NFS: Remove BKL requirement from attribute updates
The main problem is dealing with inode->i_size: we need to set the
inode->i_lock on all attribute updates, and so vmtruncate won't cut it.
Make an NFS-private version of vmtruncate that has the necessary locking
semantics.
The result should be that the following inode attribute updates are
protected by inode->i_lock
nfsi->cache_validity
nfsi->read_cache_jiffies
nfsi->attrtimeo
nfsi->attrtimeo_timestamp
nfsi->change_attr
nfsi->last_updated
nfsi->cache_change_attribute
nfsi->access_cache
nfsi->access_cache_entry_lru
nfsi->access_cache_inode_lru
nfsi->acl_access
nfsi->acl_default
nfsi->nfs_page_tree
nfsi->ncommit
nfsi->npages
nfsi->open_files
nfsi->silly_list
nfsi->acl
nfsi->open_states
inode->i_size
inode->i_atime
inode->i_mtime
inode->i_ctime
inode->i_nlink
inode->i_uid
inode->i_gid
The following is protected by dir->i_mutex
nfsi->cookieverf
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index feca8c6..3229e21 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -133,16 +133,21 @@
static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
{
struct inode *inode = page->mapping->host;
- loff_t end, i_size = i_size_read(inode);
- pgoff_t end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
+ loff_t end, i_size;
+ pgoff_t end_index;
+ spin_lock(&inode->i_lock);
+ i_size = i_size_read(inode);
+ end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
if (i_size > 0 && page->index < end_index)
- return;
+ goto out;
end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
if (i_size >= end)
- return;
- nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
+ goto out;
i_size_write(inode, end);
+ nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
+out:
+ spin_unlock(&inode->i_lock);
}
/* A writeback failed: mark the page as bad, and invalidate the page cache */