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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /fs/smb/client/misc.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/smb/client/misc.c')
-rw-r--r--fs/smb/client/misc.c1360
1 files changed, 1360 insertions, 0 deletions
diff --git a/fs/smb/client/misc.c b/fs/smb/client/misc.c
new file mode 100644
index 0000000000..c2137ea3c2
--- /dev/null
+++ b/fs/smb/client/misc.c
@@ -0,0 +1,1360 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ *
+ * Copyright (C) International Business Machines Corp., 2002,2008
+ * Author(s): Steve French (sfrench@us.ibm.com)
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/ctype.h>
+#include <linux/mempool.h>
+#include <linux/vmalloc.h>
+#include "cifspdu.h"
+#include "cifsglob.h"
+#include "cifsproto.h"
+#include "cifs_debug.h"
+#include "smberr.h"
+#include "nterr.h"
+#include "cifs_unicode.h"
+#include "smb2pdu.h"
+#include "cifsfs.h"
+#ifdef CONFIG_CIFS_DFS_UPCALL
+#include "dns_resolve.h"
+#include "dfs_cache.h"
+#include "dfs.h"
+#endif
+#include "fs_context.h"
+#include "cached_dir.h"
+
+extern mempool_t *cifs_sm_req_poolp;
+extern mempool_t *cifs_req_poolp;
+
+/* The xid serves as a useful identifier for each incoming vfs request,
+ in a similar way to the mid which is useful to track each sent smb,
+ and CurrentXid can also provide a running counter (although it
+ will eventually wrap past zero) of the total vfs operations handled
+ since the cifs fs was mounted */
+
+unsigned int
+_get_xid(void)
+{
+ unsigned int xid;
+
+ spin_lock(&GlobalMid_Lock);
+ GlobalTotalActiveXid++;
+
+ /* keep high water mark for number of simultaneous ops in filesystem */
+ if (GlobalTotalActiveXid > GlobalMaxActiveXid)
+ GlobalMaxActiveXid = GlobalTotalActiveXid;
+ if (GlobalTotalActiveXid > 65000)
+ cifs_dbg(FYI, "warning: more than 65000 requests active\n");
+ xid = GlobalCurrentXid++;
+ spin_unlock(&GlobalMid_Lock);
+ return xid;
+}
+
+void
+_free_xid(unsigned int xid)
+{
+ spin_lock(&GlobalMid_Lock);
+ /* if (GlobalTotalActiveXid == 0)
+ BUG(); */
+ GlobalTotalActiveXid--;
+ spin_unlock(&GlobalMid_Lock);
+}
+
+struct cifs_ses *
+sesInfoAlloc(void)
+{
+ struct cifs_ses *ret_buf;
+
+ ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
+ if (ret_buf) {
+ atomic_inc(&sesInfoAllocCount);
+ spin_lock_init(&ret_buf->ses_lock);
+ ret_buf->ses_status = SES_NEW;
+ ++ret_buf->ses_count;
+ INIT_LIST_HEAD(&ret_buf->smb_ses_list);
+ INIT_LIST_HEAD(&ret_buf->tcon_list);
+ mutex_init(&ret_buf->session_mutex);
+ spin_lock_init(&ret_buf->iface_lock);
+ INIT_LIST_HEAD(&ret_buf->iface_list);
+ spin_lock_init(&ret_buf->chan_lock);
+ }
+ return ret_buf;
+}
+
+void
+sesInfoFree(struct cifs_ses *buf_to_free)
+{
+ struct cifs_server_iface *iface = NULL, *niface = NULL;
+
+ if (buf_to_free == NULL) {
+ cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
+ return;
+ }
+
+ unload_nls(buf_to_free->local_nls);
+ atomic_dec(&sesInfoAllocCount);
+ kfree(buf_to_free->serverOS);
+ kfree(buf_to_free->serverDomain);
+ kfree(buf_to_free->serverNOS);
+ kfree_sensitive(buf_to_free->password);
+ kfree(buf_to_free->user_name);
+ kfree(buf_to_free->domainName);
+ kfree_sensitive(buf_to_free->auth_key.response);
+ spin_lock(&buf_to_free->iface_lock);
+ list_for_each_entry_safe(iface, niface, &buf_to_free->iface_list,
+ iface_head)
+ kref_put(&iface->refcount, release_iface);
+ spin_unlock(&buf_to_free->iface_lock);
+ kfree_sensitive(buf_to_free);
+}
+
+struct cifs_tcon *
+tcon_info_alloc(bool dir_leases_enabled)
+{
+ struct cifs_tcon *ret_buf;
+
+ ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
+ if (!ret_buf)
+ return NULL;
+
+ if (dir_leases_enabled == true) {
+ ret_buf->cfids = init_cached_dirs();
+ if (!ret_buf->cfids) {
+ kfree(ret_buf);
+ return NULL;
+ }
+ }
+ /* else ret_buf->cfids is already set to NULL above */
+
+ atomic_inc(&tconInfoAllocCount);
+ ret_buf->status = TID_NEW;
+ ++ret_buf->tc_count;
+ spin_lock_init(&ret_buf->tc_lock);
+ INIT_LIST_HEAD(&ret_buf->openFileList);
+ INIT_LIST_HEAD(&ret_buf->tcon_list);
+ spin_lock_init(&ret_buf->open_file_lock);
+ spin_lock_init(&ret_buf->stat_lock);
+ atomic_set(&ret_buf->num_local_opens, 0);
+ atomic_set(&ret_buf->num_remote_opens, 0);
+#ifdef CONFIG_CIFS_DFS_UPCALL
+ INIT_LIST_HEAD(&ret_buf->dfs_ses_list);
+#endif
+
+ return ret_buf;
+}
+
+void
+tconInfoFree(struct cifs_tcon *tcon)
+{
+ if (tcon == NULL) {
+ cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
+ return;
+ }
+ free_cached_dirs(tcon->cfids);
+ atomic_dec(&tconInfoAllocCount);
+ kfree(tcon->nativeFileSystem);
+ kfree_sensitive(tcon->password);
+#ifdef CONFIG_CIFS_DFS_UPCALL
+ dfs_put_root_smb_sessions(&tcon->dfs_ses_list);
+#endif
+ kfree(tcon->origin_fullpath);
+ kfree(tcon);
+}
+
+struct smb_hdr *
+cifs_buf_get(void)
+{
+ struct smb_hdr *ret_buf = NULL;
+ /*
+ * SMB2 header is bigger than CIFS one - no problems to clean some
+ * more bytes for CIFS.
