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558 lines
13 KiB
558 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Functions to handle the cached directory entries |
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* |
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* Copyright (c) 2022, Ronnie Sahlberg <[email protected]> |
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*/ |
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|
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#include <linux/namei.h> |
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#include "cifsglob.h" |
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#include "cifsproto.h" |
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#include "cifs_debug.h" |
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#include "smb2proto.h" |
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#include "cached_dir.h" |
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static struct cached_fid *init_cached_dir(const char *path); |
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static void free_cached_dir(struct cached_fid *cfid); |
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|
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static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids, |
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const char *path, |
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bool lookup_only) |
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{ |
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struct cached_fid *cfid; |
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|
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spin_lock(&cfids->cfid_list_lock); |
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list_for_each_entry(cfid, &cfids->entries, entry) { |
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if (!strcmp(cfid->path, path)) { |
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/* |
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* If it doesn't have a lease it is either not yet |
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* fully cached or it may be in the process of |
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* being deleted due to a lease break. |
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*/ |
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if (!cfid->has_lease) { |
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spin_unlock(&cfids->cfid_list_lock); |
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return NULL; |
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} |
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kref_get(&cfid->refcount); |
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spin_unlock(&cfids->cfid_list_lock); |
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return cfid; |
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} |
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} |
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if (lookup_only) { |
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spin_unlock(&cfids->cfid_list_lock); |
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return NULL; |
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} |
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if (cfids->num_entries >= MAX_CACHED_FIDS) { |
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spin_unlock(&cfids->cfid_list_lock); |
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return NULL; |
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} |
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cfid = init_cached_dir(path); |
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if (cfid == NULL) { |
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spin_unlock(&cfids->cfid_list_lock); |
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return NULL; |
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} |
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cfid->cfids = cfids; |
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cfids->num_entries++; |
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list_add(&cfid->entry, &cfids->entries); |
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cfid->on_list = true; |
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kref_get(&cfid->refcount); |
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spin_unlock(&cfids->cfid_list_lock); |
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return cfid; |
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} |
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|
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static struct dentry * |
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path_to_dentry(struct cifs_sb_info *cifs_sb, const char *path) |
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{ |
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struct dentry *dentry; |
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const char *s, *p; |
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char sep; |
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sep = CIFS_DIR_SEP(cifs_sb); |
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dentry = dget(cifs_sb->root); |
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s = path; |
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do { |
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struct inode *dir = d_inode(dentry); |
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struct dentry *child; |
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if (!S_ISDIR(dir->i_mode)) { |
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dput(dentry); |
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dentry = ERR_PTR(-ENOTDIR); |
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break; |
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} |
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|
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/* skip separators */ |
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while (*s == sep) |
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s++; |
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if (!*s) |
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break; |
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p = s++; |
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/* next separator */ |
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while (*s && *s != sep) |
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s++; |
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child = lookup_positive_unlocked(p, dentry, s - p); |
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dput(dentry); |
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dentry = child; |
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} while (!IS_ERR(dentry)); |
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return dentry; |
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} |
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|
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/* |
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* Open the and cache a directory handle. |
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* If error then *cfid is not initialized. |
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*/ |
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int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, |
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const char *path, |
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struct cifs_sb_info *cifs_sb, |
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bool lookup_only, struct cached_fid **ret_cfid) |
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{ |
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struct cifs_ses *ses; |
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struct TCP_Server_Info *server; |
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struct cifs_open_parms oparms; |
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struct smb2_create_rsp *o_rsp = NULL; |
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struct smb2_query_info_rsp *qi_rsp = NULL; |
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int resp_buftype[2]; |
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struct smb_rqst rqst[2]; |
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struct kvec rsp_iov[2]; |
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struct kvec open_iov[SMB2_CREATE_IOV_SIZE]; |
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struct kvec qi_iov[1]; |
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int rc, flags = 0; |
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__le16 *utf16_path = NULL; |
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u8 oplock = SMB2_OPLOCK_LEVEL_II; |
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struct cifs_fid *pfid; |
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struct dentry *dentry = NULL; |
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struct cached_fid *cfid; |
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struct cached_fids *cfids; |
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if (tcon == NULL || tcon->cfids == NULL || tcon->nohandlecache || |
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is_smb1_server(tcon->ses->server)) |
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return -EOPNOTSUPP; |
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ses = tcon->ses; |
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server = ses->server; |
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cfids = tcon->cfids; |
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if (!server->ops->new_lease_key) |
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return -EIO; |
