ср, 27 июн. 2018 г. в 5:39, Pavel Shilovsky <piastryyy@xxxxxxxxx>:
>
> вт, 12 июн. 2018 г. в 21:50, Ronnie Sahlberg <lsahlber@xxxxxxxxxx>:
> >
> > Use a read lease for the cached root fid so that we can detect
> > when the content of the directory changes (via a break) at which time
> > we close the handle. On next access to the root the handle will be reopened
> > and cached again.
> >
> > Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
> > ---
> > fs/cifs/cifsglob.h | 12 +++++++++---
> > fs/cifs/cifsproto.h | 1 +
> > fs/cifs/cifssmb.c | 8 ++++----
> > fs/cifs/misc.c | 7 ++++---
> > fs/cifs/smb2misc.c | 16 +++++++++++++++-
> > fs/cifs/smb2ops.c | 32 +++++++++++++++++++++++---------
> > 6 files changed, 56 insertions(+), 20 deletions(-)
> >
> > diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> > index 1efa2e65bc1a..ff71fbd619bf 100644
> > --- a/fs/cifs/cifsglob.h
> > +++ b/fs/cifs/cifsglob.h
> > @@ -883,6 +883,14 @@ cap_unix(struct cifs_ses *ses)
> > return ses->server->vals->cap_unix & ses->capabilities;
> > }
> >
> > +struct cached_fid {
> > + bool is_valid:1; /* Do we have a useable root fid */
> > + struct cifs_fid *fid;
> > + struct mutex fid_mutex;
> > + struct cifs_tcon *tcon;
> > + struct work_struct lease_break;
> > +};
> > +
> > /*
> > * there is one of these for each connection to a resource on a particular
> > * session
> > @@ -987,9 +995,7 @@ struct cifs_tcon {
> > struct fscache_cookie *fscache; /* cookie for share */
> > #endif
> > struct list_head pending_opens; /* list of incomplete opens */
> > - bool valid_root_fid:1; /* Do we have a useable root fid */
> > - struct mutex prfid_mutex; /* prevents reopen race after dead ses*/
> > - struct cifs_fid *prfid; /* handle to the directory at top of share */
> > + struct cached_fid crfid; /* Cached root fid */
> > /* BB add field for back pointer to sb struct(s)? */
> > };
> >
> > diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> > index e19c27196182..03018be17283 100644
> > --- a/fs/cifs/cifsproto.h
> > +++ b/fs/cifs/cifsproto.h
> > @@ -548,6 +548,7 @@ enum securityEnum cifs_select_sectype(struct TCP_Server_Info *,
> > struct cifs_aio_ctx *cifs_aio_ctx_alloc(void);
> > void cifs_aio_ctx_release(struct kref *refcount);
> > int setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw);
> > +void smb2_cached_lease_break(struct work_struct *work);
> >
> > int cifs_alloc_hash(const char *name, struct crypto_shash **shash,
> > struct sdesc **sdesc);
> > diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> > index 5aca336642c0..c23cd2c9cc25 100644
> > --- a/fs/cifs/cifssmb.c
> > +++ b/fs/cifs/cifssmb.c
> > @@ -107,10 +107,10 @@ cifs_mark_open_files_invalid(struct cifs_tcon *tcon)
> > }
> > spin_unlock(&tcon->open_file_lock);
> >
> > - mutex_lock(&tcon->prfid_mutex);
> > - tcon->valid_root_fid = false;
> > - memset(tcon->prfid, 0, sizeof(struct cifs_fid));
> > - mutex_unlock(&tcon->prfid_mutex);
> > + mutex_lock(&tcon->crfid.fid_mutex);
> > + tcon->crfid.is_valid = false;
> > + memset(tcon->crfid.fid, 0, sizeof(struct cifs_fid));
> > + mutex_unlock(&tcon->crfid.fid_mutex);
> >
> > /*