+ */
+ size_t buf_size = sizeof(struct smb2_hdr);
+
+ /*
+ * We could use negotiated size instead of max_msgsize -
+ * but it may be more efficient to always alloc same size
+ * albeit slightly larger than necessary and maxbuffersize
+ * defaults to this and can not be bigger.
+ */
+ ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
+
+ /* clear the first few header bytes */
+ /* for most paths, more is cleared in header_assemble */
+ memset(ret_buf, 0, buf_size + 3);
+ atomic_inc(&buf_alloc_count);
+#ifdef CONFIG_CIFS_STATS2
+ atomic_inc(&total_buf_alloc_count);
+#endif /* CONFIG_CIFS_STATS2 */
+
+ return ret_buf;
+}
+
+void
+cifs_buf_release(void *buf_to_free)
+{
+ if (buf_to_free == NULL) {
+ /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
+ return;
+ }
+ mempool_free(buf_to_free, cifs_req_poolp);
+
+ atomic_dec(&buf_alloc_count);
+ return;
+}
+
+struct smb_hdr *
+cifs_small_buf_get(void)
+{
+ struct smb_hdr *ret_buf = NULL;
+
+/* We could use negotiated size instead of max_msgsize -
+ but it may be more efficient to always alloc same size
+ albeit slightly larger than necessary and maxbuffersize
+ defaults to this and can not be bigger */
+ ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
+ /* No need to clear memory here, cleared in header assemble */
+ /* memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
+ atomic_inc(&small_buf_alloc_count);
+#ifdef CONFIG_CIFS_STATS2
+ atomic_inc(&total_small_buf_alloc_count);
+#endif /* CONFIG_CIFS_STATS2 */
+
+ return ret_buf;
+}
+
+void
+cifs_small_buf_release(void *buf_to_free)
+{
+
+ if (buf_to_free == NULL) {
+ cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
+ return;
+ }
+ mempool_free(buf_to_free, cifs_sm_req_poolp);
+
+ atomic_dec(&small_buf_alloc_count);
+ return;
+}
+
+void
+free_rsp_buf(int resp_buftype, void *rsp)
+{
+ if (resp_buftype == CIFS_SMALL_BUFFER)
+ cifs_small_buf_release(rsp);
+ else if (resp_buftype == CIFS_LARGE_BUFFER)
+ cifs_buf_release(rsp);
+}
+
+/* NB: MID can not be set if treeCon not passed in, in that
+ case it is responsbility of caller to set the mid */
+void
+header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
+ const struct cifs_tcon *treeCon, int word_count
+ /* length of fixed section (word count) in two byte units */)
+{
+ char *temp = (char *) buffer;
+
+ memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
+
+ buffer->smb_buf_length = cpu_to_be32(
+ (2 * word_count) + sizeof(struct smb_hdr) -
+ 4 /* RFC 1001 length field does not count */ +
+ 2 /* for bcc field itself */) ;
+
+ buffer->Protocol[0] = 0xFF;
+ buffer->Protocol[1] = 'S';
+ buffer->Protocol[2] = 'M';
+ buffer->Protocol[3] = 'B';
+ buffer->Command = smb_command;
+ buffer->Flags = 0x00; /* case sensitive */
+ buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
+ buffer->Pid = cpu_to_le16((__u16)current->tgid);
+ buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
+ if (treeCon) {
+ buffer->Tid = treeCon->tid;
+ if (treeCon->ses) {
+ if (treeCon->ses->capabilities & CAP_UNICODE)
+ buffer->Flags2 |= SMBFLG2_UNICODE;
+ if (treeCon->ses->capabilities & CAP_STATUS32)
+ buffer->Flags2 |= SMBFLG2_ERR_STATUS;
+
+ /* Uid is not converted */
+ buffer->Uid = treeCon->ses->Suid;
+ if (treeCon->ses->server)
+ buffer->Mid = get_next_mid(treeCon->ses->server);
+ }
+ if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
+ buffer->Flags2 |= SMBFLG2_DFS;
+ if (treeCon->nocase)
+ buffer->Flags |= SMBFLG_CASELESS;
+ if ((treeCon->ses) && (treeCon->ses->server))
+ if (treeCon->ses->server->sign)
+ buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
+ }
+
+/* endian conversion of flags is now done just before sending */
+ buffer->WordCount = (char) word_count;
+ return;
+}
+
+static int
+check_smb_hdr(struct smb_hdr *smb)
+{
+ /* does it have the right SMB "signature" ? */
+ if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
+ cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
+ *(unsigned int *)smb->Protocol);
+ return 1;
+ }
+
+ /* if it's a response then accept */
+ if (smb->Flags & SMBFLG_RESPONSE)
+ return 0;
+
+ /* only one valid case where server sends us request */
+ if (smb->Command == SMB_COM_LOCKING_ANDX)
+ return 0;
+
+ cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
+ get_mid(smb));
+ return 1;
+}
+
+int
+checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
+{
+ struct smb_hdr *smb = (struct smb_hdr *)buf;
+ __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
+ __u32 clc_len; /* calculated length */
+ cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
+ total_read, rfclen);
+
+ /* is this frame too small to even get to a BCC? */
+ if (total_read < 2 + sizeof(struct smb_hdr)) {
+ if ((total_read >= sizeof(struct smb_hdr) - 1)
+ && (smb->Status.CifsError != 0)) {
+ /* it's an error return */
+ smb->WordCount = 0;
+ /* some error cases do not return wct and bcc */
+ return 0;
+ } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
+ (smb->WordCount == 0)) {
+ char *tmp = (char *)smb;
+ /* Need to work around a bug in two servers here */
+ /* First, check if the part of bcc they sent was zero */
+ if (tmp[sizeof(struct smb_hdr)] == 0) {
+ /* some servers return only half of bcc
+ * on simple responses (wct, bcc both zero)
+ * in particular have seen this on
+ * ulogoffX and FindClose. This leaves
+ * one byte of bcc potentially unitialized
+ */
+ /* zero rest of bcc */
+ tmp[sizeof(struct smb_hdr)+1] = 0;
+ return 0;
+ }
+ cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
+ } else {
+ cifs_dbg(VFS, "Length less than smb header size\n");
+ }
+ return -EIO;
+ } else if (total_read < sizeof(*smb) + 2 * smb->WordCount) {
+ cifs_dbg(VFS, "%s: can't read BCC due to invalid WordCount(%u)\n",
+ __func__, smb->WordCount);
+ return -EIO;
+ }
+
+ /* otherwise, there is enough to get to the BCC */
+ if (check_smb_hdr(smb))
+ return -EIO;
+ clc_len = smbCalcSize(smb);
+
+ if (4 + rfclen != total_read) {
+ cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
+ rfclen);
+ return -EIO;
+ }
+
+ if (4 + rfclen != clc_len) {
+ __u16 mid = get_mid(smb);
+ /* check if bcc wrapped around for large read responses */
+ if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
+ /* check if lengths match mod 64K */
+ if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
+ return 0; /* bcc wrapped */
+ }
+ cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
+ clc_len, 4 + rfclen, mid);
+
+ if (4 + rfclen < clc_len) {
+ cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
+ rfclen, mid);
+ return -EIO;
+ } else if (rfclen > clc_len + 512) {
+ /*
+ * Some servers (Windows XP in particular) send more
+ * data than the lengths in the SMB packet would
+ * indicate on certain calls (byte range locks and
+ * trans2 find first calls in particular). While the
+ * client can handle such a frame by ignoring the
+ * trailing data, we choose limit the amount of extra
+ * data to 512 bytes.
+ */
+ cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
+ rfclen, mid);
+ return -EIO;
+ }
+ }
+ return 0;
+}
+
+bool
+is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
+{
+ struct smb_hdr *buf = (struct smb_hdr *)buffer;
+ struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
+ struct TCP_Server_Info *pserver;
+ struct cifs_ses *ses;
+ struct cifs_tcon *tcon;
+ struct cifsInodeInfo *pCifsInode;
+ struct cifsFileInfo *netfile;
+
+ cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
+ if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
+ (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
+ struct smb_com_transaction_change_notify_rsp *pSMBr =
+ (struct smb_com_transaction_change_notify_rsp *)buf;
+ struct file_notify_information *pnotify;
+ __u32 data_offset = 0;
+ size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
+
+ if (get_bcc(buf) > sizeof(struct file_notify_information)) {
+ data_offset = le32_to_cpu(pSMBr->DataOffset);
+
+ if (data_offset >
+ len - sizeof(struct file_notify_information)) {
+ cifs_dbg(FYI, "Invalid data_offset %u\n",
+ data_offset);
+ return true;
+ }
+ pnotify = (struct file_notify_information *)
+ ((char *)&pSMBr->hdr.Protocol + data_offset);
+ cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
+ pnotify->FileName, pnotify->Action);
+ /* cifs_dump_mem("Rcvd notify Data: ",buf,
+ sizeof(struct smb_hdr)+60); */
+ return true;
+ }
+ if (pSMBr->hdr.Status.CifsError) {
+ cifs_dbg(FYI, "notify err 0x%x\n",
+ pSMBr->hdr.Status.CifsError);
+ return true;
+ }
+ return false;
+ }
+ if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
+ return false;
+ if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
+ /* no sense logging error on invalid handle on oplock
+ break - harmless race between close request and oplock
+ break response is expected from time to time writing out
+ large dirty files cached on the client */
+ if ((NT_STATUS_INVALID_HANDLE) ==
+ le32_to_cpu(pSMB->hdr.Status.CifsError)) {
+ cifs_dbg(FYI, "Invalid handle on oplock break\n");
+ return true;
+ } else if (ERRbadfid ==
