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authorChao Yu <yuchao0@huawei.com>2018-08-05 23:02:22 +0800
committerJaegeuk Kim <jaegeuk@kernel.org>2018-08-13 10:48:17 -0700
commitc7079853c859c910b9d047a37891b4aafb8f8dd7 (patch)
tree9d5f827b0c96b80858080012618f1d634c1f3e1e /fs/f2fs
parent91291e9998d208370eb8156c760691b873bd7522 (diff)
f2fs: avoid race between zero_range and background GC
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>
Diffstat (limited to 'fs/f2fs')
-rw-r--r--fs/f2fs/file.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 67c9c2d4e2d9..4cb02027827e 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1314,8 +1314,6 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len,
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;
@@ -1345,12 +1343,19 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len,
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;
}
@@ -1359,7 +1364,9 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len,
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);