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f2fs: call f2fs_balance_fs outside of locked page

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[ Upstream commit bdf03299248916640a835a05d32841bb3d31912d ]

Otherwise, we can hit deadlock by waiting for the locked page in
move_data_block in GC.

 Thread A                     Thread B
 - do_page_mkwrite
  - f2fs_vm_page_mkwrite
   - lock_page
                              - f2fs_balance_fs
                                  - mutex_lock(gc_mutex)
                               - f2fs_gc
                                - do_garbage_collect
                                 - ra_data_block
                                  - grab_cache_page
   - f2fs_balance_fs
    - mutex_lock(gc_mutex)

Fixes: 39a8695824510 ("f2fs: refactor ->page_mkwrite() flow")
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jaegeuk Kim 2019-12-03 15:53:16 -08:00 committed by Greg Kroah-Hartman
parent 678b25bfd9
commit 85275286d1
1 changed files with 4 additions and 3 deletions
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7
fs/f2fs/file.c
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@ -50,7 +50,7 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf)
struct page *page = vmf->page;
struct inode *inode = file_inode(vmf->vma->vm_file);
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct dnode_of_data dn = { .node_changed = false };
struct dnode_of_data dn;
int err;
if (unlikely(f2fs_cp_error(sbi))) {
@ -63,6 +63,9 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf)
goto err;
}
/* should do out of any locked page */
f2fs_balance_fs(sbi, true);
sb_start_pagefault(inode->i_sb);
f2fs_bug_on(sbi, f2fs_has_inline_data(inode));
@ -120,8 +123,6 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf)
out_sem:
up_read(&F2FS_I(inode)->i_mmap_sem);
f2fs_balance_fs(sbi, dn.node_changed);
sb_end_pagefault(inode->i_sb);
err:
return block_page_mkwrite_return(err);