+ le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
+ return true;
+ } else {
+ return false; /* on valid oplock brk we get "request" */
+ }
+ }
+ if (pSMB->hdr.WordCount != 8)
+ return false;
+
+ cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
+ pSMB->LockType, pSMB->OplockLevel);
+ if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
+ return false;
+
+ /* If server is a channel, select the primary channel */
+ pserver = SERVER_IS_CHAN(srv) ? srv->primary_server : srv;
+
+ /* look up tcon based on tid & uid */
+ spin_lock(&cifs_tcp_ses_lock);
+ list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
+ list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
+ if (tcon->tid != buf->Tid)
+ continue;
+
+ cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
+ spin_lock(&tcon->open_file_lock);
+ list_for_each_entry(netfile, &tcon->openFileList, tlist) {
+ if (pSMB->Fid != netfile->fid.netfid)
+ continue;
+
+ cifs_dbg(FYI, "file id match, oplock break\n");
+ pCifsInode = CIFS_I(d_inode(netfile->dentry));
+
+ set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
+ &pCifsInode->flags);
+
+ netfile->oplock_epoch = 0;
+ netfile->oplock_level = pSMB->OplockLevel;
+ netfile->oplock_break_cancelled = false;
+ cifs_queue_oplock_break(netfile);
+
+ spin_unlock(&tcon->open_file_lock);
+ spin_unlock(&cifs_tcp_ses_lock);
+ return true;
+ }
+ spin_unlock(&tcon->open_file_lock);
+ spin_unlock(&cifs_tcp_ses_lock);
+ cifs_dbg(FYI, "No matching file for oplock break\n");
+ return true;
+ }
+ }
+ spin_unlock(&cifs_tcp_ses_lock);
+ cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
+ return true;
+}
+
+void
+dump_smb(void *buf, int smb_buf_length)
+{
+ if (traceSMB == 0)
+ return;
+
+ print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
+ smb_buf_length, true);
+}
+
+void
+cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
+{
+ if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
+ struct cifs_tcon *tcon = NULL;
+
+ if (cifs_sb->master_tlink)
+ tcon = cifs_sb_master_tcon(cifs_sb);
+
+ cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
+ cifs_sb->mnt_cifs_serverino_autodisabled = true;
+ cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
+ tcon ? tcon->tree_name : "new server");
+ cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
+ cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
+
+ }
+}
+
+void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
+{
+ oplock &= 0xF;
+
+ if (oplock == OPLOCK_EXCLUSIVE) {
+ cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
+ cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
+ &cinode->netfs.inode);
+ } else if (oplock == OPLOCK_READ) {
+ cinode->oplock = CIFS_CACHE_READ_FLG;
+ cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
+ &cinode->netfs.inode);
+ } else
+ cinode->oplock = 0;
+}
+
+/*
+ * We wait for oplock breaks to be processed before we attempt to perform
+ * writes.
+ */
+int cifs_get_writer(struct cifsInodeInfo *cinode)
+{
+ int rc;
+
+start:
+ rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
+ TASK_KILLABLE);
+ if (rc)
+ return rc;
+
+ spin_lock(&cinode->writers_lock);
+ if (!cinode->writers)
+ set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
+ cinode->writers++;
+ /* Check to see if we have started servicing an oplock break */
+ if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
+ cinode->writers--;
+ if (cinode->writers == 0) {
+ clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
+ wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
+ }
+ spin_unlock(&cinode->writers_lock);
+ goto start;
+ }
+ spin_unlock(&cinode->writers_lock);
+ return 0;
+}
+
+void cifs_put_writer(struct cifsInodeInfo *cinode)
+{
+ spin_lock(&cinode->writers_lock);
+ cinode->writers--;
+ if (cinode->writers == 0) {
+ clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
+ wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
+ }
+ spin_unlock(&cinode->writers_lock);
+}
+
+/**
+ * cifs_queue_oplock_break - queue the oplock break handler for cfile
+ * @cfile: The file to break the oplock on
+ *
+ * This function is called from the demultiplex thread when it
+ * receives an oplock break for @cfile.
+ *
+ * Assumes the tcon->open_file_lock is held.
+ * Assumes cfile->file_info_lock is NOT held.
+ */
+void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
+{
+ /*
+ * Bump the handle refcount now while we hold the
+ * open_file_lock to enforce the validity of it for the oplock
+ * break handler. The matching put is done at the end of the
+ * handler.
