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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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82
fs/cifs/file.c
View File

@@ -725,8 +725,8 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
else
posix_lock_type = CIFS_WRLCK;
rc = CIFSSMBPosixLock(xid, tcon, netfid, 1 /* get */,
length, pfLock,
posix_lock_type, wait_flag);
length, pfLock, posix_lock_type,
wait_flag);
FreeXid(xid);
return rc;
}
@@ -797,8 +797,8 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
posix_lock_type = CIFS_UNLCK;
rc = CIFSSMBPosixLock(xid, tcon, netfid, 0 /* set */,
length, pfLock,
posix_lock_type, wait_flag);
length, pfLock, posix_lock_type,
wait_flag);
} else {
struct cifsFileInfo *fid = file->private_data;
@@ -1346,6 +1346,14 @@ static int cifs_write_end(struct file *file, struct address_space *mapping,
{
int rc;
struct inode *inode = mapping->host;
struct cifsFileInfo *cfile = file->private_data;
struct cifs_sb_info *cifs_sb = CIFS_SB(cfile->dentry->d_sb);
__u32 pid;
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
pid = cfile->pid;
else
pid = current->tgid;
cFYI(1, "write_end for page %p from pos %lld with %d bytes",
page, pos, copied);
@@ -1369,8 +1377,7 @@ static int cifs_write_end(struct file *file, struct address_space *mapping,
/* BB check if anything else missing out of ppw
such as updating last write time */
page_data = kmap(page);
rc = cifs_write(file->private_data, current->tgid,
page_data + offset, copied, &pos);
rc = cifs_write(cfile, pid, page_data + offset, copied, &pos);
/* if (rc < 0) should we set writebehind rc? */
kunmap(page);
@@ -1523,6 +1530,7 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
struct cifs_sb_info *cifs_sb;
struct cifs_io_parms io_parms;
int xid, rc;
__u32 pid;
len = iov_length(iov, nr_segs);
if (!len)
@@ -1554,6 +1562,12 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
xid = GetXid();
open_file = file->private_data;
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
pid = open_file->pid;
else
pid = current->tgid;
pTcon = tlink_tcon(open_file->tlink);
inode = file->f_path.dentry->d_inode;
@@ -1581,7 +1595,7 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
break;
}
io_parms.netfid = open_file->netfid;
io_parms.pid = current->tgid;
io_parms.pid = pid;
io_parms.tcon = pTcon;
io_parms.offset = *poffset;
io_parms.length = cur_len;
@@ -1682,7 +1696,9 @@ cifs_iovec_read(struct file *file, const struct iovec *iov,
struct cifsTconInfo *pTcon;
struct cifsFileInfo *open_file;
struct smb_com_read_rsp *pSMBr;
struct cifs_io_parms io_parms;
char *read_data;
__u32 pid;
if (!nr_segs)
return 0;
@@ -1697,6 +1713,11 @@ cifs_iovec_read(struct file *file, const struct iovec *iov,
open_file = file->private_data;
pTcon = tlink_tcon(open_file->tlink);
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
pid = open_file->pid;
else
pid = current->tgid;
if ((file->f_flags & O_ACCMODE) == O_WRONLY)
cFYI(1, "attempting read on write only file instance");
@@ -1712,8 +1733,12 @@ cifs_iovec_read(struct file *file, const struct iovec *iov,
if (rc != 0)
break;
}
rc = CIFSSMBRead(xid, pTcon, open_file->netfid,
cur_len, *poffset, &bytes_read,
io_parms.netfid = open_file->netfid;
io_parms.pid = pid;
io_parms.tcon = pTcon;
io_parms.offset = *poffset;
io_parms.length = len;
rc = CIFSSMBRead(xid, &io_parms, &bytes_read,
&read_data, &buf_type);
pSMBr = (struct smb_com_read_rsp *)read_data;
if (read_data) {
@@ -1794,7 +1819,9 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
int xid;
char *current_offset;
struct cifsFileInfo *open_file;
struct cifs_io_parms io_parms;
int buf_type = CIFS_NO_BUFFER;
__u32 pid;
xid = GetXid();
cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
@@ -1807,6 +1834,11 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
open_file = file->private_data;
pTcon = tlink_tcon(open_file->tlink);
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
pid = open_file->pid;
else
pid = current->tgid;
if ((file->f_flags & O_ACCMODE) == O_WRONLY)
cFYI(1, "attempting read on write only file instance");
@@ -1829,11 +1861,13 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
if (rc != 0)
break;
}
rc = CIFSSMBRead(xid, pTcon,
open_file->netfid,
current_read_size, *poffset,
&bytes_read, &current_offset,
&buf_type);
io_parms.netfid = open_file->netfid;
io_parms.pid = pid;
io_parms.tcon = pTcon;
io_parms.offset = *poffset;
io_parms.length = current_read_size;
rc = CIFSSMBRead(xid, &io_parms, &bytes_read,
&current_offset, &buf_type);
}
if (rc || (bytes_read == 0)) {
if (total_read) {
@@ -1970,7 +2004,9 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
char *smb_read_data = NULL;
struct smb_com_read_rsp *pSMBr;
struct cifsFileInfo *open_file;
struct cifs_io_parms io_parms;
int buf_type = CIFS_NO_BUFFER;
__u32 pid;
xid = GetXid();
if (file->private_data == NULL) {
@@ -1992,6 +2028,11 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
goto read_complete;
cFYI(DBG2, "rpages: num pages %d", num_pages);
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
pid = open_file->pid;
else
pid = current->tgid;
for (i = 0; i < num_pages; ) {
unsigned contig_pages;
struct page *tmp_page;
@@ -2033,12 +2074,13 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
if (rc != 0)
break;
}
rc = CIFSSMBRead(xid, pTcon,
open_file->netfid,
read_size, offset,
&bytes_read, &smb_read_data,
&buf_type);
io_parms.netfid = open_file->netfid;
io_parms.pid = pid;
io_parms.tcon = pTcon;
io_parms.offset = offset;
io_parms.length = read_size;
rc = CIFSSMBRead(xid, &io_parms, &bytes_read,
&smb_read_data, &buf_type);
/* BB more RC checks ? */
if (rc == -EAGAIN) {
if (smb_read_data) {