> > * BB Add call to invalidate_inodes(sb) for all superblocks mounted
> > diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
> > index f90d4ad6624c..0da609cfac95 100644
> > --- a/fs/cifs/misc.c
> > +++ b/fs/cifs/misc.c
> > @@ -117,8 +117,9 @@ tconInfoAlloc(void)
> > INIT_LIST_HEAD(&ret_buf->openFileList);
> > INIT_LIST_HEAD(&ret_buf->tcon_list);
> > spin_lock_init(&ret_buf->open_file_lock);
> > - mutex_init(&ret_buf->prfid_mutex);
> > - ret_buf->prfid = kzalloc(sizeof(struct cifs_fid), GFP_KERNEL);
> > + mutex_init(&ret_buf->crfid.fid_mutex);
> > + ret_buf->crfid.fid = kzalloc(sizeof(struct cifs_fid),
> > + GFP_KERNEL);
> > #ifdef CONFIG_CIFS_STATS
> > spin_lock_init(&ret_buf->stat_lock);
> > #endif
> > @@ -136,7 +137,7 @@ tconInfoFree(struct cifs_tcon *buf_to_free)
> > atomic_dec(&tconInfoAllocCount);
> > kfree(buf_to_free->nativeFileSystem);
> > kzfree(buf_to_free->password);
> > - kfree(buf_to_free->prfid);
> > + kfree(buf_to_free->crfid.fid);
> > kfree(buf_to_free);
> > }
> >
> > diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
> > index e2bec47c6845..0de87ca33e2e 100644
> > --- a/fs/cifs/smb2misc.c
> > +++ b/fs/cifs/smb2misc.c
> > @@ -492,10 +492,11 @@ cifs_ses_oplock_break(struct work_struct *work)
> > {
> > struct smb2_lease_break_work *lw = container_of(work,
> > struct smb2_lease_break_work, lease_break);
> > - int rc;
> > + int rc = 0;
> >
> > rc = SMB2_lease_break(0, tlink_tcon(lw->tlink), lw->lease_key,
> > lw->lease_state);
> > +
> > cifs_dbg(FYI, "Lease release rc %d\n", rc);
> > cifs_put_tlink(lw->tlink);
> > kfree(lw);
> > @@ -561,6 +562,7 @@ smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp,
> >
> > open->oplock = lease_state;
> > }
> > +
> > return found;
> > }
> >
> > @@ -603,6 +605,18 @@ smb2_is_valid_lease_break(char *buffer)
> > return true;
> > }
> > spin_unlock(&tcon->open_file_lock);
> > +
> > + if (tcon->crfid.is_valid &&
> > + !memcmp(rsp->LeaseKey,
> > + tcon->crfid.fid->lease_key,
> > + SMB2_LEASE_KEY_SIZE)) {
> > + INIT_WORK(&tcon->crfid.lease_break,
> > + smb2_cached_lease_break);
> > + queue_work(cifsiod_wq,
> > + &tcon->crfid.lease_break);
> > + spin_unlock(&cifs_tcp_ses_lock);
> > + return true;
> > + }
> > }
> > }
> > }
> > diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> > index d1648a9753d0..a6cd0f6c053b 100644
> > --- a/fs/cifs/smb2ops.c
> > +++ b/fs/cifs/smb2ops.c
> > @@ -323,6 +323,19 @@ SMB3_request_interfaces(const unsigned int xid, struct cifs_tcon *tcon)
> > }
> > #endif /* STATS2 */
> >
> > +void
> > +smb2_cached_lease_break(struct work_struct *work)
> > +{
> > + struct cached_fid *cfid = container_of(work,
> > + struct cached_fid, lease_break);
> > + if (cfid->is_valid) {
> > + cifs_dbg(FYI, "clear cached root file handle\n");
> > + SMB2_close(0, cfid->tcon, cfid->fid->persistent_fid,
> > + cfid->fid->volatile_fid);
> > + cfid->is_valid = false;
> > + }
> > +}
>
> What will prevent another thread to use the cached FID while it is being closed?
Sorry, didn't noticed the next version of the patch where this problem
was fixed.
--
To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
