fs/cifs/misc.c

0001 // SPDX-License-Identifier: LGPL-2.1
0002 /*
0003  *
0004  *   Copyright (C) International Business Machines  Corp., 2002,2008
0005  *   Author(s): Steve French (sfrench@us.ibm.com)
0006  *
0007  */
0008
0009 #include <linux/slab.h>
0010 #include <linux/ctype.h>
0011 #include <linux/mempool.h>
0012 #include <linux/vmalloc.h>
0013 #include "cifspdu.h"
0014 #include "cifsglob.h"
0015 #include "cifsproto.h"
0016 #include "cifs_debug.h"
0017 #include "smberr.h"
0018 #include "nterr.h"
0019 #include "cifs_unicode.h"
0020 #include "smb2pdu.h"
0021 #include "cifsfs.h"
0022 #ifdef CONFIG_CIFS_DFS_UPCALL
0023 #include "dns_resolve.h"
0024 #endif
0025 #include "fs_context.h"
0026 #include "cached_dir.h"
0027
0028 extern mempool_t *cifs_sm_req_poolp;
0029 extern mempool_t *cifs_req_poolp;
0030
0031 /* The xid serves as a useful identifier for each incoming vfs request,
0032    in a similar way to the mid which is useful to track each sent smb,
0033    and CurrentXid can also provide a running counter (although it
0034    will eventually wrap past zero) of the total vfs operations handled
0035    since the cifs fs was mounted */
0036
0037 unsigned int
0038 _get_xid(void)
0039 {
0040     unsigned int xid;
0041
0042     spin_lock(&GlobalMid_Lock);
0043     GlobalTotalActiveXid++;
0044
0045     /* keep high water mark for number of simultaneous ops in filesystem */
0046     if (GlobalTotalActiveXid > GlobalMaxActiveXid)
0047         GlobalMaxActiveXid = GlobalTotalActiveXid;
0048     if (GlobalTotalActiveXid > 65000)
0049         cifs_dbg(FYI, "warning: more than 65000 requests active\n");
0050     xid = GlobalCurrentXid++;
0051     spin_unlock(&GlobalMid_Lock);
0052     return xid;
0053 }
0054
0055 void
0056 _free_xid(unsigned int xid)
0057 {
0058     spin_lock(&GlobalMid_Lock);
0059     /* if (GlobalTotalActiveXid == 0)
0060         BUG(); */
0061     GlobalTotalActiveXid--;
0062     spin_unlock(&GlobalMid_Lock);
0063 }
0064
0065 struct cifs_ses *
0066 sesInfoAlloc(void)
0067 {
0068     struct cifs_ses *ret_buf;
0069
0070     ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
0071     if (ret_buf) {
0072         atomic_inc(&sesInfoAllocCount);
0073         spin_lock_init(&ret_buf->ses_lock);
0074         ret_buf->ses_status = SES_NEW;
0075         ++ret_buf->ses_count;
0076         INIT_LIST_HEAD(&ret_buf->smb_ses_list);
0077         INIT_LIST_HEAD(&ret_buf->tcon_list);
0078         mutex_init(&ret_buf->session_mutex);
0079         spin_lock_init(&ret_buf->iface_lock);
0080         INIT_LIST_HEAD(&ret_buf->iface_list);
0081         spin_lock_init(&ret_buf->chan_lock);
0082     }
0083     return ret_buf;
0084 }
0085
0086 void
0087 sesInfoFree(struct cifs_ses *buf_to_free)
0088 {
0089     struct cifs_server_iface *iface = NULL, *niface = NULL;
0090
0091     if (buf_to_free == NULL) {
0092         cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
0093         return;
0094     }
0095
0096     atomic_dec(&sesInfoAllocCount);
0097     kfree(buf_to_free->serverOS);
0098     kfree(buf_to_free->serverDomain);
0099     kfree(buf_to_free->serverNOS);
0100     kfree_sensitive(buf_to_free->password);
0101     kfree(buf_to_free->user_name);
0102     kfree(buf_to_free->domainName);
0103     kfree_sensitive(buf_to_free->auth_key.response);
0104     spin_lock(&buf_to_free->iface_lock);
0105     list_for_each_entry_safe(iface, niface, &buf_to_free->iface_list,
0106                  iface_head)
0107         kref_put(&iface->refcount, release_iface);
0108     spin_unlock(&buf_to_free->iface_lock);
0109     kfree_sensitive(buf_to_free);
0110 }
0111
0112 struct cifs_tcon *
0113 tconInfoAlloc(void)
0114 {
0115     struct cifs_tcon *ret_buf;
0116
0117     ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
0118     if (!ret_buf)
0119         return NULL;
0120     ret_buf->cfid = init_cached_dir();
0121     if (!ret_buf->cfid) {
0122         kfree(ret_buf);
0123         return NULL;
0124     }
0125
0126     atomic_inc(&tconInfoAllocCount);
0127     ret_buf->status = TID_NEW;
0128     ++ret_buf->tc_count;
0129     spin_lock_init(&ret_buf->tc_lock);
0130     INIT_LIST_HEAD(&ret_buf->openFileList);
0131     INIT_LIST_HEAD(&ret_buf->tcon_list);
0132     spin_lock_init(&ret_buf->open_file_lock);
0133     spin_lock_init(&ret_buf->stat_lock);
0134     atomic_set(&ret_buf->num_local_opens, 0);
0135     atomic_set(&ret_buf->num_remote_opens, 0);
0136
0137     return ret_buf;
0138 }
0139
0140 void
0141 tconInfoFree(struct cifs_tcon *tcon)
0142 {
0143     if (tcon == NULL) {
0144         cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
0145         return;
0146     }
0147     free_cached_dir(tcon);
0148     atomic_dec(&tconInfoAllocCount);
0149     kfree(tcon->nativeFileSystem);
0150     kfree_sensitive(tcon->password);
0151     kfree(tcon);
0152 }
0153
0154 struct smb_hdr *
0155 cifs_buf_get(void)
0156 {
0157     struct smb_hdr *ret_buf = NULL;
0158     /*
0159      * SMB2 header is bigger than CIFS one - no problems to clean some
0160      * more bytes for CIFS.
