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cifs: use a refcount to protect open/closing the cached file handle

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commit 9da6ec7775d2cd76df53fbf4f1f35f6d490204f5 upstream.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ronnie Sahlberg 2018-07-31 08:48:22 +10:00 committed by Greg Kroah-Hartman
parent 5ba293d099
commit a1ac808c81
4 changed files with 31 additions and 6 deletions
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1
fs/cifs/cifsglob.h
View File

@ -913,6 +913,7 @@ cap_unix(struct cifs_ses *ses)
struct cached_fid {
bool is_valid:1; /* Do we have a useable root fid */
struct kref refcount;
struct cifs_fid *fid;
struct mutex fid_mutex;
struct cifs_tcon *tcon;

4
fs/cifs/smb2inode.c
View File

@ -120,7 +120,9 @@ smb2_open_op_close(const unsigned int xid, struct cifs_tcon *tcon,
break;
}
if (use_cached_root_handle == false)
if (use_cached_root_handle)
close_shroot(&tcon->crfid);
else
rc = SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
if (tmprc)
rc = tmprc;

31
fs/cifs/smb2ops.c
View File

@ -466,21 +466,36 @@ out:
return rc;
}
void
smb2_cached_lease_break(struct work_struct *work)
static void
smb2_close_cached_fid(struct kref *ref)
{
struct cached_fid *cfid = container_of(work,
struct cached_fid, lease_break);
mutex_lock(&cfid->fid_mutex);
struct cached_fid *cfid = container_of(ref, struct cached_fid,
refcount);
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;
}
}
void close_shroot(struct cached_fid *cfid)
{
mutex_lock(&cfid->fid_mutex);
kref_put(&cfid->refcount, smb2_close_cached_fid);
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);
}
/*
* Open the directory at the root of a share
*/
@ -495,6 +510,7 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
if (tcon->crfid.is_valid) {
cifs_dbg(FYI, "found a cached root file handle\n");
memcpy(pfid, tcon->crfid.fid, sizeof(struct cifs_fid));
kref_get(&tcon->crfid.refcount);
mutex_unlock(&tcon->crfid.fid_mutex);
return 0;
}
@ -511,6 +527,8 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
memcpy(tcon->crfid.fid, pfid, sizeof(struct cifs_fid));
tcon->crfid.tcon = tcon;
tcon->crfid.is_valid = true;
kref_init(&tcon->crfid.refcount);
kref_get(&tcon->crfid.refcount);
}
mutex_unlock(&tcon->crfid.fid_mutex);
return rc;
@ -552,6 +570,9 @@ smb3_qfs_tcon(const unsigned int xid, struct cifs_tcon *tcon)
FS_SECTOR_SIZE_INFORMATION); /* SMB3 specific */
if (no_cached_open)
SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
else
close_shroot(&tcon->crfid);
return;
}

1
fs/cifs/smb2proto.h
View File

@ -68,6 +68,7 @@ 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 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,