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cifs: handle RESP_GET_DFS_REFERRAL.PathConsumed in reconnect
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Use PathConsumed field when parsing prefixes of referral paths that
either match a cache entry or are a complete prefix path of an
existing entry.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Paulo Alcantara authored and Steve French committed Aug 2, 2020
1 parent a529303 commit 7548e1d
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Showing 5 changed files with 62 additions and 29 deletions.
3 changes: 1 addition & 2 deletions fs/cifs/cifsproto.h
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Original file line number Diff line number Diff line change
Expand Up @@ -617,8 +617,7 @@ int smb2_parse_query_directory(struct cifs_tcon *tcon, struct kvec *rsp_iov,

struct super_block *cifs_get_tcp_super(struct TCP_Server_Info *server);
void cifs_put_tcp_super(struct super_block *sb);
int update_super_prepath(struct cifs_tcon *tcon, const char *prefix,
size_t prefix_len);
int update_super_prepath(struct cifs_tcon *tcon, char *prefix);

#ifdef CONFIG_CIFS_DFS_UPCALL
static inline int get_dfs_path(const unsigned int xid, struct cifs_ses *ses,
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17 changes: 11 additions & 6 deletions fs/cifs/connect.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5547,6 +5547,7 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
size_t tcp_host_len;
const char *dfs_host;
size_t dfs_host_len;
char *share = NULL, *prefix = NULL;

tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
if (!tree)
Expand All @@ -5569,11 +5570,12 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
extract_unc_hostname(server->hostname, &tcp_host, &tcp_host_len);

for (it = dfs_cache_get_tgt_iterator(&tl); it; it = dfs_cache_get_next_tgt(&tl, it)) {
const char *share, *prefix;
size_t share_len, prefix_len;
bool target_match;

rc = dfs_cache_get_tgt_share(it, &share, &share_len, &prefix, &prefix_len);
kfree(share);
kfree(prefix);

rc = dfs_cache_get_tgt_share(tcon->dfs_path + 1, it, &share, &prefix);
if (rc) {
cifs_dbg(VFS, "%s: failed to parse target share %d\n",
__func__, rc);
Expand All @@ -5600,20 +5602,23 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
}

if (tcon->ipc) {
scnprintf(tree, MAX_TREE_SIZE, "\\\\%.*s\\IPC$", (int)share_len, share);
scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", share);
rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
} else {
scnprintf(tree, MAX_TREE_SIZE, "\\%.*s", (int)share_len, share);
scnprintf(tree, MAX_TREE_SIZE, "\\%s", share);
rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
if (!rc) {
rc = update_super_prepath(tcon, prefix, prefix_len);
rc = update_super_prepath(tcon, prefix);
break;
}
}
if (rc == -EREMOTE)
break;
}

kfree(share);
kfree(prefix);

if (!rc) {
if (it)
rc = dfs_cache_noreq_update_tgthint(tcon->dfs_path + 1, it);
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57 changes: 44 additions & 13 deletions fs/cifs/dfs_cache.c
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@

struct cache_dfs_tgt {
char *name;
int path_consumed;
struct list_head list;
};

Expand Down Expand Up @@ -350,7 +351,7 @@ static inline struct timespec64 get_expire_time(int ttl)
}

/* Allocate a new DFS target */
static struct cache_dfs_tgt *alloc_target(const char *name)
static struct cache_dfs_tgt *alloc_target(const char *name, int path_consumed)
{
struct cache_dfs_tgt *t;

Expand All @@ -362,6 +363,7 @@ static struct cache_dfs_tgt *alloc_target(const char *name)
kfree(t);
return ERR_PTR(-ENOMEM);
}
t->path_consumed = path_consumed;
INIT_LIST_HEAD(&t->list);
return t;
}
Expand All @@ -384,7 +386,7 @@ static int copy_ref_data(const struct dfs_info3_param *refs, int numrefs,
for (i = 0; i < numrefs; i++) {
struct cache_dfs_tgt *t;

t = alloc_target(refs[i].node_name);
t = alloc_target(refs[i].node_name, refs[i].path_consumed);
if (IS_ERR(t)) {
free_tgts(ce);
return PTR_ERR(t);
Expand Down Expand Up @@ -830,6 +832,7 @@ static int get_targets(struct cache_entry *ce, struct dfs_cache_tgt_list *tl)
rc = -ENOMEM;
goto err_free_it;
}
it->it_path_consumed = t->path_consumed;

