Commit 28aa2f9e authored by Trond Myklebust's avatar Trond Myklebust Committed by Anna Schumaker
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NFS: Always clear an invalid mapping when attempting a buffered write 



If the page cache is invalid, then we can't do read-modify-write, so
ensure that we do clear it when we know it is invalid.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent fc9dc401

fs/nfs/file.c

+2 −0
Original line number Diff line number Diff line
@@ -632,6 +632,8 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from) 
			goto out;

	}



	nfs_clear_invalid_mapping(file->f_mapping);



	since = filemap_sample_wb_err(file->f_mapping);

	nfs_start_io_write(inode);

	result = generic_write_checks(iocb, from);

fs/nfs/inode.c

+54 −43
Original line number Diff line number Diff line
@@ -1257,55 +1257,19 @@ static int nfs_invalidate_mapping(struct inode *inode, struct address_space *map 
	return 0;

}



bool nfs_mapping_need_revalidate_inode(struct inode *inode)

{

	return nfs_check_cache_invalid(inode, NFS_INO_REVAL_PAGECACHE) ||

		NFS_STALE(inode);

}



int nfs_revalidate_mapping_rcu(struct inode *inode)

{

	struct nfs_inode *nfsi = NFS_I(inode);

	unsigned long *bitlock = &nfsi->flags;

	int ret = 0;



	if (IS_SWAPFILE(inode))

		goto out;

	if (nfs_mapping_need_revalidate_inode(inode)) {

		ret = -ECHILD;

		goto out;

	}

	spin_lock(&inode->i_lock);

	if (test_bit(NFS_INO_INVALIDATING, bitlock) ||

	    (nfsi->cache_validity & NFS_INO_INVALID_DATA))

		ret = -ECHILD;

	spin_unlock(&inode->i_lock);

out:

	return ret;

}



/**

 * nfs_revalidate_mapping - Revalidate the pagecache

 * @inode: pointer to host inode

 * nfs_clear_invalid_mapping - Conditionally clear a mapping

 * @mapping: pointer to mapping

 *

 * If the NFS_INO_INVALID_DATA inode flag is set, clear the mapping.

 */

int nfs_revalidate_mapping(struct inode *inode,

		struct address_space *mapping)

int nfs_clear_invalid_mapping(struct address_space *mapping)

{

	struct inode *inode = mapping->host;

	struct nfs_inode *nfsi = NFS_I(inode);

	unsigned long *bitlock = &nfsi->flags;

	int ret = 0;



	/* swapfiles are not supposed to be shared. */

	if (IS_SWAPFILE(inode))

		goto out;



	if (nfs_mapping_need_revalidate_inode(inode)) {

		ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);

		if (ret < 0)

			goto out;

	}



	/*

	 * We must clear NFS_INO_INVALID_DATA first to ensure that

	 * invalidations that come in while we're shooting down the mappings
@@ -1336,8 +1300,8 @@ int nfs_revalidate_mapping(struct inode *inode, 


	set_bit(NFS_INO_INVALIDATING, bitlock);

	smp_wmb();

	nfsi->cache_validity &= ~(NFS_INO_INVALID_DATA|

			NFS_INO_DATA_INVAL_DEFER);

	nfsi->cache_validity &=

		~(NFS_INO_INVALID_DATA | NFS_INO_DATA_INVAL_DEFER);

	spin_unlock(&inode->i_lock);

	trace_nfs_invalidate_mapping_enter(inode);

	ret = nfs_invalidate_mapping(inode, mapping);
@@ -1350,6 +1314,53 @@ int nfs_revalidate_mapping(struct inode *inode, 
	return ret;

}



bool nfs_mapping_need_revalidate_inode(struct inode *inode)

{

	return nfs_check_cache_invalid(inode, NFS_INO_REVAL_PAGECACHE) ||

		NFS_STALE(inode);

}



int nfs_revalidate_mapping_rcu(struct inode *inode)

{

	struct nfs_inode *nfsi = NFS_I(inode);

	unsigned long *bitlock = &nfsi->flags;

	int ret = 0;



	if (IS_SWAPFILE(inode))

		goto out;

	if (nfs_mapping_need_revalidate_inode(inode)) {

		ret = -ECHILD;

		goto out;

	}

	spin_lock(&inode->i_lock);

	if (test_bit(NFS_INO_INVALIDATING, bitlock) ||

	    (nfsi->cache_validity & NFS_INO_INVALID_DATA))

		ret = -ECHILD;

	spin_unlock(&inode->i_lock);

out:

	return ret;

}



/**

 * nfs_revalidate_mapping - Revalidate the pagecache

 * @inode: pointer to host inode

 * @mapping: pointer to mapping

 */

int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)

{

	/* swapfiles are not supposed to be shared. */

	if (IS_SWAPFILE(inode))

		return 0;



	if (nfs_mapping_need_revalidate_inode(inode)) {

		int ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);

		if (ret < 0)

			return ret;

	}



	return nfs_clear_invalid_mapping(mapping);

}



static bool nfs_file_has_writers(struct nfs_inode *nfsi)

{

	struct inode *inode = &nfsi->vfs_inode;

include/linux/nfs_fs.h

+1 −0
Original line number Diff line number Diff line
@@ -387,6 +387,7 @@ extern int nfs_open(struct inode *, struct file *); 
extern int nfs_attribute_cache_expired(struct inode *inode);

extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode);

extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);

extern int nfs_clear_invalid_mapping(struct address_space *mapping);

extern bool nfs_mapping_need_revalidate_inode(struct inode *inode);

extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);

extern int nfs_revalidate_mapping_rcu(struct inode *inode);