FUSE currently disallows O_DIRECT flag in open(). It is tricky dealing with setting/unsetting of O_DIRECT flag on an open file. There are applications (primarily VMs and databases) which open files with O_DIRECT flag. These applications do not work on FUSE due to this limitation. The approach with this patch is to permit opens with O_DIRECT, but instead disable setting/unsetting of the O_DIRECT flag no matter how the file was opened. This limitation is for more practical than disallowing O_DIRECT altogether. Signed-off-by: Anand Avati <avati@xxxxxxxxxxx> --- fs/fuse/file.c | 36 ++++++++++++++++++++++++++++++++---- 1 files changed, 32 insertions(+), 4 deletions(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 82a6646..355c30f 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -154,6 +154,27 @@ int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, return err; } + if (file->f_flags & O_DIRECT) { + if (!(outarg.open_flags & FOPEN_DIRECT_IO)) { + /* filesystem process did not acknowledge the O_DIRECT + flag with FOPEN_DIRECT_IO bit in ourarg. Hence + we fail the open(). + + Notify the filesystem process about the failed + open with fuse_sync_release right here itself as + file->private_data is not yet set up for release + notification. + */ + fuse_sync_release(ff, file->f_flags); + return -EINVAL; + } + + /* make VFS believe we don't support O_DIRECT till we + implement a_ops->direct_IO + */ + file->f_flags &= ~O_DIRECT; + } + if (isdir) outarg.open_flags &= ~FOPEN_DIRECT_IO; @@ -193,10 +214,6 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir) struct fuse_conn *fc = get_fuse_conn(inode); int err; - /* VFS checks this, but only _after_ ->open() */ - if (file->f_flags & O_DIRECT) - return -EINVAL; - err = generic_file_open(inode, file); if (err) return err; @@ -2132,6 +2149,15 @@ int fuse_notify_poll_wakeup(struct fuse_conn *fc, return 0; } + +static int fuse_check_flags(struct file *filp, int flags) +{ + if ((filp->f_flags ^ flags) & O_DIRECT) + return -EINVAL; + return 0; +} + + static const struct file_operations fuse_file_operations = { .llseek = fuse_file_llseek, .read = do_sync_read, @@ -2149,6 +2175,7 @@ static const struct file_operations fuse_file_operations = { .unlocked_ioctl = fuse_file_ioctl, .compat_ioctl = fuse_file_compat_ioctl, .poll = fuse_file_poll, + .check_flags = fuse_check_flags, }; static const struct file_operations fuse_direct_io_file_operations = { @@ -2165,6 +2192,7 @@ static const struct file_operations fuse_direct_io_file_operations = { .unlocked_ioctl = fuse_file_ioctl, .compat_ioctl = fuse_file_compat_ioctl, .poll = fuse_file_poll, + .check_flags = fuse_check_flags, /* no splice_read */ }; -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html