f2fs: avoid infinite GC loop due to stale atomic files
If committing atomic pages is failed when doing f2fs_do_sync_file(), we can
get committed pages but atomic_file being still set like:
- inmem: 0, atomic IO: 4 (Max. 10), volatile IO: 0 (Max. 0)
If GC selects this block, we can get an infinite loop like this:
f2fs_submit_page_bio: dev = (253,7), ino = 2, page_index = 0x2359a8,
oldaddr = 0x2359a8, newaddr = 0x2359a8, rw = READ(), type = COLD_DATA
f2fs_submit_read_bio: dev = (253,7)/(253,7), rw = READ(), DATA,
sector = 18533696, size = 4096
f2fs_get_victim: dev = (253,7), type = No TYPE,
policy = (Foreground GC, LFS-mode, Greedy), victim = 4355, cost = 1,
ofs_unit = 1, pre_victim_secno = 4355, prefree = 0, free = 234
f2fs_iget: dev = (253,7), ino = 6247, pino = 5845, i_mode = 0x81b0,
i_size = 319488, i_nlink = 1, i_blocks = 624, i_advise = 0x2c
In that moment, we can observe:
[Before]
Try to move 5084219 blocks (BG: 384508)
- data blocks : 4962373 (274483)
- node blocks : 121846 (110025)
Skipped : atomic write 4534686 (10)
[After]
Try to move 5088973 blocks (BG: 384508)
- data blocks : 4967127 (274483)
- node blocks : 121846 (110025)
Skipped : atomic write 4539440 (10)
So, refactor atomic_write flow like this:
1. start_atomic_write
- add inmem_list and set atomic_file
2. write()
- register it in inmem_pages
3. commit_atomic_write
- if no error, f2fs_drop_inmem_pages()
- f2fs_commit_inmme_pages() failed
: __revoked_inmem_pages() was done
- f2fs_do_sync_file failed
: abort_atomic_write later
4. abort_atomic_write
- f2fs_drop_inmem_pages
5. f2fs_drop_inmem_pages
- clear atomic_file
- remove inmem_list
Based on this change, when GC fails to move block in atomic_file,
f2fs_drop_inmem_pages_all() can call f2fs_drop_inmem_pages().
Change-Id: I876038ae8ab980a9d7ab30f3a4416a9a7b9c9998
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Git-commit: 743b620cb0516f6b6cbc45b48df00fe6d14d00ba
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/
Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 2a8dc33..d45a18c 100755
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -185,8 +185,6 @@
void f2fs_register_inmem_page(struct inode *inode, struct page *page)
{
- struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
- struct f2fs_inode_info *fi = F2FS_I(inode);
struct inmem_pages *new;
f2fs_trace_pid(page);
@@ -200,15 +198,11 @@
INIT_LIST_HEAD(&new->list);
/* increase reference count with clean state */
- mutex_lock(&fi->inmem_lock);
get_page(page);
- list_add_tail(&new->list, &fi->inmem_pages);
- spin_lock(&sbi->inode_lock[ATOMIC_FILE]);
- if (list_empty(&fi->inmem_ilist))
- list_add_tail(&fi->inmem_ilist, &sbi->inode_list[ATOMIC_FILE]);
- spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
+ mutex_lock(&F2FS_I(inode)->inmem_lock);
+ list_add_tail(&new->list, &F2FS_I(inode)->inmem_pages);
inc_page_count(F2FS_I_SB(inode), F2FS_INMEM_PAGES);
- mutex_unlock(&fi->inmem_lock);
+ mutex_unlock(&F2FS_I(inode)->inmem_lock);
trace_f2fs_register_inmem_page(page, INMEM);
}
@@ -330,19 +324,17 @@
mutex_lock(&fi->inmem_lock);
__revoke_inmem_pages(inode, &fi->inmem_pages,
true, false, true);
-
- if (list_empty(&fi->inmem_pages)) {
- spin_lock(&sbi->inode_lock[ATOMIC_FILE]);
- if (!list_empty(&fi->inmem_ilist))
- list_del_init(&fi->inmem_ilist);
- spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
- }
mutex_unlock(&fi->inmem_lock);
}
clear_inode_flag(inode, FI_ATOMIC_FILE);
fi->i_gc_failures[GC_FAILURE_ATOMIC] = 0;
stat_dec_atomic_write(inode);
+
+ spin_lock(&sbi->inode_lock[ATOMIC_FILE]);
+ if (!list_empty(&fi->inmem_ilist))
+ list_del_init(&fi->inmem_ilist);
+ spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
}
void f2fs_drop_inmem_page(struct inode *inode, struct page *page)
@@ -471,11 +463,6 @@
mutex_lock(&fi->inmem_lock);
err = __f2fs_commit_inmem_pages(inode);
-
- spin_lock(&sbi->inode_lock[ATOMIC_FILE]);
- if (!list_empty(&fi->inmem_ilist))
- list_del_init(&fi->inmem_ilist);
- spin_unlock(&sbi->inode_lock[ATOMIC_FILE]);
mutex_unlock(&fi->inmem_lock);
clear_inode_flag(inode, FI_ATOMIC_COMMIT);