Commit ab0a9735e06914ce4d2a94ffa41497dbc142fe7f
Committed by
Jens Axboe
Jens Axboe
1 parent
b9d128f108
Exists in
master
and in
4 other branches
blkdev: flush disk cache on ->fsync
Currently there is no barrier support in the block device code. That means we cannot guarantee any sort of data integerity when using the block device node with dis kwrite caches enabled. Using the raw block device node is a typical use case for virtualization (and I assume databases, too). This patch changes block_fsync to issue a cache flush and thus make fsync on block device nodes actually useful. Note that in mainline we would also need to add such code to the ->aio_write method for O_SYNC handling, but assuming that Jan's patch series for the O_SYNC rewrite goes in it will also call into ->fsync for 2.6.32. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Showing 1 changed file with 11 additions and 1 deletions Side-by-side Diff
fs/block_dev.c
| ... | ... | @@ -405,7 +405,17 @@ |
| 405 | 405 | |
| 406 | 406 | static int block_fsync(struct file *filp, struct dentry *dentry, int datasync) |
| 407 | 407 | { |
| 408 | - return sync_blockdev(I_BDEV(filp->f_mapping->host)); | |
| 408 | + struct block_device *bdev = I_BDEV(filp->f_mapping->host); | |
| 409 | + int error; | |
| 410 | + | |
| 411 | + error = sync_blockdev(bdev); | |
| 412 | + if (error) | |
| 413 | + return error; | |
| 414 | + | |
| 415 | + error = blkdev_issue_flush(bdev, NULL); | |
| 416 | + if (error == -EOPNOTSUPP) | |
| 417 | + error = 0; | |
| 418 | + return error; | |
| 409 | 419 | } |
| 410 | 420 | |
| 411 | 421 | /* |