From bf03e5bc2e20e11b68e5ecb75050e48a57f8daaf Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@osdl.org>
Date: Thu, 29 Jun 2006 02:24:26 -0700
Subject: [PATCH] --- yaml --- r: 31039 b: refs/heads/master c:
 81b0c8713385ce1b1b9058e916edcf9561ad76d6 h: refs/heads/master i:   31037:
 31c246b6dd5cc822d9d67871069838cb2484a58e   31035:
 8d79380608394567ae4e6cfba3b9e740e2e77277   31031:
 706f8f424020a13a88ac9fb6ad4ba39f7a215bfe   31023:
 ef92152f33503866faf06f59c9f0df576374c02b   31007:
 9b365cad22e4564ae0a1a4da3e13bc396f9b48a4   30975:
 abd44fd7a7b5932d02fecdc412299905642d5779 v: v3

---
 [refs]             | 2 +-
 trunk/mm/filemap.c | 9 ++++++++-
 trunk/mm/filemap.h | 4 ++--
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index fcfa2c738a04..edfaf8f9749d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0686cd8fbe3e5fb1441ae84b9cbc813f9297b879
+refs/heads/master: 81b0c8713385ce1b1b9058e916edcf9561ad76d6
diff --git a/trunk/mm/filemap.c b/trunk/mm/filemap.c
index 4082b3b3cea7..648f2c0c8e18 100644
--- a/trunk/mm/filemap.c
+++ b/trunk/mm/filemap.c
@@ -2125,6 +2125,12 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
 			break;
 		}
 
+		if (unlikely(bytes == 0)) {
+			status = 0;
+			copied = 0;
+			goto zero_length_segment;
+		}
+
 		status = a_ops->prepare_write(file, page, offset, offset+bytes);
 		if (unlikely(status)) {
 			loff_t isize = i_size_read(inode);
@@ -2154,7 +2160,8 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
 			page_cache_release(page);
 			continue;
 		}
-		if (likely(copied > 0)) {
+zero_length_segment:
+		if (likely(copied >= 0)) {
 			if (!status)
 				status = copied;
 
diff --git a/trunk/mm/filemap.h b/trunk/mm/filemap.h
index 536979fb4ba7..3f2a343c6015 100644
--- a/trunk/mm/filemap.h
+++ b/trunk/mm/filemap.h
@@ -88,7 +88,7 @@ filemap_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes)
 	const struct iovec *iov = *iovp;
 	size_t base = *basep;
 
-	while (bytes) {
+	do {
 		int copy = min(bytes, iov->iov_len - base);
 
 		bytes -= copy;
@@ -97,7 +97,7 @@ filemap_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes)
 			iov++;
 			base = 0;
 		}
-	}
+	} while (bytes);
 	*iovp = iov;
 	*basep = base;
 }