f2fs: avoid f2fs_lock_op for IPU writes
Currently, if we do get_node_of_data before f2fs_lock_op, there may be dead lock
as follows, where process A would be in infinite loop, and B will NOT be awaked.
Process A(cp): Process B:
f2fs_lock_all(sbi)
get_dnode_of_data <---- lock dn.node_page
flush_nodes f2fs_lock_op
So, this patch adds f2fs_trylock_op to avoid f2fs_lock_op done by IPU.
Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 4ca0899..779a3068 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1383,12 +1383,12 @@
if (valid_ipu_blkaddr(fio)) {
ipu_force = true;
- fio->need_lock = false;
+ fio->need_lock = LOCK_DONE;
goto got_it;
}
}
- if (fio->need_lock)
+ if (fio->need_lock == LOCK_REQ)
f2fs_lock_op(fio->sbi);
err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);
@@ -1403,19 +1403,18 @@
goto out_writepage;
}
got_it:
- err = encrypt_one_page(fio);
- if (err)
- goto out_writepage;
-
- set_page_writeback(page);
-
/*
* If current allocation needs SSR,
* it had better in-place writes for updated data.
*/
if (ipu_force || (valid_ipu_blkaddr(fio) && need_inplace_update(fio))) {
+ err = encrypt_one_page(fio);
+ if (err)
+ goto out_writepage;
+
+ set_page_writeback(page);
f2fs_put_dnode(&dn);
- if (fio->need_lock)
+ if (fio->need_lock == LOCK_REQ)
f2fs_unlock_op(fio->sbi);
err = rewrite_data_page(fio);
trace_f2fs_do_write_data_page(fio->page, IPU);
@@ -1423,6 +1422,20 @@
return err;
}
+ if (fio->need_lock == LOCK_RETRY) {
+ if (!f2fs_trylock_op(fio->sbi)) {
+ err = -EAGAIN;
+ goto out_writepage;
+ }
+ fio->need_lock = LOCK_REQ;
+ }
+
+ err = encrypt_one_page(fio);
+ if (err)
+ goto out_writepage;
+
+ set_page_writeback(page);
+
/* LFS mode write path */
write_data_page(&dn, fio);
trace_f2fs_do_write_data_page(page, OPU);
@@ -1432,7 +1445,7 @@
out_writepage:
f2fs_put_dnode(&dn);
out:
- if (fio->need_lock)
+ if (fio->need_lock == LOCK_REQ)
f2fs_unlock_op(fio->sbi);
return err;
}
@@ -1458,7 +1471,7 @@
.page = page,
.encrypted_page = NULL,
.submitted = false,
- .need_lock = true,
+ .need_lock = LOCK_RETRY,
};
trace_f2fs_writepage(page, DATA);
@@ -1494,7 +1507,7 @@
/* Dentry blocks are controlled by checkpoint */
if (S_ISDIR(inode->i_mode)) {
- fio.need_lock = false;
+ fio.need_lock = LOCK_DONE;
err = do_write_data_page(&fio);
goto done;
}
@@ -1513,8 +1526,13 @@
goto out;
}
- if (err == -EAGAIN)
+ if (err == -EAGAIN) {
err = do_write_data_page(&fio);
+ if (err == -EAGAIN) {
+ fio.need_lock = LOCK_REQ;
+ err = do_write_data_page(&fio);
+ }
+ }
if (F2FS_I(inode)->last_disk_size < psize)
F2FS_I(inode)->last_disk_size = psize;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c664378..f61e095 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -799,6 +799,12 @@
NR_TEMP_TYPE,
};
+enum need_lock_type {
+ LOCK_REQ = 0,
+ LOCK_DONE,
+ LOCK_RETRY,
+};
+
struct f2fs_io_info {
struct f2fs_sb_info *sbi; /* f2fs_sb_info pointer */
enum page_type type; /* contains DATA/NODE/META/META_FLUSH */
@@ -810,7 +816,7 @@
struct page *page; /* page to be written */
struct page *encrypted_page; /* encrypted page */
bool submitted; /* indicate IO submission */
- bool need_lock; /* indicate we need to lock cp_rwsem */
+ int need_lock; /* indicate we need to lock cp_rwsem */
};
#define is_read_io(rw) ((rw) == READ)
@@ -1279,6 +1285,11 @@
down_read(&sbi->cp_rwsem);
}
+static inline int f2fs_trylock_op(struct f2fs_sb_info *sbi)
+{
+ return down_read_trylock(&sbi->cp_rwsem);
+}
+
static inline void f2fs_unlock_op(struct f2fs_sb_info *sbi)
{
up_read(&sbi->cp_rwsem);
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index e2b1355..14c71ac 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -719,7 +719,7 @@
.old_blkaddr = NULL_ADDR,
.page = page,
.encrypted_page = NULL,
- .need_lock = true,
+ .need_lock = LOCK_REQ,
};
bool is_dirty = PageDirty(page);
int err;
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index fcada9d..3bc3676 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -312,7 +312,7 @@
fio.page = page;
fio.old_blkaddr = NULL_ADDR;
fio.encrypted_page = NULL;
- fio.need_lock = false,
+ fio.need_lock = LOCK_DONE;
err = do_write_data_page(&fio);
if (err) {
unlock_page(page);