Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull third hunk of vfs changes from Al Viro:
 "This contains the ->direct_IO() changes from Omar + saner
  generic_write_checks() + dealing with fcntl()/{read,write}() races
  (mirroring O_APPEND/O_DIRECT into iocb->ki_flags and instead of
  repeatedly looking at ->f_flags, which can be changed by fcntl(2),
  check ->ki_flags - which cannot) + infrastructure bits for dhowells'
  d_inode annotations + Christophs switch of /dev/loop to
  vfs_iter_write()"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (30 commits)
  block: loop: switch to VFS ITER_BVEC
  configfs: Fix inconsistent use of file_inode() vs file->f_path.dentry->d_inode
  VFS: Make pathwalk use d_is_reg() rather than S_ISREG()
  VFS: Fix up debugfs to use d_is_dir() in place of S_ISDIR()
  VFS: Combine inode checks with d_is_negative() and d_is_positive() in pathwalk
  NFS: Don't use d_inode as a variable name
  VFS: Impose ordering on accesses of d_inode and d_flags
  VFS: Add owner-filesystem positive/negative dentry checks
  nfs: generic_write_checks() shouldn't be done on swapout...
  ocfs2: use __generic_file_write_iter()
  mirror O_APPEND and O_DIRECT into iocb->ki_flags
  switch generic_write_checks() to iocb and iter
  ocfs2: move generic_write_checks() before the alignment checks
  ocfs2_file_write_iter: stop messing with ppos
  udf_file_write_iter: reorder and simplify
  fuse: ->direct_IO() doesn't need generic_write_checks()
  ext4_file_write_iter: move generic_write_checks() up
  xfs_file_aio_write_checks: switch to iocb/iov_iter
  generic_write_checks(): drop isblk argument
  blkdev_write_iter: expand generic_file_checks() call in there
  ...

1 files changed, 10 insertions, 16 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index cdc801c85105..faa7d390841b 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1739,27 +1739,19 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
         u64 start_pos;
         u64 end_pos;
         ssize_t num_written = 0;
-        ssize_t err = 0;
-        size_t count = iov_iter_count(from);
         bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
-        loff_t pos = iocb->ki_pos;
+        ssize_t err;
+        loff_t pos;
+        size_t count;
 
         mutex_lock(&inode->i_mutex);
-
-        current->backing_dev_info = inode_to_bdi(inode);
-        err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
-        if (err) {
+        err = generic_write_checks(iocb, from);
+        if (err <= 0) {
                 mutex_unlock(&inode->i_mutex);
-                goto out;
-        }
-
-        if (count == 0) {
-                mutex_unlock(&inode->i_mutex);
-                goto out;
+                return err;
         }
 
-        iov_iter_truncate(from, count);
-
+        current->backing_dev_info = inode_to_bdi(inode);
         err = file_remove_suid(file);
         if (err) {
                 mutex_unlock(&inode->i_mutex);
@@ -1786,6 +1778,8 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
          */
         update_time_for_write(inode);
 
+        pos = iocb->ki_pos;
+        count = iov_iter_count(from);
         start_pos = round_down(pos, root->sectorsize);
         if (start_pos > i_size_read(inode)) {
                 /* Expand hole size to cover write data, preventing empty gap */
@@ -1800,7 +1794,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
         if (sync)
                 atomic_inc(&BTRFS_I(inode)->sync_writers);
 
-        if (file->f_flags & O_DIRECT) {
+        if (iocb->ki_flags & IOCB_DIRECT) {
                 num_written = __btrfs_direct_write(iocb, from, pos);
         } else {
                 num_written = __btrfs_buffered_write(file, from, pos);