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OpenCloudOS-Kernel/fs/cifs/misc.c

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/*
* fs/cifs/misc.c
*
* Copyright (C) International Business Machines Corp., 2002,2008
* Author(s): Steve French (sfrench@us.ibm.com)
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#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"
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);
ret_buf->status = CifsNew;
++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);
}
return ret_buf;
}
void
sesInfoFree(struct cifs_ses *buf_to_free)
{
if (buf_to_free == NULL) {
cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
return;
}
atomic_dec(&sesInfoAllocCount);
kfree(buf_to_free->serverOS);
kfree(buf_to_free->serverDomain);
kfree(buf_to_free->serverNOS);
if (buf_to_free->password) {
memset(buf_to_free->password, 0, strlen(buf_to_free->password));
kfree(buf_to_free->password);
}
kfree(buf_to_free->user_name);
kfree(buf_to_free->domainName);
kfree(buf_to_free->auth_key.response);
kfree(buf_to_free);
}
struct cifs_tcon *
tconInfoAlloc(void)
{
struct cifs_tcon *ret_buf;
ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
if (ret_buf) {
atomic_inc(&tconInfoAllocCount);
ret_buf->tidStatus = CifsNew;
++ret_buf->tc_count;
INIT_LIST_HEAD(&ret_buf->openFileList);
INIT_LIST_HEAD(&ret_buf->tcon_list);
spin_lock_init(&ret_buf->open_file_lock);
#ifdef CONFIG_CIFS_STATS
spin_lock_init(&ret_buf->stat_lock);
#endif
}
return ret_buf;
}
void
tconInfoFree(struct cifs_tcon *buf_to_free)
{
if (buf_to_free == NULL) {
cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
return;
}
atomic_dec(&tconInfoAllocCount);
kfree(buf_to_free->nativeFileSystem);
if (buf_to_free->password) {
memset(buf_to_free->password, 0, strlen(buf_to_free->password));
kfree(buf_to_free->password);
}
kfree(buf_to_free);
}
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(&bufAllocCount);
#ifdef CONFIG_CIFS_STATS2
atomic_inc(&totBufAllocCount);
#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(&bufAllocCount);
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(&smBufAllocCount);
#ifdef CONFIG_CIFS_STATS2
atomic_inc(&totSmBufAllocCount);
#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(&smBufAllocCount);
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;
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;
}
/* 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 list_head *tmp, *tmp1, *tmp2;
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;
if (get_bcc(buf) > sizeof(struct file_notify_information)) {
data_offset = le32_to_cpu(pSMBr->DataOffset);
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;
/* look up tcon based on tid & uid */
spin_lock(&cifs_tcp_ses_lock);
list_for_each(tmp, &srv->smb_ses_list) {
ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
list_for_each(tmp1, &ses->tcon_list) {
tcon = list_entry(tmp1, struct cifs_tcon, 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(tmp2, &tcon->openFileList) {
netfile = list_entry(tmp2, struct cifsFileInfo,
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);
/*
* Set flag if the server downgrades the oplock
* to L2 else clear.
*/
if (pSMB->OplockLevel)
set_bit(
CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
&pCifsInode->flags);
else
clear_bit(
CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
&pCifsInode->flags);
queue_work(cifsoplockd_wq,
&netfile->oplock_break);
netfile->oplock_break_cancelled = false;
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) {
cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s. This server doesn't seem to support them properly. Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n",
cifs_sb_master_tcon(cifs_sb)->treeName);
}
}
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->vfs_inode);
} else if (oplock == OPLOCK_READ) {
cinode->oplock = CIFS_CACHE_READ_FLG;
cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
&cinode->vfs_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);
}
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->mnt_backupuid, current_fsuid()))
return true;
}
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
if (in_group_p(cifs_sb->mnt_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);
}
/* parses DFS refferal 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;
}
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;
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);
kvfree(ctx->bv);
kfree(ctx);
}
#define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
int
setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
{
ssize_t rc;
unsigned int cur_npages;
unsigned int npages = 0;
unsigned int i;
size_t len;
size_t count = iov_iter_count(iter);
unsigned int saved_len;
size_t start;
unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
struct page **pages = NULL;
struct bio_vec *bv = NULL;
if (iter->type & ITER_KVEC) {
memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
ctx->len = count;
iov_iter_advance(iter, count);
return 0;
}
if (max_pages * sizeof(struct bio_vec) <= CIFS_AIO_KMALLOC_LIMIT)
bv = kmalloc_array(max_pages, sizeof(struct bio_vec),
GFP_KERNEL);
if (!bv) {
bv = vmalloc(max_pages * sizeof(struct bio_vec));
if (!bv)
return -ENOMEM;
}
if (max_pages * sizeof(struct page *) <= CIFS_AIO_KMALLOC_LIMIT)
pages = kmalloc_array(max_pages, sizeof(struct page *),
GFP_KERNEL);
if (!pages) {
pages = vmalloc(max_pages * sizeof(struct page *));
if (!pages) {
kvfree(bv);
return -ENOMEM;
}
}
saved_len = count;
while (count && npages < max_pages) {
rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
if (rc < 0) {
cifs_dbg(VFS, "couldn't get user pages (rc=%zd)\n", rc);
break;
}
if (rc > count) {
cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
count);
break;
}
iov_iter_advance(iter, rc);
count -= rc;
rc += start;
cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
if (npages + cur_npages > max_pages) {
cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
npages + cur_npages, max_pages);
break;
}
for (i = 0; i < cur_npages; i++) {
len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
bv[npages + i].bv_page = pages[i];
bv[npages + i].bv_offset = start;
bv[npages + i].bv_len = len - start;
rc -= len;
start = 0;
}
npages += cur_npages;
}
kvfree(pages);
ctx->bv = bv;
ctx->len = saved_len - count;
ctx->npages = npages;
iov_iter_bvec(&ctx->iter, ITER_BVEC | rw, ctx->bv, npages, ctx->len);
return 0;
}
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