Commit a3d01454 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

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: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 1b83d707

fs/nfs/inode.c

+61 −6
Original line number Diff line number Diff line
@@ -388,6 +388,62 @@ nfs_setattr(struct dentry *dentry, struct iattr *attr) 
	return error;

}



/**

 * nfs_vmtruncate - unmap mappings "freed" by truncate() syscall

 * @inode: inode of the file used

 * @offset: file offset to start truncating

 *

 * This is a copy of the common vmtruncate, but with the locking

 * corrected to take into account the fact that NFS requires

 * inode->i_size to be updated under the inode->i_lock.

 */

static int nfs_vmtruncate(struct inode * inode, loff_t offset)

{

	if (i_size_read(inode) < offset) {

		unsigned long limit;



		limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;

		if (limit != RLIM_INFINITY && offset > limit)

			goto out_sig;

		if (offset > inode->i_sb->s_maxbytes)

			goto out_big;

		spin_lock(&inode->i_lock);

		i_size_write(inode, offset);

		spin_unlock(&inode->i_lock);

	} else {

		struct address_space *mapping = inode->i_mapping;



		/*

		 * truncation of in-use swapfiles is disallowed - it would

		 * cause subsequent swapout to scribble on the now-freed

		 * blocks.

		 */

		if (IS_SWAPFILE(inode))

			return -ETXTBSY;

		spin_lock(&inode->i_lock);

		i_size_write(inode, offset);

		spin_unlock(&inode->i_lock);



		/*

		 * unmap_mapping_range is called twice, first simply for

		 * efficiency so that truncate_inode_pages does fewer

		 * single-page unmaps.  However after this first call, and

		 * before truncate_inode_pages finishes, it is possible for

		 * private pages to be COWed, which remain after

		 * truncate_inode_pages finishes, hence the second

		 * unmap_mapping_range call must be made for correctness.

		 */

		unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);

		truncate_inode_pages(mapping, offset);

		unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);

	}

	return 0;

out_sig:

	send_sig(SIGXFSZ, current, 0);

out_big:

	return -EFBIG;

}



/**

 * nfs_setattr_update_inode - Update inode metadata after a setattr call.

 * @inode: pointer to struct inode
@@ -414,8 +470,7 @@ void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr) 
	}

	if ((attr->ia_valid & ATTR_SIZE) != 0) {

		nfs_inc_stats(inode, NFSIOS_SETATTRTRUNC);

		inode->i_size = attr->ia_size;

		vmtruncate(inode, attr->ia_size);

		nfs_vmtruncate(inode, attr->ia_size);

	}

}
@@ -829,9 +884,9 @@ static void nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr) 
			if (S_ISDIR(inode->i_mode))

				nfsi->cache_validity |= NFS_INO_INVALID_DATA;

		}

		if (inode->i_size == nfs_size_to_loff_t(fattr->pre_size) &&

		if (i_size_read(inode) == nfs_size_to_loff_t(fattr->pre_size) &&

		    nfsi->npages == 0)

			inode->i_size = nfs_size_to_loff_t(fattr->size);

			i_size_write(inode, nfs_size_to_loff_t(fattr->size));

	}

}
@@ -972,7 +1027,7 @@ int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fa 
			(fattr->valid & NFS_ATTR_WCC) == 0) {

		memcpy(&fattr->pre_ctime, &inode->i_ctime, sizeof(fattr->pre_ctime));

		memcpy(&fattr->pre_mtime, &inode->i_mtime, sizeof(fattr->pre_mtime));

		fattr->pre_size = inode->i_size;

		fattr->pre_size = i_size_read(inode);

		fattr->valid |= NFS_ATTR_WCC;

	}

	return nfs_post_op_update_inode(inode, fattr);
@@ -1057,7 +1112,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) 
		/* Do we perhaps have any outstanding writes, or has

		 * the file grown beyond our last write? */

		if (nfsi->npages == 0 || new_isize > cur_isize) {

			inode->i_size = new_isize;

			i_size_write(inode, new_isize);

			invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA;

		}

		dprintk("NFS: isize change on server for file %s/%ld\n",

fs/nfs/write.c

+10 −5
Original line number Diff line number Diff line
@@ -133,16 +133,21 @@ static struct nfs_page *nfs_page_find_request(struct page *page) 
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 */

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