buffer: set errors in mapping at the time that the error occurs

I noticed on xfs that I could still sometimes get back an error on fsync
on a fd that was opened after the error condition had been cleared.

The problem is that the buffer code sets the write_io_error flag and
then later checks that flag to set the error in the mapping. That flag
perisists for quite a while however. If the file is later opened with
O_TRUNC, the buffers will then be invalidated and the mapping's error
set such that a subsequent fsync will return error. I think this is
incorrect, as there was no writeback between the open and fsync.

Add a new mark_buffer_write_io_error operation that sets the flag and
the error in the mapping at the same time. Replace all calls to
set_buffer_write_io_error with mark_buffer_write_io_error, and remove
the places that check this flag in order to set the error in the
mapping.

This sets the error in the mapping earlier, at the time that it's first
detected.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>

diff --git a/fs/buffer.c b/fs/buffer.c
index 4be8b914a222546f7122ac4d5c992506138ae827..b946149e821492842dc2158ae322266ae848be26 100644 (file)
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -178,7 +178,7 @@ void end_buffer_write_sync(struct buffer_head *bh, int uptodate)
                set_buffer_uptodate(bh);
        } else {
                buffer_io_error(bh, ", lost sync page write");
-               set_buffer_write_io_error(bh);
+               mark_buffer_write_io_error(bh);
                clear_buffer_uptodate(bh);
        }
        unlock_buffer(bh);
@@ -352,8 +352,7 @@ void end_buffer_async_write(struct buffer_head *bh, int uptodate)
                set_buffer_uptodate(bh);
        } else {
                buffer_io_error(bh, ", lost async page write");
-               mapping_set_error(page->mapping, -EIO);
-               set_buffer_write_io_error(bh);
+               mark_buffer_write_io_error(bh);
                clear_buffer_uptodate(bh);
                SetPageError(page);
        }
@@ -481,8 +480,6 @@ static void __remove_assoc_queue(struct buffer_head *bh)
 {
        list_del_init(&bh->b_assoc_buffers);
        WARN_ON(!bh->b_assoc_map);
-       if (buffer_write_io_error(bh))
-               mapping_set_error(bh->b_assoc_map, -EIO);
        bh->b_assoc_map = NULL;
 }
 
@@ -1181,6 +1178,17 @@ void mark_buffer_dirty(struct buffer_head *bh)
 }
 EXPORT_SYMBOL(mark_buffer_dirty);
 
+void mark_buffer_write_io_error(struct buffer_head *bh)
+{
+       set_buffer_write_io_error(bh);
+       /* FIXME: do we need to set this in both places? */
+       if (bh->b_page && bh->b_page->mapping)
+               mapping_set_error(bh->b_page->mapping, -EIO);
+       if (bh->b_assoc_map)
+               mapping_set_error(bh->b_assoc_map, -EIO);
+}
+EXPORT_SYMBOL(mark_buffer_write_io_error);
+
 /*
  * Decrement a buffer_head's reference count.  If all buffers against a page
  * have zero reference count, are clean and unlocked, and if the page is clean
@@ -3279,8 +3287,6 @@ drop_buffers(struct page *page, struct buffer_head **buffers_to_free)
 
        bh = head;
        do {
-               if (buffer_write_io_error(bh) && page->mapping)
-                       mapping_set_error(page->mapping, -EIO);
                if (buffer_busy(bh))
                        goto failed;
                bh = bh->b_this_page;

diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index b1f9144b42c7fd6ae4f0f24f82adaf142bfa4922..cd7857ab1a6aeadc2204eb5164c3aeb9c407cf35 100644 (file)
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -182,7 +182,7 @@ static void gfs2_end_log_write_bh(struct gfs2_sbd *sdp, struct bio_vec *bvec,
                bh = bh->b_this_page;
        do {
                if (error)
-                       set_buffer_write_io_error(bh);
+                       mark_buffer_write_io_error(bh);
                unlock_buffer(bh);
                next = bh->b_this_page;
                size -= bh->b_size;

diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index bd029e52ef5ee232f77ff28ef3a7b4ec391f1d71..e0abeba3ced75aca77b7cc5ac3ab00668678d3a8 100644 (file)
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -149,6 +149,7 @@ void buffer_check_dirty_writeback(struct page *page,
  */
 
 void mark_buffer_dirty(struct buffer_head *bh);
+void mark_buffer_write_io_error(struct buffer_head *bh);
 void init_buffer(struct buffer_head *, bh_end_io_t *, void *);
 void touch_buffer(struct buffer_head *bh);
 void set_bh_page(struct buffer_head *bh,