0161      */
0162     size_t buf_size = sizeof(struct smb2_hdr);
0163
0164     /*
0165      * We could use negotiated size instead of max_msgsize -
0166      * but it may be more efficient to always alloc same size
0167      * albeit slightly larger than necessary and maxbuffersize
0168      * defaults to this and can not be bigger.
0169      */
0170     ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
0171
0172     /* clear the first few header bytes */
0173     /* for most paths, more is cleared in header_assemble */
0174     memset(ret_buf, 0, buf_size + 3);
0175     atomic_inc(&buf_alloc_count);
0176 #ifdef CONFIG_CIFS_STATS2
0177     atomic_inc(&total_buf_alloc_count);
0178 #endif /* CONFIG_CIFS_STATS2 */
0179
0180     return ret_buf;
0181 }
0182
0183 void
0184 cifs_buf_release(void *buf_to_free)
0185 {
0186     if (buf_to_free == NULL) {
0187         /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
0188         return;
0189     }
0190     mempool_free(buf_to_free, cifs_req_poolp);
0191
0192     atomic_dec(&buf_alloc_count);
0193     return;
0194 }
0195
0196 struct smb_hdr *
0197 cifs_small_buf_get(void)
0198 {
0199     struct smb_hdr *ret_buf = NULL;
0200
0201 /* We could use negotiated size instead of max_msgsize -
0202    but it may be more efficient to always alloc same size
0203    albeit slightly larger than necessary and maxbuffersize
0204    defaults to this and can not be bigger */
0205     ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
0206     /* No need to clear memory here, cleared in header assemble */
0207     /*  memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
0208     atomic_inc(&small_buf_alloc_count);
0209 #ifdef CONFIG_CIFS_STATS2
0210     atomic_inc(&total_small_buf_alloc_count);
0211 #endif /* CONFIG_CIFS_STATS2 */
0212
0213     return ret_buf;
0214 }
0215
0216 void
0217 cifs_small_buf_release(void *buf_to_free)
0218 {
0219
0220     if (buf_to_free == NULL) {
0221         cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
0222         return;
0223     }
0224     mempool_free(buf_to_free, cifs_sm_req_poolp);
0225
0226     atomic_dec(&small_buf_alloc_count);
0227     return;
0228 }
0229
0230 void
0231 free_rsp_buf(int resp_buftype, void *rsp)
0232 {
0233     if (resp_buftype == CIFS_SMALL_BUFFER)
0234         cifs_small_buf_release(rsp);
0235     else if (resp_buftype == CIFS_LARGE_BUFFER)
0236         cifs_buf_release(rsp);
0237 }
0238
0239 /* NB: MID can not be set if treeCon not passed in, in that
0240    case it is responsbility of caller to set the mid */
0241 void
0242 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
0243         const struct cifs_tcon *treeCon, int word_count
0244         /* length of fixed section (word count) in two byte units  */)
0245 {
0246     char *temp = (char *) buffer;
0247
0248     memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
0249
0250     buffer->smb_buf_length = cpu_to_be32(
0251         (2 * word_count) + sizeof(struct smb_hdr) -
0252         4 /*  RFC 1001 length field does not count */  +
0253         2 /* for bcc field itself */) ;
0254
0255     buffer->Protocol[0] = 0xFF;
0256     buffer->Protocol[1] = 'S';
0257     buffer->Protocol[2] = 'M';
0258     buffer->Protocol[3] = 'B';
0259     buffer->Command = smb_command;
0260     buffer->Flags = 0x00;   /* case sensitive */
0261     buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
0262     buffer->Pid = cpu_to_le16((__u16)current->tgid);
0263     buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
0264     if (treeCon) {
0265         buffer->Tid = treeCon->tid;
0266         if (treeCon->ses) {
0267             if (treeCon->ses->capabilities & CAP_UNICODE)
0268                 buffer->Flags2 |= SMBFLG2_UNICODE;
0269             if (treeCon->ses->capabilities & CAP_STATUS32)
0270                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
0271
0272             /* Uid is not converted */
0273             buffer->Uid = treeCon->ses->Suid;
0274             if (treeCon->ses->server)
0275                 buffer->Mid = get_next_mid(treeCon->ses->server);
0276         }
0277         if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
0278             buffer->Flags2 |= SMBFLG2_DFS;
0279         if (treeCon->nocase)
0280             buffer->Flags  |= SMBFLG_CASELESS;
0281         if ((treeCon->ses) && (treeCon->ses->server))
0282             if (treeCon->ses->server->sign)
0283                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
0284     }
0285
0286 /*  endian conversion of flags is now done just before sending */
0287     buffer->WordCount = (char) word_count;
0288     return;
0289 }
0290
0291 static int
0292 check_smb_hdr(struct smb_hdr *smb)
0293 {
0294     /* does it have the right SMB "signature" ? */
0295     if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
0296         cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
0297              *(unsigned int *)smb->Protocol);
0298         return 1;
0299     }
0300
0301     /* if it's a response then accept */
0302     if (smb->Flags & SMBFLG_RESPONSE)
0303         return 0;
0304
0305     /* only one valid case where server sends us request */
0306     if (smb->Command == SMB_COM_LOCKING_ANDX)
0307         return 0;
0308
0309     cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
0310          get_mid(smb));
0311     return 1;
0312 }
0313
0314 int
0315 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
0316 {
0317     struct smb_hdr *smb = (struct smb_hdr *)buf;
0318     __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
0319     __u32 clc_len;  /* calculated length */
0320     cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
0321          total_read, rfclen);
0322
0323     /* is this frame too small to even get to a BCC? */
0324     if (total_read < 2 + sizeof(struct smb_hdr)) {
0325         if ((total_read >= sizeof(struct smb_hdr) - 1)
0326                 && (smb->Status.CifsError != 0)) {
0327             /* it's an error return */
0328             smb->WordCount = 0;
0329             /* some error cases do not return wct and bcc */
0330             return 0;
0331         } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
0332                 (smb->WordCount == 0)) {
0333             char *tmp = (char *)smb;
0334             /* Need to work around a bug in two servers here */
