From 3e24ad2ff9d477f949acd0982cf12e58812210cb Mon Sep 17 00:00:00 2001 From: jvrao Date: Tue, 24 Aug 2010 15:43:28 +0000 Subject: [PATCH] 9p: Add a Direct IO support for non-cached operations. The presence of v9fs_direct_IO() in the address space ops vector allowes open() O_DIRECT flags which would have failed otherwise. In the non-cached mode, we shunt off direct read and write requests before the VFS gets them, so this method should never be called. Direct IO is not 'yet' supported in the cached mode. Hence when this routine is called through generic_file_aio_read(), the read/write fails with an error. Signed-off-by: Venkateswararao Jujjuri Signed-off-by: Eric Van Hensbergen --- fs/9p/vfs_addr.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c index 90e38449f4b3..b7f2a8e3863e 100644 --- a/fs/9p/vfs_addr.c +++ b/fs/9p/vfs_addr.c @@ -154,10 +154,40 @@ static int v9fs_launder_page(struct page *page) return 0; } +/** + * v9fs_direct_IO - 9P address space operation for direct I/O + * @rw: direction (read or write) + * @iocb: target I/O control block + * @iov: array of vectors that define I/O buffer + * @pos: offset in file to begin the operation + * @nr_segs: size of iovec array + * + * The presence of v9fs_direct_IO() in the address space ops vector + * allowes open() O_DIRECT flags which would have failed otherwise. + * + * In the non-cached mode, we shunt off direct read and write requests before + * the VFS gets them, so this method should never be called. + * + * Direct IO is not 'yet' supported in the cached mode. Hence when + * this routine is called through generic_file_aio_read(), the read/write fails + * with an error. + * + */ +ssize_t v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, + loff_t pos, unsigned long nr_segs) +{ + P9_DPRINTK(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) " + "off/no(%lld/%lu) EINVAL\n", + iocb->ki_filp->f_path.dentry->d_name.name, + (long long) pos, nr_segs); + + return -EINVAL; +} const struct address_space_operations v9fs_addr_operations = { .readpage = v9fs_vfs_readpage, .readpages = v9fs_vfs_readpages, .releasepage = v9fs_release_page, .invalidatepage = v9fs_invalidate_page, .launder_page = v9fs_launder_page, + .direct_IO = v9fs_direct_IO, }; -- 2.20.1