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if (cifs_sb->root == NULL) |
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return -ENOENT; |
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utf16_path = cifs_convert_path_to_utf16(path, cifs_sb); |
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if (!utf16_path) |
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return -ENOMEM; |
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cfid = find_or_create_cached_dir(cfids, path, lookup_only); |
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if (cfid == NULL) { |
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kfree(utf16_path); |
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return -ENOENT; |
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} |
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/* |
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* At this point we either have a lease already and we can just |
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* return it. If not we are guaranteed to be the only thread accessing |
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* this cfid. |
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*/ |
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if (cfid->has_lease) { |
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*ret_cfid = cfid; |
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kfree(utf16_path); |
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return 0; |
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} |
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/* |
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* We do not hold the lock for the open because in case |
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* SMB2_open needs to reconnect. |
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* This is safe because no other thread will be able to get a ref |
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* to the cfid until we have finished opening the file and (possibly) |
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* acquired a lease. |
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*/ |
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if (smb3_encryption_required(tcon)) |
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flags |= CIFS_TRANSFORM_REQ; |
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pfid = &cfid->fid; |
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server->ops->new_lease_key(pfid); |
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memset(rqst, 0, sizeof(rqst)); |
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resp_buftype[0] = resp_buftype[1] = CIFS_NO_BUFFER; |
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memset(rsp_iov, 0, sizeof(rsp_iov)); |
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/* Open */ |
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memset(&open_iov, 0, sizeof(open_iov)); |
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rqst[0].rq_iov = open_iov; |
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rqst[0].rq_nvec = SMB2_CREATE_IOV_SIZE; |
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oparms.tcon = tcon; |
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oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_FILE); |
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oparms.desired_access = FILE_READ_ATTRIBUTES; |
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oparms.disposition = FILE_OPEN; |
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oparms.fid = pfid; |
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oparms.reconnect = false; |
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rc = SMB2_open_init(tcon, server, |
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&rqst[0], &oplock, &oparms, utf16_path); |
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if (rc) |
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goto oshr_free; |
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smb2_set_next_command(tcon, &rqst[0]); |
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memset(&qi_iov, 0, sizeof(qi_iov)); |
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rqst[1].rq_iov = qi_iov; |
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rqst[1].rq_nvec = 1; |
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rc = SMB2_query_info_init(tcon, server, |
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&rqst[1], COMPOUND_FID, |
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COMPOUND_FID, FILE_ALL_INFORMATION, |
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SMB2_O_INFO_FILE, 0, |
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sizeof(struct smb2_file_all_info) + |
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PATH_MAX * 2, 0, NULL); |
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if (rc) |
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goto oshr_free; |
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smb2_set_related(&rqst[1]); |
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rc = compound_send_recv(xid, ses, server, |
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flags, 2, rqst, |
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resp_buftype, rsp_iov); |
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if (rc) { |
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if (rc == -EREMCHG) { |
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tcon->need_reconnect = true; |
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pr_warn_once("server share %s deleted\n", |
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tcon->tree_name); |
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} |
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goto oshr_free; |
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} |
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atomic_inc(&tcon->num_remote_opens); |
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o_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base; |
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oparms.fid->persistent_fid = o_rsp->PersistentFileId; |
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oparms.fid->volatile_fid = o_rsp->VolatileFileId; |
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#ifdef CONFIG_CIFS_DEBUG2 |
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oparms.fid->mid = le64_to_cpu(o_rsp->hdr.MessageId); |
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#endif /* CIFS_DEBUG2 */ |
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if (o_rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE) |
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goto oshr_free; |
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smb2_parse_contexts(server, o_rsp, |
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&oparms.fid->epoch, |
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oparms.fid->lease_key, &oplock, |
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NULL, NULL); |
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qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base; |
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if (le32_to_cpu(qi_rsp->OutputBufferLength) < sizeof(struct smb2_file_all_info)) |
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goto oshr_free; |
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if (!smb2_validate_and_copy_iov( |
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le16_to_cpu(qi_rsp->OutputBufferOffset), |
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sizeof(struct smb2_file_all_info), |
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&rsp_iov[1], sizeof(struct smb2_file_all_info), |
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(char *)&cfid->file_all_info)) |
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cfid->file_all_info_is_valid = true; |
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if (!path[0]) |
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dentry = dget(cifs_sb->root); |
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else { |
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dentry = path_to_dentry(cifs_sb, path); |
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if (IS_ERR(dentry)) { |
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rc = -ENOENT; |
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goto oshr_free; |
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} |
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} |
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cfid->dentry = dentry; |
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cfid->tcon = tcon; |
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cfid->time = jiffies; |
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cfid->is_open = true; |
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cfid->has_lease = true; |
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oshr_free: |
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kfree(utf16_path); |
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SMB2_open_free(&rqst[0]); |
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SMB2_query_info_free(&rqst[1]); |
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free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base); |
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free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base); |
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spin_lock(&cfids->cfid_list_lock); |
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if (!cfid->has_lease) { |
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if (cfid->on_list) { |
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list_del(&cfid->entry); |
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cfid->on_list = false; |
