summaryrefslogtreecommitdiff
path: root/mm/filemap.c
diff options
context:
space:
mode:
authorJeff Layton <jlayton@redhat.com>2017-07-06 07:02:24 -0400
committerJeff Layton <jlayton@redhat.com>2017-07-06 07:02:24 -0400
commit5e8fcc1a0ffa0fb794b3c0efa2c3c7612a771c36 (patch)
tree2df735706ee4006f12f2ab77fd24e7ae019310fe /mm/filemap.c
parentcbeaf9510a8631e9bb0077a95fd8b0db0b3be200 (diff)
mm: don't TestClearPageError in __filemap_fdatawait_range
The -EIO returned here can end up overriding whatever error is marked in the address space, and be returned at fsync time, even when there is a more appropriate error stored in the mapping. Read errors are also sometimes tracked on a per-page level using PG_error. Suppose we have a read error on a page, and then that page is subsequently dirtied by overwriting the whole page. Writeback doesn't clear PG_error, so we can then end up successfully writing back that page and still return -EIO on fsync. Worse yet, PG_error is cleared during a sync() syscall, but the -EIO return from that is silently discarded. Any subsystem that is relying on PG_error to report errors during fsync can easily lose writeback errors due to this. All you need is a stray sync() call to wait for writeback to complete and you've lost the error. Since the handling of the PG_error flag is somewhat inconsistent across subsystems, let's just rely on marking the address space when there are writeback errors. Change the TestClearPageError call to ClearPageError, and make __filemap_fdatawait_range a void return function. Signed-off-by: Jeff Layton <jlayton@redhat.com>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c20
1 files changed, 5 insertions, 15 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 49bc9720fb00..eb99b5f23c61 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -386,17 +386,16 @@ int filemap_flush(struct address_space *mapping)
}
EXPORT_SYMBOL(filemap_flush);
-static int __filemap_fdatawait_range(struct address_space *mapping,
+static void __filemap_fdatawait_range(struct address_space *mapping,
loff_t start_byte, loff_t end_byte)
{
pgoff_t index = start_byte >> PAGE_SHIFT;
pgoff_t end = end_byte >> PAGE_SHIFT;
struct pagevec pvec;
int nr_pages;
- int ret = 0;
if (end_byte < start_byte)
- goto out;
+ return;
pagevec_init(&pvec, 0);
while ((index <= end) &&
@@ -413,14 +412,11 @@ static int __filemap_fdatawait_range(struct address_space *mapping,
continue;
wait_on_page_writeback(page);
- if (TestClearPageError(page))
- ret = -EIO;
+ ClearPageError(page);
}
pagevec_release(&pvec);
cond_resched();
}
-out:
- return ret;
}
/**
@@ -440,14 +436,8 @@ out:
int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte,
loff_t end_byte)
{
- int ret, ret2;
-
- ret = __filemap_fdatawait_range(mapping, start_byte, end_byte);
- ret2 = filemap_check_errors(mapping);
- if (!ret)
- ret = ret2;
-
- return ret;
+ __filemap_fdatawait_range(mapping, start_byte, end_byte);
+ return filemap_check_errors(mapping);
}
EXPORT_SYMBOL(filemap_fdatawait_range);