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nfs: page group syncing in write path

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Operations that modify state for a whole page must be syncronized across
all requests within a page group. In the write path, this is calling
end_page_writeback and removing the head request from an inode.
Both of these operations should not be called until all requests
in a page group have reached the point where they would call them.

This patch should have no effect yet since all page groups currently
have one request, but will come into play when pg_test functions are
modified to split pages into sub-page regions.

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
Weston Andros Adamson 2014-05-15 11:56:47 -04:00 committed by Trond Myklebust
parent 67d0338edd
commit 20633f042f
3 changed files with 24 additions and 12 deletions
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2
fs/nfs/pagelist.c
View File

@ -397,6 +397,8 @@ static void nfs_free_request(struct nfs_page *req)
WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags));
/* Release struct file and open context */
nfs_clear_request(req);

32
fs/nfs/write.c
View File

@ -201,12 +201,15 @@ static void nfs_set_page_writeback(struct page *page)
}
}
static void nfs_end_page_writeback(struct page *page)
static void nfs_end_page_writeback(struct nfs_page *req)
{
struct inode *inode = page_file_mapping(page)->host;
struct inode *inode = page_file_mapping(req->wb_page)->host;
struct nfs_server *nfss = NFS_SERVER(inode);
end_page_writeback(page);
if (!nfs_page_group_sync_on_bit(req, PG_WB_END))
return;
end_page_writeback(req->wb_page);
if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
}
@ -397,15 +400,20 @@ static void nfs_inode_remove_request(struct nfs_page *req)
{
struct inode *inode = req->wb_context->dentry->d_inode;
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_page *head;
spin_lock(&inode->i_lock);
if (likely(!PageSwapCache(req->wb_page))) {
set_page_private(req->wb_page, 0);
ClearPagePrivate(req->wb_page);
clear_bit(PG_MAPPED, &req->wb_flags);
if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
head = req->wb_head;
spin_lock(&inode->i_lock);
if (likely(!PageSwapCache(head->wb_page))) {
set_page_private(head->wb_page, 0);
ClearPagePrivate(head->wb_page);
clear_bit(PG_MAPPED, &head->wb_flags);
}
nfsi->npages--;
spin_unlock(&inode->i_lock);
}
nfsi->npages--;
spin_unlock(&inode->i_lock);
nfs_release_request(req);
}
@ -599,7 +607,7 @@ static void nfs_write_completion(struct nfs_pgio_header *hdr)
nfs_inode_remove_request(req);
next:
nfs_unlock_request(req);
nfs_end_page_writeback(req->wb_page);
nfs_end_page_writeback(req);
do_destroy = !test_bit(NFS_IOHDR_NEED_COMMIT, &hdr->flags);
nfs_release_request(req);
}
@ -964,7 +972,7 @@ static void nfs_redirty_request(struct nfs_page *req)
{
nfs_mark_request_dirty(req);
nfs_unlock_request(req);
nfs_end_page_writeback(req->wb_page);
nfs_end_page_writeback(req);
nfs_release_request(req);
}

2
include/linux/nfs_page.h
View File

@ -31,6 +31,8 @@ enum {
PG_TEARDOWN, /* page group sync for destroy */
PG_UNLOCKPAGE, /* page group sync bit in read path */
PG_UPTODATE, /* page group sync bit in read path */
PG_WB_END, /* page group sync bit in write path */
PG_REMOVE, /* page group sync bit in write path */
};
struct nfs_inode;