NFS: various changes relating to reporting IO errors.

1/ remove 'start' and 'end' args from nfs_file_fsync_commit().
   They aren't used.

2/ Make nfs_context_set_write_error() a "static inline" in internal.h
   so we can...

3/ Use nfs_context_set_write_error() instead of mapping_set_error()
   if nfs_pageio_add_request() fails before sending any request.
   NFS generally keeps errors in the open_context, not the mapping,
   so this is more consistent.

4/ If filemap_write_and_write_range() reports any error, still
   check ctx->error.  The value in ctx->error is likely to be
   more useful.  As part of this, NFS_CONTEXT_ERROR_WRITE is
   cleared slightly earlier, before nfs_file_fsync_commit() is called,
   rather than at the start of that function.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

4 files changed, 19 insertions, 15 deletions

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index a385d1c3f146..0214dd1e1060 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -208,21 +208,19 @@ EXPORT_SYMBOL_GPL(nfs_file_mmap);
  * fall back to doing a synchronous write.
  */
 static int
-nfs_file_fsync_commit(struct file *file, loff_t start, loff_t end, int datasync)
+nfs_file_fsync_commit(struct file *file, int datasync)
 {
         struct nfs_open_context *ctx = nfs_file_open_context(file);
         struct inode *inode = file_inode(file);
-        int have_error, do_resend, status;
+        int do_resend, status;
         int ret = 0;
 
         dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync);
 
         nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
         do_resend = test_and_clear_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
-        have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
         status = nfs_commit_inode(inode, FLUSH_SYNC);
-        have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
-        if (have_error) {
+        if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags)) {
                 ret = xchg(&ctx->error, 0);
                 if (ret)
                         goto out;
@@ -247,10 +245,16 @@ nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
         trace_nfs_fsync_enter(inode);
 
         do {
+                struct nfs_open_context *ctx = nfs_file_open_context(file);
                 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+                if (test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags)) {
+                        int ret2 = xchg(&ctx->error, 0);
+                        if (ret2)
+                                ret = ret2;
+                }
                 if (ret != 0)
                         break;
-                ret = nfs_file_fsync_commit(file, start, end, datasync);
+                ret = nfs_file_fsync_commit(file, datasync);
                 if (!ret)
                         ret = pnfs_sync_inode(inode, !!datasync);
                 /*
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 68cc22083639..5bdf952f414b 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -768,3 +768,10 @@ static inline bool nfs_error_is_fatal(int err)
                 return false;
         }
 }
+
+static inline void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
+{
+        ctx->error = error;
+        smp_wmb();
+        set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
+}
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index bec120ec1967..d0543e19098a 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -1170,8 +1170,8 @@ out_failed:
 
                 /* remember fatal errors */
                 if (nfs_error_is_fatal(desc->pg_error))
-                        mapping_set_error(desc->pg_inode->i_mapping,
-                                          desc->pg_error);
+                        nfs_context_set_write_error(req->wb_context,
+                                                    desc->pg_error);
 
                 func = desc->pg_completion_ops->error_cleanup;
                 for (midx = 0; midx < desc->pg_mirror_count; midx++) {
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index c66206ac4ebf..babebbccae2a 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -145,13 +145,6 @@ static void nfs_io_completion_put(struct nfs_io_completion *ioc)
                 kref_put(&ioc->refcount, nfs_io_completion_release);
 }
 
-static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
-{
-        ctx->error = error;
-        smp_wmb();
-        set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
-}
-
 static struct nfs_page *
 nfs_page_private_request(struct page *page)
 {