+ */
+ cifsFileInfo_get(cfile);
+
+ queue_work(cifsoplockd_wq, &cfile->oplock_break);
+}
+
+void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
+{
+ clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
+ wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
+}
+
+bool
+backup_cred(struct cifs_sb_info *cifs_sb)
+{
+ if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
+ if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
+ return true;
+ }
+ if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
+ if (in_group_p(cifs_sb->ctx->backupgid))
+ return true;
+ }
+
+ return false;
+}
+
+void
+cifs_del_pending_open(struct cifs_pending_open *open)
+{
+ spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
+ list_del(&open->olist);
+ spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
+}
+
+void
+cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
+ struct cifs_pending_open *open)
+{
+ memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
+ open->oplock = CIFS_OPLOCK_NO_CHANGE;
+ open->tlink = tlink;
+ fid->pending_open = open;
+ list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
+}
+
+void
+cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
+ struct cifs_pending_open *open)
+{
+ spin_lock(&tlink_tcon(tlink)->open_file_lock);
+ cifs_add_pending_open_locked(fid, tlink, open);
+ spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
+}
+
+/*
+ * Critical section which runs after acquiring deferred_lock.
+ * As there is no reference count on cifs_deferred_close, pdclose
+ * should not be used outside deferred_lock.
+ */
+bool
+cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
+{
+ struct cifs_deferred_close *dclose;
+
+ list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
+ if ((dclose->netfid == cfile->fid.netfid) &&
+ (dclose->persistent_fid == cfile->fid.persistent_fid) &&
+ (dclose->volatile_fid == cfile->fid.volatile_fid)) {
+ *pdclose = dclose;
+ return true;
+ }
+ }
+ return false;
+}
+
+/*
+ * Critical section which runs after acquiring deferred_lock.
+ */
+void
+cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
+{
+ bool is_deferred = false;
+ struct cifs_deferred_close *pdclose;
+
+ is_deferred = cifs_is_deferred_close(cfile, &pdclose);
+ if (is_deferred) {
+ kfree(dclose);
+ return;
+ }
+
+ dclose->tlink = cfile->tlink;
+ dclose->netfid = cfile->fid.netfid;
+ dclose->persistent_fid = cfile->fid.persistent_fid;
+ dclose->volatile_fid = cfile->fid.volatile_fid;
+ list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
+}
+
+/*
+ * Critical section which runs after acquiring deferred_lock.
+ */
+void
+cifs_del_deferred_close(struct cifsFileInfo *cfile)
+{
+ bool is_deferred = false;
+ struct cifs_deferred_close *dclose;
+
+ is_deferred = cifs_is_deferred_close(cfile, &dclose);
+ if (!is_deferred)
+ return;
+ list_del(&dclose->dlist);
+ kfree(dclose);
+}
+
+void
+cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
+{
+ struct cifsFileInfo *cfile = NULL;
+ struct file_list *tmp_list, *tmp_next_list;
+ struct list_head file_head;
+
+ if (cifs_inode == NULL)
+ return;
+
+ INIT_LIST_HEAD(&file_head);
+ spin_lock(&cifs_inode->open_file_lock);
+ list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
+ if (delayed_work_pending(&cfile->deferred)) {
+ if (cancel_delayed_work(&cfile->deferred)) {
+ spin_lock(&cifs_inode->deferred_lock);
+ cifs_del_deferred_close(cfile);
+ spin_unlock(&cifs_inode->deferred_lock);
+
+ tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
+ if (tmp_list == NULL)
+ break;
+ tmp_list->cfile = cfile;
+ list_add_tail(&tmp_list->list, &file_head);
+ }
+ }
+ }
+ spin_unlock(&cifs_inode->open_file_lock);
+
+ list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
+ _cifsFileInfo_put(tmp_list->cfile, false, false);
+ list_del(&tmp_list->list);
+ kfree(tmp_list);
+ }
+}
+
+void
+cifs_close_all_deferred_files(struct cifs_tcon *tcon)
+{
+ struct cifsFileInfo *cfile;
+ struct file_list *tmp_list, *tmp_next_list;
+ struct list_head file_head;
+
+ INIT_LIST_HEAD(&file_head);
+ spin_lock(&tcon->open_file_lock);
+ list_for_each_entry(cfile, &tcon->openFileList, tlist) {
+ if (delayed_work_pending(&cfile->deferred)) {
+ if (cancel_delayed_work(&cfile->deferred)) {
+ spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
+ cifs_del_deferred_close(cfile);
+ spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
+
+ tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
+ if (tmp_list == NULL)
+ break;
+ tmp_list->cfile = cfile;
+ list_add_tail(&tmp_list->list, &file_head);
+ }
+ }
+ }
+ spin_unlock(&tcon->open_file_lock);
+
+ list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
+ _cifsFileInfo_put(tmp_list->cfile, true, false);
+ list_del(&tmp_list->list);
+ kfree(tmp_list);
+ }
+}
+void
+cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon, const char *path)
+{
+ struct cifsFileInfo *cfile;
+ struct file_list *tmp_list, *tmp_next_list;
+ struct list_head file_head;
+ void *page;
+ const char *full_path;
+
+ INIT_LIST_HEAD(&file_head);
+ page = alloc_dentry_path();
+ spin_lock(&tcon->open_file_lock);
+ list_for_each_entry(cfile, &tcon->openFileList, tlist) {
