On Wed, 29 Sep 2010 15:27:08 -0400 Jeff Layton <[email protected]> wrote:
> cifs_reconnect_tcon is called from smb_init. After a successful > reconnect, cifs_reconnect_tcon will call reset_cifs_unix_caps. That > function will, in turn call CIFSSMBQFSUnixInfo and CIFSSMBSetFSUnixInfo. > Those functions also call smb_init. > > It's possible for the session and tcon reconnect to succeed, and then > for another cifs_reconnect to occur before CIFSSMBQFSUnixInfo or > CIFSSMBSetFSUnixInfo to be called. That'll cause those functions to call > smb_init and cifs_reconnect_tcon again, ad infinitum... > > Break the infinite recursion by having those functions use a new > smb_init variant that doesn't attempt to perform a reconnect. > > Reported-and-Tested-by: Michal Suchanek <[email protected]> > Signed-off-by: Jeff Layton <[email protected]> I should also note that this fixes the following kernel.org bug: https://bugzilla.kernel.org/show_bug.cgi?id=18582 > --- > fs/cifs/cifssmb.c | 49 +++++++++++++++++++++++++++++++++---------------- > 1 files changed, 33 insertions(+), 16 deletions(-) > > diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c > index 13c854e..54bd83a 100644 > --- a/fs/cifs/cifssmb.c > +++ b/fs/cifs/cifssmb.c > @@ -232,7 +232,7 @@ static int > small_smb_init(int smb_command, int wct, struct cifsTconInfo *tcon, > void **request_buf) > { > - int rc = 0; > + int rc; > > rc = cifs_reconnect_tcon(tcon, smb_command); > if (rc) > @@ -250,7 +250,7 @@ small_smb_init(int smb_command, int wct, struct > cifsTconInfo *tcon, > if (tcon != NULL) > cifs_stats_inc(&tcon->num_smbs_sent); > > - return rc; > + return 0; > } > > int > @@ -281,16 +281,9 @@ small_smb_init_no_tc(const int smb_command, const int > wct, > > /* If the return code is zero, this function must fill in request_buf > pointer */ > static int > -smb_init(int smb_command, int wct, struct cifsTconInfo *tcon, > - void **request_buf /* returned */ , > - void **response_buf /* returned */ ) > +__smb_init(int smb_command, int wct, struct cifsTconInfo *tcon, > + void **request_buf, void **response_buf) > { > - int rc = 0; > - > - rc = cifs_reconnect_tcon(tcon, smb_command); > - if (rc) > - return rc; > - > *request_buf = cifs_buf_get(); > if (*request_buf == NULL) { > /* BB should we add a retry in here if not a writepage? */ > @@ -309,7 +302,31 @@ smb_init(int smb_command, int wct, struct cifsTconInfo > *tcon, > if (tcon != NULL) > cifs_stats_inc(&tcon->num_smbs_sent); > > - return rc; > + return 0; > +} > + > +/* If the return code is zero, this function must fill in request_buf > pointer */ > +static int > +smb_init(int smb_command, int wct, struct cifsTconInfo *tcon, > + void **request_buf, void **response_buf) > +{ > + int rc; > + > + rc = cifs_reconnect_tcon(tcon, smb_command); > + if (rc) > + return rc; > + > + return __smb_init(smb_command, wct, tcon, request_buf, response_buf); > +} > + > +static int > +smb_init_no_reconnect(int smb_command, int wct, struct cifsTconInfo *tcon, > + void **request_buf, void **response_buf) > +{ > + if (tcon->ses->need_reconnect || tcon->need_reconnect) > + return -EHOSTDOWN; > + > + return __smb_init(smb_command, wct, tcon, request_buf, response_buf); > } > > static int validate_t2(struct smb_t2_rsp *pSMB) > @@ -4536,8 +4553,8 @@ CIFSSMBQFSUnixInfo(const int xid, struct cifsTconInfo > *tcon) > > cFYI(1, "In QFSUnixInfo"); > QFSUnixRetry: > - rc = smb_init(SMB_COM_TRANSACTION2, 15, tcon, (void **) &pSMB, > - (void **) &pSMBr); > + rc = smb_init_no_reconnect(SMB_COM_TRANSACTION2, 15, tcon, > + (void **) &pSMB, (void **) &pSMBr); > if (rc) > return rc; > > @@ -4606,8 +4623,8 @@ CIFSSMBSetFSUnixInfo(const int xid, struct cifsTconInfo > *tcon, __u64 cap) > cFYI(1, "In SETFSUnixInfo"); > SETFSUnixRetry: > /* BB switch to small buf init to save memory */ > - rc = smb_init(SMB_COM_TRANSACTION2, 15, tcon, (void **) &pSMB, > - (void **) &pSMBr); > + rc = smb_init_no_reconnect(SMB_COM_TRANSACTION2, 15, tcon, > + (void **) &pSMB, (void **) &pSMBr); > if (rc) > return rc; > -- Jeff Layton <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
