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, 17 insertions, 16 deletions

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 7a6defcf3352..e576d682b353 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -95,11 +95,9 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
         struct inode *inode = file_inode(iocb->ki_filp);
         struct mutex *aio_mutex = NULL;
         struct blk_plug plug;
-        int o_direct = io_is_direct(file);
+        int o_direct = iocb->ki_flags & IOCB_DIRECT;
         int overwrite = 0;
-        size_t length = iov_iter_count(from);
         ssize_t ret;
-        loff_t pos = iocb->ki_pos;
 
         /*
          * Unaligned direct AIO must be serialized; see comment above
@@ -108,16 +106,17 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
         if (o_direct &&
             ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
             !is_sync_kiocb(iocb) &&
-            (file->f_flags & O_APPEND ||
-             ext4_unaligned_aio(inode, from, pos))) {
+            (iocb->ki_flags & IOCB_APPEND ||
+             ext4_unaligned_aio(inode, from, iocb->ki_pos))) {
                 aio_mutex = ext4_aio_mutex(inode);
                 mutex_lock(aio_mutex);
                 ext4_unwritten_wait(inode);
         }
 
         mutex_lock(&inode->i_mutex);
-        if (file->f_flags & O_APPEND)
-                iocb->ki_pos = pos = i_size_read(inode);
+        ret = generic_write_checks(iocb, from);
+        if (ret <= 0)
+                goto out;
 
         /*
          * If we have encountered a bitmap-format file, the size limit
@@ -126,22 +125,19 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 
-                if ((pos > sbi->s_bitmap_maxbytes) ||
-                    (pos == sbi->s_bitmap_maxbytes && length > 0)) {
-                        mutex_unlock(&inode->i_mutex);
+                if (iocb->ki_pos >= sbi->s_bitmap_maxbytes) {
                         ret = -EFBIG;
-                        goto errout;
+                        goto out;
                 }
-
-                if (pos + length > sbi->s_bitmap_maxbytes)
-                        iov_iter_truncate(from, sbi->s_bitmap_maxbytes - pos);
+                iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
         }
 
         iocb->private = &overwrite;
         if (o_direct) {
+                size_t length = iov_iter_count(from);
+                loff_t pos = iocb->ki_pos;
                 blk_start_plug(&plug);
 
-
                 /* check whether we do a DIO overwrite or not */
                 if (ext4_should_dioread_nolock(inode) && !aio_mutex &&
                     !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
@@ -185,7 +181,12 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
         if (o_direct)
                 blk_finish_plug(&plug);
 
-errout:
+        if (aio_mutex)
+                mutex_unlock(aio_mutex);
+        return ret;
+
+out:
+        mutex_unlock(&inode->i_mutex);
         if (aio_mutex)
                 mutex_unlock(aio_mutex);
         return ret;