提交 728fbc0e 编写于 作者: G Goldwyn Rodrigues 提交者: Jens Axboe

ext4: nowait aio support

Return EAGAIN if any of the following checks fail for direct I/O:
  + i_rwsem is lockable
  + Writing beyond end of file (will trigger allocation)
  + Blocks are not allocated at the write location
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
上级 03a07c92
......@@ -37,7 +37,11 @@ static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
struct inode *inode = file_inode(iocb->ki_filp);
ssize_t ret;
inode_lock_shared(inode);
if (!inode_trylock_shared(inode)) {
if (iocb->ki_flags & IOCB_NOWAIT)
return -EAGAIN;
inode_lock_shared(inode);
}
/*
* Recheck under inode lock - at this point we are sure it cannot
* change anymore
......@@ -179,7 +183,11 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
struct inode *inode = file_inode(iocb->ki_filp);
ssize_t ret;
inode_lock(inode);
if (!inode_trylock(inode)) {
if (iocb->ki_flags & IOCB_NOWAIT)
return -EAGAIN;
inode_lock(inode);
}
ret = ext4_write_checks(iocb, from);
if (ret <= 0)
goto out;
......@@ -216,7 +224,12 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
return ext4_dax_write_iter(iocb, from);
#endif
inode_lock(inode);
if (!inode_trylock(inode)) {
if (iocb->ki_flags & IOCB_NOWAIT)
return -EAGAIN;
inode_lock(inode);
}
ret = ext4_write_checks(iocb, from);
if (ret <= 0)
goto out;
......@@ -235,9 +248,15 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
iocb->private = &overwrite;
/* Check whether we do a DIO overwrite or not */
if (o_direct && ext4_should_dioread_nolock(inode) && !unaligned_aio &&
ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from)))
overwrite = 1;
if (o_direct && !unaligned_aio) {
if (ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from))) {
if (ext4_should_dioread_nolock(inode))
overwrite = 1;
} else if (iocb->ki_flags & IOCB_NOWAIT) {
ret = -EAGAIN;
goto out;
}
}
ret = __generic_file_write_iter(iocb, from);
inode_unlock(inode);
......@@ -435,6 +454,10 @@ static int ext4_file_open(struct inode * inode, struct file * filp)
if (ret < 0)
return ret;
}
/* Set the flags to support nowait AIO */
filp->f_mode |= FMODE_AIO_NOWAIT;
return dquot_file_open(inode, filp);
}
......
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