+ full_path = build_path_from_dentry(cfile->dentry, page);
+ if (strstr(full_path, path)) {
+ if (delayed_work_pending(&cfile->deferred)) {
+ if (cancel_delayed_work(&cfile->deferred)) {
+ spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
+ cifs_del_deferred_close(cfile);
+ spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
+
+ tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
+ if (tmp_list == NULL)
+ break;
+ tmp_list->cfile = cfile;
+ list_add_tail(&tmp_list->list, &file_head);
+ }
+ }
+ }
+ }
+ spin_unlock(&tcon->open_file_lock);
+
+ list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
+ _cifsFileInfo_put(tmp_list->cfile, true, false);
+ list_del(&tmp_list->list);
+ kfree(tmp_list);
+ }
+ free_dentry_path(page);
+}
+
+/* parses DFS referral V3 structure
+ * caller is responsible for freeing target_nodes
+ * returns:
+ * - on success - 0
+ * - on failure - errno
+ */
+int
+parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
+ unsigned int *num_of_nodes,
+ struct dfs_info3_param **target_nodes,
+ const struct nls_table *nls_codepage, int remap,
+ const char *searchName, bool is_unicode)
+{
+ int i, rc = 0;
+ char *data_end;
+ struct dfs_referral_level_3 *ref;
+
+ *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
+
+ if (*num_of_nodes < 1) {
+ cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
+ *num_of_nodes);
+ rc = -EINVAL;
+ goto parse_DFS_referrals_exit;
+ }
+
+ ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
+ if (ref->VersionNumber != cpu_to_le16(3)) {
+ cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
+ le16_to_cpu(ref->VersionNumber));
+ rc = -EINVAL;
+ goto parse_DFS_referrals_exit;
+ }
+
+ /* get the upper boundary of the resp buffer */
+ data_end = (char *)rsp + rsp_size;
+
+ cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
+ *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
+
+ *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
+ GFP_KERNEL);
+ if (*target_nodes == NULL) {
+ rc = -ENOMEM;
+ goto parse_DFS_referrals_exit;
+ }
+
+ /* collect necessary data from referrals */
+ for (i = 0; i < *num_of_nodes; i++) {
+ char *temp;
+ int max_len;
+ struct dfs_info3_param *node = (*target_nodes)+i;
+
+ node->flags = le32_to_cpu(rsp->DFSFlags);
+ if (is_unicode) {
+ __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
+ GFP_KERNEL);
+ if (tmp == NULL) {
+ rc = -ENOMEM;
+ goto parse_DFS_referrals_exit;
+ }
+ cifsConvertToUTF16((__le16 *) tmp, searchName,
+ PATH_MAX, nls_codepage, remap);
+ node->path_consumed = cifs_utf16_bytes(tmp,
+ le16_to_cpu(rsp->PathConsumed),
+ nls_codepage);
+ kfree(tmp);
+ } else
+ node->path_consumed = le16_to_cpu(rsp->PathConsumed);
+
+ node->server_type = le16_to_cpu(ref->ServerType);
+ node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
+
+ /* copy DfsPath */
+ temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
+ max_len = data_end - temp;
+ node->path_name = cifs_strndup_from_utf16(temp, max_len,
+ is_unicode, nls_codepage);
+ if (!node->path_name) {
+ rc = -ENOMEM;
+ goto parse_DFS_referrals_exit;
+ }
+
+ /* copy link target UNC */
+ temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
+ max_len = data_end - temp;
+ node->node_name = cifs_strndup_from_utf16(temp, max_len,
+ is_unicode, nls_codepage);
+ if (!node->node_name) {
+ rc = -ENOMEM;
+ goto parse_DFS_referrals_exit;
+ }
+
+ node->ttl = le32_to_cpu(ref->TimeToLive);
+
+ ref++;
+ }
+
+parse_DFS_referrals_exit:
+ if (rc) {
+ free_dfs_info_array(*target_nodes, *num_of_nodes);
+ *target_nodes = NULL;
+ *num_of_nodes = 0;
+ }
+ return rc;
+}
+
+struct cifs_aio_ctx *
+cifs_aio_ctx_alloc(void)
+{
+ struct cifs_aio_ctx *ctx;
+
+ /*
+ * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
+ * to false so that we know when we have to unreference pages within
+ * cifs_aio_ctx_release()
+ */
+ ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
+ if (!ctx)
+ return NULL;
+
+ INIT_LIST_HEAD(&ctx->list);
+ mutex_init(&ctx->aio_mutex);
+ init_completion(&ctx->done);
+ kref_init(&ctx->refcount);
+ return ctx;
+}
+
+void
+cifs_aio_ctx_release(struct kref *refcount)
+{
+ struct cifs_aio_ctx *ctx = container_of(refcount,
+ struct cifs_aio_ctx, refcount);
+
+ cifsFileInfo_put(ctx->cfile);
+
+ /*
+ * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
+ * which means that iov_iter_extract_pages() was a success and thus
+ * that we may have references or pins on pages that we need to
+ * release.
+ */
+ if (ctx->bv) {
+ if (ctx->should_dirty || ctx->bv_need_unpin) {
+ unsigned int i;
+
+ for (i = 0; i < ctx->nr_pinned_pages; i++) {
+ struct page *page = ctx->bv[i].bv_page;
+
+ if (ctx->should_dirty)
+ set_page_dirty(page);
+ if (ctx->bv_need_unpin)
+ unpin_user_page(page);
+ }
+ }
+ kvfree(ctx->bv);
+ }
+
+ kfree(ctx);
+}
+
+/**
+ * cifs_alloc_hash - allocate hash and hash context together
+ * @name: The name of the crypto hash algo
+ * @sdesc: SHASH descriptor where to put the pointer to the hash TFM
+ *
+ * The caller has to make sure @sdesc is initialized to either NULL or
+ * a valid context. It can be freed via cifs_free_hash().
