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authorAl Viro <viro@zeniv.linux.org.uk>2014-02-09 15:18:09 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2014-02-09 15:18:09 -0500
commitd311d79de305f1ada47cadd672e6ed1b28a949eb (patch)
treeed5fe40264a27e1d8cc4410352585dfb34af50d8 /mm
parent38dbfb59d1175ef458d006556061adeaa8751b72 (diff)
downloadlinux-d311d79de305f1ada47cadd672e6ed1b28a949eb.tar.gz
fix O_SYNC|O_APPEND syncing the wrong range on write()
It actually goes back to 2004 ([PATCH] Concurrent O_SYNC write support) when sync_page_range() had been introduced; generic_file_write{,v}() correctly synced pos_after_write - written .. pos_after_write - 1 but generic_file_aio_write() synced pos_before_write .. pos_before_write + written - 1 instead. Which is not the same thing with O_APPEND, obviously. A couple of years later correct variant had been killed off when everything switched to use of generic_file_aio_write(). All users of generic_file_aio_write() are affected, and the same bug has been copied into other instances of ->aio_write(). The fix is trivial; the only subtle point is that generic_write_sync() ought to be inlined to avoid calculations useless for the majority of calls. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'mm')
-rw-r--r--mm/filemap.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index d56d3c145b9..7a13f6ac542 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2553,8 +2553,8 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
if (ret > 0) {
ssize_t err;
- err = generic_write_sync(file, pos, ret);
- if (err < 0 && ret > 0)
+ err = generic_write_sync(file, iocb->ki_pos - ret, ret);
+ if (err < 0)
ret = err;
}
return ret;