On Thu, 23 Oct 2008, Manish Lachwani wrote:
> Hi Alan,
>
> >
> > Hmm. On my system (2.6.27) the code has moved to fs/sync.c/do_fsync(),
> > and it has changed a fair amount. Maybe file_storage.c should be
> > changed to match.
>
> I have the latest git checkout of
> http://www.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
> and it seems that do_fsync() is still quite similar to fsync_sub().
> Also, I checked older trees like 2.6.22 and do_fsync() is still in
> fs/sync.c
That just goes to show how old file_storage.c is.
> > In fact, the easiest approach would be to EXPORT do_fsync() and then
> > call it directly. I don't know whether people would like this, though.
> >
>
> I could try this. But I don't see much difference b/w do_fsync() and
> fsync_sub(). However in do_fsync(), filemap_fdatawrite() is called
> before the mutex_lock() and filemap_fdatawait() is called after the
> mutex_unlock().
>
> Here is do_fsync() -
>
> long do_fsync(struct file *file, int datasync)
> {
> int ret;
> int err;
> struct address_space *mapping = file->f_mapping;
file_storage does
inode = filp->f_path.dentry->d_inode;
instead, and uses inode in place of mapping->host and inode->i_mapping
in place of mapping. Should this be changed? I have no idea, beyond
feeling that the core kernel code has got to be more up-to-date. Same
goes for the ordering of the locks and the filemap_* calls.
> if (!file->f_op || !file->f_op->fsync) {
> /* Why? We can still call filemap_fdatawrite */
> ret = -EINVAL;
> goto out;
> }
>
> ret = filemap_fdatawrite(mapping);
>
> /*
> * We need to protect against concurrent writers, which could cause
> * livelocks in fsync_buffers_list().
> */
> mutex_lock(&mapping->host->i_mutex);
> err = file->f_op->fsync(file, file->f_path.dentry, datasync);
> if (!ret)
> ret = err;
> mutex_unlock(&mapping->host->i_mutex);
> err = filemap_fdatawait(mapping);
> if (!ret)
> ret = err;
> out:
> return ret;
> }
If the EXPORT route is acceptable, I'd prefer to use it.
Alan Stern
Hi Alan,
Yes, I am trying out the changes below. Will let you know how it goes.
If it works well, I will send an updated patch.
diff --git a/drivers/usb/gadget/file_storage.c
b/drivers/usb/gadget/file_storage.c
index 3e807f0..844f992 100644
--- a/drivers/usb/gadget/file_storage.c
+++ b/drivers/usb/gadget/file_storage.c
@@ -1927,26 +1927,11 @@ static int do_write(struct fsg_dev *fsg)
static int fsync_sub(struct lun *curlun)
{
struct file *filp = curlun->filp;
- struct inode *inode;
- int rc, err;
if (curlun->ro || !filp)
return 0;
- if (!filp->f_op || !filp->f_op->fsync)
- return -EINVAL;
- inode = filp->f_path.dentry->d_inode;
- mutex_lock(&inode->i_mutex);
- rc = filemap_fdatawrite(inode->i_mapping);
- err = filp->f_op->fsync(filp, filp->f_path.dentry, 1);
- if (!rc)
- rc = err;
- err = filemap_fdatawait(inode->i_mapping);
- if (!rc)
- rc = err;
- mutex_unlock(&inode->i_mutex);
- VLDBG(curlun, "fdatasync -> %d\n", rc);
- return rc;
+ return do_fsync(filp, 0);
}
static void fsync_all(struct fsg_dev *fsg)
diff --git a/fs/sync.c b/fs/sync.c
index e700eb1..53ff1f3 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -111,6 +111,7 @@ long do_fsync(struct file *file, int datasync)
out:
return ret;
}
+EXPORT_SYMBOL(do_fsync);
static long __do_fsync(unsigned int fd, int datasync)
{
On Thu, Oct 23, 2008 at 9:46 AM, Alan Stern <[email protected]> wrote:
> On Thu, 23 Oct 2008, Manish Lachwani wrote:
>
>> Hi Alan,
>>
>> >
>> > Hmm. On my system (2.6.27) the code has moved to fs/sync.c/do_fsync(),
>> > and it has changed a fair amount. Maybe file_storage.c should be
>> > changed to match.
>>
>> I have the latest git checkout of
>> http://www.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
>> and it seems that do_fsync() is still quite similar to fsync_sub().
>> Also, I checked older trees like 2.6.22 and do_fsync() is still in
>> fs/sync.c
>
> That just goes to show how old file_storage.c is.
>
>> > In fact, the easiest approach would be to EXPORT do_fsync() and then
>> > call it directly. I don't know whether people would like this, though.
>> >
>>
>> I could try this. But I don't see much difference b/w do_fsync() and
>> fsync_sub(). However in do_fsync(), filemap_fdatawrite() is called
>> before the mutex_lock() and filemap_fdatawait() is called after the
>> mutex_unlock().
>>
>> Here is do_fsync() -
>>
>> long do_fsync(struct file *file, int datasync)
>> {
>> int ret;
>> int err;
>> struct address_space *mapping = file->f_mapping;
>
> file_storage does
>
> inode = filp->f_path.dentry->d_inode;
>
> instead, and uses inode in place of mapping->host and inode->i_mapping
> in place of mapping. Should this be changed? I have no idea, beyond
> feeling that the core kernel code has got to be more up-to-date. Same
> goes for the ordering of the locks and the filemap_* calls.
