Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull misc vfs updates from Al Viro:
 "Assorted fixes (really no common topic here)"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: Make __vfs_write() static
  vfs: fix preadv64v2 and pwritev64v2 compat syscalls with offset == -1
  pipe: stop using ->can_merge
  splice: don't merge into linked buffers
  fs: move generic stat response attr handling to vfs_getattr_nosec
  orangefs: don't reinitialize result_mask in ->getattr
  fs/devpts: always delete dcache dentry-s in dput()

fs/devpts/inode.c

@@ -455,6 +455,7 @@ devpts_fill_super(struct super_block *s, void *data, int silent)
 	s->s_blocksize_bits = 10;
 	s->s_magic = DEVPTS_SUPER_MAGIC;
 	s->s_op = &devpts_sops;
+	s->s_d_op = &simple_dentry_operations;
 	s->s_time_gran = 1;
 
 	error = -ENOMEM;

fs/orangefs/inode.c

@@ -261,11 +261,8 @@ int orangefs_getattr(const struct path *path, struct kstat *stat,
 		generic_fillattr(inode, stat);
 
 		/* override block size reported to stat */
-		if (request_mask & STATX_SIZE)
+		if (!(request_mask & STATX_SIZE))
-			stat->result_mask = STATX_BASIC_STATS;
+			stat->result_mask &= ~STATX_SIZE;
-		else
-			stat->result_mask = STATX_BASIC_STATS &
-			    ~STATX_SIZE;
 
 		stat->attributes_mask = STATX_ATTR_IMMUTABLE |
 		    STATX_ATTR_APPEND;

fs/pipe.c

@@ -225,8 +225,15 @@ void generic_pipe_buf_release(struct pipe_inode_info *pipe,
 }
 EXPORT_SYMBOL(generic_pipe_buf_release);
 
+/* New data written to a pipe may be appended to a buffer with this type. */
 static const struct pipe_buf_operations anon_pipe_buf_ops = {
-	.can_merge = 1,
+	.confirm = generic_pipe_buf_confirm,
+	.release = anon_pipe_buf_release,
+	.steal = anon_pipe_buf_steal,
+	.get = generic_pipe_buf_get,
+};
+
+static const struct pipe_buf_operations anon_pipe_buf_nomerge_ops = {
 	.confirm = generic_pipe_buf_confirm,
 	.release = anon_pipe_buf_release,
 	.steal = anon_pipe_buf_steal,
@@ -234,13 +241,32 @@ static const struct pipe_buf_operations anon_pipe_buf_ops = {
 };
 
 static const struct pipe_buf_operations packet_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = anon_pipe_buf_release,
 	.steal = anon_pipe_buf_steal,
 	.get = generic_pipe_buf_get,
 };
 
+/**
+ * pipe_buf_mark_unmergeable - mark a &struct pipe_buffer as unmergeable
+ * @buf:	the buffer to mark
+ *
+ * Description:
+ *	This function ensures that no future writes will be merged into the
+ *	given &struct pipe_buffer. This is necessary when multiple pipe buffers
+ *	share the same backing page.
+ */
+void pipe_buf_mark_unmergeable(struct pipe_buffer *buf)
+{
+	if (buf->ops == &anon_pipe_buf_ops)
+		buf->ops = &anon_pipe_buf_nomerge_ops;
+}
+
+static bool pipe_buf_can_merge(struct pipe_buffer *buf)
+{
+	return buf->ops == &anon_pipe_buf_ops;
+}
+
 static ssize_t
 pipe_read(struct kiocb *iocb, struct iov_iter *to)
 {
@@ -378,7 +404,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 		struct pipe_buffer *buf = pipe->bufs + lastbuf;
 		int offset = buf->offset + buf->len;
 
-		if (buf->ops->can_merge && offset + chars <= PAGE_SIZE) {
+		if (pipe_buf_can_merge(buf) && offset + chars <= PAGE_SIZE) {
 			ret = pipe_buf_confirm(pipe, buf);
 			if (ret)
 				goto out;

fs/read_write.c

@@ -478,8 +478,8 @@ static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t
 	return ret;
 }
 
-ssize_t __vfs_write(struct file *file, const char __user *p, size_t count,
+static ssize_t __vfs_write(struct file *file, const char __user *p,
-		    loff_t *pos)
+			   size_t count, loff_t *pos)
 {
 	if (file->f_op->write)
 		return file->f_op->write(file, p, count, pos);
@@ -1238,6 +1238,9 @@ COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd,
 		const struct compat_iovec __user *,vec,
 		unsigned long, vlen, loff_t, pos, rwf_t, flags)
 {
+	if (pos == -1)
+		return do_compat_readv(fd, vec, vlen, flags);
+
 	return do_compat_preadv64(fd, vec, vlen, pos, flags);
 }
 #endif
@@ -1344,6 +1347,9 @@ COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd,
 		const struct compat_iovec __user *,vec,
 		unsigned long, vlen, loff_t, pos, rwf_t, flags)
 {
+	if (pos == -1)
+		return do_compat_writev(fd, vec, vlen, flags);
+
 	return do_compat_pwritev64(fd, vec, vlen, pos, flags);
 }
 #endif