0335             /* First, check if the part of bcc they sent was zero */
0336             if (tmp[sizeof(struct smb_hdr)] == 0) {
0337                 /* some servers return only half of bcc
0338                  * on simple responses (wct, bcc both zero)
0339                  * in particular have seen this on
0340                  * ulogoffX and FindClose. This leaves
0341                  * one byte of bcc potentially unitialized
0342                  */
0343                 /* zero rest of bcc */
0344                 tmp[sizeof(struct smb_hdr)+1] = 0;
0345                 return 0;
0346             }
0347             cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
0348         } else {
0349             cifs_dbg(VFS, "Length less than smb header size\n");
0350         }
0351         return -EIO;
0352     }
0353
0354     /* otherwise, there is enough to get to the BCC */
0355     if (check_smb_hdr(smb))
0356         return -EIO;
0357     clc_len = smbCalcSize(smb);
0358
0359     if (4 + rfclen != total_read) {
0360         cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
0361              rfclen);
0362         return -EIO;
0363     }
0364
0365     if (4 + rfclen != clc_len) {
0366         __u16 mid = get_mid(smb);
0367         /* check if bcc wrapped around for large read responses */
0368         if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
0369             /* check if lengths match mod 64K */
0370             if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
0371                 return 0; /* bcc wrapped */
0372         }
0373         cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
0374              clc_len, 4 + rfclen, mid);
0375
0376         if (4 + rfclen < clc_len) {
0377             cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
0378                  rfclen, mid);
0379             return -EIO;
0380         } else if (rfclen > clc_len + 512) {
0381             /*
0382              * Some servers (Windows XP in particular) send more
0383              * data than the lengths in the SMB packet would
0384              * indicate on certain calls (byte range locks and
0385              * trans2 find first calls in particular). While the
0386              * client can handle such a frame by ignoring the
0387              * trailing data, we choose limit the amount of extra
0388              * data to 512 bytes.
0389              */
0390             cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
0391                  rfclen, mid);
0392             return -EIO;
0393         }
0394     }
0395     return 0;
0396 }
0397
0398 bool
0399 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
0400 {
0401     struct smb_hdr *buf = (struct smb_hdr *)buffer;
0402     struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
0403     struct cifs_ses *ses;
0404     struct cifs_tcon *tcon;
0405     struct cifsInodeInfo *pCifsInode;
0406     struct cifsFileInfo *netfile;
0407
0408     cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
0409     if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
0410        (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
0411         struct smb_com_transaction_change_notify_rsp *pSMBr =
0412             (struct smb_com_transaction_change_notify_rsp *)buf;
0413         struct file_notify_information *pnotify;
0414         __u32 data_offset = 0;
0415         size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
0416
0417         if (get_bcc(buf) > sizeof(struct file_notify_information)) {
0418             data_offset = le32_to_cpu(pSMBr->DataOffset);
0419
0420             if (data_offset >
0421                 len - sizeof(struct file_notify_information)) {
0422                 cifs_dbg(FYI, "Invalid data_offset %u\n",
0423                      data_offset);
0424                 return true;
0425             }
0426             pnotify = (struct file_notify_information *)
0427                 ((char *)&pSMBr->hdr.Protocol + data_offset);
0428             cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
0429                  pnotify->FileName, pnotify->Action);
0430             /*   cifs_dump_mem("Rcvd notify Data: ",buf,
0431                 sizeof(struct smb_hdr)+60); */
0432             return true;
0433         }
0434         if (pSMBr->hdr.Status.CifsError) {
0435             cifs_dbg(FYI, "notify err 0x%x\n",
0436                  pSMBr->hdr.Status.CifsError);
0437             return true;
0438         }
0439         return false;
0440     }
0441     if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
0442         return false;
0443     if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
0444         /* no sense logging error on invalid handle on oplock
0445            break - harmless race between close request and oplock
0446            break response is expected from time to time writing out
0447            large dirty files cached on the client */
0448         if ((NT_STATUS_INVALID_HANDLE) ==
0449            le32_to_cpu(pSMB->hdr.Status.CifsError)) {
0450             cifs_dbg(FYI, "Invalid handle on oplock break\n");
0451             return true;
0452         } else if (ERRbadfid ==
0453            le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
0454             return true;
0455         } else {
0456             return false; /* on valid oplock brk we get "request" */
0457         }
0458     }
0459     if (pSMB->hdr.WordCount != 8)
0460         return false;
0461
0462     cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
0463          pSMB->LockType, pSMB->OplockLevel);
0464     if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
0465         return false;
0466
0467     /* look up tcon based on tid & uid */
0468     spin_lock(&cifs_tcp_ses_lock);
0469     list_for_each_entry(ses, &srv->smb_ses_list, smb_ses_list) {
0470         list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
0471             if (tcon->tid != buf->Tid)
0472                 continue;
0473
0474             cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
0475             spin_lock(&tcon->open_file_lock);
0476             list_for_each_entry(netfile, &tcon->openFileList, tlist) {
0477                 if (pSMB->Fid != netfile->fid.netfid)
0478                     continue;
0479
0480                 cifs_dbg(FYI, "file id match, oplock break\n");
