From: yangerkun yangerkun@huawei.com
[ Upstream commit a46c68a318b08f819047843abf349aeee5d10ac2 ]
While do swap, we should make sure there has no new dirty page since we should swap i_data between two inode: 1.We should lock i_mmap_sem with write to avoid new pagecache from mmap read/write; 2.Change filemap_flush to filemap_write_and_wait and move them to the space protected by inode lock to avoid new pagecache from buffer read/write.
Signed-off-by: yangerkun yangerkun@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- fs/ext4/ioctl.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 3dbf4e414706..ca6d27bfcdd8 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -116,9 +116,6 @@ static long swap_inode_boot_loader(struct super_block *sb, return PTR_ERR(inode_bl); ei_bl = EXT4_I(inode_bl);
- filemap_flush(inode->i_mapping); - filemap_flush(inode_bl->i_mapping); - /* Protect orig inodes against a truncate and make sure, * that only 1 swap_inode_boot_loader is running. */ lock_two_nondirectories(inode, inode_bl); @@ -126,6 +123,15 @@ static long swap_inode_boot_loader(struct super_block *sb, truncate_inode_pages(&inode->i_data, 0); truncate_inode_pages(&inode_bl->i_data, 0);
+ down_write(&EXT4_I(inode)->i_mmap_sem); + err = filemap_write_and_wait(inode->i_mapping); + if (err) + goto err_out; + + err = filemap_write_and_wait(inode_bl->i_mapping); + if (err) + goto err_out; + /* Wait for all existing dio workers */ ext4_inode_block_unlocked_dio(inode); ext4_inode_block_unlocked_dio(inode_bl); @@ -135,7 +141,7 @@ static long swap_inode_boot_loader(struct super_block *sb, handle = ext4_journal_start(inode_bl, EXT4_HT_MOVE_EXTENTS, 2); if (IS_ERR(handle)) { err = -EINVAL; - goto journal_err_out; + goto err_out; }
/* Protect extent tree against block allocations via delalloc */ @@ -190,6 +196,8 @@ static long swap_inode_boot_loader(struct super_block *sb, ext4_journal_stop(handle); ext4_double_up_write_data_sem(inode, inode_bl);
+err_out: + up_write(&EXT4_I(inode)->i_mmap_sem); journal_err_out: ext4_inode_resume_unlocked_dio(inode); ext4_inode_resume_unlocked_dio(inode_bl);