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CIFS: Add rwpidforward mount option

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Add rwpidforward mount option that switches on a mode when we forward
pid of a process who opened a file to any read and write operation.

This can prevent applications like WINE from failing on read or write
operation on a previously locked file region from the same netfd from
another process if we use mandatory brlock style.

It is actual for WINE because during a run of WINE program two processes
work on the same netfd - share the same file struct between several VFS
fds:
1) WINE-server does open and lock;
2) WINE-application does read and write.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This commit is contained in:
Pavel Shilovsky
2011-05-26 06:02:00 +00:00
committed by Steve French
parent 25c7f41e92
commit d4ffff1fa9
10 changed files with 115 additions and 39 deletions
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22
fs/cifs/link.c
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@@ -235,6 +235,7 @@ CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
unsigned int bytes_read = 0;
int buf_type = CIFS_NO_BUFFER;
unsigned int link_len = 0;
struct cifs_io_parms io_parms;
FILE_ALL_INFO file_info;
rc = CIFSSMBOpen(xid, tcon, searchName, FILE_OPEN, GENERIC_READ,
@@ -253,11 +254,13 @@ CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
if (!buf)
return -ENOMEM;
pbuf = buf;
io_parms.netfid = netfid;
io_parms.pid = current->tgid;
io_parms.tcon = tcon;
io_parms.offset = 0;
io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
rc = CIFSSMBRead(xid, tcon, netfid,
CIFS_MF_SYMLINK_FILE_SIZE /* length */,
0 /* offset */,
&bytes_read, &pbuf, &buf_type);
rc = CIFSSMBRead(xid, &io_parms, &bytes_read, &pbuf, &buf_type);
CIFSSMBClose(xid, tcon, netfid);
if (rc != 0) {
kfree(buf);
@@ -296,6 +299,7 @@ CIFSCheckMFSymlink(struct cifs_fattr *fattr,
__u16 netfid = 0;
struct tcon_link *tlink;
struct cifsTconInfo *pTcon;
struct cifs_io_parms io_parms;
u8 *buf;
char *pbuf;
unsigned int bytes_read = 0;
@@ -332,11 +336,13 @@ CIFSCheckMFSymlink(struct cifs_fattr *fattr,
goto out;
}
pbuf = buf;
io_parms.netfid = netfid;
io_parms.pid = current->tgid;
io_parms.tcon = pTcon;
io_parms.offset = 0;
io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
rc = CIFSSMBRead(xid, pTcon, netfid,
CIFS_MF_SYMLINK_FILE_SIZE /* length */,
0 /* offset */,
&bytes_read, &pbuf, &buf_type);
rc = CIFSSMBRead(xid, &io_parms, &bytes_read, &pbuf, &buf_type);
CIFSSMBClose(xid, pTcon, netfid);
if (rc != 0) {
kfree(buf);