This is a note to let you know that I've just added the patch titled
nfs: don't allow reexport reclaims
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfs-don-t-allow-reexport-reclaims.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b012c492a25db8ab031497c0da3ef1341f142285
Author: J. Bruce Fields <bfields@xxxxxxxxxxxx>
Date: Fri Aug 20 17:02:06 2021 -0400
nfs: don't allow reexport reclaims
[ Upstream commit bb0a55bb7148a49e549ee992200860e7a040d3a5 ]
In the reexport case, nfsd is currently passing along locks with the
reclaim bit set. The client sends a new lock request, which is granted
if there's currently no conflict--even if it's possible a conflicting
lock could have been briefly held in the interim.
We don't currently have any way to safely grant reclaim, so for now
let's just deny them all.
I'm doing this by passing the reclaim bit to nfs and letting it fail the
call, with the idea that eventually the client might be able to do
something more forgiving here.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Acked-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 7be1a7f7fcb2a..d35aae47b062b 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -798,6 +798,9 @@ int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
nfs_inc_stats(inode, NFSIOS_VFSLOCK);
+ if (fl->fl_flags & FL_RECLAIM)
+ return -ENOGRACE;
+
/* No mandatory locks over NFS */
if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
goto out_err;
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index fd3bdf0bf0052..e9ac77c28741e 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -6946,6 +6946,9 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
if (!locks_in_grace(net) && lock->lk_reclaim)
goto out;
+ if (lock->lk_reclaim)
+ fl_flags |= FL_RECLAIM;
+
fp = lock_stp->st_stid.sc_file;
switch (lock->lk_type) {
case NFS4_READW_LT:
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 72f8bc4a7ea48..78bdfdc253fd3 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -881,6 +881,7 @@ nfserrno (int errno)
{ nfserr_serverfault, -ENFILE },
{ nfserr_io, -EUCLEAN },
{ nfserr_perm, -ENOKEY },
+ { nfserr_no_grace, -ENOGRACE},
};
int i;
diff --git a/include/linux/errno.h b/include/linux/errno.h
index d73f597a24849..8b0c754bab025 100644
--- a/include/linux/errno.h
+++ b/include/linux/errno.h
@@ -31,5 +31,6 @@
#define EJUKEBOX 528 /* Request initiated, but will not complete before timeout */
#define EIOCBQUEUED 529 /* iocb queued, will get completion event */
#define ERECALLCONFLICT 530 /* conflict with recalled state */
+#define ENOGRACE 531 /* NFS file lock reclaim refused */
#endif
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a9ac60d3be1d6..c0459446e1440 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -996,6 +996,7 @@ static inline struct file *get_file(struct file *f)
#define FL_UNLOCK_PENDING 512 /* Lease is being broken */
#define FL_OFDLCK 1024 /* lock is "owned" by struct file */
#define FL_LAYOUT 2048 /* outstanding pNFS layout */
+#define FL_RECLAIM 4096 /* reclaiming from a reboot server */
#define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE)
