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()

10 files changed, 52 insertions, 30 deletions

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index c53814539070..553a3f3300ae 100644
--- a/fs/devpts/inode.c
+++ b/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;
diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c
index f038235c64bd..c3334eca18c7 100644
--- a/fs/orangefs/inode.c
+++ b/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)
-                        stat->result_mask = STATX_BASIC_STATS;
-                else
-                        stat->result_mask = STATX_BASIC_STATS &
-                            ~STATX_SIZE;
+                if (!(request_mask & STATX_SIZE))
+                        stat->result_mask &= ~STATX_SIZE;
 
                 stat->attributes_mask = STATX_ATTR_IMMUTABLE |
                     STATX_ATTR_APPEND;
diff --git a/fs/pipe.c b/fs/pipe.c
index 51d5fd8840ab..070aad543382 100644
--- a/fs/pipe.c
+++ b/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;
diff --git a/fs/read_write.c b/fs/read_write.c
index 30df848b7451..177ccc3d405a 100644
--- a/fs/read_write.c
+++ b/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,
-                    loff_t *pos)
+static ssize_t __vfs_write(struct file *file, const char __user *p,
+                           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
diff --git a/fs/splice.c b/fs/splice.c
index 6489fb9436e4..3ee7e82df48f 100644
--- a/fs/splice.c
+++ b/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;
 
diff --git a/fs/stat.c b/fs/stat.c
index adbfcd86c81b..c38e4c2e1221 100644
--- a/fs/stat.c
+++ b/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);
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 5a3bb3b7c9ad..787d224ff43e 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -74,13 +74,6 @@ struct pipe_inode_info {
  */
 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
          * to a file system, we may need to wait for IO completion in this
@@ -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;
 
diff --git a/kernel/relay.c b/kernel/relay.c
index 9e0f52375487..ade14fb7ce2e 100644
--- a/kernel/relay.c
+++ b/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,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index d7325eb1bc83..94ffc1c559d5 100644
--- a/kernel/trace/trace.c
+++ b/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,
diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index bbcf0fe4ae10..413a6abf227e 100644
--- a/net/smc/smc_rx.c
+++ b/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,