>
>> if (!file->f_op || !file->f_op->fsync) {
>> /* Why? We can still call filemap_fdatawrite */
>> ret = -EINVAL;
>> goto out;
>> }
>>
>> ret = filemap_fdatawrite(mapping);
>>
>> /*
>> * We need to protect against concurrent writers, which could cause
>> * livelocks in fsync_buffers_list().
>> */
>> mutex_lock(&mapping->host->i_mutex);
>> err = file->f_op->fsync(file, file->f_path.dentry, datasync);
>> if (!ret)
>> ret = err;
>> mutex_unlock(&mapping->host->i_mutex);
>> err = filemap_fdatawait(mapping);
>> if (!ret)
>> ret = err;
>> out:
>> return ret;
>> }
>
> If the EXPORT route is acceptable, I'd prefer to use it.
>
> Alan Stern
>
>
On Thu, 23 Oct 2008, Manish Lachwani wrote:
> Hi Alan,
>
> Yes, I am trying out the changes below. Will let you know how it goes.
> If it works well, I will send an updated patch.
>
> diff --git a/drivers/usb/gadget/file_storage.c
> b/drivers/usb/gadget/file_storage.c
> index 3e807f0..844f992 100644
> --- a/drivers/usb/gadget/file_storage.c
> +++ b/drivers/usb/gadget/file_storage.c
> @@ -1927,26 +1927,11 @@ static int do_write(struct fsg_dev *fsg)
> static int fsync_sub(struct lun *curlun)
> {
> struct file *filp = curlun->filp;
> - struct inode *inode;
> - int rc, err;
>
> if (curlun->ro || !filp)
> return 0;
> - if (!filp->f_op || !filp->f_op->fsync)
> - return -EINVAL;
>
> - inode = filp->f_path.dentry->d_inode;
> - mutex_lock(&inode->i_mutex);
> - rc = filemap_fdatawrite(inode->i_mapping);
> - err = filp->f_op->fsync(filp, filp->f_path.dentry, 1);
> - if (!rc)
> - rc = err;
> - err = filemap_fdatawait(inode->i_mapping);
> - if (!rc)
> - rc = err;
> - mutex_unlock(&inode->i_mutex);
> - VLDBG(curlun, "fdatasync -> %d\n", rc);
> - return rc;
> + return do_fsync(filp, 0);
The fsync call above uses 1, not 0.
> }
>
> static void fsync_all(struct fsg_dev *fsg)
> diff --git a/fs/sync.c b/fs/sync.c
> index e700eb1..53ff1f3 100644
> --- a/fs/sync.c
> +++ b/fs/sync.c
> @@ -111,6 +111,7 @@ long do_fsync(struct file *file, int datasync)
> out:
> return ret;
> }
> +EXPORT_SYMBOL(do_fsync);
>
> static long __do_fsync(unsigned int fd, int datasync)
> {
Apart from that one mistake, this is fine with me. But you should
check with the core kernel developers; there may an objection to
exporting do_fsync().
Alan Stern
On Thu, 23 Oct 2008, Manish Lachwani wrote:
> Hi Alan,
>
> Yes, I am trying out the changes below. Will let you know how it goes.
> If it works well, I will send an updated patch.
>
> diff --git a/drivers/usb/gadget/file_storage.c
> b/drivers/usb/gadget/file_storage.c index 3e807f0..844f992 100644 ---
> a/drivers/usb/gadget/file_storage.c +++
> b/drivers/usb/gadget/file_storage.c @@ -1927,26 +1927,11 @@ static
> int do_write(struct fsg_dev *fsg)
> static int fsync_sub(struct lun *curlun)
> {
> struct file *filp = curlun->filp;
> - struct inode *inode;
> - int rc, err;
>
> if (curlun->ro || !filp)
> return 0;
> - if (!filp->f_op || !filp->f_op->fsync)
> - return -EINVAL;
>
> - inode = filp->f_path.dentry->d_inode;
> - mutex_lock(&inode->i_mutex);
> - rc = filemap_fdatawrite(inode->i_mapping);
> - err = filp->f_op->fsync(filp, filp->f_path.dentry, 1);
> - if (!rc)
> - rc = err;
> - err = filemap_fdatawait(inode->i_mapping);
> - if (!rc)
> - rc = err;
> - mutex_unlock(&inode->i_mutex);
> - VLDBG(curlun, "fdatasync -> %d\n", rc);
> - return rc;
> + return do_fsync(filp, 0);
> }
>
> static void fsync_all(struct fsg_dev *fsg)
> diff --git a/fs/sync.c b/fs/sync.c
> index e700eb1..53ff1f3 100644
> --- a/fs/sync.c
> +++ b/fs/sync.c
> @@ -111,6 +111,7 @@ long do_fsync(struct file *file, int datasync)
> out:
> return ret;
> }
> +EXPORT_SYMBOL(do_fsync);
>
> static long __do_fsync(unsigned int fd, int datasync)
> {
Any news on this?
Alan Stern