+ */
+int
+cifs_alloc_hash(const char *name, struct shash_desc **sdesc)
+{
+ int rc = 0;
+ struct crypto_shash *alg = NULL;
+
+ if (*sdesc)
+ return 0;
+
+ alg = crypto_alloc_shash(name, 0, 0);
+ if (IS_ERR(alg)) {
+ cifs_dbg(VFS, "Could not allocate shash TFM '%s'\n", name);
+ rc = PTR_ERR(alg);
+ *sdesc = NULL;
+ return rc;
+ }
+
+ *sdesc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(alg), GFP_KERNEL);
+ if (*sdesc == NULL) {
+ cifs_dbg(VFS, "no memory left to allocate shash TFM '%s'\n", name);
+ crypto_free_shash(alg);
+ return -ENOMEM;
+ }
+
+ (*sdesc)->tfm = alg;
+ return 0;
+}
+
+/**
+ * cifs_free_hash - free hash and hash context together
+ * @sdesc: Where to find the pointer to the hash TFM
+ *
+ * Freeing a NULL descriptor is safe.
+ */
+void
+cifs_free_hash(struct shash_desc **sdesc)
+{
+ if (unlikely(!sdesc) || !*sdesc)
+ return;
+
+ if ((*sdesc)->tfm) {
+ crypto_free_shash((*sdesc)->tfm);
+ (*sdesc)->tfm = NULL;
+ }
+
+ kfree_sensitive(*sdesc);
+ *sdesc = NULL;
+}
+
+void extract_unc_hostname(const char *unc, const char **h, size_t *len)
+{
+ const char *end;
+
+ /* skip initial slashes */
+ while (*unc && (*unc == '\\' || *unc == '/'))
+ unc++;
+
+ end = unc;
+
+ while (*end && !(*end == '\\' || *end == '/'))
+ end++;
+
+ *h = unc;
+ *len = end - unc;
+}
+
+/**
+ * copy_path_name - copy src path to dst, possibly truncating
+ * @dst: The destination buffer
+ * @src: The source name
+ *
+ * returns number of bytes written (including trailing nul)
+ */
+int copy_path_name(char *dst, const char *src)
+{
+ int name_len;
+
+ /*
+ * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
+ * will truncate and strlen(dst) will be PATH_MAX-1
+ */
+ name_len = strscpy(dst, src, PATH_MAX);
+ if (WARN_ON_ONCE(name_len < 0))
+ name_len = PATH_MAX-1;
+
+ /* we count the trailing nul */
+ name_len++;
+ return name_len;
+}
+
+struct super_cb_data {
+ void *data;
+ struct super_block *sb;
+};
+
+static void tcon_super_cb(struct super_block *sb, void *arg)
+{
+ struct super_cb_data *sd = arg;
+ struct cifs_sb_info *cifs_sb;
+ struct cifs_tcon *t1 = sd->data, *t2;
+
+ if (sd->sb)
+ return;
+
+ cifs_sb = CIFS_SB(sb);
+ t2 = cifs_sb_master_tcon(cifs_sb);
+
+ spin_lock(&t2->tc_lock);
+ if (t1->ses == t2->ses &&
+ t1->ses->server == t2->ses->server &&
+ t2->origin_fullpath &&
+ dfs_src_pathname_equal(t2->origin_fullpath, t1->origin_fullpath))
+ sd->sb = sb;
+ spin_unlock(&t2->tc_lock);
+}
+
+static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
+ void *data)
+{
+ struct super_cb_data sd = {
+ .data = data,
+ .sb = NULL,
+ };
+ struct file_system_type **fs_type = (struct file_system_type *[]) {
+ &cifs_fs_type, &smb3_fs_type, NULL,
+ };
+
+ for (; *fs_type; fs_type++) {
+ iterate_supers_type(*fs_type, f, &sd);
+ if (sd.sb) {
+ /*
+ * Grab an active reference in order to prevent automounts (DFS links)
+ * of expiring and then freeing up our cifs superblock pointer while
+ * we're doing failover.
