[CIFS] Fix hang in find_writable_file (a403a0a3) · Commits · 戴 / test

fs/cifs/CHANGES

+4 −1

Original line number	Diff line number	Diff line
		@@ -3,7 +3,10 @@ Version 1.50
		Fix NTLMv2 signing. NFS server mounted over cifs works (if cifs mount is
		done with "serverino" mount option). Add support for POSIX Unlink
		(helps with certain sharing violation cases when server such as
		Samba supports newer POSIX CIFS Protocol Extensions).
		Samba supports newer POSIX CIFS Protocol Extensions). Add "nounix"
		mount option to allow disabling the CIFS Unix Extensions for just
		that mount. Fix hang on spinlock in find_writable_file (race when
		reopening file after session crash).

		Version 1.49
		------------

+7 −0

Original line number	Diff line number	Diff line
		@@ -444,6 +444,13 @@ A partial list of the supported mount options follows:
		noposixpaths If CIFS Unix extensions are supported, do not request
		posix path name support (this may cause servers to
		reject creatingfile with certain reserved characters).
		nounix Disable the CIFS Unix Extensions for this mount (tree
		connection). This is rarely needed, but it may be useful
		in order to turn off multiple settings all at once (ie
		posix acls, posix locks, posix paths, symlink support
		and retrieving uids/gids/mode from the server) or to
		work around a bug in server which implement the Unix
		Extensions.
		nobrl Do not send byte range lock requests to the server.
		This is necessary for certain applications that break
		with cifs style mandatory byte range locks (and most

+1 −2

Original line number	Diff line number	Diff line
		@@ -82,8 +82,7 @@ u) DOS attrs - returned as pseudo-xattr in Samba format (check VFAT and NTFS for

		v) mount check for unmatched uids

		w) Add mount option for Linux extension disable per mount, and partial
		disable per mount (uid off, symlink/fifo/mknod on but what about posix acls?)
		w) Add support for new vfs entry points for setlease and fallocate

		x) Fix Samba 3 server to handle Linux kernel aio so dbench with lots of
		processes can proceed better in parallel (on the server)

+23 −10

Original line number	Diff line number	Diff line
		@@ -1904,6 +1904,25 @@ static int cifs_readpage(struct file file, struct page page)
		return rc;
		}

		static int is_inode_writable(struct cifsInodeInfo *cifs_inode)
		{
		struct cifsFileInfo *open_file;

		read_lock(&GlobalSMBSeslock);
		list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
		if (open_file->closePend)
		continue;
		if (open_file->pfile &&
		((open_file->pfile->f_flags & O_RDWR) \|\|
		(open_file->pfile->f_flags & O_WRONLY))) {
		read_unlock(&GlobalSMBSeslock);
		return 1;
		}
		}
		read_unlock(&GlobalSMBSeslock);
		return 0;
		}

		/* We do not want to update the file size from server for inodes
		open for write - to avoid races with writepage extending
		the file - in the future we could consider allowing
		@@ -1912,19 +1931,13 @@ static int cifs_readpage(struct file file, struct page page)
		page caching in the current Linux kernel design */
		int is_size_safe_to_change(struct cifsInodeInfo *cifsInode, __u64 end_of_file)
		{
		struct cifsFileInfo *open_file = NULL;

		if (cifsInode)
		open_file = find_writable_file(cifsInode);
		if (!cifsInode)
		return 1;

		if (open_file) {
		if (is_inode_writable(cifsInode)) {
		/* This inode is open for write at least once */
		struct cifs_sb_info *cifs_sb;

		/* there is not actually a write pending so let
		this handle go free and allow it to
		be closable if needed */
		atomic_dec(&open_file->wrtPending);

		cifs_sb = CIFS_SB(cifsInode->vfs_inode.i_sb);
		if ( cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO ) {
		/* since no page cache to corrupt on directio