0481                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
0482
0483                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
0484                     &pCifsInode->flags);
0485
0486                 netfile->oplock_epoch = 0;
0487                 netfile->oplock_level = pSMB->OplockLevel;
0488                 netfile->oplock_break_cancelled = false;
0489                 cifs_queue_oplock_break(netfile);
0490
0491                 spin_unlock(&tcon->open_file_lock);
0492                 spin_unlock(&cifs_tcp_ses_lock);
0493                 return true;
0494             }
0495             spin_unlock(&tcon->open_file_lock);
0496             spin_unlock(&cifs_tcp_ses_lock);
0497             cifs_dbg(FYI, "No matching file for oplock break\n");
0498             return true;
0499         }
0500     }
0501     spin_unlock(&cifs_tcp_ses_lock);
0502     cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
0503     return true;
0504 }
0505
0506 void
0507 dump_smb(void *buf, int smb_buf_length)
0508 {
0509     if (traceSMB == 0)
0510         return;
0511
0512     print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
0513                smb_buf_length, true);
0514 }
0515
0516 void
0517 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
0518 {
0519     if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
0520         struct cifs_tcon *tcon = NULL;
0521
0522         if (cifs_sb->master_tlink)
0523             tcon = cifs_sb_master_tcon(cifs_sb);
0524
0525         cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
0526         cifs_sb->mnt_cifs_serverino_autodisabled = true;
0527         cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
0528              tcon ? tcon->treeName : "new server");
0529         cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
0530         cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
0531
0532     }
0533 }
0534
0535 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
0536 {
0537     oplock &= 0xF;
0538
0539     if (oplock == OPLOCK_EXCLUSIVE) {
0540         cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
0541         cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
0542              &cinode->netfs.inode);
0543     } else if (oplock == OPLOCK_READ) {
0544         cinode->oplock = CIFS_CACHE_READ_FLG;
0545         cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
0546              &cinode->netfs.inode);
0547     } else
0548         cinode->oplock = 0;
0549 }
0550
0551 /*
0552  * We wait for oplock breaks to be processed before we attempt to perform
0553  * writes.
0554  */
0555 int cifs_get_writer(struct cifsInodeInfo *cinode)
0556 {
0557     int rc;
0558
0559 start:
0560     rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
0561              TASK_KILLABLE);
0562     if (rc)
0563         return rc;
0564
0565     spin_lock(&cinode->writers_lock);
0566     if (!cinode->writers)
0567         set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
0568     cinode->writers++;
0569     /* Check to see if we have started servicing an oplock break */
0570     if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
0571         cinode->writers--;
0572         if (cinode->writers == 0) {
0573             clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
0574             wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
0575         }
0576         spin_unlock(&cinode->writers_lock);
0577         goto start;
0578     }
0579     spin_unlock(&cinode->writers_lock);
0580     return 0;
0581 }
0582
0583 void cifs_put_writer(struct cifsInodeInfo *cinode)
0584 {
0585     spin_lock(&cinode->writers_lock);
0586     cinode->writers--;
0587     if (cinode->writers == 0) {
0588         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
0589         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
0590     }
0591     spin_unlock(&cinode->writers_lock);
0592 }
0593
0594 /**
0595  * cifs_queue_oplock_break - queue the oplock break handler for cfile
0596  * @cfile: The file to break the oplock on
0597  *
0598  * This function is called from the demultiplex thread when it
0599  * receives an oplock break for @cfile.
0600  *
0601  * Assumes the tcon->open_file_lock is held.
0602  * Assumes cfile->file_info_lock is NOT held.
0603  */
0604 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
0605 {
0606     /*
0607      * Bump the handle refcount now while we hold the
0608      * open_file_lock to enforce the validity of it for the oplock
0609      * break handler. The matching put is done at the end of the
0610      * handler.
0611      */
0612     cifsFileInfo_get(cfile);
0613
0614     queue_work(cifsoplockd_wq, &cfile->oplock_break);
0615 }
0616
0617 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
0618 {
0619     clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
0620     wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
0621 }
0622
0623 bool
0624 backup_cred(struct cifs_sb_info *cifs_sb)
0625 {
0626     if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
0627         if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
0628             return true;
0629     }
0630     if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
0631         if (in_group_p(cifs_sb->ctx->backupgid))
0632             return true;
0633     }
0634
0635     return false;
0636 }
0637
0638 void
0639 cifs_del_pending_open(struct cifs_pending_open *open)
0640 {
0641     spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
0642     list_del(&open->olist);
0643     spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
0644 }
0645
0646 void
0647 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
0648                  struct cifs_pending_open *open)
0649 {
0650     memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
0651     open->oplock = CIFS_OPLOCK_NO_CHANGE;
0652     open->tlink = tlink;
0653     fid->pending_open = open;
0654     list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
0655 }
0656
0657 void
0658 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
0659               struct cifs_pending_open *open)
0660 {
0661     spin_lock(&tlink_tcon(tlink)->open_file_lock);
0662     cifs_add_pending_open_locked(fid, tlink, open);
0663     spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
0664 }
0665
0666 /*
0667  * Critical section which runs after acquiring deferred_lock.
