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3d61631308
In get_more_blocks(), we may override @create as below code:
create = dio->op == REQ_OP_WRITE;
if (dio->flags & DIO_SKIP_HOLES) {
if (fs_startblk <= ((i_size_read(dio->inode) - 1) >>
i_blkbits))
create = 0;
}
But in f2fs_map_blocks(), we only trigger f2fs_balance_fs() if @create
is 1, so in LFS mode, dio overwrite under LFS mode can easily run out
of free segments, result in below panic.
Call Trace:
allocate_segment_by_default+0xa8/0x270 [f2fs]
f2fs_allocate_data_block+0x1ea/0x5c0 [f2fs]
__allocate_data_block+0x306/0x480 [f2fs]
f2fs_map_blocks+0x6f6/0x920 [f2fs]
__get_data_block+0x4f/0xb0 [f2fs]
get_data_block_dio_write+0x50/0x60 [f2fs]
do_blockdev_direct_IO+0xcd5/0x21e0
__blockdev_direct_IO+0x3a/0x3c
f2fs_direct_IO+0x1ff/0x4a0 [f2fs]
generic_file_direct_write+0xd9/0x160
__generic_file_write_iter+0xbb/0x1e0
f2fs_file_write_iter+0xaf/0x220 [f2fs]
__vfs_write+0xd0/0x130
vfs_write+0xb2/0x1b0
SyS_pwrite64+0x69/0xa0
? vtime_user_exit+0x29/0x70
do_syscall_64+0x6e/0x160
entry_SYSCALL64_slow_path+0x25/0x25
RIP: new_curseg+0x36f/0x380 [f2fs] RSP: ffffac570393f7a8
So this patch introduces a parameter map.m_may_create to indicate that
f2fs_map_blocks() is called from write or read path, which can give the
right hint to let f2fs_map_blocks() trigger OPU allocation and call
f2fs_balanc_fs() correctly.
BTW, it disables physical address preallocation for direct IO in
f2fs_preallocate_blocks, which is redundant to OPU allocation of
f2fs_map_blocks.
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.