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ce04127c58
With current implementation, when a nested DFS link is found during mount(2), the client follows the referral and then try to connect to all of its targets. If all targets failed, the client bails out rather than retrying remaining targets from previous referral. Fix this by stacking all referrals and targets so the client can retry remaining targets from previous referrals in case all targets of current referral have failed. Thanks to samba, this can be easily tested like below * Run the following under dfs folder in samba server $ ln -s "msdfs:srv\\bad-share" link1 $ ln -s "msdfs:srv\\dfs\\link1,srv\\good-share" link0 * Before patch $ mount.cifs //srv/dfs/link0 /mnt -o ... mount error(2): No such file or directory Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)... * After patch $ mount.cifs //srv/dfs/link0 /mnt -o ... # ls /mnt bar fileshare1 sub Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
105 lines
2.9 KiB
C
105 lines
2.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* DFS referral cache routines
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*
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* Copyright (c) 2018-2019 Paulo Alcantara <palcantara@suse.de>
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*/
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#ifndef _CIFS_DFS_CACHE_H
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#define _CIFS_DFS_CACHE_H
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#include <linux/nls.h>
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#include <linux/list.h>
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#include <linux/uuid.h>
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#include "cifsglob.h"
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extern struct workqueue_struct *dfscache_wq;
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extern atomic_t dfs_cache_ttl;
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#define DFS_CACHE_TGT_LIST_INIT(var) \
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{ .tl_numtgts = 0, .tl_list = LIST_HEAD_INIT((var).tl_list), }
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#define DFS_CACHE_TGT_LIST(var) \
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struct dfs_cache_tgt_list var = DFS_CACHE_TGT_LIST_INIT(var)
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struct dfs_cache_tgt_list {
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int tl_numtgts;
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struct list_head tl_list;
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};
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struct dfs_cache_tgt_iterator {
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char *it_name;
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int it_path_consumed;
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struct list_head it_list;
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};
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int dfs_cache_init(void);
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void dfs_cache_destroy(void);
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extern const struct proc_ops dfscache_proc_ops;
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int dfs_cache_find(const unsigned int xid, struct cifs_ses *ses, const struct nls_table *cp,
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int remap, const char *path, struct dfs_info3_param *ref,
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struct dfs_cache_tgt_list *tgt_list);
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int dfs_cache_noreq_find(const char *path, struct dfs_info3_param *ref,
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struct dfs_cache_tgt_list *tgt_list);
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void dfs_cache_noreq_update_tgthint(const char *path, const struct dfs_cache_tgt_iterator *it);
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int dfs_cache_get_tgt_referral(const char *path, const struct dfs_cache_tgt_iterator *it,
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struct dfs_info3_param *ref);
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int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it, char **share,
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char **prefix);
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char *dfs_cache_canonical_path(const char *path, const struct nls_table *cp, int remap);
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int dfs_cache_remount_fs(struct cifs_sb_info *cifs_sb);
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void dfs_cache_refresh(struct work_struct *work);
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static inline struct dfs_cache_tgt_iterator *
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dfs_cache_get_next_tgt(struct dfs_cache_tgt_list *tl,
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struct dfs_cache_tgt_iterator *it)
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{
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if (!tl || !tl->tl_numtgts || list_empty(&tl->tl_list) ||
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!it || list_is_last(&it->it_list, &tl->tl_list))
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return NULL;
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return list_next_entry(it, it_list);
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}
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static inline struct dfs_cache_tgt_iterator *
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dfs_cache_get_tgt_iterator(struct dfs_cache_tgt_list *tl)
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{
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if (!tl)
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return NULL;
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return list_first_entry_or_null(&tl->tl_list,
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struct dfs_cache_tgt_iterator,
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it_list);
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}
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static inline void dfs_cache_free_tgts(struct dfs_cache_tgt_list *tl)
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{
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struct dfs_cache_tgt_iterator *it, *nit;
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if (!tl || !tl->tl_numtgts || list_empty(&tl->tl_list))
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return;
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list_for_each_entry_safe(it, nit, &tl->tl_list, it_list) {
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list_del(&it->it_list);
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kfree(it->it_name);
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kfree(it);
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}
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tl->tl_numtgts = 0;
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}
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static inline const char *
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dfs_cache_get_tgt_name(const struct dfs_cache_tgt_iterator *it)
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{
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return it ? it->it_name : NULL;
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}
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static inline int
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dfs_cache_get_nr_tgts(const struct dfs_cache_tgt_list *tl)
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{
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return tl ? tl->tl_numtgts : 0;
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}
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static inline int dfs_cache_get_ttl(void)
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{
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return atomic_read(&dfs_cache_ttl);
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}
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#endif /* _CIFS_DFS_CACHE_H */
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