0668  * As there is no reference count on cifs_deferred_close, pdclose
0669  * should not be used outside deferred_lock.
0670  */
0671 bool
0672 cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
0673 {
0674     struct cifs_deferred_close *dclose;
0675
0676     list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
0677         if ((dclose->netfid == cfile->fid.netfid) &&
0678             (dclose->persistent_fid == cfile->fid.persistent_fid) &&
0679             (dclose->volatile_fid == cfile->fid.volatile_fid)) {
0680             *pdclose = dclose;
0681             return true;
0682         }
0683     }
0684     return false;
0685 }
0686
0687 /*
0688  * Critical section which runs after acquiring deferred_lock.
0689  */
0690 void
0691 cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
0692 {
0693     bool is_deferred = false;
0694     struct cifs_deferred_close *pdclose;
0695
0696     is_deferred = cifs_is_deferred_close(cfile, &pdclose);
0697     if (is_deferred) {
0698         kfree(dclose);
0699         return;
0700     }
0701
0702     dclose->tlink = cfile->tlink;
0703     dclose->netfid = cfile->fid.netfid;
0704     dclose->persistent_fid = cfile->fid.persistent_fid;
0705     dclose->volatile_fid = cfile->fid.volatile_fid;
0706     list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
0707 }
0708
0709 /*
0710  * Critical section which runs after acquiring deferred_lock.
0711  */
0712 void
0713 cifs_del_deferred_close(struct cifsFileInfo *cfile)
0714 {
0715     bool is_deferred = false;
0716     struct cifs_deferred_close *dclose;
0717
0718     is_deferred = cifs_is_deferred_close(cfile, &dclose);
0719     if (!is_deferred)
0720         return;
0721     list_del(&dclose->dlist);
0722     kfree(dclose);
0723 }
0724
0725 void
0726 cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
0727 {
0728     struct cifsFileInfo *cfile = NULL;
0729     struct file_list *tmp_list, *tmp_next_list;
0730     struct list_head file_head;
0731
0732     if (cifs_inode == NULL)
0733         return;
0734
0735     INIT_LIST_HEAD(&file_head);
0736     spin_lock(&cifs_inode->open_file_lock);
0737     list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
0738         if (delayed_work_pending(&cfile->deferred)) {
0739             if (cancel_delayed_work(&cfile->deferred)) {
0740                 cifs_del_deferred_close(cfile);
0741
0742                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
0743                 if (tmp_list == NULL)
0744                     break;
0745                 tmp_list->cfile = cfile;
0746                 list_add_tail(&tmp_list->list, &file_head);
0747             }
0748         }
0749     }
0750     spin_unlock(&cifs_inode->open_file_lock);
0751
0752     list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
0753         _cifsFileInfo_put(tmp_list->cfile, true, false);
0754         list_del(&tmp_list->list);
0755         kfree(tmp_list);
0756     }
0757 }
0758
0759 void
0760 cifs_close_all_deferred_files(struct cifs_tcon *tcon)
0761 {
0762     struct cifsFileInfo *cfile;
0763     struct file_list *tmp_list, *tmp_next_list;
0764     struct list_head file_head;
0765
0766     INIT_LIST_HEAD(&file_head);
0767     spin_lock(&tcon->open_file_lock);
0768     list_for_each_entry(cfile, &tcon->openFileList, tlist) {
0769         if (delayed_work_pending(&cfile->deferred)) {
0770             if (cancel_delayed_work(&cfile->deferred)) {
0771                 cifs_del_deferred_close(cfile);
0772
0773                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
0774                 if (tmp_list == NULL)
0775                     break;
0776                 tmp_list->cfile = cfile;
0777                 list_add_tail(&tmp_list->list, &file_head);
0778             }
0779         }
0780     }
0781     spin_unlock(&tcon->open_file_lock);
0782
0783     list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
0784         _cifsFileInfo_put(tmp_list->cfile, true, false);
0785         list_del(&tmp_list->list);
0786         kfree(tmp_list);
0787     }
0788 }
0789 void
0790 cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon, const char *path)
0791 {
0792     struct cifsFileInfo *cfile;
0793     struct file_list *tmp_list, *tmp_next_list;
0794     struct list_head file_head;
0795     void *page;
0796     const char *full_path;
0797
0798     INIT_LIST_HEAD(&file_head);
0799     page = alloc_dentry_path();
0800     spin_lock(&tcon->open_file_lock);
0801     list_for_each_entry(cfile, &tcon->openFileList, tlist) {
0802         full_path = build_path_from_dentry(cfile->dentry, page);
0803         if (strstr(full_path, path)) {
0804             if (delayed_work_pending(&cfile->deferred)) {
0805                 if (cancel_delayed_work(&cfile->deferred)) {
0806                     cifs_del_deferred_close(cfile);
0807
0808                     tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
0809                     if (tmp_list == NULL)
0810                         break;
0811                     tmp_list->cfile = cfile;
0812                     list_add_tail(&tmp_list->list, &file_head);
0813                 }
0814             }
0815         }
0816     }
0817     spin_unlock(&tcon->open_file_lock);
