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cifs: reinstate sharing of tree connections

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Use a similar approach to the SMB session sharing. Add a list of tcons
attached to each SMB session. Move the refcount to non-atomic. Protect
all of the above with the cifs_tcp_ses_lock. Add functions to
properly find and put references to the tcons.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This commit is contained in:
Jeff Layton
2008-11-15 11:12:47 -05:00
committed by Steve French
parent d82c2df54e
commit f1987b44f6
6 changed files with 249 additions and 218 deletions
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93
fs/cifs/connect.c
View File

@@ -124,7 +124,7 @@ static int
cifs_reconnect(struct TCP_Server_Info *server)
{
int rc = 0;
struct list_head *tmp;
struct list_head *tmp, *tmp2;
struct cifsSesInfo *ses;
struct cifsTconInfo *tcon;
struct mid_q_entry *mid_entry;
@@ -149,13 +149,12 @@ cifs_reconnect(struct TCP_Server_Info *server)
ses = list_entry(tmp, struct cifsSesInfo, smb_ses_list);
ses->need_reconnect = true;
ses->ipc_tid = 0;
list_for_each(tmp2, &ses->tcon_list) {
tcon = list_entry(tmp2, struct cifsTconInfo, tcon_list);
tcon->need_reconnect = true;
}
}
read_unlock(&cifs_tcp_ses_lock);
list_for_each(tmp, &GlobalTreeConnectionList) {
tcon = list_entry(tmp, struct cifsTconInfo, cifsConnectionList);
if ((tcon->ses) && (tcon->ses->server == server))
tcon->need_reconnect = true;
}
/* do not want to be sending data on a socket we are freeing */
down(&server->tcpSem);
if (server->ssocket) {
@@ -1462,6 +1461,52 @@ cifs_put_smb_ses(struct cifsSesInfo *ses)
cifs_put_tcp_session(server);
}
static struct cifsTconInfo *
cifs_find_tcon(struct cifsSesInfo *ses, const char *unc)
{
struct list_head *tmp;
struct cifsTconInfo *tcon;
write_lock(&cifs_tcp_ses_lock);
list_for_each(tmp, &ses->tcon_list) {
tcon = list_entry(tmp, struct cifsTconInfo, tcon_list);
if (tcon->tidStatus == CifsExiting)
continue;
if (strncmp(tcon->treeName, unc, MAX_TREE_SIZE))
continue;
++tcon->tc_count;
write_unlock(&cifs_tcp_ses_lock);
return tcon;
}
write_unlock(&cifs_tcp_ses_lock);
return NULL;
}
static void
cifs_put_tcon(struct cifsTconInfo *tcon)
{
int xid;
struct cifsSesInfo *ses = tcon->ses;
write_lock(&cifs_tcp_ses_lock);
if (--tcon->tc_count > 0) {
write_unlock(&cifs_tcp_ses_lock);
return;
}
list_del_init(&tcon->tcon_list);
write_unlock(&cifs_tcp_ses_lock);
xid = GetXid();
CIFSSMBTDis(xid, tcon);
_FreeXid(xid);
DeleteTconOplockQEntries(tcon);
tconInfoFree(tcon);
cifs_put_smb_ses(ses);
}
int
get_dfs_path(int xid, struct cifsSesInfo *pSesInfo, const char *old_path,
const struct nls_table *nls_codepage, unsigned int *pnum_referrals,
@@ -2220,11 +2265,11 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
if (!rc) {
setup_cifs_sb(&volume_info, cifs_sb);
tcon = cifs_find_tcon(pSesInfo, volume_info.UNC);
if (tcon) {
cFYI(1, ("Found match on UNC path"));
if (tcon->seal != volume_info.seal)
cERROR(1, ("transport encryption setting "
"conflicts with existing tid"));
/* existing tcon already has a reference */
cifs_put_smb_ses(pSesInfo);
} else {
tcon = tconInfoAlloc();
if (tcon == NULL) {
@@ -2257,6 +2302,10 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
if (rc)
goto mount_fail_check;
tcon->seal = volume_info.seal;
tcon->ses = pSesInfo;
write_lock(&cifs_tcp_ses_lock);
list_add(&tcon->tcon_list, &pSesInfo->tcon_list);
write_unlock(&cifs_tcp_ses_lock);
}
/* we can have only one retry value for a connection
@@ -2283,18 +2332,14 @@ mount_fail_check:
/* If find_unc succeeded then rc == 0 so we can not end */
/* up accidently freeing someone elses tcon struct */
if (tcon)
tconInfoFree(tcon);
/* should also end up putting our tcp session ref if needed */
if (pSesInfo)
cifs_put_tcon(tcon);
else if (pSesInfo)
cifs_put_smb_ses(pSesInfo);
else
cifs_put_tcp_session(srvTcp);
goto out;
}
atomic_inc(&tcon->useCount);
cifs_sb->tcon = tcon;
tcon->ses = pSesInfo;
/* do not care if following two calls succeed - informational */
if (!tcon->ipc) {
@@ -3565,23 +3610,10 @@ int
cifs_umount(struct super_block *sb, struct cifs_sb_info *cifs_sb)
{
int rc = 0;
int xid;
struct cifsSesInfo *ses = NULL;
char *tmp;
xid = GetXid();
if (cifs_sb->tcon) {
ses = cifs_sb->tcon->ses; /* save ptr to ses before delete tcon!*/
rc = CIFSSMBTDis(xid, cifs_sb->tcon);
if (rc == -EBUSY) {
FreeXid(xid);
return 0;
}
DeleteTconOplockQEntries(cifs_sb->tcon);
tconInfoFree(cifs_sb->tcon);
cifs_put_smb_ses(ses);
}
if (cifs_sb->tcon)
cifs_put_tcon(cifs_sb->tcon);
cifs_sb->tcon = NULL;
tmp = cifs_sb->prepath;
@@ -3589,7 +3621,6 @@ cifs_umount(struct super_block *sb, struct cifs_sb_info *cifs_sb)
cifs_sb->prepath = NULL;
kfree(tmp);
FreeXid(xid);
return rc;
}