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CIFS: Close cached root handle only if it has a lease
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SMB2_tdis() checks if a root handle is valid in order to decide
whether it needs to close the handle or not. However if another
thread has reference for the handle, it may end up with putting
the reference twice. The extra reference that we want to put
during the tree disconnect is the reference that has a directory
lease. So, track the fact that we have a directory lease and
close the handle only in that case.

Signed-off-by: Pavel Shilovsky <[email protected]>
Reviewed-by: Ronnie Sahlberg <[email protected]>
Signed-off-by: Steve French <[email protected]>
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piastry authored and Steve French committed Dec 13, 2019
1 parent e0fc5b1 commit d919131
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Showing 5 changed files with 25 additions and 4 deletions.
2 changes: 1 addition & 1 deletion fs/cifs/cifsglob.h
Original file line number Diff line number Diff line change
Expand Up @@ -1061,7 +1061,7 @@ cap_unix(struct cifs_ses *ses)
struct cached_fid {
bool is_valid:1; /* Do we have a useable root fid */
bool file_all_info_is_valid:1;

bool has_lease:1;
struct kref refcount;
struct cifs_fid *fid;
struct mutex fid_mutex;
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3 changes: 3 additions & 0 deletions fs/cifs/cifssmb.c
Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@
#include "cifsproto.h"
#include "cifs_unicode.h"
#include "cifs_debug.h"
#include "smb2proto.h"
#include "fscache.h"
#include "smbdirect.h"
#ifdef CONFIG_CIFS_DFS_UPCALL
Expand Down Expand Up @@ -112,6 +113,8 @@ cifs_mark_open_files_invalid(struct cifs_tcon *tcon)

mutex_lock(&tcon->crfid.fid_mutex);
tcon->crfid.is_valid = false;
/* cached handle is not valid, so SMB2_CLOSE won't be sent below */
close_shroot_lease_locked(&tcon->crfid);
memset(tcon->crfid.fid, 0, sizeof(struct cifs_fid));
mutex_unlock(&tcon->crfid.fid_mutex);

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19 changes: 18 additions & 1 deletion fs/cifs/smb2ops.c
Original file line number Diff line number Diff line change
Expand Up @@ -616,6 +616,7 @@ smb2_close_cached_fid(struct kref *ref)
cfid->fid->volatile_fid);
cfid->is_valid = false;
cfid->file_all_info_is_valid = false;
cfid->has_lease = false;
}
}

Expand All @@ -626,13 +627,28 @@ void close_shroot(struct cached_fid *cfid)
mutex_unlock(&cfid->fid_mutex);
}

void close_shroot_lease_locked(struct cached_fid *cfid)
{
if (cfid->has_lease) {
cfid->has_lease = false;
kref_put(&cfid->refcount, smb2_close_cached_fid);
}
}

void close_shroot_lease(struct cached_fid *cfid)
{
mutex_lock(&cfid->fid_mutex);
close_shroot_lease_locked(cfid);
mutex_unlock(&cfid->fid_mutex);
}

void
smb2_cached_lease_break(struct work_struct *work)
{
struct cached_fid *cfid = container_of(work,
struct cached_fid, lease_break);

close_shroot(cfid);
close_shroot_lease(cfid);
}

/*
Expand Down Expand Up @@ -773,6 +789,7 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
/* BB TBD check to see if oplock level check can be removed below */
if (o_rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE) {
kref_get(&tcon->crfid.refcount);
tcon->crfid.has_lease = true;
smb2_parse_contexts(server, o_rsp,
&oparms.fid->epoch,
oparms.fid->lease_key, &oplock, NULL);
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3 changes: 1 addition & 2 deletions fs/cifs/smb2pdu.c
Original file line number Diff line number Diff line change
Expand Up @@ -1847,8 +1847,7 @@ SMB2_tdis(const unsigned int xid, struct cifs_tcon *tcon)
if ((tcon->need_reconnect) || (tcon->ses->need_reconnect))
return 0;

if (tcon->crfid.is_valid)
close_shroot(&tcon->crfid);
close_shroot_lease(&tcon->crfid);

rc = smb2_plain_req_init(SMB2_TREE_DISCONNECT, tcon, (void **) &req,
&total_len);
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2 changes: 2 additions & 0 deletions fs/cifs/smb2proto.h
Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,8 @@ extern int smb3_handle_read_data(struct TCP_Server_Info *server,
extern int open_shroot(unsigned int xid, struct cifs_tcon *tcon,
struct cifs_fid *pfid);
extern void close_shroot(struct cached_fid *cfid);
extern void close_shroot_lease(struct cached_fid *cfid);
extern void close_shroot_lease_locked(struct cached_fid *cfid);
extern void move_smb2_info_to_cifs(FILE_ALL_INFO *dst,
struct smb2_file_all_info *src);
extern int smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
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