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| author | Eryu Guan <guaneryu@gmail.com> | 2018-03-22 11:41:25 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2018-03-22 11:41:25 -0400 |
| commit | 73fdad00b208b139cf43f3163fbc0f67e4c6047c (patch) | |
| tree | df87fefb83a3a4a7a2416dcd08b6ce3c717d7f5e /fs | |
| parent | 044e6e3d74a3d7103a0c8a9305dfd94d64000660 (diff) | |
| download | linux-73fdad00b208b139cf43f3163fbc0f67e4c6047c.tar.gz | |
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')
| -rw-r--r-- | fs/ext4/inode.c | 5 |
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' |