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author | 2010-09-29 15:27:08 -0400 | |
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committer | 2010-10-01 17:50:08 +0000 | |
commit | f569599ae70f0899035f8d5876a7939f629c5976 (patch) | |
tree | 4d7f7c32b9c89f15841bdbf372e75afe09bdef53 /fs | |
parent | cifs: set backing_dev_info on new S_ISREG inodes (diff) | |
download | linux-f569599ae70f0899035f8d5876a7939f629c5976.tar.gz linux-f569599ae70f0899035f8d5876a7939f629c5976.tar.bz2 linux-f569599ae70f0899035f8d5876a7939f629c5976.zip |
cifs: prevent infinite recursion in cifs_reconnect_tcon
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 <hramrach@centrum.cz>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs')
-rw-r--r-- | 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 c65c3419dd37..7e83b356cc9e 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) @@ -4534,8 +4551,8 @@ 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; @@ -4604,8 +4621,8 @@ 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; |