qubes-linux-kernel/patches.fixes/nfs-write.c-bug-removal.patch
2010-07-07 13:12:45 +02:00

171 lines
5.0 KiB
Diff

From: ffilz@us.ibm.com
Subject: Revert "NFS: Allow redirtying of a completed unstable write."
Patch-mainline: REVERT patch from 2.6.27
References: 442267
mainline commit e468bae97d243fe0e1515abaa1f7d0edf1476ad0
introduces a BUG() that is apprently fairly easy to trigger.
As it is just making a minor performance enhancement, it is best to
revert the patch until the issue is better understood.
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Neil Brown <neilb@suse.de>
---
fs/nfs/write.c | 65 ++++++++++++++++++++++++++++-----------------------------
1 file changed, 33 insertions(+), 32 deletions(-)
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -250,9 +250,12 @@ static int nfs_page_async_flush(struct n
return ret;
spin_lock(&inode->i_lock);
}
- if (test_bit(PG_CLEAN, &req->wb_flags)) {
+ if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
+ /* This request is marked for commit */
spin_unlock(&inode->i_lock);
- BUG();
+ nfs_clear_page_tag_locked(req);
+ nfs_pageio_complete(pgio);
+ return 0;
}
if (nfs_set_page_writeback(page) != 0) {
spin_unlock(&inode->i_lock);
@@ -411,6 +414,19 @@ nfs_mark_request_dirty(struct nfs_page *
__set_page_dirty_nobuffers(req->wb_page);
}
+/*
+ * Check if a request is dirty
+ */
+static inline int
+nfs_dirty_request(struct nfs_page *req)
+{
+ struct page *page = req->wb_page;
+
+ if (page == NULL || test_bit(PG_NEED_COMMIT, &req->wb_flags))
+ return 0;
+ return !PageWriteback(page);
+}
+
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
/*
* Add a request to the inode's commit list.
@@ -422,7 +438,7 @@ nfs_mark_request_commit(struct nfs_page
struct nfs_inode *nfsi = NFS_I(inode);
spin_lock(&inode->i_lock);
- set_bit(PG_CLEAN, &(req)->wb_flags);
+ set_bit(PG_NEED_COMMIT, &(req)->wb_flags);
radix_tree_tag_set(&nfsi->nfs_page_tree,
req->wb_index,
NFS_PAGE_TAG_COMMIT);
@@ -432,19 +448,6 @@ nfs_mark_request_commit(struct nfs_page
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
}
-static int
-nfs_clear_request_commit(struct nfs_page *req)
-{
- struct page *page = req->wb_page;
-
- if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) {
- dec_zone_page_state(page, NR_UNSTABLE_NFS);
- dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
- return 1;
- }
- return 0;
-}
-
static inline
int nfs_write_need_commit(struct nfs_write_data *data)
{
@@ -454,7 +457,7 @@ int nfs_write_need_commit(struct nfs_wri
static inline
int nfs_reschedule_unstable_write(struct nfs_page *req)
{
- if (test_and_clear_bit(PG_NEED_COMMIT, &req->wb_flags)) {
+ if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
nfs_mark_request_commit(req);
return 1;
}
@@ -470,12 +473,6 @@ nfs_mark_request_commit(struct nfs_page
{
}
-static inline int
-nfs_clear_request_commit(struct nfs_page *req)
-{
- return 0;
-}
-
static inline
int nfs_write_need_commit(struct nfs_write_data *data)
{
@@ -533,8 +530,11 @@ static void nfs_cancel_commit_list(struc
while(!list_empty(head)) {
req = nfs_list_entry(head->next);
+ dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
+ dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
+ BDI_RECLAIMABLE);
nfs_list_remove_request(req);
- nfs_clear_request_commit(req);
+ clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);
nfs_inode_remove_request(req);
nfs_unlock_request(req);
}
@@ -614,7 +614,8 @@ static struct nfs_page *nfs_try_to_updat
* Note: nfs_flush_incompatible() will already
* have flushed out requests having wrong owners.
*/
- if (offset > rqend
+ if (!nfs_dirty_request(req)
+ || offset > rqend
|| end < req->wb_offset)
goto out_flushme;
@@ -630,10 +631,6 @@ static struct nfs_page *nfs_try_to_updat
spin_lock(&inode->i_lock);
}
- if (nfs_clear_request_commit(req))
- radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
- req->wb_index, NFS_PAGE_TAG_COMMIT);
-
/* Okay, the request matches. Update the region */
if (offset < req->wb_offset) {
req->wb_offset = offset;
@@ -715,7 +712,8 @@ int nfs_flush_incompatible(struct file *
req = nfs_page_find_request(page);
if (req == NULL)
return 0;
- do_flush = req->wb_page != page || req->wb_context != ctx;
+ do_flush = req->wb_page != page || req->wb_context != ctx
+ || !nfs_dirty_request(req);
nfs_release_request(req);
if (!do_flush)
return 0;
@@ -1341,7 +1339,10 @@ static void nfs_commit_release(void *cal
while (!list_empty(&data->pages)) {
req = nfs_list_entry(data->pages.next);
nfs_list_remove_request(req);
- nfs_clear_request_commit(req);
+ clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);
+ dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
+ dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
+ BDI_RECLAIMABLE);
dprintk("NFS: commit (%s/%lld %d@%lld)",
req->wb_context->path.dentry->d_inode->i_sb->s_id,
@@ -1516,7 +1517,7 @@ int nfs_wb_page_cancel(struct inode *ino
req = nfs_page_find_request(page);
if (req == NULL)
goto out;
- if (test_bit(PG_CLEAN, &req->wb_flags)) {
+ if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
nfs_release_request(req);
break;
}