Juggle dirty pages and dirty inodes and dirty superblocks and various
different writeback modes and livelock avoidance and fairness to recover from
the loss of mapping->io_pages.
---
25-akpm/fs/fs-writeback.c | 50 +++++++++++++++++++++++++++++++++-------------
1 files changed, 36 insertions(+), 14 deletions(-)
diff -puN fs/fs-writeback.c~kupdate-function-fix fs/fs-writeback.c
--- 25/fs/fs-writeback.c~kupdate-function-fix 2004-03-20 23:20:24.414803896 -0800
+++ 25-akpm/fs/fs-writeback.c 2004-03-20 23:20:24.416803592 -0800
@@ -147,12 +147,6 @@ __sync_single_inode(struct inode *inode,
inode->i_state |= I_LOCK;
inode->i_state &= ~I_DIRTY;
- /*
- * smp_rmb(); note: if you remove write_lock below, you must add this.
- * mark_inode_dirty doesn't take spinlock, make sure that inode is not
- * read speculatively by this cpu before &= ~I_DIRTY -- mikulas
- */
-
spin_unlock(&inode_lock);
ret = do_writepages(mapping, wbc);
@@ -170,18 +164,46 @@ __sync_single_inode(struct inode *inode,
spin_lock(&inode_lock);
inode->i_state &= ~I_LOCK;
if (!(inode->i_state & I_FREEING)) {
- if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
- /* Redirtied */
- inode->i_state |= I_DIRTY_PAGES;
- inode->dirtied_when = jiffies;
- list_move(&inode->i_list, &sb->s_dirty);
+ if (!(inode->i_state & I_DIRTY) &&
+ mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
+ /*
+ * We didn't write back all the pages. Redirty the
+ * inode. It is still on sb->s_dirty.
+ */
+ if (wbc->for_kupdate) {
+ /*
+ * For the kupdate function we leave the inode
+ * where it is on sb_dirty so it will get more
+ * writeout as soon as the queue becomes
+ * uncongested.
+ */
+ inode->i_state |= I_DIRTY_PAGES;
+ } else {
+ /*
+ * Otherwise fully redirty the inode so that
+ * other inodes on this superblock will get some
+ * writeout. Otherwise heavy writing to one
+ * file would indefinitely suspend writeout of
+ * all the other files.
+ */
+ inode->i_state |= I_DIRTY_PAGES;
+ inode->dirtied_when = jiffies;
+ list_move(&inode->i_list, &sb->s_dirty);
+ }
} else if (inode->i_state & I_DIRTY) {
- /* Redirtied */
- inode->dirtied_when = jiffies;
- list_move(&inode->i_list, &sb->s_dirty);
+ /*
+ * Someone redirtied the inode while were writing back
+ * the pages: nothing to do.
+ */
} else if (atomic_read(&inode->i_count)) {
+ /*
+ * The inode is clean, inuse
+ */
list_move(&inode->i_list, &inode_in_use);
} else {
+ /*
+ * The inode is clean, unused
+ */
list_move(&inode->i_list, &inode_unused);
}
}
_