CIFS: Respect epoch value from create lease context v2

that force a client to purge cache pages when a server requests it.

Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>

6 files changed, 71 insertions, 17 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index ab88efe014a5..a16b4e58bcc6 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -255,6 +255,7 @@ cifs_alloc_inode(struct super_block *sb)
         cifs_inode->server_eof = 0;
         cifs_inode->uniqueid = 0;
         cifs_inode->createtime = 0;
+        cifs_inode->epoch = 0;
 #ifdef CONFIG_CIFS_SMB2
         get_random_bytes(cifs_inode->lease_key, SMB2_LEASE_KEY_SIZE);
 #endif
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 38118938f0b6..cfa14c80ef3b 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -373,11 +373,12 @@ struct smb_version_operations {
         /* if we can do cache read operations */
         bool (*is_read_op)(__u32);
         /* set oplock level for the inode */
-        void (*set_oplock_level)(struct cifsInodeInfo *, __u32);
+        void (*set_oplock_level)(struct cifsInodeInfo *, __u32, unsigned int,
+                                 bool *);
         /* create lease context buffer for CREATE request */
         char * (*create_lease_buf)(u8 *, u8);
-        /* parse lease context buffer and return oplock info */
-        __u8 (*parse_lease_buf)(void *);
+        /* parse lease context buffer and return oplock/epoch info */
+        __u8 (*parse_lease_buf)(void *, unsigned int *);
 };
 
 struct smb_version_values {
@@ -940,6 +941,8 @@ struct cifs_fid {
         __u8 lease_key[SMB2_LEASE_KEY_SIZE];    /* lease key for smb2 */
 #endif
         struct cifs_pending_open *pending_open;
+        unsigned int epoch;
+        bool purge_cache;
 };
 
 struct cifs_fid_locks {
@@ -1039,7 +1042,10 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file);
 
 #define CIFS_CACHE_READ_FLG     1
 #define CIFS_CACHE_HANDLE_FLG   2
+#define CIFS_CACHE_RH_FLG       (CIFS_CACHE_READ_FLG | CIFS_CACHE_HANDLE_FLG)
 #define CIFS_CACHE_WRITE_FLG    4
+#define CIFS_CACHE_RW_FLG       (CIFS_CACHE_READ_FLG | CIFS_CACHE_WRITE_FLG)
+#define CIFS_CACHE_RHW_FLG      (CIFS_CACHE_RW_FLG | CIFS_CACHE_HANDLE_FLG)
 
 #define CIFS_CACHE_READ(cinode) (cinode->oplock & CIFS_CACHE_READ_FLG)
 #define CIFS_CACHE_HANDLE(cinode) (cinode->oplock & CIFS_CACHE_HANDLE_FLG)
@@ -1057,6 +1063,7 @@ struct cifsInodeInfo {
         struct list_head openFileList;
         __u32 cifsAttrs; /* e.g. DOS archive bit, sparse, compressed, system */
         unsigned int oplock;            /* oplock/lease level we have */
+        unsigned int epoch;             /* used to track lease state changes */
         bool delete_pending;            /* DELETE_ON_CLOSE is set */
         bool invalid_mapping;           /* pagecache is invalid */
         unsigned long time;             /* jiffies of last update of inode */
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 188b2470b1fb..d044b35ce228 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -323,6 +323,7 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
                 oplock = fid->pending_open->oplock;
         list_del(&fid->pending_open->olist);
 
+        fid->purge_cache = false;
         server->ops->set_fid(cfile, fid, oplock);
 
         list_add(&cfile->tlist, &tcon->openFileList);
@@ -333,6 +334,9 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
                 list_add_tail(&cfile->flist, &cinode->openFileList);
         spin_unlock(&cifs_file_list_lock);
 
+        if (fid->purge_cache)
+                cifs_invalidate_mapping(inode);
+
         file->private_data = cfile;
         return cfile;
 }
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index 4aa59b34ec23..fb3966265b6e 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -420,6 +420,7 @@ smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp,
         __u8 lease_state;
         struct list_head *tmp;
         struct cifsFileInfo *cfile;
+        struct TCP_Server_Info *server = tcon->ses->server;
         struct cifs_pending_open *open;
         struct cifsInodeInfo *cinode;
         int ack_req = le32_to_cpu(rsp->Flags &
@@ -439,7 +440,7 @@ smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp,
                 cifs_dbg(FYI, "lease key match, lease break 0x%d\n",
                          le32_to_cpu(rsp->NewLeaseState));
 
-                tcon->ses->server->ops->set_oplock_level(cinode, lease_state);
+                server->ops->set_oplock_level(cinode, lease_state, 0, NULL);
 
                 if (ack_req)
                         cfile->oplock_break_cancelled = false;
@@ -575,7 +576,8 @@ smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
                                         cfile->oplock_break_cancelled = false;
 
                                 server->ops->set_oplock_level(cinode,
-                                  rsp->OplockLevel ? SMB2_OPLOCK_LEVEL_II : 0);
+                                  rsp->OplockLevel ? SMB2_OPLOCK_LEVEL_II : 0,
+                                  0, NULL);
 
                                 queue_work(cifsiod_wq, &cfile->oplock_break);
 
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index a9256bd374f8..861b33214144 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -381,7 +381,8 @@ smb2_set_fid(struct cifsFileInfo *cfile, struct cifs_fid *fid, __u32 oplock)
 
         cfile->fid.persistent_fid = fid->persistent_fid;
         cfile->fid.volatile_fid = fid->volatile_fid;
-        server->ops->set_oplock_level(cinode, oplock);
+        server->ops->set_oplock_level(cinode, oplock, fid->epoch,
+                                      &fid->purge_cache);
         cinode->can_cache_brlcks = CIFS_CACHE_WRITE(cinode);
 }
 