0818
0819     list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
0820         _cifsFileInfo_put(tmp_list->cfile, true, false);
0821         list_del(&tmp_list->list);
0822         kfree(tmp_list);
0823     }
0824     free_dentry_path(page);
0825 }
0826
0827 /* parses DFS refferal V3 structure
0828  * caller is responsible for freeing target_nodes
0829  * returns:
0830  * - on success - 0
0831  * - on failure - errno
0832  */
0833 int
0834 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
0835             unsigned int *num_of_nodes,
0836             struct dfs_info3_param **target_nodes,
0837             const struct nls_table *nls_codepage, int remap,
0838             const char *searchName, bool is_unicode)
0839 {
0840     int i, rc = 0;
0841     char *data_end;
0842     struct dfs_referral_level_3 *ref;
0843
0844     *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
0845
0846     if (*num_of_nodes < 1) {
0847         cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
0848              *num_of_nodes);
0849         rc = -EINVAL;
0850         goto parse_DFS_referrals_exit;
0851     }
0852
0853     ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
0854     if (ref->VersionNumber != cpu_to_le16(3)) {
0855         cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
0856              le16_to_cpu(ref->VersionNumber));
0857         rc = -EINVAL;
0858         goto parse_DFS_referrals_exit;
0859     }
0860
0861     /* get the upper boundary of the resp buffer */
0862     data_end = (char *)rsp + rsp_size;
0863
0864     cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
0865          *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
0866
0867     *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
0868                 GFP_KERNEL);
0869     if (*target_nodes == NULL) {
0870         rc = -ENOMEM;
0871         goto parse_DFS_referrals_exit;
0872     }
0873
0874     /* collect necessary data from referrals */
0875     for (i = 0; i < *num_of_nodes; i++) {
0876         char *temp;
0877         int max_len;
0878         struct dfs_info3_param *node = (*target_nodes)+i;
0879
0880         node->flags = le32_to_cpu(rsp->DFSFlags);
0881         if (is_unicode) {
0882             __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
0883                         GFP_KERNEL);
0884             if (tmp == NULL) {
0885                 rc = -ENOMEM;
0886                 goto parse_DFS_referrals_exit;
0887             }
0888             cifsConvertToUTF16((__le16 *) tmp, searchName,
0889                        PATH_MAX, nls_codepage, remap);
0890             node->path_consumed = cifs_utf16_bytes(tmp,
0891                     le16_to_cpu(rsp->PathConsumed),
0892                     nls_codepage);
0893             kfree(tmp);
0894         } else
0895             node->path_consumed = le16_to_cpu(rsp->PathConsumed);
0896
0897         node->server_type = le16_to_cpu(ref->ServerType);
0898         node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
0899
0900         /* copy DfsPath */
0901         temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
0902         max_len = data_end - temp;
0903         node->path_name = cifs_strndup_from_utf16(temp, max_len,
0904                         is_unicode, nls_codepage);
0905         if (!node->path_name) {
0906             rc = -ENOMEM;
0907             goto parse_DFS_referrals_exit;
0908         }
0909
0910         /* copy link target UNC */
0911         temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
0912         max_len = data_end - temp;
0913         node->node_name = cifs_strndup_from_utf16(temp, max_len,
0914                         is_unicode, nls_codepage);
0915         if (!node->node_name) {
0916             rc = -ENOMEM;
0917             goto parse_DFS_referrals_exit;
0918         }
0919
0920         node->ttl = le32_to_cpu(ref->TimeToLive);
0921
0922         ref++;
0923     }
0924
0925 parse_DFS_referrals_exit:
0926     if (rc) {
0927         free_dfs_info_array(*target_nodes, *num_of_nodes);
0928         *target_nodes = NULL;
0929         *num_of_nodes = 0;
0930     }
0931     return rc;
0932 }
0933
0934 struct cifs_aio_ctx *
0935 cifs_aio_ctx_alloc(void)
0936 {
0937     struct cifs_aio_ctx *ctx;
0938
0939     /*
0940      * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
0941      * to false so that we know when we have to unreference pages within
0942      * cifs_aio_ctx_release()
0943      */
0944     ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
0945     if (!ctx)
0946         return NULL;
0947
0948     INIT_LIST_HEAD(&ctx->list);
0949     mutex_init(&ctx->aio_mutex);
0950     init_completion(&ctx->done);
0951     kref_init(&ctx->refcount);
0952     return ctx;
0953 }
0954
0955 void
0956 cifs_aio_ctx_release(struct kref *refcount)
0957 {
0958     struct cifs_aio_ctx *ctx = container_of(refcount,
0959                     struct cifs_aio_ctx, refcount);
0960
0961     cifsFileInfo_put(ctx->cfile);
0962
0963     /*
0964      * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
0965      * which means that iov_iter_get_pages() was a success and thus that
0966      * we have taken reference on pages.
