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ext4: fix ext4_ext_direct_IO()'s return value after converting uninit extents

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After a direct I/O request covering an uninitalized extent (i.e.,
created using the fallocate system call) or a hole in a file, ext4
will convert the uninitialized extent so it is marked as initialized
by calling ext4_convert_unwritten_extents().  This function returns
zero on success.

This return value was getting returned by ext4_direct_IO(); however
the file system's direct_IO function is supposed to return the number
of bytes read or written on a success.  By returning zero, it confused
the direct I/O code into falling back to buffered I/O unnecessarily.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Mingming 2009-11-10 10:48:08 -05:00 committed by Theodore Ts'o
parent fa5d11133b
commit 109f556519
2 changed files with 8 additions and 3 deletions
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1
fs/ext4/extents.c
View File

@ -3519,6 +3519,7 @@ retry:
* *
* This function is called from the direct IO end io call back * This function is called from the direct IO end io call back
* function, to convert the fallocated extents after IO is completed. * function, to convert the fallocated extents after IO is completed.
* Returns 0 on success.
*/ */
int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset, int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
loff_t len) loff_t len)

10
fs/ext4/inode.c
View File

@ -3772,13 +3772,17 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) { if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
ext4_free_io_end(iocb->private); ext4_free_io_end(iocb->private);
iocb->private = NULL; iocb->private = NULL;
} else if (ret > 0) } else if (ret > 0) {
int err;
/* /*
* for non AIO case, since the IO is already * for non AIO case, since the IO is already
* completed, we could do the convertion right here * completed, we could do the convertion right here
*/ */
ret = ext4_convert_unwritten_extents(inode, err = ext4_convert_unwritten_extents(inode,
offset, ret); offset, ret);
if (err < 0)
ret = err;
}
return ret; return ret;
} }