NFSv4.2: Fix writeback races in nfs4_copy_file_range
We need to ensure that any writes to the destination file are serialised
with the copy, meaning that the writeback has to occur under the inode lock.
Also relax the writeback requirement on the source, and rely on the
stateid checking to tell us if the source rebooted. Add the helper
nfs_filemap_write_and_wait_range() to call pnfs_sync_inode() as
is appropriate for pNFS servers that may need a layoutcommit.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 01dccf18..3b01c91 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -512,6 +512,9 @@
bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx);
void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio);
+int nfs_filemap_write_and_wait_range(struct address_space *mapping,
+ loff_t lstart, loff_t lend);
+
#ifdef CONFIG_NFS_V4_1
static inline
void nfs_clear_pnfs_ds_commit_verifiers(struct pnfs_ds_commit_info *cinfo)