0967      */
0968     if (ctx->bv) {
0969         unsigned i;
0970
0971         for (i = 0; i < ctx->npages; i++) {
0972             if (ctx->should_dirty)
0973                 set_page_dirty(ctx->bv[i].bv_page);
0974             put_page(ctx->bv[i].bv_page);
0975         }
0976         kvfree(ctx->bv);
0977     }
0978
0979     kfree(ctx);
0980 }
0981
0982 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
0983
0984 int
0985 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
0986 {
0987     ssize_t rc;
0988     unsigned int cur_npages;
0989     unsigned int npages = 0;
0990     unsigned int i;
0991     size_t len;
0992     size_t count = iov_iter_count(iter);
0993     unsigned int saved_len;
0994     size_t start;
0995     unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
0996     struct page **pages = NULL;
0997     struct bio_vec *bv = NULL;
0998
0999     if (iov_iter_is_kvec(iter)) {
1000         memcpy(&ctx->iter, iter, sizeof(*iter));
1001         ctx->len = count;
1002         iov_iter_advance(iter, count);
1003         return 0;
1004     }
1005
1006     if (array_size(max_pages, sizeof(*bv)) <= CIFS_AIO_KMALLOC_LIMIT)
1007         bv = kmalloc_array(max_pages, sizeof(*bv), GFP_KERNEL);
1008
1009     if (!bv) {
1010         bv = vmalloc(array_size(max_pages, sizeof(*bv)));
1011         if (!bv)
1012             return -ENOMEM;
1013     }
1014
1015     if (array_size(max_pages, sizeof(*pages)) <= CIFS_AIO_KMALLOC_LIMIT)
1016         pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
1017
1018     if (!pages) {
1019         pages = vmalloc(array_size(max_pages, sizeof(*pages)));
1020         if (!pages) {
1021             kvfree(bv);
1022             return -ENOMEM;
1023         }
1024     }
1025
1026     saved_len = count;
1027
1028     while (count && npages < max_pages) {
1029         rc = iov_iter_get_pages2(iter, pages, count, max_pages, &start);
1030         if (rc < 0) {
1031             cifs_dbg(VFS, "Couldn't get user pages (rc=%zd)\n", rc);
1032             break;
1033         }
1034
1035         if (rc > count) {
1036             cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
1037                  count);
1038             break;
1039         }
1040
1041         count -= rc;
1042         rc += start;
1043         cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
1044
1045         if (npages + cur_npages > max_pages) {
1046             cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
1047                  npages + cur_npages, max_pages);
1048             break;
1049         }
1050
1051         for (i = 0; i < cur_npages; i++) {
1052             len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
1053             bv[npages + i].bv_page = pages[i];
1054             bv[npages + i].bv_offset = start;
1055             bv[npages + i].bv_len = len - start;
1056             rc -= len;
1057             start = 0;
1058         }
1059
1060         npages += cur_npages;
1061     }
1062
1063     kvfree(pages);
1064     ctx->bv = bv;
1065     ctx->len = saved_len - count;
1066     ctx->npages = npages;
1067     iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
1068     return 0;
1069 }
1070
1071 /**
1072  * cifs_alloc_hash - allocate hash and hash context together
1073  * @name: The name of the crypto hash algo
1074  * @shash: Where to put the pointer to the hash algo
1075  * @sdesc: Where to put the pointer to the hash descriptor
1076  *
1077  * The caller has to make sure @sdesc is initialized to either NULL or
1078  * a valid context. Both can be freed via cifs_free_hash().
1079  */
1080 int
1081 cifs_alloc_hash(const char *name,
1082         struct crypto_shash **shash, struct sdesc **sdesc)
1083 {
1084     int rc = 0;
1085     size_t size;
1086
1087     if (*sdesc != NULL)
1088         return 0;
1089
1090     *shash = crypto_alloc_shash(name, 0, 0);
1091     if (IS_ERR(*shash)) {
1092         cifs_dbg(VFS, "Could not allocate crypto %s\n", name);
1093         rc = PTR_ERR(*shash);
1094         *shash = NULL;
1095         *sdesc = NULL;
1096         return rc;
1097     }
1098
1099     size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
1100     *sdesc = kmalloc(size, GFP_KERNEL);
1101     if (*sdesc == NULL) {
1102         cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
1103         crypto_free_shash(*shash);
1104         *shash = NULL;
1105         return -ENOMEM;
1106     }
1107
1108     (*sdesc)->shash.tfm = *shash;
1109     return 0;
1110 }
1111
1112 /**
1113  * cifs_free_hash - free hash and hash context together
1114  * @shash: Where to find the pointer to the hash algo
1115  * @sdesc: Where to find the pointer to the hash descriptor
1116  *
1117  * Freeing a NULL hash or context is safe.
1118  */
1119 void
1120 cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
1121 {
1122     kfree(*sdesc);
1123     *sdesc = NULL;
1124     if (*shash)
1125         crypto_free_shash(*shash);
1126     *shash = NULL;
1127 }
1128
1129 /**
1130  * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
1131  * @rqst: The request descriptor
1132  * @page: The index of the page to query
1133  * @len: Where to store the length for this page:
1134  * @offset: Where to store the offset for this page
1135  */
1136 void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,
1137                 unsigned int *len, unsigned int *offset)
1138 {
1139     *len = rqst->rq_pagesz;
1140     *offset = (page == 0) ? rqst->rq_offset : 0;
1141
1142     if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
1143         *len = rqst->rq_tailsz;
1144     else if (page == 0)
1145         *len = rqst->rq_pagesz - rqst->rq_offset;
1146 }
1147
1148 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
1149 {
1150     const char *end;
1151
1152     /* skip initial slashes */
1153     while (*unc && (*unc == '\\' || *unc == '/'))
1154         unc++;
1155
1156     end = unc;
1157
1158     while (*end && !(*end == '\\' || *end == '/'))
1159         end++;
1160
1161     *h = unc;
1162     *len = end - unc;
1163 }
1164
1165 /**
1166  * copy_path_name - copy src path to dst, possibly truncating
1167  * @dst: The destination buffer
1168  * @src: The source name
1169  *
1170  * returns number of bytes written (including trailing nul)
1171  */
1172 int copy_path_name(char *dst, const char *src)
1173 {
1174     int name_len;
1175
1176     /*
1177      * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1178      * will truncate and strlen(dst) will be PATH_MAX-1
1179      */
1180     name_len = strscpy(dst, src, PATH_MAX);
1181     if (WARN_ON_ONCE(name_len < 0))
1182         name_len = PATH_MAX-1;
1183
1184     /* we count the trailing nul */
1185     name_len++;
1186     return name_len;
1187 }
1188
1189 struct super_cb_data {
1190     void *data;
1191     struct super_block *sb;
1192 };
1193
1194 static void tcp_super_cb(struct super_block *sb, void *arg)
1195 {
1196     struct super_cb_data *sd = arg;
1197     struct TCP_Server_Info *server = sd->data;
1198     struct cifs_sb_info *cifs_sb;
1199     struct cifs_tcon *tcon;
1200
1201     if (sd->sb)
1202         return;
1203
1204     cifs_sb = CIFS_SB(sb);
1205     tcon = cifs_sb_master_tcon(cifs_sb);
1206     if (tcon->ses->server == server)
1207         sd->sb = sb;
1208 }
1209
1210 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1211                         void *data)
1212 {
1213     struct super_cb_data sd = {
1214         .data = data,
1215         .sb = NULL,
1216     };
1217     struct file_system_type **fs_type = (struct file_system_type *[]) {
1218         &cifs_fs_type, &smb3_fs_type, NULL,
1219     };
1220
1221     for (; *fs_type; fs_type++) {
1222         iterate_supers_type(*fs_type, f, &sd);
1223         if (sd.sb) {
1224             /*
1225              * Grab an active reference in order to prevent automounts (DFS links)
1226              * of expiring and then freeing up our cifs superblock pointer while
1227              * we're doing failover.
