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8b7de4d008
Under heavy fsstress, we may triggle panic while issuing discard,
because __check_sit_bitmap() detects that discard command may earse
valid data blocks, the root cause is as below race stack described,
since we removed lock when flushing quota data, quota data writeback
may race with write_checkpoint(), so that it causes inconsistency in
between cached discard entry and segment bitmap.
- f2fs_write_checkpoint
- block_operations
- set_sbi_flag(sbi, SBI_QUOTA_SKIP_FLUSH)
- f2fs_flush_sit_entries
- add_discard_addrs
- __set_bit_le(i, (void *)de->discard_map);
- f2fs_write_data_pages
- f2fs_write_single_data_page
: inode is quota one, cp_rwsem won't be locked
- f2fs_do_write_data_page
- f2fs_allocate_data_block
- f2fs_wait_discard_bio
: discard entry has not been added yet.
- update_sit_entry
- f2fs_clear_prefree_segments
- f2fs_issue_discard
: add discard entry
In order to fix this, this patch uses node_write to serialize
f2fs_allocate_data_block and checkpoint.
Fixes: 435cbab95e ("f2fs: fix quota_sync failure due to f2fs_lock_op")
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.