Commit e9e62243 authored by David Howells's avatar David Howells Committed by Steve French
Browse files

cifs: Fix caching to try to do open O_WRONLY as rdwr on server 



When we're engaged in local caching of a cifs filesystem, we cannot perform
caching of a partially written cache granule unless we can read the rest of
the granule.  This can result in unexpected access errors being reported to
the user.

Fix this by the following: if a file is opened O_WRONLY locally, but the
mount was given the "-o fsc" flag, try first opening the remote file with
GENERIC_READ|GENERIC_WRITE and if that returns -EACCES, try dropping the
GENERIC_READ and doing the open again.  If that last succeeds, invalidate
the cache for that file as for O_DIRECT.

Fixes: 70431bfd ("cifs: Support fscache indexing rewrite")
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 24a9799a

fs/smb/client/dir.c

+15 −0
Original line number Diff line number Diff line
@@ -189,6 +189,7 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned 
	int disposition;

	struct TCP_Server_Info *server = tcon->ses->server;

	struct cifs_open_parms oparms;

	int rdwr_for_fscache = 0;



	*oplock = 0;

	if (tcon->ses->server->oplocks)
@@ -200,6 +201,10 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned 
		return PTR_ERR(full_path);

	}



	/* If we're caching, we need to be able to fill in around partial writes. */

	if (cifs_fscache_enabled(inode) && (oflags & O_ACCMODE) == O_WRONLY)

		rdwr_for_fscache = 1;



#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY

	if (tcon->unix_ext && cap_unix(tcon->ses) && !tcon->broken_posix_open &&

	    (CIFS_UNIX_POSIX_PATH_OPS_CAP &
@@ -276,6 +281,8 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned 
		desired_access |= GENERIC_READ; /* is this too little? */

	if (OPEN_FMODE(oflags) & FMODE_WRITE)

		desired_access |= GENERIC_WRITE;

	if (rdwr_for_fscache == 1)

		desired_access |= GENERIC_READ;



	disposition = FILE_OVERWRITE_IF;

	if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
@@ -304,6 +311,7 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned 
	if (!tcon->unix_ext && (mode & S_IWUGO) == 0)

		create_options |= CREATE_OPTION_READONLY;



retry_open:

	oparms = (struct cifs_open_parms) {

		.tcon = tcon,

		.cifs_sb = cifs_sb,
@@ -317,8 +325,15 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned 
	rc = server->ops->open(xid, &oparms, oplock, buf);

	if (rc) {

		cifs_dbg(FYI, "cifs_create returned 0x%x\n", rc);

		if (rc == -EACCES && rdwr_for_fscache == 1) {

			desired_access &= ~GENERIC_READ;

			rdwr_for_fscache = 2;

			goto retry_open;

		}

		goto out;

	}

	if (rdwr_for_fscache == 2)

		cifs_invalidate_cache(inode, FSCACHE_INVAL_DIO_WRITE);



#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY

	/*

fs/smb/client/file.c

+38 −10
Original line number Diff line number Diff line
@@ -206,12 +206,12 @@ cifs_mark_open_files_invalid(struct cifs_tcon *tcon) 
	 */

}



static inline int cifs_convert_flags(unsigned int flags)

static inline int cifs_convert_flags(unsigned int flags, int rdwr_for_fscache)

{

	if ((flags & O_ACCMODE) == O_RDONLY)

		return GENERIC_READ;

	else if ((flags & O_ACCMODE) == O_WRONLY)

		return GENERIC_WRITE;

		return rdwr_for_fscache == 1 ? (GENERIC_READ | GENERIC_WRITE) : GENERIC_WRITE;

	else if ((flags & O_ACCMODE) == O_RDWR) {

		/* GENERIC_ALL is too much permission to request

		   can cause unnecessary access denied on create */
@@ -348,11 +348,16 @@ static int cifs_nt_open(const char *full_path, struct inode *inode, struct cifs_ 
	int create_options = CREATE_NOT_DIR;

	struct TCP_Server_Info *server = tcon->ses->server;

	struct cifs_open_parms oparms;

	int rdwr_for_fscache = 0;



	if (!server->ops->open)

		return -ENOSYS;



	desired_access = cifs_convert_flags(f_flags);

	/* If we're caching, we need to be able to fill in around partial writes. */

	if (cifs_fscache_enabled(inode) && (f_flags & O_ACCMODE) == O_WRONLY)

		rdwr_for_fscache = 1;



	desired_access = cifs_convert_flags(f_flags, rdwr_for_fscache);



