ext4: implement ext4_file_write_iter

It was a mistake to have ext4 use generic_file_write_iter(). Its
write_iter function needs to act like ext4_file_write()

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 6601989bc974361a07ce8f48d98f364dbd348646..d953559738c95a51fdbaec5caa504c2d98276ea0 100644 (file)
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -72,12 +72,11 @@ static void ext4_aiodio_wait(struct inode *inode)
  * or one thread will zero the other's data, causing corruption.
  */
 static int
-ext4_unaligned_aio(struct inode *inode, const struct iovec *iov,
-                  unsigned long nr_segs, loff_t pos)
+ext4_unaligned_aio(struct inode *inode, struct iov_iter *iter, loff_t pos)
 {
        struct super_block *sb = inode->i_sb;
        int blockmask = sb->s_blocksize - 1;
-       size_t count = iov_length(iov, nr_segs);
+       size_t count = iov_iter_count(iter);
        loff_t final_size = pos + count;
 
        if (pos >= inode->i_size)
@@ -90,8 +89,7 @@ ext4_unaligned_aio(struct inode *inode, const struct iovec *iov,
 }
 
 static ssize_t
-ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
-               unsigned long nr_segs, loff_t pos)
+ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
 {
        struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
        int unaligned_aio = 0;
@@ -104,19 +102,21 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
 
        if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
                struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
-               size_t length = iov_length(iov, nr_segs);
+               size_t length = iov_iter_count(iter);
 
                if ((pos > sbi->s_bitmap_maxbytes ||
                    (pos == sbi->s_bitmap_maxbytes && length > 0)))
                        return -EFBIG;
 
                if (pos + length > sbi->s_bitmap_maxbytes) {
-                       nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
-                                             sbi->s_bitmap_maxbytes - pos);
+                       ret = iov_iter_shorten(iter,
+                                              sbi->s_bitmap_maxbytes - pos);
+                       if (ret)
+                               return ret;
                }
        } else if (unlikely((iocb->ki_filp->f_flags & O_DIRECT) &&
                   !is_sync_kiocb(iocb))) {
-               unaligned_aio = ext4_unaligned_aio(inode, iov, nr_segs, pos);
+               unaligned_aio = ext4_unaligned_aio(inode, iter, pos);
        }
 
        /* Unaligned direct AIO must be serialized; see comment above */
@@ -133,7 +133,7 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
                ext4_aiodio_wait(inode);
        }
 
-       ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
+       ret = generic_file_write_iter(iocb, iter, pos);
 
        if (unaligned_aio)
                mutex_unlock(ext4_aio_mutex(inode));
@@ -141,6 +141,23 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
        return ret;
 }
 
+static ssize_t
+ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
+               unsigned long nr_segs, loff_t pos)
+{
+       struct iov_iter i;
+       int ret;
+       size_t count;
+
+       ret = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
+       if (ret)
+               return ret;
+
+       iov_iter_init(&i, iov, nr_segs, count, 0);
+
+       return ext4_file_write_iter(iocb, &i, pos);
+}
+
 static const struct vm_operations_struct ext4_file_vm_ops = {
        .fault          = filemap_fault,
        .page_mkwrite   = ext4_page_mkwrite,
@@ -257,9 +274,9 @@ const struct file_operations ext4_file_operations = {
        .read           = do_sync_read,
        .write          = do_sync_write,
        .aio_read       = generic_file_aio_read,
-       .aio_write      = ext4_file_write,
        .read_iter      = generic_file_read_iter,
-       .write_iter     = generic_file_write_iter,
+       .aio_write      = ext4_file_write,
+       .write_iter     = ext4_file_write_iter,
        .unlocked_ioctl = ext4_ioctl,
 #ifdef CONFIG_COMPAT
        .compat_ioctl   = ext4_compat_ioctl,