+ */
+ cifs_sb_active(sd.sb);
+ return sd.sb;
+ }
+ }
+ pr_warn_once("%s: could not find dfs superblock\n", __func__);
+ return ERR_PTR(-EINVAL);
+}
+
+static void __cifs_put_super(struct super_block *sb)
+{
+ if (!IS_ERR_OR_NULL(sb))
+ cifs_sb_deactive(sb);
+}
+
+struct super_block *cifs_get_dfs_tcon_super(struct cifs_tcon *tcon)
+{
+ spin_lock(&tcon->tc_lock);
+ if (!tcon->origin_fullpath) {
+ spin_unlock(&tcon->tc_lock);
+ return ERR_PTR(-ENOENT);
+ }
+ spin_unlock(&tcon->tc_lock);
+ return __cifs_get_super(tcon_super_cb, tcon);
+}
+
+void cifs_put_tcp_super(struct super_block *sb)
+{
+ __cifs_put_super(sb);
+}
+
+#ifdef CONFIG_CIFS_DFS_UPCALL
+int match_target_ip(struct TCP_Server_Info *server,
+ const char *share, size_t share_len,
+ bool *result)
+{
+ int rc;
+ char *target;
+ struct sockaddr_storage ss;
+
+ *result = false;
+
+ target = kzalloc(share_len + 3, GFP_KERNEL);
+ if (!target)
+ return -ENOMEM;
+
+ scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
+
+ cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
+
+ rc = dns_resolve_server_name_to_ip(target, (struct sockaddr *)&ss, NULL);
+ kfree(target);
+
+ if (rc < 0)
+ return rc;
+
+ spin_lock(&server->srv_lock);
+ *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, (struct sockaddr *)&ss);
+ spin_unlock(&server->srv_lock);
+ cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
+ return 0;
+}
+
+int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
+{
+ int rc;
+
+ kfree(cifs_sb->prepath);
+ cifs_sb->prepath = NULL;
+
+ if (prefix && *prefix) {
+ cifs_sb->prepath = cifs_sanitize_prepath(prefix, GFP_ATOMIC);
+ if (IS_ERR(cifs_sb->prepath)) {
+ rc = PTR_ERR(cifs_sb->prepath);
+ cifs_sb->prepath = NULL;
+ return rc;
+ }
+ if (cifs_sb->prepath)
+ convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
+ }
+
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
+ return 0;
+}
+
+/*
+ * Handle weird Windows SMB server behaviour. It responds with
+ * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request for
+ * "\<server>\<dfsname>\<linkpath>" DFS reference, where <dfsname> contains
+ * non-ASCII unicode symbols.
+ */
+int cifs_inval_name_dfs_link_error(const unsigned int xid,
+ struct cifs_tcon *tcon,
+ struct cifs_sb_info *cifs_sb,
+ const char *full_path,
+ bool *islink)
+{
+ struct cifs_ses *ses = tcon->ses;
+ size_t len;
+ char *path;
+ char *ref_path;
+
+ *islink = false;
+
+ /*
+ * Fast path - skip check when @full_path doesn't have a prefix path to
+ * look up or tcon is not DFS.
+ */
+ if (strlen(full_path) < 2 || !cifs_sb ||
+ (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
+ !is_tcon_dfs(tcon))
+ return 0;
+
+ spin_lock(&tcon->tc_lock);
+ if (!tcon->origin_fullpath) {
+ spin_unlock(&tcon->tc_lock);
+ return 0;
+ }
+ spin_unlock(&tcon->tc_lock);
+
+ /*
+ * Slow path - tcon is DFS and @full_path has prefix path, so attempt
+ * to get a referral to figure out whether it is an DFS link.
+ */
+ len = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1) + strlen(full_path) + 1;
+ path = kmalloc(len, GFP_KERNEL);
+ if (!path)
+ return -ENOMEM;
+
+ scnprintf(path, len, "%s%s", tcon->tree_name, full_path);
+ ref_path = dfs_cache_canonical_path(path + 1, cifs_sb->local_nls,
+ cifs_remap(cifs_sb));
+ kfree(path);
+
+ if (IS_ERR(ref_path)) {
+ if (PTR_ERR(ref_path) != -EINVAL)
+ return PTR_ERR(ref_path);
+ } else {
+ struct dfs_info3_param *refs = NULL;
+ int num_refs = 0;
+
+ /*
+ * XXX: we are not using dfs_cache_find() here because we might
+ * end up filling all the DFS cache and thus potentially
+ * removing cached DFS targets that the client would eventually
+ * need during failover.
+ */
+ ses = CIFS_DFS_ROOT_SES(ses);
+ if (ses->server->ops->get_dfs_refer &&
+ !ses->server->ops->get_dfs_refer(xid, ses, ref_path, &refs,
+ &num_refs, cifs_sb->local_nls,
+ cifs_remap(cifs_sb)))
+ *islink = refs[0].server_type == DFS_TYPE_LINK;
+ free_dfs_info_array(refs, num_refs);
+ kfree(ref_path);
+ }
+ return 0;
+}
+#endif
+
+int cifs_wait_for_server_reconnect(struct TCP_Server_Info *server, bool retry)
+{
+ int timeout = 10;
+ int rc;
+
+ spin_lock(&server->srv_lock);
+ if (server->tcpStatus != CifsNeedReconnect) {
+ spin_unlock(&server->srv_lock);
+ return 0;
+ }
+ timeout *= server->nr_targets;
+ spin_unlock(&server->srv_lock);
+
+ /*
+ * Give demultiplex thread up to 10 seconds to each target available for
+ * reconnect -- should be greater than cifs socket timeout which is 7
+ * seconds.
+ *
+ * On "soft" mounts we wait once. Hard mounts keep retrying until
+ * process is killed or server comes back on-line.
+ */
+ do {
+ rc = wait_event_interruptible_timeout(server->response_q,
+ (server->tcpStatus != CifsNeedReconnect),
+ timeout * HZ);
+ if (rc < 0) {
+ cifs_dbg(FYI, "%s: aborting reconnect due to received signal\n",
+ __func__);
+ return -ERESTARTSYS;
+ }
+
+ /* are we still trying to reconnect? */
+ spin_lock(&server->srv_lock);
+ if (server->tcpStatus != CifsNeedReconnect) {
+ spin_unlock(&server->srv_lock);
+ return 0;
+ }
+ spin_unlock(&server->srv_lock);
+ } while (retry);
+
+ cifs_dbg(FYI, "%s: gave up waiting on reconnect\n", __func__);
+ return -EHOSTDOWN;
+}