From: Miklos Szeredi <[email protected]>
Extract common code for setting i_size in write functions into a
common helper.
Signed-off-by: Miklos Szeredi <[email protected]>
---
fs/fuse/file.c | 28 +++++++++++++++-------------
1 file changed, 15 insertions(+), 13 deletions(-)
Index: linux/fs/fuse/file.c
===================================================================
--- linux.orig/fs/fuse/file.c 2008-03-17 18:26:04.000000000 +0100
+++ linux/fs/fuse/file.c 2008-03-17 18:26:28.000000000 +0100
@@ -610,13 +610,24 @@ static int fuse_write_begin(struct file
return 0;
}
+static void fuse_write_update_size(struct inode *inode, loff_t pos)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ spin_lock(&fc->lock);
+ fi->attr_version = ++fc->attr_version;
+ if (pos > inode->i_size)
+ i_size_write(inode, pos);
+ spin_unlock(&fc->lock);
+}
+
static int fuse_buffered_write(struct file *file, struct inode *inode,
loff_t pos, unsigned count, struct page *page)
{
int err;
size_t nres;
struct fuse_conn *fc = get_fuse_conn(inode);
- struct fuse_inode *fi = get_fuse_inode(inode);
unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
struct fuse_req *req;
@@ -643,12 +654,7 @@ static int fuse_buffered_write(struct fi
err = -EIO;
if (!err) {
pos += nres;
- spin_lock(&fc->lock);
- fi->attr_version = ++fc->attr_version;
- if (pos > inode->i_size)
- i_size_write(inode, pos);
- spin_unlock(&fc->lock);
-
+ fuse_write_update_size(inode, pos);
if (count == PAGE_CACHE_SIZE)
SetPageUptodate(page);
}
@@ -766,12 +772,8 @@ static ssize_t fuse_direct_io(struct fil
}
fuse_put_request(fc, req);
if (res > 0) {
- if (write) {
- spin_lock(&fc->lock);
- if (pos > inode->i_size)
- i_size_write(inode, pos);
- spin_unlock(&fc->lock);
- }
+ if (write)
+ fuse_write_update_size(inode, pos);
*ppos = pos;
}
fuse_invalidate_attr(inode);
--
On Mon, 17 Mar 2008 20:19:14 +0100 Miklos Szeredi <[email protected]> wrote:
> From: Miklos Szeredi <[email protected]>
>
> Extract common code for setting i_size in write functions into a
> common helper.
>
> Signed-off-by: Miklos Szeredi <[email protected]>
> ---
> fs/fuse/file.c | 28 +++++++++++++++-------------
> 1 file changed, 15 insertions(+), 13 deletions(-)
>
> Index: linux/fs/fuse/file.c
> ===================================================================
> --- linux.orig/fs/fuse/file.c 2008-03-17 18:26:04.000000000 +0100
> +++ linux/fs/fuse/file.c 2008-03-17 18:26:28.000000000 +0100
> @@ -610,13 +610,24 @@ static int fuse_write_begin(struct file
> return 0;
> }
>
> +static void fuse_write_update_size(struct inode *inode, loff_t pos)
> +{
> + struct fuse_conn *fc = get_fuse_conn(inode);
> + struct fuse_inode *fi = get_fuse_inode(inode);
> +
> + spin_lock(&fc->lock);
> + fi->attr_version = ++fc->attr_version;
> + if (pos > inode->i_size)
> + i_size_write(inode, pos);
> + spin_unlock(&fc->lock);
> +}
>
> ...
>
> @@ -766,12 +772,8 @@ static ssize_t fuse_direct_io(struct fil
> }
> fuse_put_request(fc, req);
> if (res > 0) {
> - if (write) {
> - spin_lock(&fc->lock);
> - if (pos > inode->i_size)
> - i_size_write(inode, pos);
> - spin_unlock(&fc->lock);
> - }
> + if (write)
> + fuse_write_update_size(inode, pos);
We require that i_mutex be held here, to prevent i_size_write() deadlocks.
Is it held?
> On Mon, 17 Mar 2008 20:19:14 +0100 Miklos Szeredi <[email protected]> wrote:
>
> > From: Miklos Szeredi <[email protected]>
> >
> > Extract common code for setting i_size in write functions into a
> > common helper.
> >
> > Signed-off-by: Miklos Szeredi <[email protected]>
> > ---
> > fs/fuse/file.c | 28 +++++++++++++++-------------
> > 1 file changed, 15 insertions(+), 13 deletions(-)
> >
> > Index: linux/fs/fuse/file.c
> > ===================================================================
> > --- linux.orig/fs/fuse/file.c 2008-03-17 18:26:04.000000000 +0100
> > +++ linux/fs/fuse/file.c 2008-03-17 18:26:28.000000000 +0100
> > @@ -610,13 +610,24 @@ static int fuse_write_begin(struct file
> > return 0;
> > }
> >
> > +static void fuse_write_update_size(struct inode *inode, loff_t pos)
> > +{
> > + struct fuse_conn *fc = get_fuse_conn(inode);
> > + struct fuse_inode *fi = get_fuse_inode(inode);
> > +
> > + spin_lock(&fc->lock);
> > + fi->attr_version = ++fc->attr_version;
> > + if (pos > inode->i_size)
> > + i_size_write(inode, pos);
> > + spin_unlock(&fc->lock);
> > +}
> >
> > ...
> >
> > @@ -766,12 +772,8 @@ static ssize_t fuse_direct_io(struct fil
> > }
> > fuse_put_request(fc, req);
> > if (res > 0) {
> > - if (write) {
> > - spin_lock(&fc->lock);
> > - if (pos > inode->i_size)
> > - i_size_write(inode, pos);
> > - spin_unlock(&fc->lock);
> > - }
> > + if (write)
> > + fuse_write_update_size(inode, pos);
>
> We require that i_mutex be held here, to prevent i_size_write() deadlocks.
> Is it held?
>
No, fuse uses the per connection spinlock to protect against
concurrent calls to i_size_write(), because in some cases holding
i_mutex would be difficult.
Fuse already got painfully bitten by the i_size_write() deadlock, so
I'm well aware of the problem :)
Miklos