ip);
> >  
> >  	if (d_is_special(dentry))
> > -		return -ENOTTY;
> > +		return xfs_fileattr_spec_set(idmap, dentry, fa);
> >  
> >  	if (!fa->fsx_valid) {
> >  		if (fa->flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL |
> > -- 
> > 2.42.0
> > 
> > 
>
diff mbox series

Patch

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index f0117188f302..515c9b4b862d 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -459,9 +459,6 @@  xfs_fileattr_get(
 {
 	struct xfs_inode	*ip = XFS_I(d_inode(dentry));
 
-	if (d_is_special(dentry))
-		return -ENOTTY;
-
 	xfs_ilock(ip, XFS_ILOCK_SHARED);
 	xfs_fill_fsxattr(ip, XFS_DATA_FORK, fa);
 	xfs_iunlock(ip, XFS_ILOCK_SHARED);
@@ -721,6 +718,97 @@  xfs_ioctl_setattr_check_projid(
 	return 0;
 }
 
+static int
+xfs_fileattr_spec_set(
+	struct mnt_idmap	*idmap,
+	struct dentry		*dentry,
+	struct fileattr		*fa)
+{
+	struct xfs_inode *ip = XFS_I(d_inode(dentry));
+	struct xfs_mount *mp = ip->i_mount;
+	struct xfs_trans *tp;
+	struct xfs_dquot *pdqp = NULL;
+	struct xfs_dquot *olddquot = NULL;
+	int error;
+
+	if (!fa->fsx_valid)
+		return -EOPNOTSUPP;
+
+	if (fa->fsx_extsize ||
+	    fa->fsx_nextents ||
+	    fa->fsx_cowextsize)
+		return -EOPNOTSUPP;
+
+	error = xfs_ioctl_setattr_check_projid(ip, fa);
+	if (error)
+		return error;
+
+	/*
+	 * If disk quotas is on, we make sure that the dquots do exist on disk,
+	 * before we start any other transactions. Trying to do this later
+	 * is messy. We don't care to take a readlock to look at the ids
+	 * in inode here, because we can't hold it across the trans_reserve.
+	 * If the IDs do change before we take the ilock, we're covered
+	 * because the i_*dquot fields will get updated anyway.
+	 */
+	if (fa->fsx_valid && XFS_IS_QUOTA_ON(mp)) {
+		error = xfs_qm_vop_dqalloc(ip, VFS_I(ip)->i_uid,
+					   VFS_I(ip)->i_gid, fa->fsx_projid,
+					   XFS_QMOPT_PQUOTA, NULL, NULL, &pdqp);
+		if (error)
+			return error;
+	}
+
+	tp = xfs_ioctl_setattr_get_trans(ip, pdqp);
+	if (IS_ERR(tp)) {
+		error = PTR_ERR(tp);
+		goto error_free_dquots;
+	}
+
+	error = xfs_ioctl_setattr_xflags(tp, ip, fa);
+	if (error)
+		goto error_trans_cancel;
+
+	/*
+	 * Change file ownership.  Must be the owner or privileged.  CAP_FSETID
+	 * overrides the following restrictions:
+	 *
+	 * The set-user-ID and set-group-ID bits of a file will be cleared upon
+	 * successful return from chown()
+	 */
+
+	if ((VFS_I(ip)->i_mode & (S_ISUID | S_ISGID)) &&
+	    !capable_wrt_inode_uidgid(idmap, VFS_I(ip), CAP_FSETID))
+		VFS_I(ip)->i_mode &= ~(S_ISUID | S_ISGID);
+
+	/* Change the ownerships and register project quota modifications */
+	if (ip->i_projid != fa->fsx_projid) {
+		if (XFS_IS_PQUOTA_ON(mp)) {
+			olddquot =
+				xfs_qm_vop_chown(tp, ip, &ip->i_pdquot, pdqp);
+		}
+		ip->i_projid = fa->fsx_projid;
+	}
+
+	error = xfs_trans_commit(tp);
+
+	/*
+	 * Release any dquot(s) the inode had kept before chown.
+	 */
+	xfs_qm_dqrele(olddquot);
+	xfs_qm_dqrele(pdqp);
+
+	return error;
+
+error_trans_cancel:
+	xfs_trans_cancel(tp);
+error_free_dquots:
+	xfs_qm_dqrele(pdqp);
+	return error;
+
+	return 0;
+}
+
 int
 xfs_fileattr_set(
 	struct mnt_idmap	*idmap,
@@ -737,7 +825,7 @@  xfs_fileattr_set(
 	trace_xfs_ioctl_setattr(ip);
 
 	if (d_is_special(dentry))
-		return -ENOTTY;
+		return xfs_fileattr_spec_set(idmap, dentry, fa);
 
 	if (!fa->fsx_valid) {
 		if (fa->flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL |