This is a note to let you know that I've just added the patch titled
ext4: move test whether extent to map can be extended to one place
to the 3.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-move-test-whether-extent-to-map-can-be-extended-to-one-place.patch
and it can be found in the queue-3.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 09930042a2e94cf8ee79d22943915612c1e4ba51 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@xxxxxxx>
Date: Sat, 17 Aug 2013 09:57:56 -0400
Subject: ext4: move test whether extent to map can be extended to one place
From: Jan Kara <jack@xxxxxxx>
commit 09930042a2e94cf8ee79d22943915612c1e4ba51 upstream.
Currently the logic whether the current buffer can be added to an extent
of buffers to map is split between mpage_add_bh_to_extent() and
add_page_bufs_to_extent(). Move the whole logic to
mpage_add_bh_to_extent() which makes things a bit more straightforward
and make following i_size fixes easier.
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/inode.c | 49 +++++++++++++++++++++++++++++--------------------
1 file changed, 29 insertions(+), 20 deletions(-)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1904,34 +1904,48 @@ static int ext4_writepage(struct page *p
*
* @mpd - extent of blocks
* @lblk - logical number of the block in the file
- * @b_state - b_state of the buffer head added
+ * @bh - buffer head we want to add to the extent
*
- * the function is used to collect contig. blocks in same state
+ * The function is used to collect contig. blocks in the same state. If the
+ * buffer doesn't require mapping for writeback and we haven't started the
+ * extent of buffers to map yet, the function returns 'true' immediately - the
+ * caller can write the buffer right away. Otherwise the function returns true
+ * if the block has been added to the extent, false if the block couldn't be
+ * added.
*/
-static int mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
- unsigned long b_state)
+static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
+ struct buffer_head *bh)
{
struct ext4_map_blocks *map = &mpd->map;
- /* Don't go larger than mballoc is willing to allocate */
- if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
- return 0;
+ /* Buffer that doesn't need mapping for writeback? */
+ if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
+ (!buffer_delay(bh) && !buffer_unwritten(bh))) {
+ /* So far no extent to map => we write the buffer right away */
+ if (map->m_len == 0)
+ return true;
+ return false;
+ }
/* First block in the extent? */
if (map->m_len == 0) {
map->m_lblk = lblk;
map->m_len = 1;
- map->m_flags = b_state & BH_FLAGS;
- return 1;
+ map->m_flags = bh->b_state & BH_FLAGS;
+ return true;
}
+ /* Don't go larger than mballoc is willing to allocate */
+ if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
+ return false;
+
/* Can we merge the block to our big extent? */
if (lblk == map->m_lblk + map->m_len &&
- (b_state & BH_FLAGS) == map->m_flags) {
+ (bh->b_state & BH_FLAGS) == map->m_flags) {
map->m_len++;
- return 1;
+ return true;
}
- return 0;
+ return false;
}
static bool add_page_bufs_to_extent(struct mpage_da_data *mpd,
@@ -1946,18 +1960,13 @@ static bool add_page_bufs_to_extent(stru
do {
BUG_ON(buffer_locked(bh));
- if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
- (!buffer_delay(bh) && !buffer_unwritten(bh)) ||
- lblk >= blocks) {
+ if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
/* Found extent to map? */
if (mpd->map.m_len)
return false;
- if (lblk >= blocks)
- return true;
- continue;
+ /* Everything mapped so far and we hit EOF */
+ return true;
}
- if (!mpage_add_bh_to_extent(mpd, lblk, bh->b_state))
- return false;
} while (lblk++, (bh = bh->b_this_page) != head);
return true;
}
Patches currently in stable-queue which might be from jack@xxxxxxx are
queue-3.11/ext4-fix-ext4_writepages-in-presence-of-truncate.patch
queue-3.11/ext4-move-test-whether-extent-to-map-can-be-extended-to-one-place.patch
queue-3.11/ext4-simplify-truncation-code-in-ext4_setattr.patch
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