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authorJaegeuk Kim <jaegeuk.kim@samsung.com>2013-01-31 15:36:04 +0900
committerJaegeuk Kim <jaegeuk.kim@samsung.com>2013-02-12 07:15:01 +0900
commitd4686d56ec912d55fd8a9d6d509de50de24e90ab (patch)
treef79a5df1353af58c671c58a4eaa7339d7ba80461 /fs/f2fs/recovery.c
parent369a708c2a6557fabd409cf17a03db271c54931a (diff)
f2fs: avoid balanc_fs during evict_inode
1. Background Previously, if f2fs tries to move data blocks of an *evicting* inode during the cleaning process, it stops the process incompletely and then restarts the whole process, since it needs a locked inode to grab victim data pages in its address space. In order to get a locked inode, iget_locked() by f2fs_iget() is normally used, but, it waits if the inode is on freeing. So, here is a deadlock scenario. 1. f2fs_evict_inode() <- inode "A" 2. f2fs_balance_fs() 3. f2fs_gc() 4. gc_data_segment() 5. f2fs_iget() <- inode "A" too! If step #1 and #5 treat a same inode "A", step #5 would fall into deadlock since the inode "A" is on freeing. In order to resolve this, f2fs_iget_nowait() which skips __wait_on_freeing_inode() was introduced in step #5, and stops f2fs_gc() to complete f2fs_evict_inode(). 1. f2fs_evict_inode() <- inode "A" 2. f2fs_balance_fs() 3. f2fs_gc() 4. gc_data_segment() 5. f2fs_iget_nowait() <- inode "A", then stop f2fs_gc() w/ -ENOENT 2. Problem and Solution In the above scenario, however, f2fs cannot finish f2fs_evict_inode() only if: o there are not enough free sections, and o f2fs_gc() tries to move data blocks of the *evicting* inode repeatedly. So, the final solution is to use f2fs_iget() and remove f2fs_balance_fs() in f2fs_evict_inode(). The f2fs_evict_inode() actually truncates all the data and node blocks, which means that it doesn't produce any dirty node pages accordingly. So, we don't need to do f2fs_balance_fs() in practical. Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Diffstat (limited to 'fs/f2fs/recovery.c')
-rw-r--r--fs/f2fs/recovery.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index f42e4060b39..e2a3e1a8eae 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -226,7 +226,7 @@ static void check_index_in_prev_nodes(struct f2fs_sb_info *sbi,
f2fs_put_page(node_page, 1);
/* Deallocate previous index in the node page */
- inode = f2fs_iget_nowait(sbi->sb, ino);
+ inode = f2fs_iget(sbi->sb, ino);
if (IS_ERR(inode))
return;