f2fs: avoid deadlock during evict after f2fs_gc
o Deadlock case #1
Thread 1:
- writeback_sb_inodes
- do_writepages
- f2fs_write_data_pages
- write_cache_pages
- f2fs_write_data_page
- f2fs_balance_fs
- wait mutex_lock(gc_mutex)
Thread 2:
- f2fs_balance_fs
- mutex_lock(gc_mutex)
- f2fs_gc
- f2fs_iget
- wait iget_locked(inode->i_lock)
Thread 3:
- do_unlinkat
- iput
- lock(inode->i_lock)
- evict
- inode_wait_for_writeback
o Deadlock case #2
Thread 1:
- __writeback_single_inode
: set I_SYNC
- do_writepages
- f2fs_write_data_page
- f2fs_balance_fs
- f2fs_gc
- iput
- evict
- inode_wait_for_writeback(I_SYNC)
In order to avoid this, even though iput is called with the zero-reference
count, we need to stop the eviction procedure if the inode is on writeback.
So this patch links f2fs_drop_inode which checks the I_SYNC flag.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 4aa26e5..47abc97 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -72,6 +72,7 @@
unlock_new_inode(inode);
fail:
trace_f2fs_new_inode(inode, err);
+ make_bad_inode(inode);
iput(inode);
if (nid_free)
alloc_nid_failed(sbi, ino);
@@ -155,6 +156,7 @@
out:
clear_nlink(inode);
unlock_new_inode(inode);
+ make_bad_inode(inode);
iput(inode);
alloc_nid_failed(sbi, ino);
return err;
@@ -190,6 +192,7 @@
return 0;
out:
clear_inode_flag(F2FS_I(inode), FI_INC_LINK);
+ make_bad_inode(inode);
iput(inode);
return err;
}
@@ -295,6 +298,7 @@
out:
clear_nlink(inode);
unlock_new_inode(inode);
+ make_bad_inode(inode);
iput(inode);
alloc_nid_failed(sbi, inode->i_ino);
return err;
@@ -335,6 +339,7 @@
clear_inode_flag(F2FS_I(inode), FI_INC_LINK);
clear_nlink(inode);
unlock_new_inode(inode);
+ make_bad_inode(inode);
iput(inode);
alloc_nid_failed(sbi, inode->i_ino);
return err;
@@ -382,6 +387,7 @@
out:
clear_nlink(inode);
unlock_new_inode(inode);
+ make_bad_inode(inode);
iput(inode);
alloc_nid_failed(sbi, inode->i_ino);
return err;