The patch titled
Subject: f2fs: change retry waiting for f2fs_write_single_data_page()
has been added to the -mm tree. Its filename is
f2fs-change-retry-waiting-for-f2fs_write_single_data_page.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/f2fs-change-retry-waiting-for-f2fs_write_single_data_page.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/f2fs-change-retry-waiting-for-f2fs_write_single_data_page.patch
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------------------------------------------------------
From: NeilBrown <neilb@xxxxxxx>
Subject: f2fs: change retry waiting for f2fs_write_single_data_page()
f2fs_write_single_data_page() can return -EAGAIN if it cannot get the
cp_rwsem lock - it holds a page lock and so cannot wait for it.
Some code which calls f2fs_write_single_data_page() use congestion_wait()
and then tries again. congestion_wait() doesn't do anything useful as
congestion is no longer tracked. So this is just a simple sleep.
A better approach is it wait until the cp_rwsem lock can be taken - then
try again. There is certainly no point trying again *before* the lock can
be taken.
Link: https://lkml.kernel.org/r/164325158956.29787.7016948342209980097.stgit@noble.brown
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Cc: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Cc: Chao Yu <chao@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Darrick J. Wong <djwong@xxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Ilya Dryomov <idryomov@xxxxxxxxx>
Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Cc: Jeff Layton <jlayton@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>
Cc: Miklos Szeredi <miklos@xxxxxxxxxx>
Cc: Paolo Valente <paolo.valente@xxxxxxxxxx>
Cc: Philipp Reisner <philipp.reisner@xxxxxxxxxx>
Cc: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/f2fs/compress.c | 6 +++---
fs/f2fs/data.c | 9 ++++++---
2 files changed, 9 insertions(+), 6 deletions(-)
--- a/fs/f2fs/compress.c~f2fs-change-retry-waiting-for-f2fs_write_single_data_page
+++ a/fs/f2fs/compress.c
@@ -1505,9 +1505,9 @@ continue_unlock:
if (IS_NOQUOTA(cc->inode))
return 0;
ret = 0;
- cond_resched();
- congestion_wait(BLK_RW_ASYNC,
- DEFAULT_IO_TIMEOUT);
+ /* Wait until we can get the lock, then try again. */
+ f2fs_lock_op(F2FS_I_SB(cc->inode));
+ f2fs_unlock_op(F2FS_I_SB(cc->inode));
goto retry_write;
}
return ret;
--- a/fs/f2fs/data.c~f2fs-change-retry-waiting-for-f2fs_write_single_data_page
+++ a/fs/f2fs/data.c
@@ -3047,9 +3047,12 @@ result:
} else if (ret == -EAGAIN) {
ret = 0;
if (wbc->sync_mode == WB_SYNC_ALL) {
- cond_resched();
- congestion_wait(BLK_RW_ASYNC,
- DEFAULT_IO_TIMEOUT);
+ /* Wait until we can get the
+ * lock, then try again.
+ */
+ f2fs_lock_op(F2FS_I_SB(mapping->host));
+ f2fs_unlock_op(F2FS_I_SB(mapping->host));
+
goto retry_write;
}
goto next;
_
Patches currently in -mm which might be from neilb@xxxxxxx are
remove-inode_congested.patch
remove-bdi_congested-and-wb_congested-and-related-functions.patch
f2fs-change-retry-waiting-for-f2fs_write_single_data_page.patch
f2f2-replace-some-congestion_wait-calls-with-io_schedule_timeout.patch
cephfs-dont-set-clear-bdi_congestion.patch
fuse-dont-set-clear-bdi_congested.patch
nfs-remove-congestion-control.patch
block-bfq-ioschedc-use-false-rather-than-blk_rw_async.patch
remove-congestion-tracking-framework.patch
mm-discard-__gfp_atomic.patch
