From: Yang Erkun <yangerkun@xxxxxxxxxx>
Commit 3be5a52b30aa("fuse: support writable mmap") give a strict limit
for about 1% max dirty ratio for fuse to protect that fuse won't slow
down the hole system by hogging lots of dirty memory. It works well for
system without memcg. But now for system with memcg, since fuse does
not support writeback cgroup, this max dirty ratio won't work for the
memcg's max bytes.
So it seems reasonable to enable writeback cgroup for fuse. Same commit
as above shows why we manage wb's count within fuse itself. In order to
support writeback cgroup, we need inode_to_wb to find the right wb,
and this needs some locks to pretect it. We now choose
inode->i_mapping->i_pages.xa_lock to do this.
Signed-off-by: Yang Erkun <yangerkun@xxxxxxxxxx>
---
fs/fuse/file.c | 33 ++++++++++++++++++++++++---------
fs/fuse/inode.c | 3 ++-
2 files changed, 26 insertions(+), 10 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index f39456c65ed7..4248eaf46c39 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1774,15 +1774,20 @@ static void fuse_writepage_finish(struct
fuse_mount *fm,
{
struct fuse_args_pages *ap = &wpa->ia.ap;
struct inode *inode = wpa->inode;
+ struct address_space *mapping = inode->i_mapping;
struct fuse_inode *fi = get_fuse_inode(inode);
- struct backing_dev_info *bdi = inode_to_bdi(inode);
+ struct bdi_writeback *wb;
+ unsigned long flags;
int i;
+ xa_lock_irqsave(&mapping->i_pages, flags);
+ wb = inode_to_wb(inode);
for (i = 0; i < ap->num_pages; i++) {
- dec_wb_stat(&bdi->wb, WB_WRITEBACK);
+ dec_wb_stat(wb, WB_WRITEBACK);
dec_node_page_state(ap->pages[i], NR_WRITEBACK_TEMP);
- wb_writeout_inc(&bdi->wb);
+ wb_writeout_inc(wb);
}
+ xa_unlock_irqrestore(&mapping->i_pages, flags);
wake_up(&fi->page_waitq);
}
@@ -2084,8 +2089,10 @@ static int fuse_writepage_locked(struct folio
*folio)
ap->args.end = fuse_writepage_end;
wpa->inode = inode;
- inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
+ xa_lock(&mapping->i_pages);
+ inc_wb_stat(inode_to_wb(inode), WB_WRITEBACK);
node_stat_add_folio(tmp_folio, NR_WRITEBACK_TEMP);
+ xa_unlock(&mapping->i_pages);
spin_lock(&fi->lock);
tree_insert(&fi->writepages, wpa);
@@ -2169,7 +2176,8 @@ static void fuse_writepages_send(struct
fuse_fill_wb_data *data)
static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa,
struct page *page)
{
- struct fuse_inode *fi = get_fuse_inode(new_wpa->inode);
+ struct inode *inode = new_wpa->inode;
+ struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_writepage_args *tmp;
struct fuse_writepage_args *old_wpa;
struct fuse_args_pages *new_ap = &new_wpa->ia.ap;
@@ -2204,11 +2212,15 @@ static bool fuse_writepage_add(struct
fuse_writepage_args *new_wpa,
spin_unlock(&fi->lock);
if (tmp) {
- struct backing_dev_info *bdi = inode_to_bdi(new_wpa->inode);
+ struct address_space *mapping = inode->i_mapping;
+ struct bdi_writeback *wb;
- dec_wb_stat(&bdi->wb, WB_WRITEBACK);
+ xa_lock(&mapping->i_pages);
+ wb = inode_to_wb(new_wpa->inode);
+ dec_wb_stat(wb, WB_WRITEBACK);
dec_node_page_state(new_ap->pages[0], NR_WRITEBACK_TEMP);
- wb_writeout_inc(&bdi->wb);
+ wb_writeout_inc(wb);
+ xa_unlock(&mapping->i_pages);
fuse_writepage_free(new_wpa);
}
@@ -2256,6 +2268,7 @@ static int fuse_writepages_fill(struct folio
*folio,
struct fuse_writepage_args *wpa = data->wpa;
struct fuse_args_pages *ap = &wpa->ia.ap;
struct inode *inode = data->inode;
+ struct address_space *mapping = inode->i_mapping;
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_conn *fc = get_fuse_conn(inode);
struct page *tmp_page;
@@ -2319,8 +2332,10 @@ static int fuse_writepages_fill(struct folio
*folio,
ap->descs[ap->num_pages].length = PAGE_SIZE;
data->orig_pages[ap->num_pages] = &folio->page;
- inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
+ xa_lock(&mapping->i_pages);
+ inc_wb_stat(inode_to_wb(inode), WB_WRITEBACK);
inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
+ xa_unlock(&mapping->i_pages);
err = 0;
if (data->wpa) {
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index d8ab4e93916f..71d08f0a8514 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1566,7 +1566,8 @@ static void fuse_sb_defaults(struct super_block
*sb)
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_time_gran = 1;
sb->s_export_op = &fuse_export_operations;
- sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
+ sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE |
+ SB_I_CGROUPWB;
if (sb->s_user_ns != &init_user_ns)
sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