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cfids->num_entries--; |
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} |
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rc = -ENOENT; |
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} |
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spin_unlock(&cfids->cfid_list_lock); |
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if (rc) { |
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free_cached_dir(cfid); |
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cfid = NULL; |
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} |
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if (rc == 0) |
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*ret_cfid = cfid; |
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return rc; |
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} |
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int open_cached_dir_by_dentry(struct cifs_tcon *tcon, |
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struct dentry *dentry, |
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struct cached_fid **ret_cfid) |
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{ |
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struct cached_fid *cfid; |
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struct cached_fids *cfids = tcon->cfids; |
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if (cfids == NULL) |
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return -ENOENT; |
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spin_lock(&cfids->cfid_list_lock); |
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list_for_each_entry(cfid, &cfids->entries, entry) { |
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if (dentry && cfid->dentry == dentry) { |
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cifs_dbg(FYI, "found a cached root file handle by dentry\n"); |
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kref_get(&cfid->refcount); |
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*ret_cfid = cfid; |
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spin_unlock(&cfids->cfid_list_lock); |
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return 0; |
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} |
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} |
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spin_unlock(&cfids->cfid_list_lock); |
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return -ENOENT; |
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} |
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static void |
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smb2_close_cached_fid(struct kref *ref) |
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{ |
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struct cached_fid *cfid = container_of(ref, struct cached_fid, |
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refcount); |
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spin_lock(&cfid->cfids->cfid_list_lock); |
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if (cfid->on_list) { |
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list_del(&cfid->entry); |
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cfid->on_list = false; |
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cfid->cfids->num_entries--; |
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} |
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spin_unlock(&cfid->cfids->cfid_list_lock); |
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dput(cfid->dentry); |
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cfid->dentry = NULL; |
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if (cfid->is_open) { |
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SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid, |
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cfid->fid.volatile_fid); |
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} |
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free_cached_dir(cfid); |
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} |
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void drop_cached_dir_by_name(const unsigned int xid, struct cifs_tcon *tcon, |
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const char *name, struct cifs_sb_info *cifs_sb) |
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{ |
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struct cached_fid *cfid = NULL; |
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int rc; |
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rc = open_cached_dir(xid, tcon, name, cifs_sb, true, &cfid); |
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if (rc) { |
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cifs_dbg(FYI, "no cached dir found for rmdir(%s)\n", name); |
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return; |
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} |
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spin_lock(&cfid->cfids->cfid_list_lock); |
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if (cfid->has_lease) { |
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cfid->has_lease = false; |
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kref_put(&cfid->refcount, smb2_close_cached_fid); |
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} |
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spin_unlock(&cfid->cfids->cfid_list_lock); |
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close_cached_dir(cfid); |
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} |
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void close_cached_dir(struct cached_fid *cfid) |
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{ |
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kref_put(&cfid->refcount, smb2_close_cached_fid); |
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} |
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/* |
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* Called from cifs_kill_sb when we unmount a share |
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*/ |
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void close_all_cached_dirs(struct cifs_sb_info *cifs_sb) |
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{ |
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struct rb_root *root = &cifs_sb->tlink_tree; |
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struct rb_node *node; |
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struct cached_fid *cfid; |
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struct cifs_tcon *tcon; |
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struct tcon_link *tlink; |
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struct cached_fids *cfids; |
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for (node = rb_first(root); node; node = rb_next(node)) { |
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tlink = rb_entry(node, struct tcon_link, tl_rbnode); |
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tcon = tlink_tcon(tlink); |
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if (IS_ERR(tcon)) |
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continue; |
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cfids = tcon->cfids; |
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if (cfids == NULL) |
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continue; |
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list_for_each_entry(cfid, &cfids->entries, entry) { |
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dput(cfid->dentry); |
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cfid->dentry = NULL; |
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} |
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} |
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} |
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/* |
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* Invalidate all cached dirs when a TCON has been reset |
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* due to a session loss. |
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*/ |
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void invalidate_all_cached_dirs(struct cifs_tcon *tcon) |
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{ |
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struct cached_fids *cfids = tcon->cfids; |
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struct cached_fid *cfid, *q; |
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LIST_HEAD(entry); |
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spin_lock(&cfids->cfid_list_lock); |
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list_for_each_entry_safe(cfid, q, &cfids->entries, entry) { |
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list_move(&cfid->entry, &entry); |
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cfids->num_entries--; |
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cfid->is_open = false; |
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cfid->on_list = false; |
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/* To prevent race with smb2_cached_lease_break() */ |
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kref_get(&cfid->refcount); |
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} |
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spin_unlock(&cfids->cfid_list_lock); |
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list_for_each_entry_safe(cfid, q, &entry, entry) { |
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list_del(&cfid->entry); |
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cancel_work_sync(&cfid->lease_break); |
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if (cfid->has_lease) { |
