| Message ID | 20200518174726.GA84496@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] ceph: don't return -ESTALE if there's still an open file | expand |
On Mon, May 18, 2020 at 8:47 PM Luis Henriques <lhenriques@suse.com> wrote: > > Similarly to commit 03f219041fdb ("ceph: check i_nlink while converting > a file handle to dentry"), this fixes another corner case with > name_to_handle_at/open_by_handle_at. The issue has been detected by > xfstest generic/467, when doing: > > - name_to_handle_at("/cephfs/myfile") > - open("/cephfs/myfile") > - unlink("/cephfs/myfile") > - sync; sync; > - drop caches > - open_by_handle_at() > > The call to open_by_handle_at should not fail because the file hasn't been > deleted yet (only unlinked) and we do have a valid handle to it. -ESTALE > shall be returned only if i_nlink is 0 *and* i_count is 1. > > This patch also makes sure we have LINK caps before checking i_nlink. > > Signed-off-by: Luis Henriques <lhenriques@suse.com> > --- > Hi! > > (and sorry for the delay in my reply!) > > So, from the discussion thread and some IRC chat with Jeff, I'm sending > v2. What changed? Everything! :-) > > - Use i_count instead of __ceph_is_file_opened to check for open files > - Add call to ceph_do_getattr to make sure we have LINK caps before > accessing i_nlink > > Cheers, > -- > Luis Acked-by: Amir Goldstein <amir73il@gmail.com> Thanks, Amir.
On Mon, 2020-05-18 at 18:47 +0100, Luis Henriques wrote: > Similarly to commit 03f219041fdb ("ceph: check i_nlink while converting > a file handle to dentry"), this fixes another corner case with > name_to_handle_at/open_by_handle_at. The issue has been detected by > xfstest generic/467, when doing: > > - name_to_handle_at("/cephfs/myfile") > - open("/cephfs/myfile") > - unlink("/cephfs/myfile") > - sync; sync; > - drop caches > - open_by_handle_at() > > The call to open_by_handle_at should not fail because the file hasn't been > deleted yet (only unlinked) and we do have a valid handle to it. -ESTALE > shall be returned only if i_nlink is 0 *and* i_count is 1. > > This patch also makes sure we have LINK caps before checking i_nlink. > > Signed-off-by: Luis Henriques <lhenriques@suse.com> > --- > Hi! > > (and sorry for the delay in my reply!) > > So, from the discussion thread and some IRC chat with Jeff, I'm sending > v2. What changed? Everything! :-) > > - Use i_count instead of __ceph_is_file_opened to check for open files > - Add call to ceph_do_getattr to make sure we have LINK caps before > accessing i_nlink > > Cheers, > -- > Luis > > fs/ceph/export.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/fs/ceph/export.c b/fs/ceph/export.c > index 79dc06881e78..e088843a7734 100644 > --- a/fs/ceph/export.c > +++ b/fs/ceph/export.c > @@ -172,9 +172,16 @@ struct inode *ceph_lookup_inode(struct super_block *sb, u64 ino) > static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino) > { > struct inode *inode = __lookup_inode(sb, ino); > + int err; > + > if (IS_ERR(inode)) > return ERR_CAST(inode); > - if (inode->i_nlink == 0) { > + /* We need LINK caps to reliably check i_nlink */ > + err = ceph_do_getattr(inode, CEPH_CAP_LINK_SHARED, false); > + if (err) > + return ERR_PTR(err); > + /* -ESTALE if inode as been unlinked and no file is open */ > + if ((inode->i_nlink == 0) && (atomic_read(&inode->i_count) == 1)) { > iput(inode); > return ERR_PTR(-ESTALE); > } > Looks good. Merged into testing branch. Thanks!
diff --git a/fs/ceph/export.c b/fs/ceph/export.c index 79dc06881e78..e088843a7734 100644 --- a/fs/ceph/export.c +++ b/fs/ceph/export.c @@ -172,9 +172,16 @@ struct inode *ceph_lookup_inode(struct super_block *sb, u64 ino) static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino) { struct inode *inode = __lookup_inode(sb, ino); + int err; + if (IS_ERR(inode)) return ERR_CAST(inode); - if (inode->i_nlink == 0) { + /* We need LINK caps to reliably check i_nlink */ + err = ceph_do_getattr(inode, CEPH_CAP_LINK_SHARED, false); + if (err) + return ERR_PTR(err); + /* -ESTALE if inode as been unlinked and no file is open */ + if ((inode->i_nlink == 0) && (atomic_read(&inode->i_count) == 1)) { iput(inode); return ERR_PTR(-ESTALE); }
Similarly to commit 03f219041fdb ("ceph: check i_nlink while converting a file handle to dentry"), this fixes another corner case with name_to_handle_at/open_by_handle_at. The issue has been detected by xfstest generic/467, when doing: - name_to_handle_at("/cephfs/myfile") - open("/cephfs/myfile") - unlink("/cephfs/myfile") - sync; sync; - drop caches - open_by_handle_at() The call to open_by_handle_at should not fail because the file hasn't been deleted yet (only unlinked) and we do have a valid handle to it. -ESTALE shall be returned only if i_nlink is 0 *and* i_count is 1. This patch also makes sure we have LINK caps before checking i_nlink. Signed-off-by: Luis Henriques <lhenriques@suse.com> --- Hi! (and sorry for the delay in my reply!) So, from the discussion thread and some IRC chat with Jeff, I'm sending v2. What changed? Everything! :-) - Use i_count instead of __ceph_is_file_opened to check for open files - Add call to ceph_do_getattr to make sure we have LINK caps before accessing i_nlink Cheers, -- Luis fs/ceph/export.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)