if (ce->tgthint == t)
list_add(&it->it_list, head);
Expand Down Expand Up @@ -1320,23 +1323,26 @@ void dfs_cache_del_vol(const char *fullpath)
/**
* dfs_cache_get_tgt_share - parse a DFS target
*
* @path: DFS full path
* @it: DFS target iterator.
* @share: tree name.
* @share_len: length of tree name.
* @prefix: prefix path.
* @prefix_len: length of prefix path.
*
* Return zero if target was parsed correctly, otherwise non-zero.
*/
int dfs_cache_get_tgt_share(const struct dfs_cache_tgt_iterator *it,
const char **share, size_t *share_len,
const char **prefix, size_t *prefix_len)
int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it,
char **share, char **prefix)
{
char *s, sep;
char *s, sep, *p;
size_t len;
size_t plen1, plen2;

if (!it || !share || !share_len || !prefix || !prefix_len)
if (!it || !path || !share || !prefix || strlen(path) < it->it_path_consumed)
return -EINVAL;

*share = NULL;
*prefix = NULL;

sep = it->it_name[0];
if (sep != '\\' && sep != '/')
return -EINVAL;
Expand All @@ -1345,13 +1351,38 @@ int dfs_cache_get_tgt_share(const struct dfs_cache_tgt_iterator *it,
if (!s)
return -EINVAL;

/* point to prefix in target node */
s = strchrnul(s + 1, sep);

*share = it->it_name;
*share_len = s - it->it_name;
*prefix = *s ? s + 1 : s;
*prefix_len = &it->it_name[strlen(it->it_name)] - *prefix;
/* extract target share */
*share = kstrndup(it->it_name, s - it->it_name, GFP_KERNEL);
if (!*share)
return -ENOMEM;

/* skip separator */
if (*s)
s++;
/* point to prefix in DFS path */
p = path + it->it_path_consumed;
if (*p == sep)
p++;

/* merge prefix paths from DFS path and target node */
plen1 = it->it_name + strlen(it->it_name) - s;
plen2 = path + strlen(path) - p;
if (plen1 || plen2) {
len = plen1 + plen2 + 2;
*prefix = kmalloc(len, GFP_KERNEL);
if (!*prefix) {
kfree(*share);
*share = NULL;
return -ENOMEM;
}
if (plen1)
scnprintf(*prefix, len, "%.*s%c%.*s", (int)plen1, s, sep, (int)plen2, p);
else
strscpy(*prefix, p, len);
}
return 0;
}

Expand Down
7 changes: 3 additions & 4 deletions fs/cifs/dfs_cache.h
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ struct dfs_cache_tgt_list {

struct dfs_cache_tgt_iterator {
char *it_name;
int it_path_consumed;
struct list_head it_list;
};

Expand Down Expand Up @@ -48,10 +49,8 @@ extern int dfs_cache_add_vol(char *mntdata, struct smb_vol *vol,
extern int dfs_cache_update_vol(const char *fullpath,
struct TCP_Server_Info *server);
extern void dfs_cache_del_vol(const char *fullpath);

extern int dfs_cache_get_tgt_share(const struct dfs_cache_tgt_iterator *it,
const char **share, size_t *share_len,
const char **prefix, size_t *prefix_len);
extern int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it,
char **share, char **prefix);

static inline struct dfs_cache_tgt_iterator *
dfs_cache_get_next_tgt(struct dfs_cache_tgt_list *tl,
Expand Down
7 changes: 3 additions & 4 deletions fs/cifs/misc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1164,8 +1164,7 @@ static inline void cifs_put_tcon_super(struct super_block *sb)
}
#endif

int update_super_prepath(struct cifs_tcon *tcon, const char *prefix,
size_t prefix_len)
int update_super_prepath(struct cifs_tcon *tcon, char *prefix)
{
struct super_block *sb;
struct cifs_sb_info *cifs_sb;
Expand All @@ -1179,8 +1178,8 @@ int update_super_prepath(struct cifs_tcon *tcon, const char *prefix,

kfree(cifs_sb->prepath);

if (*prefix && prefix_len) {
cifs_sb->prepath = kstrndup(prefix, prefix_len, GFP_ATOMIC);
if (prefix && *prefix) {
cifs_sb->prepath = kstrndup(prefix, strlen(prefix), GFP_ATOMIC);
if (!cifs_sb->prepath) {
rc = -ENOMEM;
goto out;
Expand Down

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