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NFS: Fix a write request leak in nfs_invalidate_page()

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Ryusuke Konishi says:

The recent truncate_complete_page() clears the dirty flag from a page
before calling a_ops->invalidatepage(),
^^^^^^
static void
truncate_complete_page(struct address_space *mapping, struct page *page)
{
        ...
        cancel_dirty_page(page, PAGE_CACHE_SIZE);  <--- Inserted here at
kernel 2.6.20

        if (PagePrivate(page))
                do_invalidatepage(page, 0);   ---> will call
a_ops->invalidatepage()
        ...
}

and this is disturbing nfs_wb_page_priority() from calling 
nfs_writepage_locked() that is expected to handle the pending
request (=nfs_page) associated with the page.

int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
{
        ...
        if (clear_page_dirty_for_io(page)) {
                ret = nfs_writepage_locked(page, &wbc);
                if (ret < 0)
                        goto out;
        }
        ...
}

Since truncate_complete_page() will get rid of the page after
a_ops->invalidatepage() returns, the request (=nfs_page) associated
with the page becomes a garbage in nfs_inode->nfs_page_tree.
------------------------

Fix this by ensuring that nfs_wb_page_priority() recognises that it may
also need to clear out non-dirty pages that have an nfs_page associated
with them.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2007-08-28 10:29:36 -04:00
parent 7d1cca7299
commit 1b3b4a1a2d
3 changed files with 46 additions and 1 deletions
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2
fs/nfs/file.c
View File

@ -316,7 +316,7 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset)
if (offset != 0)
return;
/* Cancel any unstarted writes on this page */
nfs_wb_page_priority(page->mapping->host, page, FLUSH_INVALIDATE);
nfs_wb_page_cancel(page->mapping->host, page);
}
static int nfs_release_page(struct page *page, gfp_t gfp)

44
fs/nfs/write.c
View File

@ -1396,6 +1396,50 @@ out:
return ret;
}
int nfs_wb_page_cancel(struct inode *inode, struct page *page)
{
struct nfs_page *req;
loff_t range_start = page_offset(page);
loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
struct writeback_control wbc = {
.bdi = page->mapping->backing_dev_info,
.sync_mode = WB_SYNC_ALL,
.nr_to_write = LONG_MAX,
.range_start = range_start,
.range_end = range_end,
};
int ret = 0;
BUG_ON(!PageLocked(page));
for (;;) {
req = nfs_page_find_request(page);
if (req == NULL)
goto out;
if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
nfs_release_request(req);
break;
}
if (nfs_lock_request_dontget(req)) {
nfs_inode_remove_request(req);
/*
* In case nfs_inode_remove_request has marked the
* page as being dirty
*/
cancel_dirty_page(page, PAGE_CACHE_SIZE);
nfs_unlock_request(req);
break;
}
ret = nfs_wait_on_request(req);
if (ret < 0)
goto out;
}
if (!PagePrivate(page))
return 0;
ret = nfs_sync_mapping_wait(page->mapping, &wbc, FLUSH_INVALIDATE);
out:
return ret;
}
int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
{
loff_t range_start = page_offset(page);

1
include/linux/nfs_fs.h
View File

@ -431,6 +431,7 @@ extern int nfs_sync_mapping_range(struct address_space *, loff_t, loff_t, int);
extern int nfs_wb_all(struct inode *inode);
extern int nfs_wb_page(struct inode *inode, struct page* page);
extern int nfs_wb_page_priority(struct inode *inode, struct page* page, int how);
extern int nfs_wb_page_cancel(struct inode *inode, struct page* page);
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
extern int nfs_commit_inode(struct inode *, int);
extern struct nfs_write_data *nfs_commit_alloc(void);