summaryrefslogtreecommitdiffstats
path: root/fs/ext4
diff options
context:
space:
mode:
authorEryu Guan <guaneryu@gmail.com>2018-03-22 16:41:25 +0100
committerTheodore Ts'o <tytso@mit.edu>2018-03-22 16:41:25 +0100
commit73fdad00b208b139cf43f3163fbc0f67e4c6047c (patch)
treedf87fefb83a3a4a7a2416dcd08b6ce3c717d7f5e /fs/ext4
parentext4: don't update checksum of new initialized bitmaps (diff)
downloadlinux-73fdad00b208b139cf43f3163fbc0f67e4c6047c.tar.xz
linux-73fdad00b208b139cf43f3163fbc0f67e4c6047c.zip
ext4: protect i_disksize update by i_data_sem in direct write path
i_disksize update should be protected by i_data_sem, by either taking the lock explicitly or by using ext4_update_i_disksize() helper. But the i_disksize updates in ext4_direct_IO_write() are not protected at all, which may be racing with i_disksize updates in writeback path in delalloc buffer write path. This is found by code inspection, and I didn't hit any i_disksize corruption due to this bug. Thanks to Jan Kara for catching this bug and suggesting the fix! Reported-by: Jan Kara <jack@suse.cz> Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Eryu Guan <guaneryu@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/inode.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c94780075b04..bff44b4a0783 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3658,7 +3658,6 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
- struct ext4_inode_info *ei = EXT4_I(inode);
ssize_t ret;
loff_t offset = iocb->ki_pos;
size_t count = iov_iter_count(iter);
@@ -3682,7 +3681,7 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter)
goto out;
}
orphan = 1;
- ei->i_disksize = inode->i_size;
+ ext4_update_i_disksize(inode, inode->i_size);
ext4_journal_stop(handle);
}
@@ -3790,7 +3789,7 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter)
if (ret > 0) {
loff_t end = offset + ret;
if (end > inode->i_size) {
- ei->i_disksize = end;
+ ext4_update_i_disksize(inode, end);
i_size_write(inode, end);
/*
* We're going to return a positive `ret'