4.18-stable review patch. If anyone has any objections, please let me know.
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From: Chao Yu yuchao0@huawei.com
[ Upstream commit c7079853c859c910b9d047a37891b4aafb8f8dd7 ]
Thread A Background GC - f2fs_zero_range - truncate_pagecache_range - gc_data_segment - get_read_data_page - move_data_page - set_page_dirty - set_cold_data - f2fs_do_zero_range - dn->data_blkaddr = NEW_ADDR; - f2fs_set_data_blkaddr
Actually, we don't need to set dirty & checked flag on the page, since all valid data in the page should be zeroed by zero_range().
Use i_gc_rwsem[WRITE] to avoid such race condition.
Signed-off-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/f2fs/file.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
--- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1295,8 +1295,6 @@ static int f2fs_zero_range(struct inode if (ret) goto out_sem;
- truncate_pagecache_range(inode, offset, offset + len - 1); - pg_start = ((unsigned long long) offset) >> PAGE_SHIFT; pg_end = ((unsigned long long) offset + len) >> PAGE_SHIFT;
@@ -1326,12 +1324,19 @@ static int f2fs_zero_range(struct inode unsigned int end_offset; pgoff_t end;
+ down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); + + truncate_pagecache_range(inode, + (loff_t)index << PAGE_SHIFT, + ((loff_t)pg_end << PAGE_SHIFT) - 1); + f2fs_lock_op(sbi);
set_new_dnode(&dn, inode, NULL, NULL, 0); ret = f2fs_get_dnode_of_data(&dn, index, ALLOC_NODE); if (ret) { f2fs_unlock_op(sbi); + up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); goto out; }
@@ -1340,7 +1345,9 @@ static int f2fs_zero_range(struct inode
ret = f2fs_do_zero_range(&dn, index, end); f2fs_put_dnode(&dn); + f2fs_unlock_op(sbi); + up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
f2fs_balance_fs(sbi, dn.node_changed);