| Message ID | 20170517112107.31025-1-lhenriques@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> On 17 May 2017, at 19:21, Luis Henriques <lhenriques@suse.com> wrote: > > Converting a file handle to a dentry can be done call after the inode > unlink. This means that __fh_to_dentry() requires an extra check to > verify the number of links is not 0. > > The issue can be easily reproduced using xfstest generic/426, which does > something like: > > name_to_handle_at(&fh) > echo 3 > /proc/sys/vm/drop_caches > unlink() > open_by_handle_at(&fh) > > The call to open_by_handle_at() should fail, as the file doesn't exist > anymore. > > Cc: stable@vger.kernel.org > Link: http://tracker.ceph.com/issues/19958 > Signed-off-by: Luis Henriques <lhenriques@suse.com> > --- > fs/ceph/export.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/fs/ceph/export.c b/fs/ceph/export.c > index e8f11fa565c5..7df550c13d7f 100644 > --- a/fs/ceph/export.c > +++ b/fs/ceph/export.c > @@ -91,6 +91,10 @@ static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino) > ceph_mdsc_put_request(req); > if (!inode) > return ERR_PTR(-ESTALE); > + if (inode->i_nlink == 0) { > + iput(inode); > + return ERR_PTR(-ESTALE); > + } > } maybe we should do this check in MDS Regards Yan, Zheng > > return d_obtain_alias(inode); -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, May 18, 2017 at 09:36:44PM +0800, Yan, Zheng wrote: > > > On 17 May 2017, at 19:21, Luis Henriques <lhenriques@suse.com> wrote: > > > > Converting a file handle to a dentry can be done call after the inode > > unlink. This means that __fh_to_dentry() requires an extra check to > > verify the number of links is not 0. > > > > The issue can be easily reproduced using xfstest generic/426, which does > > something like: > > > > name_to_handle_at(&fh) > > echo 3 > /proc/sys/vm/drop_caches > > unlink() > > open_by_handle_at(&fh) > > > > The call to open_by_handle_at() should fail, as the file doesn't exist > > anymore. > > > > Cc: stable@vger.kernel.org > > Link: http://tracker.ceph.com/issues/19958 > > Signed-off-by: Luis Henriques <lhenriques@suse.com> > > --- > > fs/ceph/export.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/fs/ceph/export.c b/fs/ceph/export.c > > index e8f11fa565c5..7df550c13d7f 100644 > > --- a/fs/ceph/export.c > > +++ b/fs/ceph/export.c > > @@ -91,6 +91,10 @@ static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino) > > ceph_mdsc_put_request(req); > > if (!inode) > > return ERR_PTR(-ESTALE); > > + if (inode->i_nlink == 0) { > > + iput(inode); > > + return ERR_PTR(-ESTALE); > > + } > > } > > maybe we should do this check in MDS Thank you for your review. Are you suggesting to do this check *only* in the MDS? I guess that's probably a good thing to do too, but don't you think it's a good idea to keep it on the client side as well? Cheers, -- Luís -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> On 19 May 2017, at 00:48, Luis Henriques <lhenriques@suse.com> wrote: > > On Thu, May 18, 2017 at 09:36:44PM +0800, Yan, Zheng wrote: >> >>> On 17 May 2017, at 19:21, Luis Henriques <lhenriques@suse.com> wrote: >>> >>> Converting a file handle to a dentry can be done call after the inode >>> unlink. This means that __fh_to_dentry() requires an extra check to >>> verify the number of links is not 0. >>> >>> The issue can be easily reproduced using xfstest generic/426, which does >>> something like: >>> >>> name_to_handle_at(&fh) >>> echo 3 > /proc/sys/vm/drop_caches >>> unlink() >>> open_by_handle_at(&fh) >>> >>> The call to open_by_handle_at() should fail, as the file doesn't exist >>> anymore. >>> >>> Cc: stable@vger.kernel.org >>> Link: http://tracker.ceph.com/issues/19958 >>> Signed-off-by: Luis Henriques <lhenriques@suse.com> >>> --- >>> fs/ceph/export.c | 4 ++++ >>> 1 file changed, 4 insertions(+) >>> >>> diff --git a/fs/ceph/export.c b/fs/ceph/export.c >>> index e8f11fa565c5..7df550c13d7f 100644 >>> --- a/fs/ceph/export.c >>> +++ b/fs/ceph/export.c >>> @@ -91,6 +91,10 @@ static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino) >>> ceph_mdsc_put_request(req); >>> if (!inode) >>> return ERR_PTR(-ESTALE); >>> + if (inode->i_nlink == 0) { >>> + iput(inode); >>> + return ERR_PTR(-ESTALE); >>> + } >>> } >> >> maybe we should do this check in MDS > > Thank you for your review. Are you suggesting to do this check *only* in > the MDS? I guess that's probably a good thing to do too, but don't you > think it's a good idea to keep it on the client side as well? Applied. Thanks Yan, Zheng > > Cheers, > -- > Luís -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/ceph/export.c b/fs/ceph/export.c index e8f11fa565c5..7df550c13d7f 100644 --- a/fs/ceph/export.c +++ b/fs/ceph/export.c @@ -91,6 +91,10 @@ static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino) ceph_mdsc_put_request(req); if (!inode) return ERR_PTR(-ESTALE); + if (inode->i_nlink == 0) { + iput(inode); + return ERR_PTR(-ESTALE); + } } return d_obtain_alias(inode);
Converting a file handle to a dentry can be done call after the inode unlink. This means that __fh_to_dentry() requires an extra check to verify the number of links is not 0. The issue can be easily reproduced using xfstest generic/426, which does something like: name_to_handle_at(&fh) echo 3 > /proc/sys/vm/drop_caches unlink() open_by_handle_at(&fh) The call to open_by_handle_at() should fail, as the file doesn't exist anymore. Cc: stable@vger.kernel.org Link: http://tracker.ceph.com/issues/19958 Signed-off-by: Luis Henriques <lhenriques@suse.com> --- fs/ceph/export.c | 4 ++++ 1 file changed, 4 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html