/*********************************************************************

 *  open flag mapping table:
@@ -389,6 +394,7 @@ static int cifs_nt_open(const char *full_path, struct inode *inode, struct cifs_ 
	if (f_flags & O_DIRECT)

		create_options |= CREATE_NO_BUFFER;



retry_open:

	oparms = (struct cifs_open_parms) {

		.tcon = tcon,

		.cifs_sb = cifs_sb,
@@ -400,8 +406,16 @@ static int cifs_nt_open(const char *full_path, struct inode *inode, struct cifs_ 
	};



	rc = server->ops->open(xid, &oparms, oplock, buf);

	if (rc)

	if (rc) {

		if (rc == -EACCES && rdwr_for_fscache == 1) {

			desired_access = cifs_convert_flags(f_flags, 0);

			rdwr_for_fscache = 2;

			goto retry_open;

		}

		return rc;

	}

	if (rdwr_for_fscache == 2)

		cifs_invalidate_cache(inode, FSCACHE_INVAL_DIO_WRITE);



	/* TODO: Add support for calling posix query info but with passing in fid */

	if (tcon->unix_ext)
@@ -834,11 +848,11 @@ int cifs_open(struct inode *inode, struct file *file) 
use_cache:

	fscache_use_cookie(cifs_inode_cookie(file_inode(file)),

			   file->f_mode & FMODE_WRITE);

	if (file->f_flags & O_DIRECT &&

	    (!((file->f_flags & O_ACCMODE) != O_RDONLY) ||

	     file->f_flags & O_APPEND))

		cifs_invalidate_cache(file_inode(file),

				      FSCACHE_INVAL_DIO_WRITE);

	if (!(file->f_flags & O_DIRECT))

		goto out;

	if ((file->f_flags & (O_ACCMODE | O_APPEND)) == O_RDONLY)

		goto out;

	cifs_invalidate_cache(file_inode(file), FSCACHE_INVAL_DIO_WRITE);



out:

	free_dentry_path(page);
@@ -903,6 +917,7 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush) 
	int disposition = FILE_OPEN;

	int create_options = CREATE_NOT_DIR;

	struct cifs_open_parms oparms;

	int rdwr_for_fscache = 0;



	xid = get_xid();

	mutex_lock(&cfile->fh_mutex);
@@ -966,7 +981,11 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush) 
	}

#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */



	desired_access = cifs_convert_flags(cfile->f_flags);

	/* If we're caching, we need to be able to fill in around partial writes. */

	if (cifs_fscache_enabled(inode) && (cfile->f_flags & O_ACCMODE) == O_WRONLY)

		rdwr_for_fscache = 1;



	desired_access = cifs_convert_flags(cfile->f_flags, rdwr_for_fscache);



	/* O_SYNC also has bit for O_DSYNC so following check picks up either */

	if (cfile->f_flags & O_SYNC)
@@ -978,6 +997,7 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush) 
	if (server->ops->get_lease_key)

		server->ops->get_lease_key(inode, &cfile->fid);



retry_open:

	oparms = (struct cifs_open_parms) {

		.tcon = tcon,

		.cifs_sb = cifs_sb,
@@ -1003,6 +1023,11 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush) 
		/* indicate that we need to relock the file */

		oparms.reconnect = true;

	}

	if (rc == -EACCES && rdwr_for_fscache == 1) {

		desired_access = cifs_convert_flags(cfile->f_flags, 0);

		rdwr_for_fscache = 2;

		goto retry_open;

	}



	if (rc) {

		mutex_unlock(&cfile->fh_mutex);
@@ -1011,6 +1036,9 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush) 
		goto reopen_error_exit;

	}



	if (rdwr_for_fscache == 2)

		cifs_invalidate_cache(inode, FSCACHE_INVAL_DIO_WRITE);



#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY

reopen_success:

#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */

fs/smb/client/fscache.h

+6 −0
Original line number Diff line number Diff line
@@ -109,6 +109,11 @@ static inline void cifs_readahead_to_fscache(struct inode *inode, 
		__cifs_readahead_to_fscache(inode, pos, len);

}



static inline bool cifs_fscache_enabled(struct inode *inode)

{

	return fscache_cookie_enabled(cifs_inode_cookie(inode));

}



#else /* CONFIG_CIFS_FSCACHE */

static inline

void cifs_fscache_fill_coherency(struct inode *inode,
@@ -124,6 +129,7 @@ static inline void cifs_fscache_release_inode_cookie(struct inode *inode) {} 
static inline void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update) {}

static inline struct fscache_cookie *cifs_inode_cookie(struct inode *inode) { return NULL; }

static inline void cifs_invalidate_cache(struct inode *inode, unsigned int flags) {}

static inline bool cifs_fscache_enabled(struct inode *inode) { return false; }



static inline int cifs_fscache_query_occupancy(struct inode *inode,

					       pgoff_t first, unsigned int nr_pages,