Commit 860b69a9 authored by Rohith Surabattula's avatar Rohith Surabattula Committed by Steve French
Browse files

Fix kernel oops when CONFIG_DEBUG_ATOMIC_SLEEP is enabled. 



Removed oplock_break_received flag which was added to achieve
synchronization between oplock handler and open handler by earlier commit.

It is not needed because there is an existing lock open_file_lock to achieve
the same. find_readable_file takes open_file_lock and then traverses the
openFileList. Similarly, cifs_oplock_break while closing the deferred
handle (i.e cifsFileInfo_put) takes open_file_lock and then sends close
to the server.

Added comments for better readability.

Signed-off-by: default avatarRohith Surabattula <rohiths@microsoft.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent e83aa352

fs/cifs/cifsglob.h

+1 −2
Original line number Diff line number Diff line
@@ -1257,8 +1257,7 @@ struct cifsFileInfo { 
	struct work_struct oplock_break; /* work for oplock breaks */

	struct work_struct put; /* work for the final part of _put */

	struct delayed_work deferred;

	bool oplock_break_received; /* Flag to indicate oplock break */

	bool deferred_scheduled;

	bool deferred_close_scheduled; /* Flag to indicate close is scheduled */

};



struct cifs_io_parms {

fs/cifs/file.c

+12 −15
Original line number Diff line number Diff line
@@ -323,8 +323,7 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file, 
	cfile->dentry = dget(dentry);

	cfile->f_flags = file->f_flags;

	cfile->invalidHandle = false;

	cfile->oplock_break_received = false;

	cfile->deferred_scheduled = false;

	cfile->deferred_close_scheduled = false;

	cfile->tlink = cifs_get_tlink(tlink);

	INIT_WORK(&cfile->oplock_break, cifs_oplock_break);

	INIT_WORK(&cfile->put, cifsFileInfo_put_work);
@@ -574,21 +573,18 @@ int cifs_open(struct inode *inode, struct file *file) 
			file->f_op = &cifs_file_direct_ops;

	}



	spin_lock(&CIFS_I(inode)->deferred_lock);

	/* Get the cached handle as SMB2 close is deferred */

	rc = cifs_get_readable_path(tcon, full_path, &cfile);

	if (rc == 0) {

		if (file->f_flags == cfile->f_flags) {

			file->private_data = cfile;

			spin_lock(&CIFS_I(inode)->deferred_lock);

			cifs_del_deferred_close(cfile);

			spin_unlock(&CIFS_I(inode)->deferred_lock);

			goto out;

		} else {

			spin_unlock(&CIFS_I(inode)->deferred_lock);

			_cifsFileInfo_put(cfile, true, false);

		}

	} else {

		spin_unlock(&CIFS_I(inode)->deferred_lock);

	}



	if (server->oplocks)
@@ -878,12 +874,12 @@ void smb2_deferred_work_close(struct work_struct *work) 
			struct cifsFileInfo, deferred.work);



	spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);

	if (!cfile->deferred_scheduled) {

	if (!cfile->deferred_close_scheduled) {

		spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);

		return;

	}

	cifs_del_deferred_close(cfile);

	cfile->deferred_scheduled = false;

	cfile->deferred_close_scheduled = false;

	spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);

	_cifsFileInfo_put(cfile, true, false);

}
@@ -905,14 +901,15 @@ int cifs_close(struct inode *inode, struct file *file) 
				inode->i_ctime = inode->i_mtime = current_time(inode);

			spin_lock(&cinode->deferred_lock);

			cifs_add_deferred_close(cfile, dclose);

			if (cfile->deferred_scheduled) {

			if (cfile->deferred_close_scheduled &&

			    delayed_work_pending(&cfile->deferred)) {

				mod_delayed_work(deferredclose_wq,

						&cfile->deferred, cifs_sb->ctx->acregmax);

			} else {

				/* Deferred close for files */

				queue_delayed_work(deferredclose_wq,

						&cfile->deferred, cifs_sb->ctx->acregmax);

				cfile->deferred_scheduled = true;

				cfile->deferred_close_scheduled = true;

				spin_unlock(&cinode->deferred_lock);

				return 0;

			}
@@ -2020,8 +2017,7 @@ struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode, 
		if (fsuid_only && !uid_eq(open_file->uid, current_fsuid()))

			continue;

		if (OPEN_FMODE(open_file->f_flags) & FMODE_READ) {

			if ((!open_file->invalidHandle) &&

				(!open_file->oplock_break_received)) {

			if ((!open_file->invalidHandle)) {

				/* found a good file */

				/* lock it so it will not be closed on us */

				cifsFileInfo_get(open_file);
@@ -4874,13 +4870,14 @@ void cifs_oplock_break(struct work_struct *work) 
	}

	/*

	 * When oplock break is received and there are no active

	 * file handles but cached, then set the flag oplock_break_received.

	 * file handles but cached, then schedule deferred close immediately.

	 * So, new open will not use cached handle.

	 */

	spin_lock(&CIFS_I(inode)->deferred_lock);

	is_deferred = cifs_is_deferred_close(cfile, &dclose);

	if (is_deferred && cfile->deferred_scheduled) {

		cfile->oplock_break_received = true;

	if (is_deferred &&

	    cfile->deferred_close_scheduled &&

	    delayed_work_pending(&cfile->deferred)) {

		mod_delayed_work(deferredclose_wq, &cfile->deferred, 0);

	}

	spin_unlock(&CIFS_I(inode)->deferred_lock);

fs/cifs/misc.c

+9 −0
Original line number Diff line number Diff line
@@ -672,6 +672,9 @@ cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink, 
	spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);

}



/*

 * Critical section which runs after acquiring deferred_lock.

 */

bool

cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)

{
@@ -688,6 +691,9 @@ cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close ** 
	return false;

}



/*

 * Critical section which runs after acquiring deferred_lock.

 */

void

cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)

{
@@ -707,6 +713,9 @@ cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close * 
	list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);

}



/*

 * Critical section which runs after acquiring deferred_lock.

 */

void

cifs_del_deferred_close(struct cifsFileInfo *cfile)

{

fs/cifs/cifsfs.c

+1 −1

File changed.

Contains only whitespace changes.