Unverified Commit 9a2058ed authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!12304 btrfs: fix race setting file private on concurrent lseek using same fd 

Merge Pull Request from: @ci-robot 
 
PR sync from: Yifan Qiao <qiaoyifan4@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/OVGI56INIIV5SEZRMPN37DDGEG57SPZD/ 
 
https://gitee.com/openeuler/kernel/issues/IAYQS2 
 
Link:https://gitee.com/openeuler/kernel/pulls/12304

 

Reviewed-by: default avatarZhang Peng <zhangpeng362@huawei.com>
Signed-off-by: default avatarZhang Peng <zhangpeng362@huawei.com>
parents 06f5a659 6e87b4b3

fs/btrfs/btrfs_inode.h

+1 −0
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ struct btrfs_inode { 
	 * the log or not (last_trans, last_sub_trans, last_log_commit,

	 * logged_trans), to access/update new_delalloc_bytes and to update the

	 * VFS' inode number of bytes used.

	 * Also protects setting struct file::private_data.

	 */

	spinlock_t lock;

fs/btrfs/ctree.h

+2 −0
Original line number Diff line number Diff line
@@ -445,6 +445,8 @@ struct btrfs_file_private { 
	void *filldir_buf;

	u64 last_index;

	struct extent_state *llseek_cached_state;

	/* Task that allocated this structure. */

	struct task_struct *owner_task;

};



static inline u32 BTRFS_LEAF_DATA_SIZE(const struct btrfs_fs_info *info)

fs/btrfs/file.c

+31 −3
Original line number Diff line number Diff line
@@ -3481,7 +3481,7 @@ static bool find_desired_extent_in_hole(struct btrfs_inode *inode, int whence, 
static loff_t find_desired_extent(struct file *file, loff_t offset, int whence)

{

	struct btrfs_inode *inode = BTRFS_I(file->f_mapping->host);

	struct btrfs_file_private *private = file->private_data;

	struct btrfs_file_private *private;

	struct btrfs_fs_info *fs_info = inode->root->fs_info;

	struct extent_state *cached_state = NULL;

	struct extent_state **delalloc_cached_state;
@@ -3509,7 +3509,19 @@ static loff_t find_desired_extent(struct file *file, loff_t offset, int whence) 
	    inode_get_bytes(&inode->vfs_inode) == i_size)

		return i_size;



	if (!private) {

	spin_lock(&inode->lock);

	private = file->private_data;

	spin_unlock(&inode->lock);



	if (private && private->owner_task != current) {

		/*

		 * Not allocated by us, don't use it as its cached state is used

		 * by the task that allocated it and we don't want neither to

		 * mess with it nor get incorrect results because it reflects an

		 * invalid state for the current task.

		 */

		private = NULL;

	} else if (!private) {

		private = kzalloc(sizeof(*private), GFP_KERNEL);

		/*

		 * No worries if memory allocation failed.
@@ -3517,7 +3529,23 @@ static loff_t find_desired_extent(struct file *file, loff_t offset, int whence) 
		 * lseek SEEK_HOLE/DATA calls to a file when there's delalloc,

		 * so everything will still be correct.

		 */

		if (private) {

			bool free = false;



			private->owner_task = current;



			spin_lock(&inode->lock);

			if (file->private_data)

				free = true;

			else

				file->private_data = private;

			spin_unlock(&inode->lock);



			if (free) {

				kfree(private);

				private = NULL;

			}

		}

	}



	if (private)