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/* |
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* We lease was never cancelled from the server so we |
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* need to drop the reference. |
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*/ |
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spin_lock(&cfids->cfid_list_lock); |
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cfid->has_lease = false; |
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spin_unlock(&cfids->cfid_list_lock); |
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kref_put(&cfid->refcount, smb2_close_cached_fid); |
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} |
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/* Drop the extra reference opened above*/ |
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kref_put(&cfid->refcount, smb2_close_cached_fid); |
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} |
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} |
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static void |
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smb2_cached_lease_break(struct work_struct *work) |
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{ |
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struct cached_fid *cfid = container_of(work, |
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struct cached_fid, lease_break); |
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spin_lock(&cfid->cfids->cfid_list_lock); |
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cfid->has_lease = false; |
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spin_unlock(&cfid->cfids->cfid_list_lock); |
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kref_put(&cfid->refcount, smb2_close_cached_fid); |
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} |
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int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16]) |
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{ |
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struct cached_fids *cfids = tcon->cfids; |
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struct cached_fid *cfid; |
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if (cfids == NULL) |
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return false; |
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spin_lock(&cfids->cfid_list_lock); |
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list_for_each_entry(cfid, &cfids->entries, entry) { |
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if (cfid->has_lease && |
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!memcmp(lease_key, |
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cfid->fid.lease_key, |
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SMB2_LEASE_KEY_SIZE)) { |
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cfid->time = 0; |
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/* |
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* We found a lease remove it from the list |
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* so no threads can access it. |
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*/ |
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list_del(&cfid->entry); |
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cfid->on_list = false; |
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cfids->num_entries--; |
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queue_work(cifsiod_wq, |
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&cfid->lease_break); |
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spin_unlock(&cfids->cfid_list_lock); |
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return true; |
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} |
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} |
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spin_unlock(&cfids->cfid_list_lock); |
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return false; |
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} |
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static struct cached_fid *init_cached_dir(const char *path) |
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{ |
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struct cached_fid *cfid; |
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cfid = kzalloc(sizeof(*cfid), GFP_ATOMIC); |
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if (!cfid) |
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return NULL; |
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cfid->path = kstrdup(path, GFP_ATOMIC); |
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if (!cfid->path) { |
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kfree(cfid); |
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return NULL; |
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} |
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|
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INIT_WORK(&cfid->lease_break, smb2_cached_lease_break); |
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INIT_LIST_HEAD(&cfid->entry); |
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INIT_LIST_HEAD(&cfid->dirents.entries); |
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mutex_init(&cfid->dirents.de_mutex); |
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spin_lock_init(&cfid->fid_lock); |
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kref_init(&cfid->refcount); |
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return cfid; |
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} |
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|
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static void free_cached_dir(struct cached_fid *cfid) |
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{ |
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struct cached_dirent *dirent, *q; |
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|
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dput(cfid->dentry); |
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cfid->dentry = NULL; |
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|
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/* |
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* Delete all cached dirent names |
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*/ |
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list_for_each_entry_safe(dirent, q, &cfid->dirents.entries, entry) { |
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list_del(&dirent->entry); |
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kfree(dirent->name); |
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kfree(dirent); |
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} |
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kfree(cfid->path); |
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cfid->path = NULL; |
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kfree(cfid); |
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} |
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struct cached_fids *init_cached_dirs(void) |
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{ |
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struct cached_fids *cfids; |
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cfids = kzalloc(sizeof(*cfids), GFP_KERNEL); |
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if (!cfids) |
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return NULL; |
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spin_lock_init(&cfids->cfid_list_lock); |
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INIT_LIST_HEAD(&cfids->entries); |
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return cfids; |
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} |
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|
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/* |
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* Called from tconInfoFree when we are tearing down the tcon. |
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* There are no active users or open files/directories at this point. |
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*/ |
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void free_cached_dirs(struct cached_fids *cfids) |
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{ |
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struct cached_fid *cfid, *q; |
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LIST_HEAD(entry); |
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|
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spin_lock(&cfids->cfid_list_lock); |
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list_for_each_entry_safe(cfid, q, &cfids->entries, entry) { |
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cfid->on_list = false; |
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cfid->is_open = false; |
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list_move(&cfid->entry, &entry); |
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} |
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spin_unlock(&cfids->cfid_list_lock); |
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|
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list_for_each_entry_safe(cfid, q, &entry, entry) { |
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list_del(&cfid->entry); |
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free_cached_dir(cfid); |
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} |
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|
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kfree(cfids); |
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}
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