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authorTejun Heo <tj@kernel.org>2015-06-17 01:48:30 +0300
committerJens Axboe <axboe@fb.com>2015-06-17 21:47:37 +0300
commitdd73e4b7df9589fa603fc6d128b4f6cabb250e8e (patch)
treee729cdad58a661c89cf2203b3f2b90de3cf1e6e5 /fs/fs-writeback.c
parent412a19b64ad17f7650ff778fd2cb9032938cf71f (diff)
downloadlinux-dd73e4b7df9589fa603fc6d128b4f6cabb250e8e.tar.xz
writeback: do foreign inode detection iff cgroup writeback is enabled
Currently, even when a filesystem doesn't set the FS_CGROUP_WRITEBACK flag, if the filesystem uses wbc_init_bio() and wbc_account_io(), the foreign inode detection and migration logic still ends up activating cgroup writeback which is unexpected. This patch ensures that the foreign inode detection logic stays disabled when inode_cgwb_enabled() is false by not associating writeback_control's with bdi_writeback's. This also avoids unnecessary operations in wbc_init_bio(), wbc_account_io() and wbc_detach_inode() for filesystems which don't support cgroup writeback. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'fs/fs-writeback.c')
-rw-r--r--fs/fs-writeback.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index f60de54d2042..f0520bcf2094 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -513,6 +513,11 @@ out_free:
void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
struct inode *inode)
{
+ if (!inode_cgwb_enabled(inode)) {
+ spin_unlock(&inode->i_lock);
+ return;
+ }
+
wbc->wb = inode_to_wb(inode);
wbc->inode = inode;
@@ -575,11 +580,16 @@ void wbc_detach_inode(struct writeback_control *wbc)
{
struct bdi_writeback *wb = wbc->wb;
struct inode *inode = wbc->inode;
- u16 history = inode->i_wb_frn_history;
- unsigned long avg_time = inode->i_wb_frn_avg_time;
- unsigned long max_bytes, max_time;
+ unsigned long avg_time, max_bytes, max_time;
+ u16 history;
int max_id;
+ if (!wb)
+ return;
+
+ history = inode->i_wb_frn_history;
+ avg_time = inode->i_wb_frn_avg_time;
+
/* pick the winner of this round */
if (wbc->wb_bytes >= wbc->wb_lcand_bytes &&
wbc->wb_bytes >= wbc->wb_tcand_bytes) {