fs/splice.c

@@ -138,7 +138,6 @@ error:
 }
 
 const struct pipe_buf_operations page_cache_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = page_cache_pipe_buf_confirm,
 	.release = page_cache_pipe_buf_release,
 	.steal = page_cache_pipe_buf_steal,
@@ -156,7 +155,6 @@ static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
 }
 
 static const struct pipe_buf_operations user_page_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = page_cache_pipe_buf_release,
 	.steal = user_page_pipe_buf_steal,
@@ -326,7 +324,6 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
 EXPORT_SYMBOL(generic_file_splice_read);
 
 const struct pipe_buf_operations default_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = generic_pipe_buf_release,
 	.steal = generic_pipe_buf_steal,
@@ -341,7 +338,6 @@ static int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe,
 
 /* Pipe buffer operations for a socket and similar. */
 const struct pipe_buf_operations nosteal_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = generic_pipe_buf_release,
 	.steal = generic_pipe_buf_nosteal,
@@ -1606,6 +1602,8 @@ retry:
 			 */
 			obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
 
+			pipe_buf_mark_unmergeable(obuf);
+
 			obuf->len = len;
 			opipe->nrbufs++;
 			ibuf->offset += obuf->len;
@@ -1680,6 +1678,8 @@ static int link_pipe(struct pipe_inode_info *ipipe,
 		 */
 		obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
 
+		pipe_buf_mark_unmergeable(obuf);
+
 		if (obuf->len > len)
 			obuf->len = len;
 

fs/stat.c

@@ -45,11 +45,6 @@ void generic_fillattr(struct inode *inode, struct kstat *stat)
 	stat->ctime = inode->i_ctime;
 	stat->blksize = i_blocksize(inode);
 	stat->blocks = inode->i_blocks;
-
-	if (IS_NOATIME(inode))
-		stat->result_mask &= ~STATX_ATIME;
-	if (IS_AUTOMOUNT(inode))
-		stat->attributes |= STATX_ATTR_AUTOMOUNT;
 }
 EXPORT_SYMBOL(generic_fillattr);
 
@@ -75,6 +70,13 @@ int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
 	stat->result_mask |= STATX_BASIC_STATS;
 	request_mask &= STATX_ALL;
 	query_flags &= KSTAT_QUERY_FLAGS;
+
+	/* allow the fs to override these if it really wants to */
+	if (IS_NOATIME(inode))
+		stat->result_mask &= ~STATX_ATIME;
+	if (IS_AUTOMOUNT(inode))
+		stat->attributes |= STATX_ATTR_AUTOMOUNT;
+
 	if (inode->i_op->getattr)
 		return inode->i_op->getattr(path, stat, request_mask,
 					    query_flags);

include/linux/pipe_fs_i.h

@@ -73,13 +73,6 @@ struct pipe_inode_info {
  * in fs/pipe.c for the pipe and generic variants of these hooks.
  */
 struct pipe_buf_operations {
-	/*
-	 * This is set to 1, if the generic pipe read/write may coalesce
-	 * data into an existing buffer. If this is set to 0, a new pipe
-	 * page segment is always used for new data.
-	 */
-	int can_merge;
-
 	/*
 	 * ->confirm() verifies that the data in the pipe buffer is there
 	 * and that the contents are good. If the pages in the pipe belong
@@ -182,6 +175,7 @@ void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
 int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *);
 int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
 void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);
+void pipe_buf_mark_unmergeable(struct pipe_buffer *buf);
 
 extern const struct pipe_buf_operations nosteal_pipe_buf_ops;
 

kernel/relay.c

@@ -1177,7 +1177,6 @@ static void relay_pipe_buf_release(struct pipe_inode_info *pipe,
 }
 
 static const struct pipe_buf_operations relay_pipe_buf_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = relay_pipe_buf_release,
 	.steal = generic_pipe_buf_steal,

kernel/trace/trace.c

@@ -6023,7 +6023,6 @@ static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
 }
 
 static const struct pipe_buf_operations tracing_pipe_buf_ops = {
-	.can_merge		= 0,
 	.confirm		= generic_pipe_buf_confirm,
 	.release		= generic_pipe_buf_release,
 	.steal			= generic_pipe_buf_steal,
@@ -7050,7 +7049,6 @@ static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
 
 /* Pipe buffer operations for a buffer. */
 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
-	.can_merge		= 0,
 	.confirm		= generic_pipe_buf_confirm,
 	.release		= buffer_pipe_buf_release,
 	.steal			= generic_pipe_buf_steal,

net/smc/smc_rx.c

@@ -136,7 +136,6 @@ static int smc_rx_pipe_buf_nosteal(struct pipe_inode_info *pipe,
 }
 
 static const struct pipe_buf_operations smc_pipe_ops = {
-	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = smc_rx_pipe_buf_release,
 	.steal = smc_rx_pipe_buf_nosteal,