1228              */
1229             cifs_sb_active(sd.sb);
1230             return sd.sb;
1231         }
1232     }
1233     return ERR_PTR(-EINVAL);
1234 }
1235
1236 static void __cifs_put_super(struct super_block *sb)
1237 {
1238     if (!IS_ERR_OR_NULL(sb))
1239         cifs_sb_deactive(sb);
1240 }
1241
1242 struct super_block *cifs_get_tcp_super(struct TCP_Server_Info *server)
1243 {
1244     return __cifs_get_super(tcp_super_cb, server);
1245 }
1246
1247 void cifs_put_tcp_super(struct super_block *sb)
1248 {
1249     __cifs_put_super(sb);
1250 }
1251
1252 #ifdef CONFIG_CIFS_DFS_UPCALL
1253 int match_target_ip(struct TCP_Server_Info *server,
1254             const char *share, size_t share_len,
1255             bool *result)
1256 {
1257     int rc;
1258     char *target, *tip = NULL;
1259     struct sockaddr tipaddr;
1260
1261     *result = false;
1262
1263     target = kzalloc(share_len + 3, GFP_KERNEL);
1264     if (!target) {
1265         rc = -ENOMEM;
1266         goto out;
1267     }
1268
1269     scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
1270
1271     cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
1272
1273     rc = dns_resolve_server_name_to_ip(target, &tip, NULL);
1274     if (rc < 0)
1275         goto out;
1276
1277     cifs_dbg(FYI, "%s: target ip: %s\n", __func__, tip);
1278
1279     if (!cifs_convert_address(&tipaddr, tip, strlen(tip))) {
1280         cifs_dbg(VFS, "%s: failed to convert target ip address\n",
1281              __func__);
1282         rc = -EINVAL;
1283         goto out;
1284     }
1285
1286     *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr,
1287                     &tipaddr);
1288     cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
1289     rc = 0;
1290
1291 out:
1292     kfree(target);
1293     kfree(tip);
1294
1295     return rc;
1296 }
1297
1298 int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
1299 {
1300     kfree(cifs_sb->prepath);
1301
1302     if (prefix && *prefix) {
1303         cifs_sb->prepath = kstrdup(prefix, GFP_ATOMIC);
1304         if (!cifs_sb->prepath)
1305             return -ENOMEM;
1306
1307         convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1308     } else
1309         cifs_sb->prepath = NULL;
1310
1311     cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1312     return 0;
1313 }
1314
1315 /** cifs_dfs_query_info_nonascii_quirk
1316  * Handle weird Windows SMB server behaviour. It responds with
1317  * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request
1318  * for "\<server>\<dfsname>\<linkpath>" DFS reference,
1319  * where <dfsname> contains non-ASCII unicode symbols.
1320  *
1321  * Check such DFS reference.
1322  */
1323 int cifs_dfs_query_info_nonascii_quirk(const unsigned int xid,
1324                        struct cifs_tcon *tcon,
1325                        struct cifs_sb_info *cifs_sb,
1326                        const char *linkpath)
1327 {
1328     char *treename, *dfspath, sep;
1329     int treenamelen, linkpathlen, rc;
1330
1331     treename = tcon->treeName;
1332     /* MS-DFSC: All paths in REQ_GET_DFS_REFERRAL and RESP_GET_DFS_REFERRAL
1333      * messages MUST be encoded with exactly one leading backslash, not two
1334      * leading backslashes.
1335      */
1336     sep = CIFS_DIR_SEP(cifs_sb);
1337     if (treename[0] == sep && treename[1] == sep)
1338         treename++;
1339     linkpathlen = strlen(linkpath);
1340     treenamelen = strnlen(treename, MAX_TREE_SIZE + 1);
1341     dfspath = kzalloc(treenamelen + linkpathlen + 1, GFP_KERNEL);
1342     if (!dfspath)
1343         return -ENOMEM;
1344     if (treenamelen)
1345         memcpy(dfspath, treename, treenamelen);
1346     memcpy(dfspath + treenamelen, linkpath, linkpathlen);
1347     rc = dfs_cache_find(xid, tcon->ses, cifs_sb->local_nls,
1348                 cifs_remap(cifs_sb), dfspath, NULL, NULL);
1349     if (rc == 0) {
1350         cifs_dbg(FYI, "DFS ref '%s' is found, emulate -EREMOTE\n",
1351              dfspath);
1352         rc = -EREMOTE;
1353     } else {
1354         cifs_dbg(FYI, "%s: dfs_cache_find returned %d\n", __func__, rc);
1355     }
1356     kfree(dfspath);
1357     return rc;
1358 }
1359 #endif