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authorChao Yu <yuchao0@huawei.com>2016-07-13 09:18:29 +0800
committerJaegeuk Kim <jaegeuk@kernel.org>2016-07-15 15:21:22 -0700
commit82e0a5aa5ddf794b3e1b21fcd091228736871882 (patch)
tree4cc2beb40b6756219c2da15a5546ec9772f0ec0e /fs/f2fs/gc.c
parent44a83499dda714d9262a9bf4fdac8c077893c9e6 (diff)
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f2fs: fix to avoid data update racing between GC and DIO
Datas in file can be operated by GC and DIO simultaneously, so we will face race case as below: For write case: Thread A Thread B - generic_file_direct_write - invalidate_inode_pages2_range - f2fs_direct_IO - do_blockdev_direct_IO - do_direct_IO - get_more_blocks - f2fs_gc - do_garbage_collect - gc_data_segment - move_data_page - do_write_data_page migrate data block to new block address - dio_bio_submit update user data to old block address For read case: Thread A Thread B - generic_file_direct_write - invalidate_inode_pages2_range - f2fs_direct_IO - do_blockdev_direct_IO - do_direct_IO - get_more_blocks - f2fs_balance_fs - f2fs_gc - do_garbage_collect - gc_data_segment - move_data_page - do_write_data_page migrate data block to new block address - write_checkpoint - do_checkpoint - clear_prefree_segments - f2fs_issue_discard discard old block adress - dio_bio_submit update user buffer from obsolete block address In order to fix this, for one file, we should let DIO and GC getting exclusion against with each other. Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/gc.c')
-rw-r--r--fs/f2fs/gc.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index c61213785914..5c8acf754513 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -755,12 +755,32 @@ next_step:
/* phase 3 */
inode = find_gc_inode(gc_list, dni.ino);
if (inode) {
+ struct f2fs_inode_info *fi = F2FS_I(inode);
+ bool locked = false;
+
+ if (S_ISREG(inode->i_mode)) {
+ if (!down_write_trylock(&fi->dio_rwsem[READ]))
+ continue;
+ if (!down_write_trylock(
+ &fi->dio_rwsem[WRITE])) {
+ up_write(&fi->dio_rwsem[READ]);
+ continue;
+ }
+ locked = true;
+ }
+
start_bidx = start_bidx_of_node(nofs, inode)
+ ofs_in_node;
if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
move_encrypted_block(inode, start_bidx);
else
move_data_page(inode, start_bidx, gc_type);
+
+ if (locked) {
+ up_write(&fi->dio_rwsem[WRITE]);
+ up_write(&fi->dio_rwsem[READ]);
+ }
+
stat_inc_data_blk_count(sbi, 1, gc_type);
}
}