@@ -651,18 +652,18 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 }
 
 static void
-smb2_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
+smb2_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
+                      unsigned int epoch, bool *purge_cache)
 {
         oplock &= 0xFF;
         if (oplock == SMB2_OPLOCK_LEVEL_NOCHANGE)
                 return;
         if (oplock == SMB2_OPLOCK_LEVEL_BATCH) {
-                cinode->oplock = CIFS_CACHE_READ_FLG | CIFS_CACHE_WRITE_FLG |
-                                 CIFS_CACHE_HANDLE_FLG;
+                cinode->oplock = CIFS_CACHE_RHW_FLG;
                 cifs_dbg(FYI, "Batch Oplock granted on inode %p\n",
                          &cinode->vfs_inode);
         } else if (oplock == SMB2_OPLOCK_LEVEL_EXCLUSIVE) {
-                cinode->oplock = CIFS_CACHE_READ_FLG | CIFS_CACHE_WRITE_FLG;
+                cinode->oplock = CIFS_CACHE_RW_FLG;
                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
                          &cinode->vfs_inode);
         } else if (oplock == SMB2_OPLOCK_LEVEL_II) {
@@ -674,7 +675,8 @@ smb2_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 }
 
 static void
-smb21_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
+smb21_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
+                       unsigned int epoch, bool *purge_cache)
 {
         char message[5] = {0};
 
@@ -701,6 +703,41 @@ smb21_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
                  &cinode->vfs_inode);
 }
 
+static void
+smb3_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
+                      unsigned int epoch, bool *purge_cache)
+{
+        unsigned int old_oplock = cinode->oplock;
+
+        smb21_set_oplock_level(cinode, oplock, epoch, purge_cache);
+
+        if (purge_cache) {
+                *purge_cache = false;
+                if (old_oplock == CIFS_CACHE_READ_FLG) {
+                        if (cinode->oplock == CIFS_CACHE_READ_FLG &&
+                            (epoch - cinode->epoch > 0))
+                                *purge_cache = true;
+                        else if (cinode->oplock == CIFS_CACHE_RH_FLG &&
+                                 (epoch - cinode->epoch > 1))
+                                *purge_cache = true;
+                        else if (cinode->oplock == CIFS_CACHE_RHW_FLG &&
+                                 (epoch - cinode->epoch > 1))
+                                *purge_cache = true;
+                        else if (cinode->oplock == 0 &&
+                                 (epoch - cinode->epoch > 0))
+                                *purge_cache = true;
+                } else if (old_oplock == CIFS_CACHE_RH_FLG) {
+                        if (cinode->oplock == CIFS_CACHE_RH_FLG &&
+                            (epoch - cinode->epoch > 0))
+                                *purge_cache = true;
+                        else if (cinode->oplock == CIFS_CACHE_RHW_FLG &&
+                                 (epoch - cinode->epoch > 1))
+                                *purge_cache = true;
+                }
+                cinode->epoch = epoch;
+        }
+}
+
 static bool
 smb2_is_read_op(__u32 oplock)
 {
@@ -780,20 +817,22 @@ smb3_create_lease_buf(u8 *lease_key, u8 oplock)
 }
 
 static __u8
-smb2_parse_lease_buf(void *buf)
+smb2_parse_lease_buf(void *buf, unsigned int *epoch)
 {
         struct create_lease *lc = (struct create_lease *)buf;
 
+        *epoch = 0; /* not used */
         if (lc->lcontext.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS)
                 return SMB2_OPLOCK_LEVEL_NOCHANGE;
         return le32_to_cpu(lc->lcontext.LeaseState);
 }
 
 static __u8
-smb3_parse_lease_buf(void *buf)
+smb3_parse_lease_buf(void *buf, unsigned int *epoch)
 {
         struct create_lease_v2 *lc = (struct create_lease_v2 *)buf;
 
+        *epoch = le16_to_cpu(lc->lcontext.Epoch);
         if (lc->lcontext.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS)
                 return SMB2_OPLOCK_LEVEL_NOCHANGE;
         return le32_to_cpu(lc->lcontext.LeaseState);
@@ -1009,7 +1048,7 @@ struct smb_version_operations smb30_operations = {
         .generate_signingkey = generate_smb3signingkey,
         .calc_signature = smb3_calc_signature,
         .is_read_op = smb21_is_read_op,
-        .set_oplock_level = smb21_set_oplock_level,
+        .set_oplock_level = smb3_set_oplock_level,
         .create_lease_buf = smb3_create_lease_buf,
         .parse_lease_buf = smb3_parse_lease_buf,
 };
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 6eef8b67e709..eba0efde66d7 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -903,7 +903,8 @@ create_reconnect_durable_buf(struct cifs_fid *fid)
 }
 
 static __u8
-parse_lease_state(struct TCP_Server_Info *server, struct smb2_create_rsp *rsp)
+parse_lease_state(struct TCP_Server_Info *server, struct smb2_create_rsp *rsp,
+                  unsigned int *epoch)
 {
         char *data_offset;
         struct create_context *cc;
@@ -920,7 +921,7 @@ parse_lease_state(struct TCP_Server_Info *server, struct smb2_create_rsp *rsp)
                         next = le32_to_cpu(cc->Next);
                         continue;
                 }
-                return server->ops->parse_lease_buf(cc);
+                return server->ops->parse_lease_buf(cc, epoch);
         } while (next != 0);
 
         return 0;
@@ -1102,7 +1103,7 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
         }
 
         if (rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE)
-                *oplock = parse_lease_state(server, rsp);
+                *oplock = parse_lease_state(server, rsp, &oparms->fid->epoch);
         else
                 *oplock = rsp->OplockLevel;
 creat_exit: