[PATCH v4 0/7] Add O_DENY* support for VFS and CIFS/NFS

[PATCH v4 0/7] Add O_DENY* support for VFS and CIFS/NFS

[Pavel Shilovsky]

Main changes from the previous one:
1) O_DENYMAND is removed, sharelock mount option is introduced.
2) Patch fcntl.h and VFS patches are united into one.
3) flock/LOCK_MAND is disabled for sharelock mounts.

This patchset adds support of O_DENY* flags for Linux fs layer. These flags can be used by any application that needs share reservations to organize a file access. VFS already has some sort of this capability - now it's done through flock/LOCK_MAND mechanis, but that approach is non-atomic. This patchset build new capabilities on top of the existing one but doesn't bring any changes into the flock call semantic.

These flags can be used by NFS (built-in-kernel) and CIFS (Samba) servers and Wine applications through VFS (for local filesystems) or CIFS/NFS modules. This will help when e.g. Samba and NFS server share the same directory for Windows and Linux users or Wine applications use Samba/NFS share to access the same data from different clients.

According to the previous discussions the most problematic question is how to prevent situations like DoS attacks where e.g /lib/liba.so file can be open with DENYREAD, or smth like this. That's why extra mount option 'sharelock' is added for switching on/off O_DENY* flags processing. It allows us to avoid use of these flags on critical places (like /, /lib) and turn them on if we really want it proccessed that way.

So, we have 3 new flags:
O_DENYREAD - to prevent other opens with read access,
O_DENYWRITE - to prevent other opens with write access,
O_DENYDELETE - to prevent delete operations (this flag is not implemented in VFS and NFS part and only suitable for CIFS module),

The patchset avoid data races problem on newely created files: open with O_CREAT can return the -ETXTBSY error for a successfully created file if this files was locked with a deny lock by another task. Also, it turns flock/LOCK_MAND capability off for mounts with 'sharelock' option. This let us not mix one share reservation approach with another.

The #1 patch adds flags to fcntl and implements VFS part. The patches #3, #4, #5 are related to CIFS-specific changes, #6 and #7 describe NFS and NFSD parts.

The preliminary patch for Samba that replaces the existing use of flock/LOCK_MAND mechanism with O_DENY* flags:
http://git.etersoft.ru/people/piastry/packages/?p=samba.git;a=commitdiff;h=173070262b7f29134ad6b2e49a760017c11aec4a

The future part of open man page patch:

-----
O_DENYREAD, O_DENYWRIYE, O_DENYDELETE - used to inforce a mandatory share reservation scheme of the file access. If these flag is passed, the open fails with -EBUSY in following cases:
1) if O_DENYREAD flag is specified and there is another open with O_DENYMAND flag and READ access to the file;
2) if O_DENYWRITE flag is specified and there is another open with O_DENYMAND flag and WRITE access to the file;
3) if READ access is requested and there is another open with O_DENYMAND and O_DENYREAD flags;
4) if WRITE access is requested and there is another open with O_DENYMAND and O_DENYWRITE flags.

If O_DENYDELETE flag is specified and the open succeded, any further unlink operation will fail with -EBUSY untill this open is closed. Now this flag is processed by CIFS filesystems only.

This mechanism is done through flocks. If O_DENY* flags are specified, flock syscall is processed after the open. The share modes are translated into flock according the following rules:
1) !O_DENYREAD  -> LOCK_READ | LOCK_MAND
2) !O_DENYWRITE -> LOCK_WRITE | LOCK_MAND
-----

Pavel Shilovsky (7):
  fcntl: Introduce new O_DENY* open flags
  CIFS: Add share_access parm to open request
  CIFS: Add O_DENY* open flags support
  CIFS: Use NT_CREATE_ANDX command for forcemand mounts
  NFSv4: Add O_DENY* open flags support
  NFSD: Pass share reservations flags to VFS
  locks: Disable LOCK_MAND support for MS_SHARELOCK mounts

 fs/cifs/cifsacl.c                |   8 +--
 fs/cifs/cifsglob.h               |  18 ++++++-
 fs/cifs/cifsproto.h              |   8 +--
 fs/cifs/cifssmb.c                |  50 +++++++++---------
 fs/cifs/dir.c                    |  16 +++---
 fs/cifs/file.c                   |  20 +++++---
 fs/cifs/inode.c                  |  16 +++---
 fs/cifs/link.c                   |  25 +++------
 fs/cifs/readdir.c                |   5 +-
 fs/cifs/smb1ops.c                |  16 +++---
 fs/cifs/smb2file.c               |  10 ++--
 fs/cifs/smb2inode.c              |   4 +-
 fs/cifs/smb2ops.c                |  10 ++--
 fs/cifs/smb2pdu.c                |   6 +--
 fs/cifs/smb2proto.h              |  14 ++---
 fs/fcntl.c                       |   5 +-
 fs/locks.c                       | 108 ++++++++++++++++++++++++++++++++++++---
 fs/namei.c                       |  45 ++++++++++++++--
 fs/nfs/internal.h                |   3 +-
 fs/nfs/nfs4proc.c                |   2 +
 fs/nfs/nfs4xdr.c                 |  21 ++++++--
 fs/nfs/super.c                   |   3 +-
 fs/nfsd/nfs4state.c              |  46 ++++++++++++++++-
 fs/proc_namespace.c              |   1 +
 include/linux/fs.h               |   7 +++
 include/uapi/asm-generic/fcntl.h |  11 ++++
 include/uapi/linux/fs.h          |   1 +
 27 files changed, 355 insertions(+), 124 deletions(-)

-- 
1.8.1.5

[PATCH v4 2/7] CIFS: Add share_access parm to open request

[Pavel Shilovsky]

and simplify CIFSSMBOpen params.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
---
 fs/cifs/cifsacl.c   |  8 ++++----
 fs/cifs/cifsglob.h  |  2 +-
 fs/cifs/cifsproto.h |  8 ++++----
 fs/cifs/cifssmb.c   | 50 +++++++++++++++++++++++++++-----------------------
 fs/cifs/dir.c       | 12 ++++++------
 fs/cifs/file.c      | 10 ++++++----
 fs/cifs/inode.c     | 16 ++++++----------
 fs/cifs/link.c      | 25 ++++++++-----------------
 fs/cifs/readdir.c   |  5 ++---
 fs/cifs/smb1ops.c   | 16 +++++++---------
 fs/cifs/smb2file.c  | 10 +++++-----
 fs/cifs/smb2inode.c |  4 ++--
 fs/cifs/smb2ops.c   | 10 ++++++----
 fs/cifs/smb2pdu.c   |  6 +++---
 fs/cifs/smb2proto.h | 14 ++++++++------
 15 files changed, 95 insertions(+), 101 deletions(-)

diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index 5cbd00e..3820e61 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -891,8 +891,8 @@ static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
 		create_options |= CREATE_OPEN_BACKUP_INTENT;
 
 	rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, READ_CONTROL,
-			create_options, &fid, &oplock, NULL, cifs_sb->local_nls,
-			cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
+			FILE_SHARE_ALL, create_options, &fid, &oplock,
+			NULL, cifs_sb);
 	if (!rc) {
 		rc = CIFSSMBGetCIFSACL(xid, tcon, fid, &pntsd, pacllen);
 		CIFSSMBClose(xid, tcon, fid);
@@ -952,8 +952,8 @@ int set_cifs_acl(struct cifs_ntsd *pnntsd, __u32 acllen,
 		access_flags = WRITE_DAC;
 
 	rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, access_flags,
-			create_options, &fid, &oplock, NULL, cifs_sb->local_nls,
-			cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
+			FILE_SHARE_ALL, create_options, &fid, &oplock,
+			NULL, cifs_sb);
 	if (rc) {
 		cERROR(1, "Unable to open file to set ACL");
 		goto out;
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index e6899ce..cd4bbf3 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -310,7 +310,7 @@ struct smb_version_operations {
 			       struct cifs_sb_info *);
 	/* open a file for non-posix mounts */
 	int (*open)(const unsigned int, struct cifs_tcon *, const char *, int,
-		    int, int, struct cifs_fid *, __u32 *, FILE_ALL_INFO *,
+		    int, int, int, struct cifs_fid *, __u32 *, FILE_ALL_INFO *,
 		    struct cifs_sb_info *);
 	/* set fid protocol-specific info */
 	void (*set_fid)(struct cifsFileInfo *, struct cifs_fid *, __u32);
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 1988c1b..89f7dac 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -361,10 +361,10 @@ extern int CIFSSMBQueryReparseLinkInfo(const unsigned int xid,
 			const struct nls_table *nls_codepage);
 #endif /* temporarily unused until cifs_symlink fixed */
 extern int CIFSSMBOpen(const unsigned int xid, struct cifs_tcon *tcon,
-			const char *fileName, const int disposition,
-			const int access_flags, const int omode,
-			__u16 *netfid, int *pOplock, FILE_ALL_INFO *,
-			const struct nls_table *nls_codepage, int remap);
+			const char *file_name, const int disposition,
+			const int desired_access, const int share_access,
+			const int omode, __u16 *netfid, int *oplock,
+			FILE_ALL_INFO *, struct cifs_sb_info *);
 extern int SMBLegacyOpen(const unsigned int xid, struct cifs_tcon *tcon,
 			const char *fileName, const int disposition,
 			const int access_flags, const int omode,
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 76d0d29..d619646 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1289,10 +1289,10 @@ OldOpenRetry:
 
 int
 CIFSSMBOpen(const unsigned int xid, struct cifs_tcon *tcon,
-	    const char *fileName, const int openDisposition,
-	    const int access_flags, const int create_options, __u16 *netfid,
-	    int *pOplock, FILE_ALL_INFO *pfile_info,
-	    const struct nls_table *nls_codepage, int remap)
+	    const char *file_name, const int disposition,
+	    const int desired_access, const int share_access,
+	    const int create_options, __u16 *netfid, int *oplock,
+	    FILE_ALL_INFO *file_info, struct cifs_sb_info *cifs_sb)
 {
 	int rc = -EACCES;
 	OPEN_REQ *pSMB = NULL;
@@ -1300,6 +1300,8 @@ CIFSSMBOpen(const unsigned int xid, struct cifs_tcon *tcon,
 	int bytes_returned;
 	int name_len;
 	__u16 count;
+	struct nls_table *nls_codepage = cifs_sb->local_nls;
+	int remap = cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR;
 
 openRetry:
 	rc = smb_init(SMB_COM_NT_CREATE_ANDX, 24, tcon, (void **) &pSMB,
@@ -1313,26 +1315,28 @@ openRetry:
 		count = 1;	/* account for one byte pad to word boundary */
 		name_len =
 		    cifsConvertToUTF16((__le16 *) (pSMB->fileName + 1),
-				       fileName, PATH_MAX, nls_codepage, remap);
+				       file_name, PATH_MAX, nls_codepage,
+				       remap);
 		name_len++;	/* trailing null */
 		name_len *= 2;
 		pSMB->NameLength = cpu_to_le16(name_len);
 	} else {		/* BB improve check for buffer overruns BB */
 		count = 0;	/* no pad */
-		name_len = strnlen(fileName, PATH_MAX);
+		name_len = strnlen(file_name, PATH_MAX);
 		name_len++;	/* trailing null */
 		pSMB->NameLength = cpu_to_le16(name_len);
-		strncpy(pSMB->fileName, fileName, name_len);
+		strncpy(pSMB->fileName, file_name, name_len);
 	}
-	if (*pOplock & REQ_OPLOCK)
+	if (*oplock & REQ_OPLOCK)
 		pSMB->OpenFlags = cpu_to_le32(REQ_OPLOCK);
-	else if (*pOplock & REQ_BATCHOPLOCK)
+	else if (*oplock & REQ_BATCHOPLOCK)
 		pSMB->OpenFlags = cpu_to_le32(REQ_BATCHOPLOCK);
-	pSMB->DesiredAccess = cpu_to_le32(access_flags);
+	pSMB->DesiredAccess = cpu_to_le32(desired_access);
 	pSMB->AllocationSize = 0;
-	/* set file as system file if special file such
-	   as fifo and server expecting SFU style and
-	   no Unix extensions */
+	/*
+	 * set file as system file if special file such as fifo and server
+	 * expecting SFU style and no Unix extensions
+	 */
 	if (create_options & CREATE_OPTION_SPECIAL)
 		pSMB->FileAttributes = cpu_to_le32(ATTR_SYSTEM);
 	else
@@ -1347,8 +1351,8 @@ openRetry:
 	if (create_options & CREATE_OPTION_READONLY)
 		pSMB->FileAttributes |= cpu_to_le32(ATTR_READONLY);
 
-	pSMB->ShareAccess = cpu_to_le32(FILE_SHARE_ALL);
-	pSMB->CreateDisposition = cpu_to_le32(openDisposition);
+	pSMB->ShareAccess = cpu_to_le32(share_access);
+	pSMB->CreateDisposition = cpu_to_le32(disposition);
 	pSMB->CreateOptions = cpu_to_le32(create_options & CREATE_OPTIONS_MASK);
 	/* BB Expirement with various impersonation levels and verify */
 	pSMB->ImpersonationLevel = cpu_to_le32(SECURITY_IMPERSONATION);
@@ -1366,20 +1370,20 @@ openRetry:
 	if (rc) {
 		cFYI(1, "Error in Open = %d", rc);
 	} else {
-		*pOplock = pSMBr->OplockLevel; /* 1 byte no need to le_to_cpu */
+		*oplock = pSMBr->OplockLevel; /* 1 byte no need to le_to_cpu */
 		*netfid = pSMBr->Fid;	/* cifs fid stays in le */
 		/* Let caller know file was created so we can set the mode. */
 		/* Do we care about the CreateAction in any other cases? */
 		if (cpu_to_le32(FILE_CREATE) == pSMBr->CreateAction)
-			*pOplock |= CIFS_CREATE_ACTION;
-		if (pfile_info) {
-			memcpy((char *)pfile_info, (char *)&pSMBr->CreationTime,
+			*oplock |= CIFS_CREATE_ACTION;
+		if (file_info) {
+			memcpy((char *)file_info, (char *)&pSMBr->CreationTime,
 				36 /* CreationTime to Attributes */);
 			/* the file_info buf is endian converted by caller */
-			pfile_info->AllocationSize = pSMBr->AllocationSize;
-			pfile_info->EndOfFile = pSMBr->EndOfFile;
-			pfile_info->NumberOfLinks = cpu_to_le32(1);
-			pfile_info->DeletePending = 0;
+			file_info->AllocationSize = pSMBr->AllocationSize;
+			file_info->EndOfFile = pSMBr->EndOfFile;
+			file_info->NumberOfLinks = cpu_to_le32(1);
+			file_info->DeletePending = 0;
 		}
 	}
 
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 8719bbe..267b608 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -203,6 +203,7 @@ cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
 	FILE_ALL_INFO *buf = NULL;
 	struct inode *newinode = NULL;
 	int disposition;
+	int share_access = FILE_SHARE_ALL;
 	struct TCP_Server_Info *server = tcon->ses->server;
 
 	*oplock = 0;
@@ -320,8 +321,8 @@ cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
 		create_options |= CREATE_OPEN_BACKUP_INTENT;
 
 	rc = server->ops->open(xid, tcon, full_path, disposition,
-			       desired_access, create_options, fid, oplock,
-			       buf, cifs_sb);
+			       desired_access, share_access, create_options,
+			       fid, oplock, buf, cifs_sb);
 	if (rc) {
 		cFYI(1, "cifs_create returned 0x%x", rc);
 		goto out;
@@ -626,10 +627,9 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, umode_t mode,
 	if (backup_cred(cifs_sb))
 		create_options |= CREATE_OPEN_BACKUP_INTENT;
 
-	rc = CIFSSMBOpen(xid, pTcon, full_path, FILE_CREATE,
-			 GENERIC_WRITE, create_options,
-			 &fileHandle, &oplock, buf, cifs_sb->local_nls,
-			 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
+	rc = CIFSSMBOpen(xid, pTcon, full_path, FILE_CREATE, GENERIC_WRITE,
+			 FILE_SHARE_ALL, create_options, &fileHandle, &oplock,
+			 buf, cifs_sb);
 	if (rc)
 		goto mknod_out;
 
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 8ea6ca5..0d524a7 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -174,6 +174,7 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
 {
 	int rc;
 	int desired_access;
+	int share_access = FILE_SHARE_ALL;
 	int disposition;
 	int create_options = CREATE_NOT_DIR;
 	FILE_ALL_INFO *buf;
@@ -220,8 +221,8 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
 		create_options |= CREATE_OPEN_BACKUP_INTENT;
 
 	rc = server->ops->open(xid, tcon, full_path, disposition,
-			       desired_access, create_options, fid, oplock, buf,
-			       cifs_sb);
+			       desired_access, share_access, create_options,
+			       fid, oplock, buf, cifs_sb);
 
 	if (rc)
 		goto out;
@@ -579,6 +580,7 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 	struct inode *inode;
 	char *full_path = NULL;
 	int desired_access;
+	int share_access = FILE_SHARE_ALL;
 	int disposition = FILE_OPEN;
 	int create_options = CREATE_NOT_DIR;
 	struct cifs_fid fid;
@@ -658,8 +660,8 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 	 * not dirty locally we could do this.
 	 */
 	rc = server->ops->open(xid, tcon, full_path, disposition,
-			       desired_access, create_options, &fid, &oplock,
-			       NULL, cifs_sb);
+			       desired_access, share_access, create_options,
+			       &fid, &oplock, NULL, cifs_sb);
 	if (rc) {
 		mutex_unlock(&cfile->fh_mutex);
 		cFYI(1, "cifs_reopen returned 0x%x", rc);
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index ed6208f..233b2cc 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -396,10 +396,8 @@ cifs_sfu_type(struct cifs_fattr *fattr, const unsigned char *path,
 	tcon = tlink_tcon(tlink);
 
 	rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, GENERIC_READ,
-			 CREATE_NOT_DIR, &netfid, &oplock, NULL,
-			 cifs_sb->local_nls,
-			 cifs_sb->mnt_cifs_flags &
-				CIFS_MOUNT_MAP_SPECIAL_CHR);
+			 FILE_SHARE_ALL, CREATE_NOT_DIR, &netfid, &oplock,
+			 NULL, cifs_sb);
 	if (rc == 0) {
 		int buf_type = CIFS_NO_BUFFER;
 			/* Read header */
@@ -987,9 +985,8 @@ cifs_rename_pending_delete(const char *full_path, struct dentry *dentry,
 	tcon = tlink_tcon(tlink);
 
 	rc = CIFSSMBOpen(xid, tcon, full_path, FILE_OPEN,
-			 DELETE|FILE_WRITE_ATTRIBUTES, CREATE_NOT_DIR,
-			 &netfid, &oplock, NULL, cifs_sb->local_nls,
-			 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
+			 DELETE|FILE_WRITE_ATTRIBUTES, FILE_SHARE_ALL,
+			 CREATE_NOT_DIR, &netfid, &oplock, NULL, cifs_sb);
 	if (rc != 0)
 		goto out;
 
@@ -1509,9 +1506,8 @@ cifs_do_rename(const unsigned int xid, struct dentry *from_dentry,
 
 	/* open the file to be renamed -- we need DELETE perms */
 	rc = CIFSSMBOpen(xid, tcon, from_path, FILE_OPEN, DELETE,
-			 CREATE_NOT_DIR, &srcfid, &oplock, NULL,
-			 cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
-				CIFS_MOUNT_MAP_SPECIAL_CHR);
+			 FILE_SHARE_ALL, CREATE_NOT_DIR, &srcfid, &oplock, NULL,
+			 cifs_sb);
 	if (rc == 0) {
 		rc = CIFSSMBRenameOpenFile(xid, tcon, srcfid,
 				(const char *) to_dentry->d_name.name,
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 51dc2fb..d467881 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -187,16 +187,11 @@ CIFSCreateMFSymLink(const unsigned int xid, struct cifs_tcon *tcon,
 {
 	int rc;
 	int oplock = 0;
-	int remap;
 	int create_options = CREATE_NOT_DIR;
 	__u16 netfid = 0;
 	u8 *buf;
 	unsigned int bytes_written = 0;
 	struct cifs_io_parms io_parms;
-	struct nls_table *nls_codepage;
-
-	nls_codepage = cifs_sb->local_nls;
-	remap = cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR;
 
 	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
 	if (!buf)
@@ -212,8 +207,8 @@ CIFSCreateMFSymLink(const unsigned int xid, struct cifs_tcon *tcon,
 		create_options |= CREATE_OPEN_BACKUP_INTENT;
 
 	rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
-			 create_options, &netfid, &oplock, NULL,
-			 nls_codepage, remap);
+			 FILE_SHARE_ALL, create_options, &netfid, &oplock, NULL,
+			 cifs_sb);
 	if (rc != 0) {
 		kfree(buf);
 		return rc;
@@ -240,7 +235,7 @@ CIFSCreateMFSymLink(const unsigned int xid, struct cifs_tcon *tcon,
 static int
 CIFSQueryMFSymLink(const unsigned int xid, struct cifs_tcon *tcon,
 		   const unsigned char *searchName, char **symlinkinfo,
-		   const struct nls_table *nls_codepage, int remap)
+		   struct cifs_sb_info *cifs_sb)
 {
 	int rc;
 	int oplock = 0;
@@ -254,8 +249,8 @@ CIFSQueryMFSymLink(const unsigned int xid, struct cifs_tcon *tcon,
 	FILE_ALL_INFO file_info;
 
 	rc = CIFSSMBOpen(xid, tcon, searchName, FILE_OPEN, GENERIC_READ,
-			 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
-			 nls_codepage, remap);
+			 FILE_SHARE_ALL, CREATE_NOT_DIR, &netfid, &oplock,
+			 &file_info, cifs_sb);
 	if (rc != 0)
 		return rc;
 
@@ -332,10 +327,8 @@ CIFSCheckMFSymlink(struct cifs_fattr *fattr,
 	pTcon = tlink_tcon(tlink);
 
 	rc = CIFSSMBOpen(xid, pTcon, path, FILE_OPEN, GENERIC_READ,
-			 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
-			 cifs_sb->local_nls,
-			 cifs_sb->mnt_cifs_flags &
-				CIFS_MOUNT_MAP_SPECIAL_CHR);
+			 FILE_SHARE_ALL, CREATE_NOT_DIR, &netfid, &oplock,
+			 &file_info, cifs_sb);
 	if (rc != 0)
 		goto out;
 
@@ -530,9 +523,7 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 	 */
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
 		rc = CIFSQueryMFSymLink(xid, tcon, full_path, &target_path,
-					cifs_sb->local_nls,
-					cifs_sb->mnt_cifs_flags &
-						CIFS_MOUNT_MAP_SPECIAL_CHR);
+					cifs_sb);
 
 	if ((rc != 0) && cap_unix(tcon->ses))
 		rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index cdd6ff4..d51927b 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -224,9 +224,8 @@ int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 	char *tmpbuffer;
 
 	rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
-			OPEN_REPARSE_POINT, &fid, &oplock, NULL,
-			cifs_sb->local_nls,
-			cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
+			FILE_SHARE_ALL, OPEN_REPARSE_POINT, &fid, &oplock, NULL,
+			cifs_sb);
 	if (!rc) {
 		tmpbuffer = kmalloc(maxpath);
 		rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index 47bc5a8..a76950a 100644
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -671,9 +671,9 @@ cifs_mkdir_setinfo(struct inode *inode, const char *full_path,
 
 static int
 cifs_open_file(const unsigned int xid, struct cifs_tcon *tcon, const char *path,
-	       int disposition, int desired_access, int create_options,
-	       struct cifs_fid *fid, __u32 *oplock, FILE_ALL_INFO *buf,
-	       struct cifs_sb_info *cifs_sb)
+	       int disposition, int desired_access, int share_access,
+	       int create_options, struct cifs_fid *fid, __u32 *oplock,
+	       FILE_ALL_INFO *buf, struct cifs_sb_info *cifs_sb)
 {
 	if (!(tcon->ses->capabilities & CAP_NT_SMBS))
 		return SMBLegacyOpen(xid, tcon, path, disposition,
@@ -682,9 +682,8 @@ cifs_open_file(const unsigned int xid, struct cifs_tcon *tcon, const char *path,
 				     cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
 						& CIFS_MOUNT_MAP_SPECIAL_CHR);
 	return CIFSSMBOpen(xid, tcon, path, disposition, desired_access,
-			   create_options, &fid->netfid, oplock, buf,
-			   cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
-						CIFS_MOUNT_MAP_SPECIAL_CHR);
+			   share_access, create_options, &fid->netfid, oplock,
+			   buf, cifs_sb);
 }
 
 static void
@@ -779,9 +778,8 @@ smb_set_file_info(struct inode *inode, const char *full_path,
 	cFYI(1, "calling SetFileInfo since SetPathInfo for times not supported "
 		"by this server");
 	rc = CIFSSMBOpen(xid, tcon, full_path, FILE_OPEN,
-			 SYNCHRONIZE | FILE_WRITE_ATTRIBUTES, CREATE_NOT_DIR,
-			 &netfid, &oplock, NULL, cifs_sb->local_nls,
-			 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
+			 SYNCHRONIZE | FILE_WRITE_ATTRIBUTES, FILE_SHARE_ALL,
+			 CREATE_NOT_DIR, &netfid, &oplock, NULL, cifs_sb);
 
 	if (rc != 0) {
 		if (rc == -EIO)
diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index 71e6aed..7dfb50c 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -58,9 +58,9 @@ smb2_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 
 int
 smb2_open_file(const unsigned int xid, struct cifs_tcon *tcon, const char *path,
-	       int disposition, int desired_access, int create_options,
-	       struct cifs_fid *fid, __u32 *oplock, FILE_ALL_INFO *buf,
-	       struct cifs_sb_info *cifs_sb)
+	       int disposition, int desired_access, int share_access,
+	       int create_options, struct cifs_fid *fid, __u32 *oplock,
+	       FILE_ALL_INFO *buf, struct cifs_sb_info *cifs_sb)
 {
 	int rc;
 	__le16 *smb2_path;
@@ -87,8 +87,8 @@ smb2_open_file(const unsigned int xid, struct cifs_tcon *tcon, const char *path,
 		memcpy(smb2_oplock + 1, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 
 	rc = SMB2_open(xid, tcon, smb2_path, &fid->persistent_fid,
-		       &fid->volatile_fid, desired_access, disposition,
-		       0, 0, smb2_oplock, smb2_data);
+		       &fid->volatile_fid, desired_access, share_access,
+		       disposition, 0, 0, smb2_oplock, smb2_data);
 	if (rc)
 		goto out;
 
diff --git a/fs/cifs/smb2inode.c b/fs/cifs/smb2inode.c
index 7064824..6af174a 100644
--- a/fs/cifs/smb2inode.c
+++ b/fs/cifs/smb2inode.c
@@ -54,8 +54,8 @@ smb2_open_op_close(const unsigned int xid, struct cifs_tcon *tcon,
 		return -ENOMEM;
 
 	rc = SMB2_open(xid, tcon, utf16_path, &persistent_fid, &volatile_fid,
-		       desired_access, create_disposition, file_attributes,
-		       create_options, &oplock, NULL);
+		       desired_access, FILE_SHARE_ALL, create_disposition,
+		       file_attributes, create_options, &oplock, NULL);
 	if (rc) {
 		kfree(utf16_path);
 		return rc;
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index bceffe7..22aef1d 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -222,7 +222,8 @@ smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
 		return -ENOMEM;
 
 	rc = SMB2_open(xid, tcon, utf16_path, &persistent_fid, &volatile_fid,
-		       FILE_READ_ATTRIBUTES, FILE_OPEN, 0, 0, &oplock, NULL);
+		       FILE_READ_ATTRIBUTES, FILE_SHARE_ALL, FILE_OPEN, 0, 0,
+		       &oplock, NULL);
 	if (rc) {
 		kfree(utf16_path);
 		return rc;
@@ -432,8 +433,8 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 		return -ENOMEM;
 
 	rc = SMB2_open(xid, tcon, utf16_path, &persistent_fid, &volatile_fid,
-		       FILE_READ_ATTRIBUTES | FILE_READ_DATA, FILE_OPEN, 0, 0,
-		       &oplock, NULL);
+		       FILE_READ_ATTRIBUTES | FILE_READ_DATA, FILE_SHARE_ALL,
+		       FILE_OPEN, 0, 0, &oplock, NULL);
 	kfree(utf16_path);
 	if (rc) {
 		cERROR(1, "open dir failed");
@@ -515,7 +516,8 @@ smb2_queryfs(const unsigned int xid, struct cifs_tcon *tcon,
 	u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
 
 	rc = SMB2_open(xid, tcon, &srch_path, &persistent_fid, &volatile_fid,
-		       FILE_READ_ATTRIBUTES, FILE_OPEN, 0, 0, &oplock, NULL);
+		       FILE_READ_ATTRIBUTES, FILE_SHARE_ALL, FILE_OPEN, 0, 0,
+		       &oplock, NULL);
 	if (rc)
 		return rc;
 	buf->f_type = SMB2_MAGIC_NUMBER;
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 41d9d07..45fa2dc 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -910,8 +910,8 @@ parse_lease_state(struct smb2_create_rsp *rsp)
 int
 SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
 	  u64 *persistent_fid, u64 *volatile_fid, __u32 desired_access,
-	  __u32 create_disposition, __u32 file_attributes, __u32 create_options,
-	  __u8 *oplock, struct smb2_file_all_info *buf)
+	  __u32 share_access, __u32 create_disposition, __u32 file_attributes,
+	  __u32 create_options,  __u8 *oplock, struct smb2_file_all_info *buf)
 {
 	struct smb2_create_req *req;
 	struct smb2_create_rsp *rsp;
@@ -940,7 +940,7 @@ SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
 	req->DesiredAccess = cpu_to_le32(desired_access);
 	/* File attributes ignored on open (used in create though) */
 	req->FileAttributes = cpu_to_le32(file_attributes);
-	req->ShareAccess = FILE_SHARE_ALL_LE;
+	req->ShareAccess = cpu_to_le32(share_access);
 	req->CreateDisposition = cpu_to_le32(create_disposition);
 	req->CreateOptions = cpu_to_le32(create_options);
 	uni_path_len = (2 * UniStrnlen((wchar_t *)path, PATH_MAX)) + 2;
diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 2aa3535..edff8f6 100644
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -86,9 +86,10 @@ extern int smb2_create_hardlink(const unsigned int xid, struct cifs_tcon *tcon,
 
 extern int smb2_open_file(const unsigned int xid, struct cifs_tcon *tcon,
 			  const char *full_path, int disposition,
-			  int desired_access, int create_options,
-			  struct cifs_fid *fid, __u32 *oplock,
-			  FILE_ALL_INFO *buf, struct cifs_sb_info *cifs_sb);
+			  int desired_access, int share_access,
+			  int create_options,  struct cifs_fid *fid,
+			  __u32 *oplock, FILE_ALL_INFO *buf,
+			  struct cifs_sb_info *cifs_sb);
 extern void smb2_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock);
 extern int smb2_unlock_range(struct cifsFileInfo *cfile,
 			     struct file_lock *flock, const unsigned int xid);
@@ -108,9 +109,10 @@ extern int SMB2_tcon(const unsigned int xid, struct cifs_ses *ses,
 extern int SMB2_tdis(const unsigned int xid, struct cifs_tcon *tcon);
 extern int SMB2_open(const unsigned int xid, struct cifs_tcon *tcon,
 		     __le16 *path, u64 *persistent_fid, u64 *volatile_fid,
-		     __u32 desired_access, __u32 create_disposition,
-		     __u32 file_attributes, __u32 create_options,
-		     __u8 *oplock, struct smb2_file_all_info *buf);
+		     __u32 desired_access, __u32 share_access,
+		     __u32 create_disposition, __u32 file_attributes,
+		     __u32 create_options, __u8 *oplock,
+		     struct smb2_file_all_info *buf);
 extern int SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
 		      u64 persistent_file_id, u64 volatile_file_id);
 extern int SMB2_flush(const unsigned int xid, struct cifs_tcon *tcon,
-- 
1.8.1.5

[PATCH v4 1/7] fcntl: Introduce new O_DENY* open flags

[Pavel Shilovsky]

This patch adds 3 flags:
1) O_DENYREAD that doesn't permit read access,
2) O_DENYWRITE that doesn't permit write access,
3) O_DENYDELETE that doesn't permit delete or rename,

Network filesystems CIFS, SMB2.0, SMB3.0 and NFSv4 have such flags -
this change can benefit cifs and nfs modules as well as Samba and
NFS file servers that export the same directory for Windows clients,
or Wine applications that access the same files simultaneously.

These flags are only take affect for opens on mounts with 'sharelock'
mount option. They are translated to flock's flags:

!O_DENYREAD  -> LOCK_READ | LOCK_MAND
!O_DENYWRITE -> LOCK_WRITE | LOCK_MAND

and set through flock_lock_file on a file. If the file can't be locked
due conflicts with another open with O_DENY* flags, the -EBUSY error
code is returned.

Create codepath is slightly changed to prevent data races on
newely created files: when open with O_CREAT can return with -EBUSY
error for successfully created files due to a deny lock set by
another task.

Signed-off-by: Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org>
---
 fs/fcntl.c                       |  5 ++-
 fs/locks.c                       | 93 +++++++++++++++++++++++++++++++++++++---
 fs/namei.c                       | 45 +++++++++++++++++--
 fs/proc_namespace.c              |  1 +
 include/linux/fs.h               |  7 +++
 include/uapi/asm-generic/fcntl.h | 11 +++++
 include/uapi/linux/fs.h          |  1 +
 7 files changed, 150 insertions(+), 13 deletions(-)

diff --git a/fs/fcntl.c b/fs/fcntl.c
index 71a600a..7abce5a 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -730,14 +730,15 @@ static int __init fcntl_init(void)
 	 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
 	 * is defined as O_NONBLOCK on some platforms and not on others.
 	 */
-	BUILD_BUG_ON(19 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
+	BUILD_BUG_ON(22 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
 		O_RDONLY	| O_WRONLY	| O_RDWR	|
 		O_CREAT		| O_EXCL	| O_NOCTTY	|
 		O_TRUNC		| O_APPEND	| /* O_NONBLOCK	| */
 		__O_SYNC	| O_DSYNC	| FASYNC	|
 		O_DIRECT	| O_LARGEFILE	| O_DIRECTORY	|
 		O_NOFOLLOW	| O_NOATIME	| O_CLOEXEC	|
-		__FMODE_EXEC	| O_PATH
+		__FMODE_EXEC	| O_PATH	| O_DENYREAD	|
+		O_DENYWRITE	| O_DENYDELETE
 		));
 
 	fasync_cache = kmem_cache_create("fasync_cache",
diff --git a/fs/locks.c b/fs/locks.c
index a94e331..1eccc75 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -605,20 +605,73 @@ static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *s
 	return (locks_conflict(caller_fl, sys_fl));
 }
 
-/* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
- * checking before calling the locks_conflict().
+static unsigned int
+deny_flags_to_cmd(unsigned int flags)
+{
+	unsigned int cmd = LOCK_MAND;
+
+	if (!(flags & O_DENYREAD))
+		cmd |= LOCK_READ;
+	if (!(flags & O_DENYWRITE))
+		cmd |= LOCK_WRITE;
+
+	return cmd;
+}
+
+/*
+ * locks_mand_conflict - Determine if there's a share reservation conflict
+ * @caller_fl: lock we're attempting to acquire
+ * @sys_fl: lock already present on system that we're checking against
+ *
+ * Check to see if there's a share_reservation conflict. LOCK_READ/LOCK_WRITE
+ * tell us whether the reservation allows other readers and writers.
+ */
+static int
+locks_mand_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
+{
+	unsigned char caller_type = caller_fl->fl_type;
+	unsigned char sys_type = sys_fl->fl_type;
+	fmode_t caller_fmode = caller_fl->fl_file->f_mode;
+	fmode_t sys_fmode = sys_fl->fl_file->f_mode;
+
+	/* they can only conflict if FS is mounted with MS_SHARELOCK */
+	if (!IS_SHARELOCK(caller_fl->fl_file->f_path.dentry->d_inode))
+		return 0;
+
+	/* they can only conflict if they're both LOCK_MAND */
+	if (!(caller_type & LOCK_MAND) || !(sys_type & LOCK_MAND))
+		return 0;
+
+	if (!(caller_type & LOCK_READ) && (sys_fmode & FMODE_READ))
+		return 1;
+	if (!(caller_type & LOCK_WRITE) && (sys_fmode & FMODE_WRITE))
+		return 1;
+	if (!(sys_type & LOCK_READ) && (caller_fmode & FMODE_READ))
+		return 1;
+	if (!(sys_type & LOCK_WRITE) && (caller_fmode & FMODE_WRITE))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * Determine if lock sys_fl blocks lock caller_fl. FLOCK specific checking
+ * before calling the locks_conflict().
  */
 static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
 {
-	/* FLOCK locks referring to the same filp do not conflict with
+	if (!IS_FLOCK(sys_fl))
+		return 0;
+	if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
+		return locks_mand_conflict(caller_fl, sys_fl);
+	/*
+	 * FLOCK locks referring to the same filp do not conflict with
 	 * each other.
 	 */
-	if (!IS_FLOCK(sys_fl) || (caller_fl->fl_file == sys_fl->fl_file))
-		return (0);
-	if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
+	if (caller_fl->fl_file == sys_fl->fl_file)
 		return 0;
 
-	return (locks_conflict(caller_fl, sys_fl));
+	return locks_conflict(caller_fl, sys_fl);
 }
 
 void
@@ -783,6 +836,32 @@ out:
 	return error;
 }
 
+/*
+ * Determine if a file is allowed to be opened with specified access and deny
+ * modes. Lock the file and return 0 if checks passed, otherwise return a error
+ * code.
+ */
+int
+deny_lock_file(struct file *filp)
+{
+	struct file_lock *lock;
+	int error = 0;
+
+	if (!IS_SHARELOCK(filp->f_path.dentry->d_inode))
+		return error;
+
+	error = flock_make_lock(filp, &lock, deny_flags_to_cmd(filp->f_flags));
+	if (error)
+		return error;
+
+	error = flock_lock_file(filp, lock);
+	if (error == -EAGAIN)
+		error = -EBUSY;
+
+	locks_free_lock(lock);
+	return error;
+}
+
 static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
 {
 	struct file_lock *fl;
diff --git a/fs/namei.c b/fs/namei.c
index ec97aef..416c74f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2557,9 +2557,14 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
 	 * here.
 	 */
 	error = may_open(&file->f_path, acc_mode, open_flag);
-	if (error)
+	if (error) {
 		fput(file);
+		goto out;
+	}
 
+	error = deny_lock_file(file);
+	if (error)
+		fput(file);
 out:
 	dput(dentry);
 	return error;
@@ -2769,9 +2774,9 @@ retry_lookup:
 	}
 	mutex_lock(&dir->d_inode->i_mutex);
 	error = lookup_open(nd, path, file, op, got_write, opened);
-	mutex_unlock(&dir->d_inode->i_mutex);
 
 	if (error <= 0) {
+		mutex_unlock(&dir->d_inode->i_mutex);
 		if (error)
 			goto out;
 
@@ -2789,8 +2794,32 @@ retry_lookup:
 		will_truncate = false;
 		acc_mode = MAY_OPEN;
 		path_to_nameidata(path, nd);
-		goto finish_open_created;
+
+		/*
+		 * Unlock parent i_mutex later when the open finishes - prevent
+		 * races when a file can be locked with a deny lock by another
+		 * task that opens the file.
+		 */
+		error = may_open(&nd->path, acc_mode, open_flag);
+		if (error) {
+			mutex_unlock(&dir->d_inode->i_mutex);
+			goto out;
+		}
+		file->f_path.mnt = nd->path.mnt;
+		error = finish_open(file, nd->path.dentry, NULL, opened);
+		if (error) {
+			mutex_unlock(&dir->d_inode->i_mutex);
+			if (error == -EOPENSTALE)
+				goto stale_open;
+			goto out;
+		}
+		error = deny_lock_file(file);
+		mutex_unlock(&dir->d_inode->i_mutex);
+		if (error)
+			goto exit_fput;
+		goto opened;
 	}
+	mutex_unlock(&dir->d_inode->i_mutex);
 
 	/*
 	 * create/update audit record if it already exists.
@@ -2872,7 +2901,6 @@ finish_open:
 			goto out;
 		got_write = true;
 	}
-finish_open_created:
 	error = may_open(&nd->path, acc_mode, open_flag);
 	if (error)
 		goto out;
@@ -2883,6 +2911,15 @@ finish_open_created:
 			goto stale_open;
 		goto out;
 	}
+	/*
+	 * Lock parent i_mutex to prevent races with deny locks on newely
+	 * created files.
+	 */
+	mutex_lock(&dir->d_inode->i_mutex);
+	error = deny_lock_file(file);
+	mutex_unlock(&dir->d_inode->i_mutex);
+	if (error)
+		goto exit_fput;
 opened:
 	error = open_check_o_direct(file);
 	if (error)
diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 2033f74..6edbadc 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -44,6 +44,7 @@ static int show_sb_opts(struct seq_file *m, struct super_block *sb)
 		{ MS_SYNCHRONOUS, ",sync" },
 		{ MS_DIRSYNC, ",dirsync" },
 		{ MS_MANDLOCK, ",mand" },
+		{ MS_SHARELOCK, ",sharelock" },
 		{ 0, NULL }
 	};
 	const struct proc_fs_info *fs_infop;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1a39c33..073e31a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1005,6 +1005,7 @@ extern int lease_modify(struct file_lock **, int);
 extern int lock_may_read(struct inode *, loff_t start, unsigned long count);
 extern int lock_may_write(struct inode *, loff_t start, unsigned long count);
 extern void locks_delete_block(struct file_lock *waiter);
+extern int deny_lock_file(struct file *);
 extern void lock_flocks(void);
 extern void unlock_flocks(void);
 #else /* !CONFIG_FILE_LOCKING */
@@ -1153,6 +1154,11 @@ static inline void locks_delete_block(struct file_lock *waiter)
 {
 }
 
+static inline int deny_lock_file(struct file *filp)
+{
+	return 0;
+}
+
 static inline void lock_flocks(void)
 {
 }
@@ -1668,6 +1674,7 @@ struct super_operations {
 #define IS_PRIVATE(inode)	((inode)->i_flags & S_PRIVATE)
 #define IS_IMA(inode)		((inode)->i_flags & S_IMA)
 #define IS_AUTOMOUNT(inode)	((inode)->i_flags & S_AUTOMOUNT)
+#define IS_SHARELOCK(inode)	__IS_FLG(inode, MS_SHARELOCK)
 #define IS_NOSEC(inode)		((inode)->i_flags & S_NOSEC)
 
 /*
diff --git a/include/uapi/asm-generic/fcntl.h b/include/uapi/asm-generic/fcntl.h
index a48937d..5ac0d49 100644
--- a/include/uapi/asm-generic/fcntl.h
+++ b/include/uapi/asm-generic/fcntl.h
@@ -84,6 +84,17 @@
 #define O_PATH		010000000
 #endif
 
+#ifndef O_DENYREAD
+#define O_DENYREAD	020000000	/* Do not permit read access */
+#endif
+#ifndef O_DENYWRITE
+#define O_DENYWRITE	040000000	/* Do not permit write access */
+#endif
+/* FMODE_NONOTIFY	0100000000 */
+#ifndef O_DENYDELETE
+#define O_DENYDELETE	0200000000	/* Do not permit delete or rename */
+#endif
+
 #ifndef O_NDELAY
 #define O_NDELAY	O_NONBLOCK
 #endif
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 780d4c6..f1925f7 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -86,6 +86,7 @@ struct inodes_stat_t {
 #define MS_KERNMOUNT	(1<<22) /* this is a kern_mount call */
 #define MS_I_VERSION	(1<<23) /* Update inode I_version field */
 #define MS_STRICTATIME	(1<<24) /* Always perform atime updates */
+#define MS_SHARELOCK	(1<<25) /* Allow share locks on an FS */
 #define MS_NOSEC	(1<<28)
 #define MS_BORN		(1<<29)
 #define MS_ACTIVE	(1<<30)
-- 
1.8.1.5

[PATCH v4 3/7] CIFS: Add O_DENY* open flags support

[Pavel Shilovsky]

Construct share_access value from O_DENY* flags and send it to
the server.

Signed-off-by: Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org>
---
 fs/cifs/cifsglob.h | 16 +++++++++++++++-
 fs/cifs/dir.c      |  3 +++
 fs/cifs/file.c     |  4 ++++
 fs/locks.c         |  8 ++++++++
 4 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index cd4bbf3..7e876b9 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -465,7 +465,7 @@ struct smb_vol {
 			 CIFS_MOUNT_CIFS_BACKUPUID | CIFS_MOUNT_CIFS_BACKUPGID)
 
 #define CIFS_MS_MASK (MS_RDONLY | MS_MANDLOCK | MS_NOEXEC | MS_NOSUID | \
-		      MS_NODEV | MS_SYNCHRONOUS)
+		      MS_NODEV | MS_SYNCHRONOUS | MS_SHARELOCK)
 
 struct cifs_mnt_data {
 	struct cifs_sb_info *cifs_sb;
@@ -947,6 +947,20 @@ struct cifsFileInfo {
 	struct work_struct oplock_break; /* work for oplock breaks */
 };
 
+static inline int
+cifs_get_share_flags(unsigned int flags)
+{
+	int share_access = 0;
+
+	if (!(flags & O_DENYREAD))
+		share_access |= FILE_SHARE_READ;
+	if (!(flags & O_DENYWRITE))
+		share_access |= FILE_SHARE_WRITE;
+	if (!(flags & O_DENYDELETE))
+		share_access |= FILE_SHARE_DELETE;
+	return share_access;
+}
+
 struct cifs_io_parms {
 	__u16 netfid;
 #ifdef CONFIG_CIFS_SMB2
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 267b608..d4331de 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -294,6 +294,9 @@ cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
 	else
 		cFYI(1, "Create flag not set in create function");
 
+	if (IS_SHARELOCK(inode))
+		share_access = cifs_get_share_flags(oflags);
+
 	/*
 	 * BB add processing to set equivalent of mode - e.g. via CreateX with
 	 * ACLs
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 0d524a7..9394b2b 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -210,6 +210,8 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
  *********************************************************************/
 
 	disposition = cifs_get_disposition(f_flags);
+	if (IS_SHARELOCK(inode))
+		share_access = cifs_get_share_flags(f_flags);
 
 	/* BB pass O_SYNC flag through on file attributes .. BB */
 
@@ -645,6 +647,8 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 	}
 
 	desired_access = cifs_convert_flags(cfile->f_flags);
+	if (IS_SHARELOCK(inode))
+		share_access = cifs_get_share_flags(cfile->f_flags);
 
 	if (backup_cred(cifs_sb))
 		create_options |= CREATE_OPEN_BACKUP_INTENT;
diff --git a/fs/locks.c b/fs/locks.c
index 1eccc75..2184ddd 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -846,10 +846,18 @@ deny_lock_file(struct file *filp)
 {
 	struct file_lock *lock;
 	int error = 0;
+	const char *fsname = filp->f_path.dentry->d_inode->i_sb->s_type->name;
 
 	if (!IS_SHARELOCK(filp->f_path.dentry->d_inode))
 		return error;
 
+	/*
+	 * Don't set a lock on CIFS file systems because they can process it
+	 * themselves.
+	 */
+	if (!strncmp(fsname, "cifs", 4))
+		return error;
+
 	error = flock_make_lock(filp, &lock, deny_flags_to_cmd(filp->f_flags));
 	if (error)
 		return error;
-- 
1.8.1.5

Re: [PATCH v4 3/7] CIFS: Add O_DENY* open flags support

[Jeff Layton]

On Fri,  5 Apr 2013 20:57:51 +0400
Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org> wrote:

> Construct share_access value from O_DENY* flags and send it to
> the server.
> 
> Signed-off-by: Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org>
> ---
>  fs/cifs/cifsglob.h | 16 +++++++++++++++-
>  fs/cifs/dir.c      |  3 +++
>  fs/cifs/file.c     |  4 ++++
>  fs/locks.c         |  8 ++++++++
>  4 files changed, 30 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index cd4bbf3..7e876b9 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -465,7 +465,7 @@ struct smb_vol {
>  			 CIFS_MOUNT_CIFS_BACKUPUID | CIFS_MOUNT_CIFS_BACKUPGID)
>  
>  #define CIFS_MS_MASK (MS_RDONLY | MS_MANDLOCK | MS_NOEXEC | MS_NOSUID | \
> -		      MS_NODEV | MS_SYNCHRONOUS)
> +		      MS_NODEV | MS_SYNCHRONOUS | MS_SHARELOCK)
>  
>  struct cifs_mnt_data {
>  	struct cifs_sb_info *cifs_sb;
> @@ -947,6 +947,20 @@ struct cifsFileInfo {
>  	struct work_struct oplock_break; /* work for oplock breaks */
>  };
>  
> +static inline int
> +cifs_get_share_flags(unsigned int flags)
> +{
> +	int share_access = 0;
> +
> +	if (!(flags & O_DENYREAD))
> +		share_access |= FILE_SHARE_READ;
> +	if (!(flags & O_DENYWRITE))
> +		share_access |= FILE_SHARE_WRITE;
> +	if (!(flags & O_DENYDELETE))
> +		share_access |= FILE_SHARE_DELETE;
> +	return share_access;
> +}
> +
>  struct cifs_io_parms {
>  	__u16 netfid;
>  #ifdef CONFIG_CIFS_SMB2
> diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
> index 267b608..d4331de 100644
> --- a/fs/cifs/dir.c
> +++ b/fs/cifs/dir.c
> @@ -294,6 +294,9 @@ cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
>  	else
>  		cFYI(1, "Create flag not set in create function");
>  
> +	if (IS_SHARELOCK(inode))
> +		share_access = cifs_get_share_flags(oflags);
> +
>  	/*
>  	 * BB add processing to set equivalent of mode - e.g. via CreateX with
>  	 * ACLs
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 0d524a7..9394b2b 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -210,6 +210,8 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
>   *********************************************************************/
>  
>  	disposition = cifs_get_disposition(f_flags);
> +	if (IS_SHARELOCK(inode))
> +		share_access = cifs_get_share_flags(f_flags);
>  
>  	/* BB pass O_SYNC flag through on file attributes .. BB */
>  
> @@ -645,6 +647,8 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
>  	}
>  
>  	desired_access = cifs_convert_flags(cfile->f_flags);
> +	if (IS_SHARELOCK(inode))
> +		share_access = cifs_get_share_flags(cfile->f_flags);
>  
>  	if (backup_cred(cifs_sb))
>  		create_options |= CREATE_OPEN_BACKUP_INTENT;
> diff --git a/fs/locks.c b/fs/locks.c
> index 1eccc75..2184ddd 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -846,10 +846,18 @@ deny_lock_file(struct file *filp)
>  {
>  	struct file_lock *lock;
>  	int error = 0;
> +	const char *fsname = filp->f_path.dentry->d_inode->i_sb->s_type->name;
>  
>  	if (!IS_SHARELOCK(filp->f_path.dentry->d_inode))
>  		return error;
>  
> +	/*
> +	 * Don't set a lock on CIFS file systems because they can process it
> +	 * themselves.
> +	 */
> +	if (!strncmp(fsname, "cifs", 4))
> +		return error;
> +

NAK....

This is really nasty. Instead of doing this, you should instead create
a new file_system_type->fs_flags value. Then, set that flag for cifs
and nfs4, and test it here.


>  	error = flock_make_lock(filp, &lock, deny_flags_to_cmd(filp->f_flags));
>  	if (error)
>  		return error;


-- 
Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
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Re: [PATCH v4 3/7] CIFS: Add O_DENY* open flags support

[Pavel Shilovsky]

2013/4/8 Jeff Layton <jlayton@redhat.com>:
> On Fri,  5 Apr 2013 20:57:51 +0400
> Pavel Shilovsky <piastry@etersoft.ru> wrote:
>
>> Construct share_access value from O_DENY* flags and send it to
>> the server.
>>
>> Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
>> ---
>>  fs/cifs/cifsglob.h | 16 +++++++++++++++-
>>  fs/cifs/dir.c      |  3 +++
>>  fs/cifs/file.c     |  4 ++++
>>  fs/locks.c         |  8 ++++++++
>>  4 files changed, 30 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
>> index cd4bbf3..7e876b9 100644
>> --- a/fs/cifs/cifsglob.h
>> +++ b/fs/cifs/cifsglob.h
>> @@ -465,7 +465,7 @@ struct smb_vol {
>>                        CIFS_MOUNT_CIFS_BACKUPUID | CIFS_MOUNT_CIFS_BACKUPGID)
>>
>>  #define CIFS_MS_MASK (MS_RDONLY | MS_MANDLOCK | MS_NOEXEC | MS_NOSUID | \
>> -                   MS_NODEV | MS_SYNCHRONOUS)
>> +                   MS_NODEV | MS_SYNCHRONOUS | MS_SHARELOCK)
>>
>>  struct cifs_mnt_data {
>>       struct cifs_sb_info *cifs_sb;
>> @@ -947,6 +947,20 @@ struct cifsFileInfo {
>>       struct work_struct oplock_break; /* work for oplock breaks */
>>  };
>>
>> +static inline int
>> +cifs_get_share_flags(unsigned int flags)
>> +{
>> +     int share_access = 0;
>> +
>> +     if (!(flags & O_DENYREAD))
>> +             share_access |= FILE_SHARE_READ;
>> +     if (!(flags & O_DENYWRITE))
>> +             share_access |= FILE_SHARE_WRITE;
>> +     if (!(flags & O_DENYDELETE))
>> +             share_access |= FILE_SHARE_DELETE;
>> +     return share_access;
>> +}
>> +
>>  struct cifs_io_parms {
>>       __u16 netfid;
>>  #ifdef CONFIG_CIFS_SMB2
>> diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
>> index 267b608..d4331de 100644
>> --- a/fs/cifs/dir.c
>> +++ b/fs/cifs/dir.c
>> @@ -294,6 +294,9 @@ cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
>>       else
>>               cFYI(1, "Create flag not set in create function");
>>
>> +     if (IS_SHARELOCK(inode))
>> +             share_access = cifs_get_share_flags(oflags);
>> +
>>       /*
>>        * BB add processing to set equivalent of mode - e.g. via CreateX with
>>        * ACLs
>> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
>> index 0d524a7..9394b2b 100644
>> --- a/fs/cifs/file.c
>> +++ b/fs/cifs/file.c
>> @@ -210,6 +210,8 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
>>   *********************************************************************/
>>
>>       disposition = cifs_get_disposition(f_flags);
>> +     if (IS_SHARELOCK(inode))
>> +             share_access = cifs_get_share_flags(f_flags);
>>
>>       /* BB pass O_SYNC flag through on file attributes .. BB */
>>
>> @@ -645,6 +647,8 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
>>       }
>>
>>       desired_access = cifs_convert_flags(cfile->f_flags);
>> +     if (IS_SHARELOCK(inode))
>> +             share_access = cifs_get_share_flags(cfile->f_flags);
>>
>>       if (backup_cred(cifs_sb))
>>               create_options |= CREATE_OPEN_BACKUP_INTENT;
>> diff --git a/fs/locks.c b/fs/locks.c
>> index 1eccc75..2184ddd 100644
>> --- a/fs/locks.c
>> +++ b/fs/locks.c
>> @@ -846,10 +846,18 @@ deny_lock_file(struct file *filp)
>>  {
>>       struct file_lock *lock;
>>       int error = 0;
>> +     const char *fsname = filp->f_path.dentry->d_inode->i_sb->s_type->name;
>>
>>       if (!IS_SHARELOCK(filp->f_path.dentry->d_inode))
>>               return error;
>>
>> +     /*
>> +      * Don't set a lock on CIFS file systems because they can process it
>> +      * themselves.
>> +      */
>> +     if (!strncmp(fsname, "cifs", 4))
>> +             return error;
>> +
>
> NAK....
>
> This is really nasty. Instead of doing this, you should instead create
> a new file_system_type->fs_flags value. Then, set that flag for cifs
> and nfs4, and test it here.

It seems I missed this fs_flags opportunity. Thank you for pointing it
out - I will fix and repost.

--
Best regards,
Pavel Shilovsky.

[PATCH v4 5/7] NFSv4: Add O_DENY* open flags support

[Pavel Shilovsky]

by passing these flags to NFSv4 open request.

Signed-off-by: Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org>
---
 fs/locks.c        |  6 +++---
 fs/nfs/internal.h |  3 ++-
 fs/nfs/nfs4proc.c |  2 ++
 fs/nfs/nfs4xdr.c  | 21 +++++++++++++++++----
 fs/nfs/super.c    |  3 ++-
 5 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index 2184ddd..67c68fb 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -852,10 +852,10 @@ deny_lock_file(struct file *filp)
 		return error;
 
 	/*
-	 * Don't set a lock on CIFS file systems because they can process it
-	 * themselves.
+	 * Don't set a lock on CIFS and NFSv4 file systems because they can
+	 * process it themselves.
 	 */
-	if (!strncmp(fsname, "cifs", 4))
+	if (!strncmp(fsname, "cifs", 4) || !strncmp(fsname, "nfs4", 4))
 		return error;
 
 	error = flock_make_lock(filp, &lock, deny_flags_to_cmd(filp->f_flags));
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index f0e6c7d..c770830 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -6,7 +6,8 @@
 #include <linux/mount.h>
 #include <linux/security.h>
 
-#define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
+#define NFS_MS_MASK (MS_RDONLY | MS_NOSUID | MS_NODEV | MS_NOEXEC | \
+		     MS_SYNCHRONOUS | MS_SHARELOCK)
 
 struct nfs_string;
 
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 3cb5e77..9e33a54 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -793,6 +793,8 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 	atomic_inc(&sp->so_count);
 	p->o_arg.fh = NFS_FH(dir);
 	p->o_arg.open_flags = flags;
+	if (!IS_SHARELOCK(dir))
+		p->o_arg.open_flags &= ~(O_DENYREAD | O_DENYWRITE);
 	p->o_arg.fmode = fmode & (FMODE_READ|FMODE_WRITE);
 	/* don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
 	 * will return permission denied for all bits until close */
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 26b1439..8fe0221 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1325,7 +1325,8 @@ static void encode_lookup(struct xdr_stream *xdr, const struct qstr *name, struc
 	encode_string(xdr, name->len, name->name);
 }
 
-static void encode_share_access(struct xdr_stream *xdr, fmode_t fmode)
+static void encode_share_access(struct xdr_stream *xdr, fmode_t fmode,
+				int open_flags)
 {
 	__be32 *p;
 
@@ -1343,7 +1344,19 @@ static void encode_share_access(struct xdr_stream *xdr, fmode_t fmode)
 	default:
 		*p++ = cpu_to_be32(0);
 	}
-	*p = cpu_to_be32(0);		/* for linux, share_deny = 0 always */
+	switch (open_flags & (O_DENYREAD|O_DENYWRITE)) {
+	case O_DENYREAD:
+		*p = cpu_to_be32(NFS4_SHARE_DENY_READ);
+		break;
+	case O_DENYWRITE:
+		*p = cpu_to_be32(NFS4_SHARE_DENY_WRITE);
+		break;
+	case O_DENYREAD|O_DENYWRITE:
+		*p = cpu_to_be32(NFS4_SHARE_DENY_BOTH);
+		break;
+	default:
+		*p = cpu_to_be32(0);
+	}
 }
 
 static inline void encode_openhdr(struct xdr_stream *xdr, const struct nfs_openargs *arg)
@@ -1354,7 +1367,7 @@ static inline void encode_openhdr(struct xdr_stream *xdr, const struct nfs_opena
  * owner 4 = 32
  */
 	encode_nfs4_seqid(xdr, arg->seqid);
-	encode_share_access(xdr, arg->fmode);
+	encode_share_access(xdr, arg->fmode, arg->open_flags);
 	p = reserve_space(xdr, 36);
 	p = xdr_encode_hyper(p, arg->clientid);
 	*p++ = cpu_to_be32(24);
@@ -1491,7 +1504,7 @@ static void encode_open_downgrade(struct xdr_stream *xdr, const struct nfs_close
 	encode_op_hdr(xdr, OP_OPEN_DOWNGRADE, decode_open_downgrade_maxsz, hdr);
 	encode_nfs4_stateid(xdr, arg->stateid);
 	encode_nfs4_seqid(xdr, arg->seqid);
-	encode_share_access(xdr, arg->fmode);
+	encode_share_access(xdr, arg->fmode, 0);
 }
 
 static void
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index b056b16..ba77e01 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2589,6 +2589,7 @@ nfs_xdev_mount(struct file_system_type *fs_type, int flags,
 	struct nfs_server *server;
 	struct dentry *mntroot = ERR_PTR(-ENOMEM);
 	struct nfs_subversion *nfs_mod = NFS_SB(data->sb)->nfs_client->cl_nfs_mod;
+	int sharelock = data->sb->s_flags & MS_SHARELOCK; /* save sharelock option */
 
 	dprintk("--> nfs_xdev_mount()\n");
 
@@ -2600,7 +2601,7 @@ nfs_xdev_mount(struct file_system_type *fs_type, int flags,
 	if (IS_ERR(server))
 		mntroot = ERR_CAST(server);
 	else
-		mntroot = nfs_fs_mount_common(server, flags,
+		mntroot = nfs_fs_mount_common(server, flags | sharelock,
 				dev_name, &mount_info, nfs_mod);
 
 	dprintk("<-- nfs_xdev_mount() = %ld\n",
-- 
1.8.1.5

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[PATCH v4 6/7] NFSD: Pass share reservations flags to VFS

[Pavel Shilovsky]

that maps them into O_DENY flags and make them visible for
applications that use O_DENYMAND opens.

Signed-off-by: Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org>
---
 fs/locks.c          |  1 +
 fs/nfsd/nfs4state.c | 46 +++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/fs/locks.c b/fs/locks.c
index 67c68fb..ea5813c 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -869,6 +869,7 @@ deny_lock_file(struct file *filp)
 	locks_free_lock(lock);
 	return error;
 }
+EXPORT_SYMBOL(deny_lock_file);
 
 static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
 {
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index a8309c6..eb40c4f 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -476,6 +476,19 @@ test_deny(u32 access, struct nfs4_ol_stateid *stp)
 	return test_bit(access, &stp->st_deny_bmap);
 }
 
+static int nfs4_deny_to_odeny(u32 access)
+{
+	switch (access & NFS4_SHARE_DENY_BOTH) {
+	case NFS4_SHARE_DENY_READ:
+		return O_DENYREAD;
+	case NFS4_SHARE_DENY_WRITE:
+		return O_DENYWRITE;
+	case NFS4_SHARE_DENY_BOTH:
+		return O_DENYREAD | O_DENYWRITE;
+	}
+	return 0;
+}
+
 static int nfs4_access_to_omode(u32 access)
 {
 	switch (access & NFS4_SHARE_ACCESS_BOTH) {
@@ -2795,6 +2808,21 @@ nfsd4_truncate(struct svc_rqst *rqstp, struct svc_fh *fh,
 }
 
 static __be32
+nfs4_vfs_set_deny(struct nfs4_file *fp, unsigned long share_access,
+		  unsigned long deny_access)
+{
+	int oflag, rc;
+	__be32 status = nfs_ok;
+
+	oflag = nfs4_access_to_omode(share_access);
+	fp->fi_fds[oflag]->f_flags |= nfs4_deny_to_odeny(deny_access);
+	rc = deny_lock_file(fp->fi_fds[oflag]);
+	if (rc)
+		status = nfserrno(rc);
+	return status;
+}
+
+static __be32
 nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp, struct svc_fh *cur_fh, struct nfs4_ol_stateid *stp, struct nfsd4_open *open)
 {
 	u32 op_share_access = open->op_share_access;
@@ -2815,6 +2843,14 @@ nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp, struct svc_fh *c
 		}
 		return status;
 	}
+	status = nfs4_vfs_set_deny(fp, op_share_access, open->op_share_deny);
+	if (status) {
+		if (new_access) {
+			int oflag = nfs4_access_to_omode(op_share_access);
+			nfs4_file_put_access(fp, oflag);
+		}
+		return status;
+	}
 	/* remember the open */
 	set_access(op_share_access, stp);
 	set_deny(open->op_share_deny, stp);
@@ -3048,7 +3084,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
 
 	/*
 	 * OPEN the file, or upgrade an existing OPEN.
-	 * If truncate fails, the OPEN fails.
+	 * If truncate or setting deny fails, the OPEN fails.
 	 */
 	if (stp) {
 		/* Stateid was found, this is an OPEN upgrade */
@@ -3062,6 +3098,10 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
 		status = nfsd4_truncate(rqstp, current_fh, open);
 		if (status)
 			goto out;
+		status = nfs4_vfs_set_deny(fp, open->op_share_access,
+					   open->op_share_deny);
+		if (status)
+			goto out;
 		stp = open->op_stp;
 		open->op_stp = NULL;
 		init_open_stateid(stp, fp, open);
@@ -3760,6 +3800,10 @@ nfsd4_open_downgrade(struct svc_rqst *rqstp,
 	}
 	nfs4_stateid_downgrade(stp, od->od_share_access);
 
+	status = nfs4_vfs_set_deny(stp->st_file, od->od_share_access,
+				   od->od_share_deny);
+	if (status)
+		goto out;
 	reset_union_bmap_deny(od->od_share_deny, stp);
 
 	update_stateid(&stp->st_stid.sc_stateid);
-- 
1.8.1.5

[PATCH v4 7/7] locks: Disable LOCK_MAND support for MS_SHARELOCK mounts

[Pavel Shilovsky]

Signed-off-by: Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org>
---
 fs/locks.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/locks.c b/fs/locks.c
index ea5813c..8a59afb 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1722,6 +1722,12 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
 	if (!f.file)
 		goto out;
 
+	/* Disable LOCK_MAND support for FS mounted with MS_SHARELOCK */
+	if (IS_SHARELOCK(f.file->f_path.dentry->d_inode)) {
+		error = -EPERM;
+		goto out;
+	}
+
 	can_sleep = !(cmd & LOCK_NB);
 	cmd &= ~LOCK_NB;
 	unlock = (cmd == LOCK_UN);
-- 
1.8.1.5

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Re: [PATCH v4 0/7] Add O_DENY* support for VFS and CIFS/NFS

[Pavel Shilovsky]

2013/4/5 Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org>:
> Main changes from the previous one:
> 1) O_DENYMAND is removed, sharelock mount option is introduced.
> 2) Patch fcntl.h and VFS patches are united into one.
> 3) flock/LOCK_MAND is disabled for sharelock mounts.
>
> This patchset adds support of O_DENY* flags for Linux fs layer. These flags can be used by any application that needs share reservations to organize a file access. VFS already has some sort of this capability - now it's done through flock/LOCK_MAND mechanis, but that approach is non-atomic. This patchset build new capabilities on top of the existing one but doesn't bring any changes into the flock call semantic.
>
> These flags can be used by NFS (built-in-kernel) and CIFS (Samba) servers and Wine applications through VFS (for local filesystems) or CIFS/NFS modules. This will help when e.g. Samba and NFS server share the same directory for Windows and Linux users or Wine applications use Samba/NFS share to access the same data from different clients.
>
> According to the previous discussions the most problematic question is how to prevent situations like DoS attacks where e.g /lib/liba.so file can be open with DENYREAD, or smth like this. That's why extra mount option 'sharelock' is added for switching on/off O_DENY* flags processing. It allows us to avoid use of these flags on critical places (like /, /lib) and turn them on if we really want it proccessed that way.
>
> So, we have 3 new flags:
> O_DENYREAD - to prevent other opens with read access,
> O_DENYWRITE - to prevent other opens with write access,
> O_DENYDELETE - to prevent delete operations (this flag is not implemented in VFS and NFS part and only suitable for CIFS module),
>
> The patchset avoid data races problem on newely created files: open with O_CREAT can return the -ETXTBSY error for a successfully created file if this files was locked with a deny lock by another task. Also, it turns flock/LOCK_MAND capability off for mounts with 'sharelock' option. This let us not mix one share reservation approach with another.
>
> The #1 patch adds flags to fcntl and implements VFS part. The patches #3, #4, #5 are related to CIFS-specific changes, #6 and #7 describe NFS and NFSD parts.
>
> The preliminary patch for Samba that replaces the existing use of flock/LOCK_MAND mechanism with O_DENY* flags:
> http://git.etersoft.ru/people/piastry/packages/?p=samba.git;a=commitdiff;h=173070262b7f29134ad6b2e49a760017c11aec4a
>
> The future part of open man page patch:
>
> -----
> O_DENYREAD, O_DENYWRIYE, O_DENYDELETE - used to inforce a mandatory share reservation scheme of the file access. If these flag is passed, the open fails with -EBUSY in following cases:
> 1) if O_DENYREAD flag is specified and there is another open with O_DENYMAND flag and READ access to the file;
> 2) if O_DENYWRITE flag is specified and there is another open with O_DENYMAND flag and WRITE access to the file;
> 3) if READ access is requested and there is another open with O_DENYMAND and O_DENYREAD flags;
> 4) if WRITE access is requested and there is another open with O_DENYMAND and O_DENYWRITE flags.

Should be without O_DENYMAND (copy-and-paste issue, sorry):
1) if O_DENYREAD flag is specified and there is another open with READ
access to the file;
2) if O_DENYWRITE flag is specified and there is another open with
WRITE access to the file;
3) if READ access is requested and there is another open with O_DENYREAD flags;
4) if WRITE access is requested and there is another open with
O_DENYWRITE flags.

--
Best regards,
Pavel Shilovsky.
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[PATCH v4 4/7] CIFS: Use NT_CREATE_ANDX command for forcemand mounts

[Pavel Shilovsky]

forcemand mount option now lets us use Windows mandatory style of
byte-range locks even if server supports posix ones - switches on
Windows locking mechanism. Share flags is another locking mehanism
provided by Windows semantic that can be used by NT_CREATE_ANDX
command. This patch combines all Windows locking mechanism in one
mount option by using NT_CREATE_ANDX to open files if forcemand is on.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
---
 fs/cifs/dir.c  | 1 +
 fs/cifs/file.c | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index d4331de..8587021 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -217,6 +217,7 @@ cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
 	}
 
 	if (tcon->unix_ext && cap_unix(tcon->ses) && !tcon->broken_posix_open &&
+	    ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) &&
 	    (CIFS_UNIX_POSIX_PATH_OPS_CAP &
 			le64_to_cpu(tcon->fsUnixInfo.Capability))) {
 		rc = cifs_posix_open(full_path, &newinode, inode->i_sb, mode,
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 9394b2b..19038a4 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -455,8 +455,9 @@ int cifs_open(struct inode *inode, struct file *file)
 	else
 		oplock = 0;
 
-	if (!tcon->broken_posix_open && tcon->unix_ext &&
-	    cap_unix(tcon->ses) && (CIFS_UNIX_POSIX_PATH_OPS_CAP &
+	if (!tcon->broken_posix_open && tcon->unix_ext && cap_unix(tcon->ses)
+	    && ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) &&
+	    (CIFS_UNIX_POSIX_PATH_OPS_CAP &
 				le64_to_cpu(tcon->fsUnixInfo.Capability))) {
 		/* can not refresh inode info since size could be stale */
 		rc = cifs_posix_open(full_path, &inode, inode->i_sb,
@@ -624,6 +625,7 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 		oplock = 0;
 
 	if (tcon->unix_ext && cap_unix(tcon->ses) &&
+	    ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) &&
 	    (CIFS_UNIX_POSIX_PATH_OPS_CAP &
 				le64_to_cpu(tcon->fsUnixInfo.Capability))) {
 		/*
-- 
1.8.1.5